Risk-based Treatment Assignment
Introduction to Risk-based Treatment
Prognostic Factors Affecting Risk-based Treatment
Patient characteristics affecting prognosis
Leukemic cell characteristics affecting prognosis
Response to initial treatment affecting prognosis
Prognostic (Risk) Groups
Children’s Oncology Group (COG) risk groups
Berlin-Frankfurt-Münster (BFM) risk groups
Prognostic (risk) groups under clinical evaluation
Current Clinical Trials
Introduction to Risk-based Treatment
Children with acute lymphoblastic leukemia (ALL) are usually treated according to risk groups defined by both clinical and laboratory features. The intensity of treatment required for favorable outcome varies substantially among subsets of children with ALL. Risk-based treatment assignment is utilized in children with ALL so that patients with favorable clinical and biological features who are likely to have a very good outcome with modest therapy can be spared more intensive and toxic treatment, while a more aggressive, and potentially more toxic, therapeutic approach can be provided for patients who have a lower probability of long-term survival.[1-3]
Certain ALL study groups, such as the Children’s Oncology Group (COG), use a more or less intensive induction regimen based on a subset of pretreatment factors, while other groups give a similar induction regimen to all patients. Factors used by the COG to determine the intensity of induction include immunophenotype and the National Cancer Institute (NCI) risk group classification. The NCI risk group classification stratifies risk according to age and white blood cell (WBC) count:
- Standard risk—WBC count less than 50,000/μL and age 1 to younger than 10 years.
- High risk—WBC count 50,000/μL or greater and/or age 10 years or older.
All study groups modify the intensity of postinduction therapy based on a variety of prognostic factors, including NCI risk group, immunophenotype, early response determinations, and cytogenetics.
Risk-based treatment assignment requires the availability of prognostic factors that reliably predict outcome. For children with ALL, a number of factors have demonstrated prognostic value, some of which are described below. The factors described are grouped into the following three categories:
- Patient characteristics affecting prognosis.
- Leukemic cell characteristics affecting prognosis.
- Response to initial treatment affecting prognosis.
As in any discussion of prognostic factors, the relative order of significance and the interrelationship of the variables are often treatment dependent and require multivariate analysis to determine which factors operate independently as prognostic variables.[5,6] Because prognostic factors are treatment dependent, improvements in therapy may diminish or abrogate the significance of any of these presumed prognostic factors.
A subset of the prognostic and clinical factors discussed below is used for the initial stratification of children with ALL for treatment assignment. (Refer to the Prognostic (risk) groups under clinical evaluation section of this summary for brief descriptions of the prognostic groupings currently applied in ongoing clinical trials in the United States.)
(Refer to the Prognostic Factors After First Relapse of Childhood ALL section of this summary for information about important prognostic factors at relapse.)Prognostic Factors Affecting Risk-based Treatment
Patient characteristics affecting prognosis
Patient characteristics affecting prognosis include the following:
- Age at diagnosis.
- WBC count at diagnosis.
- Central nervous system (CNS) involvement at diagnosis.
- Testicular involvement at diagnosis.
- Down syndrome (trisomy 21).
Age at diagnosis has strong prognostic significance, reflecting the different underlying biology of ALL in different age groups.
- Infants (younger than 1 year)
- Infants younger than 6 months (with an even poorer prognosis for those aged 60 to 90 days).
- Infants with extremely high presenting leukocyte counts.
- Infants with a poor response to a prednisone prophase.
- Infants with an MLL gene rearrangement.
Approximately 80% of infants with ALL have an MLL gene rearrangement.[10,12,13] The rate of MLL gene translocations is extremely high in infants younger than 6 months; from 6 months to 1 year, the incidence of MLL translocations decreases but remains higher than that observed in older children.[10,14] Black infants with ALL are significantly less likely to have MLL translocations than white infants. Infants with leukemia and MLL translocations typically have very high WBC counts and an increased incidence of CNS involvement. Overall survival (OS) is poor, especially in infants younger than 6 months.[10,11] A gene expression profile analysis in infants with MLL-rearranged ALL revealed significant differences between patients younger than 90 days and older infants, suggesting distinctive age-related biological behaviors for MLL-translocation ALL that may relate to the significantly poorer outcome for the youngest infants.
Blasts from infants with MLL translocations are typically CD10 negative and express high levels of FLT3.[10,11,13,16] Conversely, infants whose leukemic cells show a germline MLL gene configuration frequently present with CD10-positive precursor-B immunophenotype. These infants have a significantly better outcome than do infants with ALL characterized by MLL translocations.[10,11,13]
- Young children (aged 1 to <10 years)
Young children (aged 1 to <10 years) have a better disease-free survival (DFS) than older children, adolescents, and infants.[1,7,17] The improved prognosis in young children is at least partly explained by the more frequent occurrence of favorable cytogenetic features in the leukemic blasts including hyperdiploidy with 51 or more chromosomes and/or favorable chromosome trisomies, or the ETV6-RUNX1 (t(12;21), also known as the TEL-AML1 translocation).[7,18,19]
- Adolescents and young adults (≥10 years)
In general, the outcome of patients aged 10 years and older is inferior to that of patients aged 1 to younger than 10 years. However, the outcome for older children, especially adolescents, has improved significantly over time.[20-22] Five-year survival rates for adolescents aged 15 to 19 years increased from 36% (1975–1984) to 72% (2003–2009).[23-25] Multiple retrospective studies have suggested that adolescents aged 16 to 21 years have a better outcome when treated on pediatric versus adult protocols.[26-28] (Refer to the Postinduction Treatment for Specific ALL Subgroups section of this summary for more information about adolescents with ALL.)
A WBC count of 50,000/µL is generally used as an operational cut point between better and poorer prognosis, although the relationship between WBC count and prognosis is a continuous rather than a step function. Patients with B-precursor ALL and high WBC counts at diagnosis have an increased risk of treatment failure compared with patients with low initial WBC counts.
The median WBC count at diagnosis is much higher for T-cell ALL (>50,000/µL) than for B-precursor ALL (<10,000/µL), and there is no consistent effect of WBC count at diagnosis on prognosis for T-cell ALL.[6,29-35] One factor that might explain the lack of prognostic effect for WBC count at diagnosis may be the very poor outcome observed for T-cell ALL with the early T-cell precursor phenotype, as patients with this subtype appear to have lower WBC count at diagnosis (median, <50,000/µL) than do other T-cell ALL patients.CNS involvement at diagnosis
The presence or absence of CNS leukemia at diagnosis has prognostic significance. Patients who have a nontraumatic diagnostic lumbar puncture may be placed into one of three categories according to the number of WBC/µL and the presence or absence of blasts on cytospin as follows:
- CNS1: Cerebrospinal fluid (CSF) that is cytospin negative for blasts regardless of WBC count.
- CNS2: CSF with fewer than 5 WBC/µL and cytospin positive for blasts.
- CNS3 (CNS disease): CSF with 5 or more WBC/µL and cytospin positive for blasts.
Children with ALL who present with CNS disease (CNS3) at diagnosis are at a higher risk of treatment failure (both within the CNS and systemically) than are patients who are classified as CNS1 or CNS2. Some studies have reported increased risk of CNS relapse and/or inferior event-free survival (EFS) in CNS2 patients, compared with CNS1 patients,[38,39] while others have not.[37,40-42]
A traumatic lumbar puncture (≥10 erythrocytes/µL) that includes blasts at diagnosis has also been associated with increased risk of CNS relapse and overall poorer outcome in some studies,[37,41,43,43] but not others.[38,40] Patients with CNS2, CNS3, or traumatic lumbar puncture have a higher frequency of unfavorable prognostic characteristics than do those with CNS1, including significantly higher WBC counts at diagnosis, older age at diagnosis, an increased frequency of the T-cell ALL phenotype, and MLL gene rearrangements.[37,40,41]
Some clinical trial groups have approached CNS2 and traumatic lumbar puncture by utilizing more intensive therapy, primarily additional doses of intrathecal therapy during induction.[37,44]; [Level of evidence: 2A] Other groups have not altered therapy based on CNS2 status.[38,45]
To determine whether a patient with a traumatic lumbar puncture (with blasts) should be treated as CNS3, the COG uses an algorithm relating the WBC and red blood cell counts in the spinal fluid and the peripheral blood.Testicular involvement at diagnosis
Overt testicular involvement at the time of diagnosis occurs in approximately 2% of males, most commonly in T-cell ALL.
In early ALL trials, testicular involvement at diagnosis was an adverse prognostic factor. With more aggressive initial therapy, however, it does not appear that testicular involvement at diagnosis has prognostic significance.[47,48] For example, the European Organization for Research and Treatment of Cancer (EORTC [EORTC-58881]) reported no adverse prognostic significance for overt testicular involvement at diagnosis.
The role of radiation therapy for testicular involvement is unclear. A study from St. Jude Children's Research Hospital (SJCRH) suggests that a good outcome can be achieved with aggressive conventional chemotherapy without radiation. The COG has also adopted this strategy for boys with testicular involvement that resolves completely by the end of induction therapy. The COG considers patients with testicular involvement to be high risk regardless of other presenting features, but most other large clinical trial groups in the United States and Europe do not consider testicular disease to be a high-risk feature.Down syndrome (trisomy 21)
The lower EFS and OS of children with Down syndrome appear to be related to higher rates of treatment-related mortality and the absence of favorable biological features such as ETV6-RUNX1 or trisomies of chromosomes 4 and 10.[49-53] In a report from the COG, among B-precursor ALL patients who lacked MLL translocations, BCR-ABL1, ETV6-RUNX1, or trisomies of chromosomes 4 and 10, the EFS and OS were similar in children with and without Down syndrome. Certain genomic abnormalities, such as IKZF1 deletions, CRLF2 aberrations, and JAK mutations are seen more frequently in ALL arising in children with Down syndrome than in those without Down syndrome.[54-58] In one study of Down syndrome children with ALL, the presence of IKZF1 deletions (but not CRLF2 aberrations or JAK mutations) was associated with an inferior prognosis.Gender
In some studies, the prognosis for girls with ALL is slightly better than it is for boys with ALL.[59-61] One reason for the better prognosis for girls is the occurrence of testicular relapses among boys, but boys also appear to be at increased risk of bone marrow and CNS relapse for reasons that are not well understood.[59-61] While some reports describe outcomes for boys as closely approaching those of girls,[44,62] larger clinical trial experiences and national data continue to show somewhat lower survival rates for boys.[23,24,63]Race
The reason for better outcomes in white and Asian children than in black and Hispanic children is at least partially explained by the different spectrum of ALL subtypes. For example, black children have a higher relative incidence of T-cell ALL and lower rates of favorable genetic subtypes of precursor B-cell ALL. Differences in outcome may also be related to treatment adherence, as illustrated by a study of adherence to oral 6-mercaptopurine in maintenance therapy. In this study, there was an increased risk of relapse in Hispanic children compared with non-Hispanic white children, depending on the level of adherence, even when adjusting for other known variables. However, at adherence rates of 90% or more, Hispanic children continued to demonstrate increased rates of relapse. Ancestry-related genomic variations may also contribute to racial/ethnic disparities in both the incidence and outcome of ALL. For example, the differential presence of specific host polymorphisms in different racial/ethnic groups may contribute to outcome disparities, as illustrated by the occurrence of single nucleotide polymorphisms in the ARID5B gene that occur more frequently among Hispanics and are linked to both ALL susceptibility and to relapse hazard.Leukemic cell characteristics affecting prognosis
Leukemic cell characteristics affecting prognosis include the following:Morphology
In the past, ALL lymphoblasts were classified using the French-American-British (FAB) criteria as having L1 morphology, L2 morphology, or L3 morphology. However, because of the lack of independent prognostic significance and the subjective nature of this classification system, it is no longer used.
Most cases of ALL that show L3 morphology express surface immunoglobulin (Ig) and have a C-MYC gene translocation identical to that seen in Burkitt lymphoma (i.e., t(8;14)). Patients with this specific rare form of leukemia (mature B-cell or Burkitt leukemia) should be treated according to protocols for Burkitt lymphoma. (Refer to the PDQ summary on Childhood Non-Hodgkin Lymphoma Treatment for more information about the treatment of B-cell ALL and Burkitt lymphoma.)Immunophenotype
The World Health Organization (WHO) classifies ALL as either:
- B lymphoblastic leukemia.
- T lymphoblastic leukemia.
Either B or T lymphoblastic leukemia can coexpress myeloid antigens. These cases need to be distinguished from leukemia of ambiguous lineage.
- Precursor B-cell ALL (WHO B lymphoblastic leukemia)
Before 2008, the WHO classified B lymphoblastic leukemia as precursor-B lymphoblastic leukemia, and this terminology is still frequently used in the literature of childhood ALL to distinguish it from mature B-cell ALL. Mature B-cell ALL is now termed Burkitt leukemia and requires different treatment than has been given for precursor B-cell ALL. The older terminology will continue to be used throughout this summary.
Precursor B-cell ALL, defined by the expression of cytoplasmic CD79a, CD19, HLA-DR, and other B cell-associated antigens, accounts for 80% to 85% of childhood ALL. Approximately 90% of precursor B-cell ALL cases express the CD10 surface antigen (formerly known as common ALL antigen [cALLa]). Absence of CD10 is associated with MLL translocations, particularly t(4;11), and a poor outcome.[10,71] It is not clear whether CD10-negativity has any independent prognostic significance in the absence of an MLL gene rearrangement.
The major subtypes of precursor B-cell ALL are as follows:
- Common precursor B-cell ALL (CD10 positive and no surface or cytoplasmic Ig)
Approximately three-quarters of patients with precursor B-cell ALL have the common precursor B-cell immunophenotype and have the best prognosis. Patients with favorable cytogenetics almost always show a common precursor B-cell immunophenotype.
- Pro-B ALL (CD10 negative and no surface or cytoplasmic Ig)
Approximately 5% of patients have the pro-B immunophenotype. Pro-B is the most common immunophenotype seen in infants and is often associated with MLL gene rearrangements.
- Pre-B ALL (presence of cytoplasmic Ig)
The leukemic cells of patients with pre-B ALL contain cytoplasmic Ig, and 25% of patients with pre-B ALL have the t(1;19) translocation with TCF3-PBX1 (also known as E2A-PBX1) fusion (see below).[73,74]
Approximately 3% of patients have transitional pre-B ALL with expression of surface Ig heavy chain without expression of light chain, C-MYC gene involvement, or L3 morphology. Patients with this phenotype respond well to therapy used for precursor B-cell ALL.
Approximately 2% of patients present with mature B-cell leukemia (surface Ig expression, generally with FAB L3 morphology and a translocation involving the C-MYC gene), also called Burkitt leukemia. The treatment for mature B-cell ALL is based on therapy for non-Hodgkin lymphoma and is completely different from that for precursor B-cell ALL. Rare cases of mature B-cell leukemia that lack surface Ig but have L3 morphology with C-MYC gene translocations should also be treated as mature B-cell leukemia. (Refer to the PDQ summary on Childhood Non-Hodgkin Lymphoma Treatment for more information about the treatment of children with B-cell ALL and Burkitt lymphoma.)
- Common precursor B-cell ALL (CD10 positive and no surface or cytoplasmic Ig)
- T-cell ALL
T-cell ALL is defined by expression of the T cell–associated antigens (cytoplasmic CD3, with CD7 plus CD2 or CD5) on leukemic blasts. T-cell ALL is frequently associated with a constellation of clinical features, including the following:[17,29,62]
- Male gender.
- Older age.
- Mediastinal mass.
There are few commonly accepted prognostic factors for patients with T-cell ALL. Conflicting data exist regarding the prognostic significance of presenting leukocyte counts in T-cell ALL.[6,29-35] The presence or absence of a mediastinal mass at diagnosis has no prognostic significance. In patients with a mediastinal mass, the rate of regression of the mass lacks prognostic significance.
Multiple chromosomal translocations have been identified in T-cell ALL, with many genes encoding for transcription factors (e.g., TAL1, LMO1 and LMO2, LYL1, TLX1/HOX11, and TLX3/HOX11L2) fusing to one of the T-cell receptor loci and resulting in aberrant expression of these transcription factors in leukemia cells.[77,79-83] These translocations are often not apparent by examining a standard karyotype, but are identified using more sensitive screening techniques, such as fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR). High expression of TLX1/HOX11 resulting from translocations involving this gene occurs in 5% to 10% of pediatric T-cell ALL cases and is associated with more favorable outcome in both adults and children with T-cell ALL.[79-81,83] Overexpression of TLX3/HOX11L2 resulting from the cryptic t(5;14)(q35;q32) translocation occurs in approximately 20% of pediatric T-cell ALL cases and appears to be associated with increased risk of treatment failure, although not in all studies.
Notch pathway signaling is commonly activated by NOTCH1 and FBXW7 gene mutations in T-cell ALL. NOTCH1-activating gene mutations occur in approximately 50% of T-cell ALL cases, and FBXW7 inactivating gene mutations occur in approximately 15% of cases, with the result that approximately 60% of cases having Notch pathway activation by mutations in at least one of these genes. The prognostic significance of Notch pathway activation by NOTCH1 and FBXW7 mutations in pediatric T-cell ALL is not clear, as some studies have shown a favorable prognosis for mutated cases,[85-87] while other studies have not shown prognostic significance for the presence of NOTCH1 and/or FBXW7 mutations.[88-90]
A NUP214–ABL1 fusion has been noted in 4% to 6% of T-cell ALL cases and is observed in both adults and children with a male predominance.[91-93] The fusion is cytogenetically cryptic and is seen in FISH on amplified episomes or more rarely, as a small homogeneous staining region. T-cell ALL may also uncommonly show ABL1 fusion proteins with other gene partners (e.g., ETV6, BCR, and EML1). ABL tyrosine kinase inhibitors, such as imatinib or dasatinib, may have therapeutic benefit in this T-cell ALL subtype,[91,92,94] although clinical experience with this strategy is very limited.[95-97]
Early T-cell precursor ALL
Early T-cell precursor ALL, a distinct subset of childhood T-cell ALL, was initially defined by identifying T-cell ALL cases with gene expression profiles highly related to expression profiles for normal early T-cell precursors. The subset of T-cell ALL cases, identified by these analyses represented 13% of all cases and they were characterized by a distinctive immunophenotype (CD1a and CD8 negativity, with weak expression of CD5 and coexpression of stem cell or myeloid markers). Detailed molecular characterization of early T-cell precursor ALL showed this entity to be highly heterogeneous at the molecular level, with no single gene affected by mutation or copy number alteration in more than one-third of cases. Compared with other T-ALL cases, the early T-cell precursor group had a lower rate of NOTCH1 mutations and significantly higher frequencies of alterations in genes regulating cytokine receptors and Ras signaling, hematopoietic development, and histone modification. The transcriptional profile of early T-cell precursor ALL shows similarities to that of normal hematopoietic stem cells and myeloid leukemia stem cells. Retrospective analyses have suggested that this subset has a poorer prognosis than other cases of T-cell ALL.[36,99,100] However, further study in larger patient cohorts is needed.
Studies have found that the absence of biallelic deletion of the TCRgamma locus (ABGD), as detected by comparative genomic hybridization and/or quantitative DNA-PCRn, was associated with early treatment failure in patients with T-cell ALL.[101,102] ABGD is characteristic of early thymic precursor cells, and many of the T-cell ALL patients with ABGD have an immunophenotype consistent with the diagnosis of early T-cell precursor phenotype.
- Myeloid antigen expression
Up to one-third of childhood ALL cases have leukemia cells that express myeloid-associated surface antigens. Myeloid-associated antigen expression appears to be associated with specific ALL subgroups, notably those with MLL translocations and those with the ETV6-RUNX1 gene rearrangement.[103,104] No independent adverse prognostic significance exists for myeloid-surface antigen expression.[103,104]
Leukemia of ambiguous lineage
Less than 5% of cases of acute leukemia in children are of ambiguous lineage, expressing features of both myeloid and lymphoid lineage.[105-107] These cases are distinct from ALL with myeloid coexpression in that the predominant lineage cannot be determined by immunophenotypic and histochemical studies. The definition of leukemia of ambiguous lineage varies among studies. However, most investigators now use criteria established by the European Group for the Immunological Characterization of Leukemias (EGIL) or the more stringent WHO criteria.[108-110] In the WHO classification, the presence of myeloperoxidase is required to establish myeloid lineage. This is not the case for the EGIL classification.
Leukemias of mixed phenotype comprise the following two groups:
- Bilineal leukemias in which there are two distinct populations of cells, usually one lymphoid and one myeloid.
- Biphenotypic leukemias in which individual blast cells display features of both lymphoid and myeloid lineage. Biphenotypic cases represent the majority of mixed phenotype leukemias. Patients with B-myeloid biphenotypic leukemias lacking the ETV6-RUNX1 fusion have a lower rate of complete remission and a significantly worse EFS than do patients with B-precursor ALL. Some studies suggest that patients with biphenotypic leukemia may fare better with a lymphoid, as opposed to a myeloid, treatment regimen,[106,107,111] although the optimal treatment for patients remains unclear.
A number of recurrent chromosomal abnormalities have been shown to have prognostic significance, especially in B-precursor ALL. Some chromosomal abnormalities are associated with more favorable outcomes, such as high hyperdiploidy (51–65 chromosomes) and the ETV6-RUNX1 fusion. Others are associated with a poorer prognosis, including the Philadelphia chromosome (t(9;22)), rearrangements of the MLL gene (chromosome 11q23), and intrachromosomal amplification of the AML1 gene (iAMP21).
Prognostically significant chromosomal abnormalities in childhood ALL include the following:
- Chromosome number
- High hyperdiploidy
High hyperdiploidy, defined as 51 to 65 chromosomes per cell or a DNA index greater than 1.16, occurs in 20% to 25% of cases of precursor B-cell ALL, but very rarely in cases of T-cell ALL. Hyperdiploidy can be evaluated by measuring the DNA content of cells (DNA index) or by karyotyping. In cases with a normal karyotype or in which standard cytogenetic analysis was unsuccessful, interphase FISH may detect hidden hyperdiploidy. High hyperdiploidy generally occurs in cases with clinically favorable prognostic factors (patients aged 1 to <10 years with a low WBC count) and is itself an independent favorable prognostic factor.[19,113,114] Within the hyperdiploid range of 51 to 66 chromosomes, patients with higher modal numbers (58–66) appeared to have a better prognosis in one study. Hyperdiploid leukemia cells are particularly susceptible to undergoing apoptosis and accumulate higher levels of methotrexate and its active polyglutamate metabolites, which may explain the favorable outcome commonly observed in these cases.
While the overall outcome of patients with high hyperdiploidy is considered to be favorable, factors such as age, WBC count, specific trisomies, and early response to treatment have been shown to modify its prognostic significance.
Patients with trisomies of chromosomes 4, 10, and 17 (triple trisomies) have been shown to have a particularly favorable outcome as demonstrated by both Pediatric Oncology Group (POG) and Children's Cancer Group (CCG) analyses of NCI standard-risk ALL. POG data suggest that NCI standard-risk patients with trisomies of 4 and 10, without regard to chromosome 17 status, have an excellent prognosis.
Chromosomal translocations may be seen with high hyperdiploidy, and in those cases, patients are more appropriately risk-classified based on the prognostic significance of the translocation. For instance, in one study, 8% of patients with the Philadelphia chromosome (t(9;22)) also had high hyperdiploidy, and the outcome of these patients (treated without tyrosine kinase inhibitors) was inferior to that observed in non-Philadelphia chromosome–positive (Ph+) high hyperdiploid patients.
Certain patients with hyperdiploid ALL may have a hypodiploid clone that has doubled (masked hypodiploidy). These cases may be interpretable based on the pattern of gains and losses of specific chromosomes. These patients have an unfavorable outcome, similar to those with hypodiploidy.
Near triploidy (68–80 chromosomes) and near tetraploidy (>80 chromosomes) are much less common and appear to be biologically distinct from high hyperdiploidy. Unlike high hyperdiploidy, a high proportion of near tetraploid cases harbor a cryptic ETV6-RUNX1 fusion.[121-123] Near triploidy and tetraploidy were previously thought to be associated with an unfavorable prognosis, but later studies suggest that this may not be the case.[121,123]
- Hypodiploidy (<44 chromosomes)
Precursor B-cell ALL cases with fewer than the normal number of chromosomes have been subdivided in various ways, with one report stratifying based on modal chromosome number into the following four groups:
- Near-haploid: 24 to 29 chromosomes (n = 46).
- Low-hypodiploid: 33 to 39 chromosomes (n = 26).
- High-hypodiploid: 40 to 43 chromosomes (n = 13).
- Near-diploid: 44 chromosomes (n = 54).
Most patients with hypodiploidy are in the near-haploid and low-hypodiploid groups, and both of these groups have an elevated risk of treatment failure compared with nonhypodiploid cases.[120,124] Patients with fewer than 44 chromosomes have a worse outcome than do patients with 44 or 45 chromosomes in their leukemic cells.
The recurring genomic alterations of near-haploid and low-hypodiploid ALL appear to be distinctive from each other and from other types of ALL. In near-haploid ALL, alterations targeting receptor tyrosine kinase signaling, Ras signaling, and IKZF3 are common. In low-hypodiploid ALL, genetic alterations involving TP53, RB1, and IKZF2 are common. Importantly, the TP53 alterations observed in low-hypodiploid ALL are also present in nontumor cells in approximately 40% of cases, suggesting that these mutations are germline and that low-hypodiploid ALL represents, in some cases, a manifestation of Li-Fraumeni syndrome.
- High hyperdiploidy
- Chromosomal translocations
- ETV6-RUNX1 (t(12;21) cryptic translocation, formerly known as TEL-AML1)
Fusion of the ETV6 gene on chromosome 12 to the RUNX1 gene on chromosome 21 can be detected in 20% to 25% of cases of B-precursor ALL but is rarely observed in T-cell ALL. The t(12;21) occurs most commonly in children aged 2 to 9 years.[126,127] Hispanic children with ALL have a lower incidence of t(12;21) than do white children.
- Early response to treatment.
- NCI risk category (age and WBC count at diagnosis).
- Treatment regimen.
In one study of the treatment of newly diagnosed children with ALL, multivariate analysis of prognostic factors found age and leukocyte count, but not ETV6-RUNX1, to be independent prognostic factors. There is a higher frequency of late relapses in patients with ETV6-RUNX1 fusion compared with other B-precursor ALL.[129,133] Patients with the ETV6-RUNX1 fusion who relapse seem to have a better outcome than other relapse patients, with an especially favorable prognosis for patients who relapse more than 36 months from diagnosis. Some relapses in patients with t(12;21) may represent a new independent second hit in a persistent preleukemic clone (with the first hit being the ETV6-RUNX1 translocation).[136,137]
- Philadelphia chromosome (t(9;22) translocation)
The Philadelphia chromosome t(9;22) is present in approximately 3% of children with ALL and leads to production of a BCR-ABL1 fusion protein with tyrosine kinase activity (see Figure 2).
This subtype of ALL is more common in older children with precursor B-cell ALL and high WBC count.
Historically, the Philadelphia chromosome t(9;22) was associated with an extremely poor prognosis (especially in those who presented with a high WBC count or had a slow early response to initial therapy), and its presence had been considered an indication for allogeneic hematopoietic stem cell transplantation (HSCT) in patients in first remission.[119,138-140] Inhibitors of the BCR-ABL tyrosine kinase, such as imatinib mesylate, are effective in patients with Ph+ ALL. A study by the COG, which used intensive chemotherapy and concurrent imatinib mesylate given daily, demonstrated a 3-year EFS rate of 80.5%, which was superior to the EFS rate of historical controls in the pre-tyrosine kinase inhibitor (imatinib mesylate) era.[141,142] Longer follow-up is necessary to determine whether this treatment improves the cure rate or merely prolongs DFS.
- MLL translocations
Translocations involving the MLL (11q23) gene occur in up to 5% of childhood ALL cases and are generally associated with an increased risk of treatment failure.[71,143-145] The t(4;11) translocation is the most common translocation involving the MLL gene in children with ALL and occurs in approximately 2% of cases.
Patients with the t(4;11) translocation are usually infants with high WBC counts; they are more likely than other children with ALL to have CNS disease and to have a poor response to initial therapy. While both infants and adults with the t(4;11) translocation are at high risk of treatment failure, children with the t(4;11) translocation appear to have a better outcome than either infants or adults.[71,143] Irrespective of the type of MLL gene rearrangement, infants with leukemia cells that have MLL gene rearrangements have a worse treatment outcome than older patients whose leukemia cells have an MLL gene rearrangement.[71,143] Deletion of the MLL gene has not been associated with an adverse prognosis.
Of interest, the t(11;19) translocation involving MLL and MLLT1/ENL occurs in approximately 1% of ALL cases and occurs in both early B-lineage and T-cell ALL. Outcome for infants with the t(11;19) translocation is poor, but outcome appears relatively favorable in older children with T-cell ALL and the t(11;19) translocation.
- TCF3-PBX1 (E2A-PBX1; t(1;19) translocation)
The t(1;19) translocation occurs in approximately 5% of childhood ALL cases and involves fusion of the E2A gene on chromosome 19 to the PBX1 gene on chromosome 1.[73,74] The t(1;19) translocation may occur as either a balanced translocation or as an unbalanced translocation and is primarily associated with pre-B ALL immunophenotype (cytoplasmic Ig positive). Black children are more likely than white children to have pre-B ALL with the t(1;19).
The t(1;19) translocation had been associated with inferior outcome in the context of antimetabolite-based therapy, but the adverse prognostic significance was largely negated by more aggressive multiagent therapies.[74,150] However, in a trial conducted by SJCRH on which all patients were treated without cranial radiation, patients with the t(1;19) translocation had an overall outcome comparable to children lacking this translocation, with a higher risk of CNS relapse and a lower rate of bone marrow relapse, suggesting that more intensive CNS therapy may be needed for these patients.[44,151]
- ETV6-RUNX1 (t(12;21) cryptic translocation, formerly known as TEL-AML1)
- Other genomic alterations
Numerous new genetic lesions have been discovered by various array comparative hybridization and next-generation sequencing methods. Appreciation of these submicroscopic genomic abnormalities and mutations is redefining the subclassification of ALL:[152-158]
- Intrachromosomal amplification of chromosome 21 (iAMP21): iAMP21 with multiple extra copies of the RUNX1 (AML1) gene occurs in 1% to 2% of precursor B-cell ALL cases and may be associated with an inferior outcome.[112,159,160]
- IKZF1 deletions: IKZF1 deletions, including deletions of the entire gene and deletions of specific exons, are present in approximately 15% of precursor B-cell ALL cases. Cases with IKZF1 deletions tend to occur in older children, have a higher WBC count at diagnosis, and are therefore, more common among NCI high-risk patients compared with NCI standard-risk patients.[161,162] A high proportion of BCR-ABL1 cases have a deletion of IKZF1,[162,163] and ALL arising in children with Down syndrome appears to have elevated rates of IKZF1 deletions. IKZF1 deletions are also common in cases with CRLF2 genomic alterations and in Philadelphia chromosome–like (Ph-like) ALL (see below).[152,162,164]
Multiple reports have documented the adverse prognostic significance of a IKZF1 deletion; there are differences between studies in the magnitude of effect and in whether the IKZF1 deletion maintains significance when other prognostic factors are considered using multivariate analysis.[152,162,164-167]
- CRLF2 and JAK mutations: Genomic alterations in CRLF2, a cytokine receptor gene located on the pseudoautosomal regions of the sex chromosomes, have been identified in 5% to 10% of cases of B-precursor ALL.[168,169] The chromosomal abnormalities that commonly lead to CRLF2 overexpression include translocations of the IgH locus (chromosome 14) to CRLF2 and interstitial deletions in pseudoautosomal regions of the sex chromosomes, resulting in a P2RY8-CRLF2 fusion.[168-171] CRLF2 abnormalities are strongly associated with the presence of IKZF1 deletions and JAK mutations;[54,162,169-171] they are also more common in children with Down syndrome. The results of several retrospective studies suggest that CRLF2 abnormalities may have adverse prognostic significance, although studies differ on whether CRLF2 maintains significance when other prognostic factors are considered using multivariate analysis.[155,168-170,172] However, point mutations within kinase genes are uncommon among Ph-like cases, except for JAK1 and JAK2. Additionally, there is controversy about whether prognosis should be analyzed based on CRLF2 overexpression or on the presence of CRLF2 genomic alterations.[155,172]
- Ph-like ALL: BCR-ABL1–negative patients with a gene expression profile similar to BCR-ABL1–positive patients have been referred to as Ph-like ALL.[164,165] This occurs in 10% to 15% of pediatric ALL patients, increasing in frequency with age, and is associated with a poor prognosis and with IKZF1 deletion/mutation.[157,164,165,171] The hallmark of this entity is activated kinase signaling, with 50% containing CRLF2 genomic alterations  and 25% concomitant JAK mutations. Many of the remaining cases have been noted to have a series of translocations with a common theme of involvement of either ABL1, JAK2, PDGFRB, or EPOR. Fusion proteins from these gene combinations have been noted in some cases to be transformative and have responded to tyrosine kinase inhibitors both in vitro and in vivo, suggesting potential therapeutic strategies for these patients. Point mutations in kinase genes, aside from those in JAK1 and JAK2, are uncommon in Ph-like ALL cases.
- Gene polymorphisms in drug metabolic pathways
A number of polymorphisms of genes involved in the metabolism of chemotherapeutic agents have been reported to have prognostic significance in childhood ALL.[173-175] For example, patients with mutant phenotypes of thiopurine methyltransferase (a gene involved in the metabolism of thiopurines, such as 6-mercaptopurine), appear to have more favorable outcomes, although such patients may also be at higher risk of developing significant treatment-related toxicities, including myelosuppression and infection.[177,178]
Genome-wide polymorphism analysis has identified specific single nucleotide polymorphisms associated with high end-induction minimal residual disease (MRD) and risk of relapse. Polymorphisms of IL-15, as well as genes associated with the metabolism of etoposide and methotrexate, were significantly associated with treatment response in two large cohorts of ALL patients treated on SJCRH and COG protocols. Polymorphic variants involving the reduced folate carrier have been linked to methotrexate metabolism, toxicity, and outcome. While these associations suggest that individual variations in drug metabolism can affect outcome, few studies have attempted to adjust for these variations; whether individualized dose modification based on these findings will improve outcome is unknown.
The rapidity with which leukemia cells are eliminated after initiation of treatment and the level of residual disease at the end of induction are associated with long-term outcome. Because treatment response is influenced by the drug sensitivity of leukemic cells and host pharmacodynamics and pharmacogenomics, early response has strong prognostic significance. Various ways of evaluating the leukemia cell response to treatment have been utilized, including the following:
- MRD determination.
- Day 7 and day 14 bone marrow responses.
- Peripheral blood response to steroid prophase.
- Peripheral blood response to multiagent induction therapy.
- Peripheral blood MRD before end of induction (day 8, day 15).
- Induction failure.
Morphologic assessment of residual leukemia in blood or bone marrow is often difficult and is relatively insensitive. Traditionally, a cutoff of 5% blasts in the bone marrow (detected by light microscopy) has been used to determine remission status. This corresponds to a level of 1 in 20 malignant cells. If one wishes to detect lower levels of leukemic cells in either blood or marrow, specialized techniques such as PCR assays, which determine unique Ig/T-cell receptor gene rearrangements, fusion transcripts produced by chromosome translocations, or flow cytometric assays, which detect leukemia-specific immunophenotypes, are required. With these techniques, detection of as few as 1 leukemia cell in 100,000 normal cells is possible, and MRD at the level of 1 in 10,000 cells can be detected routinely.
Multiple studies have demonstrated that end-induction MRD is an important, independent predictor of outcome in children and adolescents with B-lineage ALL.[130,183-185] MRD response discriminates outcome in subsets of patients defined by age, leukocyte count, and cytogenetic abnormalities. Patients with higher levels of end-induction MRD have a poorer prognosis than those with lower or undetectable levels.[130,182-184,187] End-induction MRD is used by almost all groups as a factor determining the intensity of postinduction treatment, with patients found to have higher levels allocated to more intensive therapies. MRD levels at earlier (e.g., day 8 and day 15 of induction) and later time points (e.g., week 12 of therapy) also predict outcome.[130,182,184,186-191]
MRD measurements, in conjunction with other presenting features, have also been used to identify subsets of patients with an extremely low risk of relapse. The COG reported a very favorable prognosis (5-year EFS of 97% ± 1%) for patients with B-precursor phenotype, NCI standard risk age/leukocyte count, CNS1 status, and favorable cytogenetic abnormalities (either high hyperdiploidy with favorable trisomies or the ETV6-RUNX1 fusion) who had less than 0.01% MRD levels at both day 8 (from peripheral blood) and end-induction (from bone marrow).
There are fewer studies documenting the prognostic significance of MRD in T-cell ALL. In the AIEOP-BFM ALL 2000 trial, MRD status at day 78 (week 12) was the most important predictor for relapse in patients with T-cell ALL. Patients with detectable MRD at end-induction who had negative MRD by day 78 did just as well as patients who achieved MRD-negativity at the earlier end-induction time point. Thus, unlike in B-cell precursor ALL, end-induction MRD levels were irrelevant in those patients whose MRD was negative at day 78. A high MRD level at day 78 was associated with a significantly higher risk of relapse.
There are few studies of MRD in the CSF. In one study, MRD was documented in about one-half of children at diagnosis. In this study, CSF MRD was not found to be prognostic when intensive chemotherapy was given.
Although MRD is the most important prognostic factor in determining outcome, there are no data to conclusively show that modifying therapy based on MRD determination significantly improves outcome in newly diagnosed ALL. However, the UKALL 2003 study demonstrated that reduction of therapy (i.e., one rather than two courses of delayed intensification) did not adversely impact outcome in non-high–risk patients with favorable end-induction MRD.[Level of evidence: 1iiDii]Day 7 and day 14 bone marrow responses
Patients who have a rapid reduction in leukemia cells to less than 5% in their bone marrow within 7 or 14 days after the initiation of multiagent chemotherapy have a more favorable prognosis than do patients who have slower clearance of leukemia cells from the bone marrow. MRD assessments at the end of induction therapy have generally replaced day 7 and day 14 morphological assessments as response to therapy prognostic indicators because the latter lose their prognostic significance in multivariate analysis once MRD is included in the analyses.[130,195]Peripheral blood response to steroid prophase
Patients with a reduction in peripheral blast count to less than 1,000/µL after a 7-day induction prophase with prednisone and one dose of intrathecal methotrexate (a good prednisone response) have a more favorable prognosis than do patients whose peripheral blast counts remain above 1,000/µL (a poor prednisone response). Poor prednisone response is observed in fewer than 10% of patients.[17,196] Treatment stratification for protocols of the Berlin-Frankfurt-Münster (BFM) clinical trials group is partially based on early response to the 7-day prednisone prophase (administered immediately before the initiation of multiagent remission induction).Peripheral blood response to multiagent induction therapy
Patients with persistent circulating leukemia cells at 7 to 10 days after the initiation of multiagent chemotherapy are at increased risk of relapse compared with patients who have clearance of peripheral blasts within 1 week of therapy initiation. Rate of clearance of peripheral blasts has been found to be of prognostic significance in both T-cell and B-lineage ALL.Peripheral blood MRD before end of induction (day 8, day 15)
MRD using peripheral blood obtained 1 week after the initiation of multiagent induction chemotherapy has also been evaluated as an early response-to-therapy prognostic factor. In a COG study involving nearly 2,000 children with ALL, the presence of MRD in the peripheral blood at day 8 was associated with adverse prognosis, with increasing MRD levels being associated with a progressively poorer outcome. In multivariate analysis, end of induction therapy MRD was the most powerful prognostic factor, but day 8 peripheral blood MRD maintained its prognostic significance, as did NCI risk group and the presence of favorable trisomies. A smaller study assessed the prognostic significance of peripheral blood MRD at day 15 after 1 week of a steroid prophase and 1 week of multiagent induction therapy. This study also observed multivariate significance for peripheral blood MRD levels after 1 week of multiagent induction therapy. Both studies identified a group of patients who achieved low MRD levels after 1 week of multiagent induction therapy who had a low rate of subsequent treatment failure.Induction failure
The vast majority of children with ALL achieve complete morphologic remission by the end of the first month of treatment. The presence of greater than 5% lymphoblasts at the end of the induction phase is observed in up to 5% of children with ALL. Patients at highest risk of induction failure have one or more of the following features:[200,201]
- T-cell phenotype (especially without a mediastinal mass).
- B-precursor ALL with very high presenting leukocyte counts.
- 11q23 rearrangement.
- Older age.
- Philadelphia chromosome.
In a large retrospective study, the OS of patients with induction failure was only 32%. However, there was significant clinical and biological heterogeneity. A relatively favorable outcome was observed in patients with B-precursor ALL between the ages of 1 and 5 years without adverse cytogenetics (MLL translocation or BCR-ABL). This group had a 10-year survival exceeding 50%, and HSCT in first remission was not associated with a survival advantage compared with chemotherapy alone for this subset. Patients with the poorest outcomes (<20% 10-year survival) included those who were aged 14 to 18 years, or who had the Philadelphia chromosome or MLL rearrangement. B-cell ALL patients younger than 6 years and T-cell ALL patients (regardless of age) appeared to have better outcomes if treated with allogeneic HSCT after achieving complete remission than those who received further treatment with chemotherapy alone.Prognostic (Risk) Groups
For decades, clinical trial groups studying childhood ALL have utilized risk classification schemes to assign patients to therapeutic regimens based on their estimated risk of treatment failure. Initial risk classification systems utilized clinical factors such as age and presenting WBC count. Response to therapy measures were subsequently added, with some groups utilizing early morphologic bone marrow response (e.g., at day 8 or day 15) and with other groups utilizing response of circulating leukemia cells to single agent prednisone. Modern risk classification systems continue to utilize clinical factors such as age and presenting WBC count, and in addition, incorporate molecular characteristics of leukemia cells at diagnosis (e.g., favorable and unfavorable translocations) and response to therapy based on detection of MRD at end of induction (and in some cases at later time points). The risk classification systems of the COG and the BFM groups are briefly described below.Children’s Oncology Group (COG) risk groups
In COG protocols, children with ALL are initially stratified into treatment groups (with varying degrees of risk of treatment failure) based on a subset of prognostic factors, including the following:
- WBC count at diagnosis.
- Cytogenetics/genomic alterations.
- Presence of extramedullary disease.
- Down syndrome.
- Steroid pretreatment.
EFS rates exceed 85% in children meeting good-risk criteria (aged 1 to <10 years, WBC count <50,000/μL, and precursor B-cell immunophenotype); in children meeting high-risk criteria, EFS rates are approximately 75%.[3,44,196,202,203] Additional factors, including cytogenetic abnormalities and measures of early response to therapy (e.g., day 7 and/or day 14 marrow blast percentage for patients with Down syndrome and MRD levels in peripheral blood on day 8 and in bone marrow samples at the end of induction), considered in conjunction with presenting age, WBC count, immunophenotype, the presence of extramedullary disease, and steroid pretreatment can identify patient groups for postinduction therapy with expected EFS rates ranging from less than 40% to more than 95%.[3,130]
- Infants with MLL translocations.
- Patients with hypodiploidy (<44 chromosomes).
- Patients with initial induction failure.
Since 2000, risk stratification on BFM protocols has been based almost solely on treatment response criteria. In addition to prednisone prophase response, treatment response is assessed via MRD measurements at two time points, end induction (week 5) and end consolidation (week 12).
The BFM risk groups include the following:
- Standard risk: Patients who are MRD-negative (i.e., <10-4) at both time points are classified as standard risk.
- Intermediate risk: Patients who have positive MRD at week 5 and low MRD (<10-3) at week 12 are considered intermediate risk.
- High risk: Patients with high MRD (≥10-3) at week 12 are high risk. Patients with a poor response to the prednisone prophase are also considered high risk, regardless of subsequent MRD.
Phenotype, leukemic cell mass estimate, also known as BFM risk factor, and CNS status at diagnosis do not factor into the current risk classification schema. However, patients with either the t(9;22) or the t(4;11) are considered high risk, regardless of early response measures.Prognostic (risk) groups under clinical evaluation
COG AALL08B1 (Classification of Newly Diagnosed ALL): COG protocol AALL08B1 stratifies four risk groups for patients with B-precursor ALL (low risk, average risk, high risk, and very high risk) based on the following criteria:
- Age and presenting leukocyte count (using NCI risk-group criteria).
- Extramedullary disease (presence or absence of CNS and/or testicular leukemia).
- Genomic alterations in leukemia cells.
- Day 8 peripheral blood MRD.
- Day 29 bone marrow morphologic response and MRD.
- Down syndrome.
- Steroid pretreatment.
Morphologic assessment of early response in the bone marrow is no longer performed on days 8 and 15 of induction as part of risk stratification. Patients with T-cell phenotype are treated on a separate study and are not risk classified in this way.
For patients with B-precursor ALL:
- Favorable genetics are defined as the presence of either hyperdiploidy with trisomies of chromosomes 4 and 10 (double trisomy) or the ETV6-RUNX1 fusion.
- Unfavorable characteristics are defined as CNS3 status at diagnosis, induction failure (M3 marrow at day 29), age 13 years and older, and the following unfavorable genomic alterations: hypodiploidy (<44 chromosomes or DNA index <0.81), MLL rearrangement, and iAMP21. The presence of any of these unfavorable characteristics is sufficient to classify a patient as very high risk, regardless of other presenting features. Infants and children with BCR-ABL (Ph+ ALL) are treated on a separate clinical trial.
- MRD levels at day 8 from peripheral blood and at day 29 from bone marrow are used in risk classification.
The four risk groups for B-precursor ALL are defined in Table 1.Table 1. Risk Groups for B-Precursor Acute Lymphoblastic Leukemiaa
|Low Risk||Average Risk||High Risk||Very High Risk|
|NCI Risk (Age/WBC)||SR||SR||SR||SR||SR||HR (age <13 y)||SR||HR||HR (age ≥13 y)||SR or HR|
|Day 8 PB MRD||<0.01%||≥0.01%||<1%||Any Level||≥1%||Any Level||Any Level||Any Level||Any Level||Any Level|
|Day 29 Marrow MRD||<0.01%||<0.01%||<0.01%||≥0.01%||<0.01%||<0.01%||≥0.01%||≥0.01%||<0.01%||Any Level|
|% of Patients (Estimated)||15%||36%||25%||24%|
|Anticipated 5-year EFS||>95%||90%–95%||88%–90%||<80%|
|EFS = event-free survival; HR = age and WBC count risk group is high risk; MRD = minimal residual disease; NCI = National Cancer Institute; PB = peripheral blood; SR = age/WBC count risk group is standard risk; WBC = white blood cell.|
|aFrom the Children's Oncology Group Classification of Newly Diagnosed ALL protocol.|
AALL0434 (NCT00408005) (Combination Chemotherapy in Treating Young Patients With Newly Diagnosed T-Cell Acute Lymphoblastic Leukemia or T-cell Lymphoblastic Lymphoma): For patients with T-cell ALL, COG uses the following criteria to assign risk category:
- NCI standard risk by age (1.00–9.99 years) and WBC count (initial ≤50,000/μL).
- M1 marrow on day 15 and M1 marrow with MRD <0.1% on day 29.
- CNS1 status and no testicular disease at diagnosis.
- Doesn’t meet criteria for low risk.
- M1 marrow with MRD <1% on day 29.
- Any CNS status.
- M2 marrow and/or MRD ≥1% on day 29.
- Any CNS status.
DFCI-11-001 (NCT01574274) (SC-PEG Asparaginase vs. Oncaspar in Pediatric ALL and Lymphoblastic Lymphoma): On the current clinical trial conducted by the Dana-Farber Cancer Institute ALL Consortium, patients with B-precursor ALL are initially classified as either standard risk or high risk based on age, presenting leukocyte count, and the presence or absence of CNS disease (CNS3). At the completion of a five-drug remission induction regimen (4 weeks from diagnosis), the level of MRD is determined via PCR assay. Patients with high MRD (≥0.001) are classified as very high risk and receive a more intensive postremission consolidation. Patients with low MRD (<0.001) continue to receive treatment based on their initial risk group classification. The goal of this new classification schema is to determine whether intensification of therapy will improve the outcome of patients with high MRD at the end of remission induction. Patients with T-cell ALL are treated as high risk, regardless of MRD status. All patients with MLL translocations or hypodiploidy (<44 chromosomes) are classified as very high risk, regardless of MRD status or phenotype. Ph+ patients are removed from study midinduction and are eligible to enroll on the COG protocol for patients with Ph+ ALL.
SJCRH (Total XVI): Patients are classified into one of three categories (low, standard, or high risk) based on the presenting age, leukocyte count, presence or absence of CNS3 status or testicular leukemia, immunophenotype, cytogenetics and molecular genetics, DNA index, and early response to therapy. Hence, definitive risk assignment (for provisional low-risk or standard-risk cases based on presenting features) will be made after completion of remission induction therapy. The criteria and the estimated proportion of patients in each category (based on data from TOTXV study) are provided below.
Criteria for low-risk ALL (approximately 48% of patients)
- B-cell precursor ALL with DNA index ≥1.16, ETV6-RUNX1 fusion, or age 1 to 9.9 years and presenting WBC <50 × 109/L.
- Must not have:
- CNS3 status (≥5 WBC/µl of CSF with morphologically identifiable blasts or cranial nerve palsy).
- Overt testicular leukemia (evidenced by ultrasonogram).
- Adverse genetic features—t(9;22) or BCR-ABL1 fusion; t(1;19) with E2A-PBX1 fusion; rearranged MLL (as measured by FISH and/or PCR); or hypodiploidy (<44 chromosomes).
- Poor early response (≥1% lymphoblasts on day 15 of remission induction, ≥0.01% lymphoblasts by immunologic or molecular methods on remission date).
Criteria for standard-risk ALL (approximately 44% of patients)
- All cases of T-cell ALL and those of B-cell precursor ALL that do not meet the criteria for low-risk or high-risk ALL.
Criteria for high-risk ALL (approximately 8% of patients)
- t(9;22) or BCR-ABL fusion.
- Infants with t(4;11) or MLL fusion.
- Induction failure or >1% leukemia lymphoblasts in the bone marrow on remission date.
- >0.1% leukemic lymphoblasts in the bone marrow in week 7 of continuation treatment (i.e., before reinduction 1, about 14 weeks postremission induction).
- Re-emergence of leukemic lymphoblasts by MRD (at any level) in patients previously MRD negative.
- Persistently detectable MRD at lower levels.
- Early T-cell precursor ALL, defined by low expression of T-cell markers together with aberrant expression of myeloid markers. The following features characterize early T-cell precursor ALL:
- Levels of CD5 expression at least tenfold lower than that of normal peripheral blood T-lymphocytes. In the study that identified this subset of T-cell ALL, CD5 expression was tenfold to more than 200-fold lower than that of normal lymphocytes and median percentage of leukemic cells expressing CD5 in the 17 atypical cases was 45%; in contrast to more than 98% for the 122 cases in the typical group.
- Absence (<10%) of CD1a and CD8 expression.
- Expression of cytoplasmic CD3 together with the expression of one or more markers associated with myeloid leukemia such as HLA-Dr, CD34, CD13, CD33, or CD11b, while myeloperoxidase is less than 3% by cytochemistry and/or flow cytometry.
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with childhood acute lymphoblastic leukemia. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.
General information about clinical trials is also available from the NCI Web site.References
- Smith M, Arthur D, Camitta B, et al.: Uniform approach to risk classification and treatment assignment for children with acute lymphoblastic leukemia. J Clin Oncol 14 (1): 18-24, 1996. [PUBMED Abstract]
- Carroll WL, Bhojwani D, Min DJ, et al.: Pediatric acute lymphoblastic leukemia. Hematology (Am Soc Hematol Educ Program) : 102-31, 2003. [PUBMED Abstract]
- Schultz KR, Pullen DJ, Sather HN, et al.: Risk- and response-based classification of childhood B-precursor acute lymphoblastic leukemia: a combined analysis of prognostic markers from the Pediatric Oncology Group (POG) and Children's Cancer Group (CCG). Blood 109 (3): 926-35, 2007. [PUBMED Abstract]
- Vrooman LM, Silverman LB: Childhood acute lymphoblastic leukemia: update on prognostic factors. Curr Opin Pediatr 21 (1): 1-8, 2009. [PUBMED Abstract]
- Pui CH, Evans WE: Treatment of acute lymphoblastic leukemia. N Engl J Med 354 (2): 166-78, 2006. [PUBMED Abstract]
- Pullen J, Shuster JJ, Link M, et al.: Significance of commonly used prognostic factors differs for children with T cell acute lymphocytic leukemia (ALL), as compared to those with B-precursor ALL. A Pediatric Oncology Group (POG) study. Leukemia 13 (11): 1696-707, 1999. [PUBMED Abstract]
- Möricke A, Zimmermann M, Reiter A, et al.: Prognostic impact of age in children and adolescents with acute lymphoblastic leukemia: data from the trials ALL-BFM 86, 90, and 95. Klin Padiatr 217 (6): 310-20, 2005 Nov-Dec. [PUBMED Abstract]
- Reaman GH, Sposto R, Sensel MG, et al.: Treatment outcome and prognostic factors for infants with acute lymphoblastic leukemia treated on two consecutive trials of the Children's Cancer Group. J Clin Oncol 17 (2): 445-55, 1999. [PUBMED Abstract]
- Kosaka Y, Koh K, Kinukawa N, et al.: Infant acute lymphoblastic leukemia with MLL gene rearrangements: outcome following intensive chemotherapy and hematopoietic stem cell transplantation. Blood 104 (12): 3527-34, 2004. [PUBMED Abstract]
- Pieters R, Schrappe M, De Lorenzo P, et al.: A treatment protocol for infants younger than 1 year with acute lymphoblastic leukaemia (Interfant-99): an observational study and a multicentre randomised trial. Lancet 370 (9583): 240-50, 2007. [PUBMED Abstract]
- Hilden JM, Dinndorf PA, Meerbaum SO, et al.: Analysis of prognostic factors of acute lymphoblastic leukemia in infants: report on CCG 1953 from the Children's Oncology Group. Blood 108 (2): 441-51, 2006. [PUBMED Abstract]
- Isoyama K, Eguchi M, Hibi S, et al.: Risk-directed treatment of infant acute lymphoblastic leukaemia based on early assessment of MLL gene status: results of the Japan Infant Leukaemia Study (MLL96). Br J Haematol 118 (4): 999-1010, 2002. [PUBMED Abstract]
- Nagayama J, Tomizawa D, Koh K, et al.: Infants with acute lymphoblastic leukemia and a germline MLL gene are highly curable with use of chemotherapy alone: results from the Japan Infant Leukemia Study Group. Blood 107 (12): 4663-5, 2006. [PUBMED Abstract]
- Sam TN, Kersey JH, Linabery AM, et al.: MLL gene rearrangements in infant leukemia vary with age at diagnosis and selected demographic factors: a Children's Oncology Group (COG) study. Pediatr Blood Cancer 58 (6): 836-9, 2012. [PUBMED Abstract]
- Kang H, Wilson CS, Harvey RC, et al.: Gene expression profiles predictive of outcome and age in infant acute lymphoblastic leukemia: a Children's Oncology Group study. Blood 119 (8): 1872-81, 2012. [PUBMED Abstract]
- Stam RW, Schneider P, de Lorenzo P, et al.: Prognostic significance of high-level FLT3 expression in MLL-rearranged infant acute lymphoblastic leukemia. Blood 110 (7): 2774-5, 2007. [PUBMED Abstract]
- Schrappe M, Reiter A, Ludwig WD, et al.: Improved outcome in childhood acute lymphoblastic leukemia despite reduced use of anthracyclines and cranial radiotherapy: results of trial ALL-BFM 90. German-Austrian-Swiss ALL-BFM Study Group. Blood 95 (11): 3310-22, 2000. [PUBMED Abstract]
- Forestier E, Schmiegelow K; on behalf of the Nordic Society of Paediatric Haematology and Oncology NOPHO.: The incidence peaks of the childhood acute leukemias reflect specific cytogenetic aberrations. J Pediatr Hematol Oncol 28 (8): 486-95, 2006. [PUBMED Abstract]
- Dastugue N, Suciu S, Plat G, et al.: Hyperdiploidy with 58-66 chromosomes in childhood B-acute lymphoblastic leukemia is highly curable: 58951 CLG-EORTC results. Blood 121 (13): 2415-23, 2013. [PUBMED Abstract]
- Nachman JB, La MK, Hunger SP, et al.: Young adults with acute lymphoblastic leukemia have an excellent outcome with chemotherapy alone and benefit from intensive postinduction treatment: a report from the children's oncology group. J Clin Oncol 27 (31): 5189-94, 2009. [PUBMED Abstract]
- Pulte D, Gondos A, Brenner H: Improvement in survival in younger patients with acute lymphoblastic leukemia from the 1980s to the early 21st century. Blood 113 (7): 1408-11, 2009. [PUBMED Abstract]
- Pui CH, Pei D, Campana D, et al.: Improved prognosis for older adolescents with acute lymphoblastic leukemia. J Clin Oncol 29 (4): 386-91, 2011. [PUBMED Abstract]
- Childhood cancer. In: Howlader N, Noone AM, Krapcho M, et al., eds.: SEER Cancer Statistics Review, 1975-2010. Bethesda, Md: National Cancer Institute, based on November 2012 SEER data submission, posted to the SEER web site, April 2013, Section 28. Also available online. Last accessed November 26, 2013.
- Childhood cancer by the ICCC. In: Howlader N, Noone AM, Krapcho M, et al., eds.: SEER Cancer Statistics Review, 1975-2010. Bethesda, Md: National Cancer Institute, based on November 2012 SEER data submission, posted to the SEER web site, April 2013, Section 29. Also available online. Last accessed November 26, 2013.
- Smith MA, Ries LA, Gurney JG, et al.: Leukemia. In: Ries LA, Smith MA, Gurney JG, et al., eds.: Cancer incidence and survival among children and adolescents: United States SEER Program 1975-1995. Bethesda, Md: National Cancer Institute, SEER Program, 1999. NIH Pub.No. 99-4649., pp 17-34. Also available online. Last accessed November 26, 2013.
- de Bont JM, Holt B, Dekker AW, et al.: Significant difference in outcome for adolescents with acute lymphoblastic leukemia treated on pediatric vs adult protocols in the Netherlands. Leukemia 18 (12): 2032-5, 2004. [PUBMED Abstract]
- Boissel N, Auclerc MF, Lhéritier V, et al.: Should adolescents with acute lymphoblastic leukemia be treated as old children or young adults? Comparison of the French FRALLE-93 and LALA-94 trials. J Clin Oncol 21 (5): 774-80, 2003. [PUBMED Abstract]
- Stock W, La M, Sanford B, et al.: What determines the outcomes for adolescents and young adults with acute lymphoblastic leukemia treated on cooperative group protocols? A comparison of Children's Cancer Group and Cancer and Leukemia Group B studies. Blood 112 (5): 1646-54, 2008. [PUBMED Abstract]
- Goldberg JM, Silverman LB, Levy DE, et al.: Childhood T-cell acute lymphoblastic leukemia: the Dana-Farber Cancer Institute acute lymphoblastic leukemia consortium experience. J Clin Oncol 21 (19): 3616-22, 2003. [PUBMED Abstract]
- Silverman LB, Stevenson KE, O'Brien JE, et al.: Long-term results of Dana-Farber Cancer Institute ALL Consortium protocols for children with newly diagnosed acute lymphoblastic leukemia (1985-2000). Leukemia 24 (2): 320-34, 2010. [PUBMED Abstract]
- Pui CH, Pei D, Sandlund JT, et al.: Long-term results of St Jude Total Therapy Studies 11, 12, 13A, 13B, and 14 for childhood acute lymphoblastic leukemia. Leukemia 24 (2): 371-82, 2010. [PUBMED Abstract]
- Gaynon PS, Angiolillo AL, Carroll WL, et al.: Long-term results of the children's cancer group studies for childhood acute lymphoblastic leukemia 1983-2002: a Children's Oncology Group Report. Leukemia 24 (2): 285-97, 2010. [PUBMED Abstract]
- Möricke A, Zimmermann M, Reiter A, et al.: Long-term results of five consecutive trials in childhood acute lymphoblastic leukemia performed by the ALL-BFM study group from 1981 to 2000. Leukemia 24 (2): 265-84, 2010. [PUBMED Abstract]
- Slack JL, Arthur DC, Lawrence D, et al.: Secondary cytogenetic changes in acute promyelocytic leukemia--prognostic importance in patients treated with chemotherapy alone and association with the intron 3 breakpoint of the PML gene: a Cancer and Leukemia Group B study. J Clin Oncol 15 (5): 1786-95, 1997. [PUBMED Abstract]
- Vaitkevičienė G, Forestier E, Hellebostad M, et al.: High white blood cell count at diagnosis of childhood acute lymphoblastic leukaemia: biological background and prognostic impact. Results from the NOPHO ALL-92 and ALL-2000 studies. Eur J Haematol 86 (1): 38-46, 2011. [PUBMED Abstract]
- Coustan-Smith E, Mullighan CG, Onciu M, et al.: Early T-cell precursor leukaemia: a subtype of very high-risk acute lymphoblastic leukaemia. Lancet Oncol 10 (2): 147-56, 2009. [PUBMED Abstract]
- Bürger B, Zimmermann M, Mann G, et al.: Diagnostic cerebrospinal fluid examination in children with acute lymphoblastic leukemia: significance of low leukocyte counts with blasts or traumatic lumbar puncture. J Clin Oncol 21 (2): 184-8, 2003. [PUBMED Abstract]
- Matloub Y, Bostrom BC, Hunger SP, et al.: Escalating intravenous methotrexate improves event-free survival in children with standard-risk acute lymphoblastic leukemia: a report from the Children's Oncology Group. Blood 118 (2): 243-51, 2011. [PUBMED Abstract]
- Mahmoud HH, Rivera GK, Hancock ML, et al.: Low leukocyte counts with blast cells in cerebrospinal fluid of children with newly diagnosed acute lymphoblastic leukemia. N Engl J Med 329 (5): 314-9, 1993. [PUBMED Abstract]
- Sirvent N, Suciu S, Rialland X, et al.: Prognostic significance of the initial cerebro-spinal fluid (CSF) involvement of children with acute lymphoblastic leukaemia (ALL) treated without cranial irradiation: results of European Organization for Research and Treatment of Cancer (EORTC) Children Leukemia Group study 58881. Eur J Cancer 47 (2): 239-47, 2011. [PUBMED Abstract]
- te Loo DM, Kamps WA, van der Does-van den Berg A, et al.: Prognostic significance of blasts in the cerebrospinal fluid without pleiocytosis or a traumatic lumbar puncture in children with acute lymphoblastic leukemia: experience of the Dutch Childhood Oncology Group. J Clin Oncol 24 (15): 2332-6, 2006. [PUBMED Abstract]
- Gilchrist GS, Tubergen DG, Sather HN, et al.: Low numbers of CSF blasts at diagnosis do not predict for the development of CNS leukemia in children with intermediate-risk acute lymphoblastic leukemia: a Childrens Cancer Group report. J Clin Oncol 12 (12): 2594-600, 1994. [PUBMED Abstract]
- Gajjar A, Harrison PL, Sandlund JT, et al.: Traumatic lumbar puncture at diagnosis adversely affects outcome in childhood acute lymphoblastic leukemia. Blood 96 (10): 3381-4, 2000. [PUBMED Abstract]
- Pui CH, Campana D, Pei D, et al.: Treating childhood acute lymphoblastic leukemia without cranial irradiation. N Engl J Med 360 (26): 2730-41, 2009. [PUBMED Abstract]
- Tubergen DG, Cullen JW, Boyett JM, et al.: Blasts in CSF with a normal cell count do not justify alteration of therapy for acute lymphoblastic leukemia in remission: a Childrens Cancer Group study. J Clin Oncol 12 (2): 273-8, 1994. [PUBMED Abstract]
- Cherlow JM, Sather H, Steinherz P, et al.: Craniospinal irradiation for acute lymphoblastic leukemia with central nervous system disease at diagnosis: a report from the Children's Cancer Group. Int J Radiat Oncol Biol Phys 36 (1): 19-27, 1996. [PUBMED Abstract]
- Hijiya N, Liu W, Sandlund JT, et al.: Overt testicular disease at diagnosis of childhood acute lymphoblastic leukemia: lack of therapeutic role of local irradiation. Leukemia 19 (8): 1399-403, 2005. [PUBMED Abstract]
- Sirvent N, Suciu S, Bertrand Y, et al.: Overt testicular disease (OTD) at diagnosis is not associated with a poor prognosis in childhood acute lymphoblastic leukemia: results of the EORTC CLG Study 58881. Pediatr Blood Cancer 49 (3): 344-8, 2007. [PUBMED Abstract]
- Bassal M, La MK, Whitlock JA, et al.: Lymphoblast biology and outcome among children with Down syndrome and ALL treated on CCG-1952. Pediatr Blood Cancer 44 (1): 21-8, 2005. [PUBMED Abstract]
- Zeller B, Gustafsson G, Forestier E, et al.: Acute leukaemia in children with Down syndrome: a population-based Nordic study. Br J Haematol 128 (6): 797-804, 2005. [PUBMED Abstract]
- Whitlock JA, Sather HN, Gaynon P, et al.: Clinical characteristics and outcome of children with Down syndrome and acute lymphoblastic leukemia: a Children's Cancer Group study. Blood 106 (13): 4043-9, 2005. [PUBMED Abstract]
- Arico M, Ziino O, Valsecchi MG, et al.: Acute lymphoblastic leukemia and Down syndrome: presenting features and treatment outcome in the experience of the Italian Association of Pediatric Hematology and Oncology (AIEOP). Cancer 113 (3): 515-21, 2008. [PUBMED Abstract]
- Maloney KW, Carroll WL, Carroll AJ, et al.: Down syndrome childhood acute lymphoblastic leukemia has a unique spectrum of sentinel cytogenetic lesions that influences treatment outcome: a report from the Children's Oncology Group. Blood 116 (7): 1045-50, 2010. [PUBMED Abstract]
- Mullighan CG, Collins-Underwood JR, Phillips LA, et al.: Rearrangement of CRLF2 in B-progenitor- and Down syndrome-associated acute lymphoblastic leukemia. Nat Genet 41 (11): 1243-6, 2009. [PUBMED Abstract]
- Bercovich D, Ganmore I, Scott LM, et al.: Mutations of JAK2 in acute lymphoblastic leukaemias associated with Down's syndrome. Lancet 372 (9648): 1484-92, 2008. [PUBMED Abstract]
- Gaikwad A, Rye CL, Devidas M, et al.: Prevalence and clinical correlates of JAK2 mutations in Down syndrome acute lymphoblastic leukaemia. Br J Haematol 144 (6): 930-2, 2009. [PUBMED Abstract]
- Kearney L, Gonzalez De Castro D, Yeung J, et al.: Specific JAK2 mutation (JAK2R683) and multiple gene deletions in Down syndrome acute lymphoblastic leukemia. Blood 113 (3): 646-8, 2009. [PUBMED Abstract]
- Buitenkamp TD, Pieters R, Gallimore NE, et al.: Outcome in children with Down's syndrome and acute lymphoblastic leukemia: role of IKZF1 deletions and CRLF2 aberrations. Leukemia 26 (10): 2204-11, 2012. [PUBMED Abstract]
- Pui CH, Boyett JM, Relling MV, et al.: Sex differences in prognosis for children with acute lymphoblastic leukemia. J Clin Oncol 17 (3): 818-24, 1999. [PUBMED Abstract]
- Shuster JJ, Wacker P, Pullen J, et al.: Prognostic significance of sex in childhood B-precursor acute lymphoblastic leukemia: a Pediatric Oncology Group Study. J Clin Oncol 16 (8): 2854-63, 1998. [PUBMED Abstract]
- Chessells JM, Richards SM, Bailey CC, et al.: Gender and treatment outcome in childhood lymphoblastic leukaemia: report from the MRC UKALL trials. Br J Haematol 89 (2): 364-72, 1995. [PUBMED Abstract]
- Silverman LB, Gelber RD, Dalton VK, et al.: Improved outcome for children with acute lymphoblastic leukemia: results of Dana-Farber Consortium Protocol 91-01. Blood 97 (5): 1211-8, 2001. [PUBMED Abstract]
- Hunger SP, Lu X, Devidas M, et al.: Improved survival for children and adolescents with acute lymphoblastic leukemia between 1990 and 2005: a report from the children's oncology group. J Clin Oncol 30 (14): 1663-9, 2012. [PUBMED Abstract]
- Bhatia S: Influence of race and socioeconomic status on outcome of children treated for childhood acute lymphoblastic leukemia. Curr Opin Pediatr 16 (1): 9-14, 2004. [PUBMED Abstract]
- Kadan-Lottick NS, Ness KK, Bhatia S, et al.: Survival variability by race and ethnicity in childhood acute lymphoblastic leukemia. JAMA 290 (15): 2008-14, 2003. [PUBMED Abstract]
- Bhatia S, Landier W, Shangguan M, et al.: Nonadherence to oral mercaptopurine and risk of relapse in Hispanic and non-Hispanic white children with acute lymphoblastic leukemia: a report from the children's oncology group. J Clin Oncol 30 (17): 2094-101, 2012. [PUBMED Abstract]
- Yang JJ, Cheng C, Devidas M, et al.: Ancestry and pharmacogenomics of relapse in acute lymphoblastic leukemia. Nat Genet 43 (3): 237-41, 2011. [PUBMED Abstract]
- Xu H, Cheng C, Devidas M, et al.: ARID5B genetic polymorphisms contribute to racial disparities in the incidence and treatment outcome of childhood acute lymphoblastic leukemia. J Clin Oncol 30 (7): 751-7, 2012. [PUBMED Abstract]
- Bennett JM, Catovsky D, Daniel MT, et al.: The morphological classification of acute lymphoblastic leukaemia: concordance among observers and clinical correlations. Br J Haematol 47 (4): 553-61, 1981. [PUBMED Abstract]
- Swerdlow SH, Campo E, Harris NL, et al., eds.: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. 4th ed. Lyon, France: International Agency for Research on Cancer, 2008.
- Pui CH, Chessells JM, Camitta B, et al.: Clinical heterogeneity in childhood acute lymphoblastic leukemia with 11q23 rearrangements. Leukemia 17 (4): 700-6, 2003. [PUBMED Abstract]
- Möricke A, Ratei R, Ludwig WD, et al.: Prognostic factors in CD10 negative precursor b-cell acute lymphoblastic leukemia in children: data from three consecutive trials ALL-BFM 86, 90, and 95. [Abstract] Blood 104 (11): A-1957, 540a, 2004.
- Hunger SP: Chromosomal translocations involving the E2A gene in acute lymphoblastic leukemia: clinical features and molecular pathogenesis. Blood 87 (4): 1211-24, 1996. [PUBMED Abstract]
- Uckun FM, Sensel MG, Sather HN, et al.: Clinical significance of translocation t(1;19) in childhood acute lymphoblastic leukemia in the context of contemporary therapies: a report from the Children's Cancer Group. J Clin Oncol 16 (2): 527-35, 1998. [PUBMED Abstract]
- Koehler M, Behm FG, Shuster J, et al.: Transitional pre-B-cell acute lymphoblastic leukemia of childhood is associated with favorable prognostic clinical features and an excellent outcome: a Pediatric Oncology Group study. Leukemia 7 (12): 2064-8, 1993. [PUBMED Abstract]
- Attarbaschi A, Mann G, Dworzak M, et al.: Mediastinal mass in childhood T-cell acute lymphoblastic leukemia: significance and therapy response. Med Pediatr Oncol 39 (6): 558-65, 2002. [PUBMED Abstract]
- Armstrong SA, Look AT: Molecular genetics of acute lymphoblastic leukemia. J Clin Oncol 23 (26): 6306-15, 2005. [PUBMED Abstract]
- Karrman K, Forestier E, Heyman M, et al.: Clinical and cytogenetic features of a population-based consecutive series of 285 pediatric T-cell acute lymphoblastic leukemias: rare T-cell receptor gene rearrangements are associated with poor outcome. Genes Chromosomes Cancer 48 (9): 795-805, 2009. [PUBMED Abstract]
- Bergeron J, Clappier E, Radford I, et al.: Prognostic and oncogenic relevance of TLX1/HOX11 expression level in T-ALLs. Blood 110 (7): 2324-30, 2007. [PUBMED Abstract]
- van Grotel M, Meijerink JP, Beverloo HB, et al.: The outcome of molecular-cytogenetic subgroups in pediatric T-cell acute lymphoblastic leukemia: a retrospective study of patients treated according to DCOG or COALL protocols. Haematologica 91 (9): 1212-21, 2006. [PUBMED Abstract]
- Cavé H, Suciu S, Preudhomme C, et al.: Clinical significance of HOX11L2 expression linked to t(5;14)(q35;q32), of HOX11 expression, and of SIL-TAL fusion in childhood T-cell malignancies: results of EORTC studies 58881 and 58951. Blood 103 (2): 442-50, 2004. [PUBMED Abstract]
- Baak U, Gökbuget N, Orawa H, et al.: Thymic adult T-cell acute lymphoblastic leukemia stratified in standard- and high-risk group by aberrant HOX11L2 expression: experience of the German multicenter ALL study group. Leukemia 22 (6): 1154-60, 2008. [PUBMED Abstract]
- Ferrando AA, Neuberg DS, Dodge RK, et al.: Prognostic importance of TLX1 (HOX11) oncogene expression in adults with T-cell acute lymphoblastic leukaemia. Lancet 363 (9408): 535-6, 2004. [PUBMED Abstract]
- Weng AP, Ferrando AA, Lee W, et al.: Activating mutations of NOTCH1 in human T cell acute lymphoblastic leukemia. Science 306 (5694): 269-71, 2004. [PUBMED Abstract]
- Breit S, Stanulla M, Flohr T, et al.: Activating NOTCH1 mutations predict favorable early treatment response and long-term outcome in childhood precursor T-cell lymphoblastic leukemia. Blood 108 (4): 1151-7, 2006. [PUBMED Abstract]
- Kox C, Zimmermann M, Stanulla M, et al.: The favorable effect of activating NOTCH1 receptor mutations on long-term outcome in T-ALL patients treated on the ALL-BFM 2000 protocol can be separated from FBXW7 loss of function. Leukemia 24 (12): 2005-13, 2010. [PUBMED Abstract]
- Jenkinson S, Koo K, Mansour MR, et al.: Impact of NOTCH1/FBXW7 mutations on outcome in pediatric T-cell acute lymphoblastic leukemia patients treated on the MRC UKALL 2003 trial. Leukemia 27 (1): 41-7, 2013. [PUBMED Abstract]
- Larson Gedman A, Chen Q, Kugel Desmoulin S, et al.: The impact of NOTCH1, FBW7 and PTEN mutations on prognosis and downstream signaling in pediatric T-cell acute lymphoblastic leukemia: a report from the Children's Oncology Group. Leukemia 23 (8): 1417-25, 2009. [PUBMED Abstract]
- Zuurbier L, Homminga I, Calvert V, et al.: NOTCH1 and/or FBXW7 mutations predict for initial good prednisone response but not for improved outcome in pediatric T-cell acute lymphoblastic leukemia patients treated on DCOG or COALL protocols. Leukemia 24 (12): 2014-22, 2010. [PUBMED Abstract]
- Clappier E, Collette S, Grardel N, et al.: NOTCH1 and FBXW7 mutations have a favorable impact on early response to treatment, but not on outcome, in children with T-cell acute lymphoblastic leukemia (T-ALL) treated on EORTC trials 58881 and 58951. Leukemia 24 (12): 2023-31, 2010. [PUBMED Abstract]
- Burmeister T, Gökbuget N, Reinhardt R, et al.: NUP214-ABL1 in adult T-ALL: the GMALL study group experience. Blood 108 (10): 3556-9, 2006. [PUBMED Abstract]
- Graux C, Stevens-Kroef M, Lafage M, et al.: Heterogeneous patterns of amplification of the NUP214-ABL1 fusion gene in T-cell acute lymphoblastic leukemia. Leukemia 23 (1): 125-33, 2009. [PUBMED Abstract]
- Hagemeijer A, Graux C: ABL1 rearrangements in T-cell acute lymphoblastic leukemia. Genes Chromosomes Cancer 49 (4): 299-308, 2010. [PUBMED Abstract]
- Quintás-Cardama A, Tong W, Manshouri T, et al.: Activity of tyrosine kinase inhibitors against human NUP214-ABL1-positive T cell malignancies. Leukemia 22 (6): 1117-24, 2008. [PUBMED Abstract]
- Clarke S, O'Reilly J, Romeo G, et al.: NUP214-ABL1 positive T-cell acute lymphoblastic leukemia patient shows an initial favorable response to imatinib therapy post relapse. Leuk Res 35 (7): e131-3, 2011. [PUBMED Abstract]
- Deenik W, Beverloo HB, van der Poel-van de Luytgaarde SC, et al.: Rapid complete cytogenetic remission after upfront dasatinib monotherapy in a patient with a NUP214-ABL1-positive T-cell acute lymphoblastic leukemia. Leukemia 23 (3): 627-9, 2009. [PUBMED Abstract]
- Crombet O, Lastrapes K, Zieske A, et al.: Complete morphologic and molecular remission after introduction of dasatinib in the treatment of a pediatric patient with t-cell acute lymphoblastic leukemia and ABL1 amplification. Pediatr Blood Cancer 59 (2): 333-4, 2012. [PUBMED Abstract]
- Zhang J, Ding L, Holmfeldt L, et al.: The genetic basis of early T-cell precursor acute lymphoblastic leukaemia. Nature 481 (7380): 157-63, 2012. [PUBMED Abstract]
- Ma M, Wang X, Tang J, et al.: Early T-cell precursor leukemia: a subtype of high risk childhood acute lymphoblastic leukemia. Front Med 6 (4): 416-20, 2012. [PUBMED Abstract]
- Inukai T, Kiyokawa N, Campana D, et al.: Clinical significance of early T-cell precursor acute lymphoblastic leukaemia: results of the Tokyo Children's Cancer Study Group Study L99-15. Br J Haematol 156 (3): 358-65, 2012. [PUBMED Abstract]
- Gutierrez A, Dahlberg SE, Neuberg DS, et al.: Absence of biallelic TCRgamma deletion predicts early treatment failure in pediatric T-cell acute lymphoblastic leukemia. J Clin Oncol 28 (24): 3816-23, 2010. [PUBMED Abstract]
- Yang YL, Hsiao CC, Chen HY, et al.: Absence of biallelic TCRγ deletion predicts induction failure and poorer outcomes in childhood T-cell acute lymphoblastic leukemia. Pediatr Blood Cancer 58 (6): 846-51, 2012. [PUBMED Abstract]
- Pui CH, Rubnitz JE, Hancock ML, et al.: Reappraisal of the clinical and biologic significance of myeloid-associated antigen expression in childhood acute lymphoblastic leukemia. J Clin Oncol 16 (12): 3768-73, 1998. [PUBMED Abstract]
- Uckun FM, Sather HN, Gaynon PS, et al.: Clinical features and treatment outcome of children with myeloid antigen positive acute lymphoblastic leukemia: a report from the Children's Cancer Group. Blood 90 (1): 28-35, 1997. [PUBMED Abstract]
- Gerr H, Zimmermann M, Schrappe M, et al.: Acute leukaemias of ambiguous lineage in children: characterization, prognosis and therapy recommendations. Br J Haematol 149 (1): 84-92, 2010. [PUBMED Abstract]
- Rubnitz JE, Onciu M, Pounds S, et al.: Acute mixed lineage leukemia in children: the experience of St Jude Children's Research Hospital. Blood 113 (21): 5083-9, 2009. [PUBMED Abstract]
- Al-Seraihy AS, Owaidah TM, Ayas M, et al.: Clinical characteristics and outcome of children with biphenotypic acute leukemia. Haematologica 94 (12): 1682-90, 2009. [PUBMED Abstract]
- Bene MC, Castoldi G, Knapp W, et al.: Proposals for the immunological classification of acute leukemias. European Group for the Immunological Characterization of Leukemias (EGIL). Leukemia 9 (10): 1783-6, 1995. [PUBMED Abstract]
- Vardiman JW, Thiele J, Arber DA, et al.: The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes. Blood 114 (5): 937-51, 2009. [PUBMED Abstract]
- Borowitz MJ, Béné MC, Harris NL: Acute leukaemias of ambiguous lineage. In: Swerdlow SH, Campo E, Harris NL, et al., eds.: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. 4th ed. Lyon, France: International Agency for Research on Cancer, 2008, pp 150-5.
- Matutes E, Pickl WF, Van't Veer M, et al.: Mixed-phenotype acute leukemia: clinical and laboratory features and outcome in 100 patients defined according to the WHO 2008 classification. Blood 117 (11): 3163-71, 2011. [PUBMED Abstract]
- Moorman AV, Ensor HM, Richards SM, et al.: Prognostic effect of chromosomal abnormalities in childhood B-cell precursor acute lymphoblastic leukaemia: results from the UK Medical Research Council ALL97/99 randomised trial. Lancet Oncol 11 (5): 429-38, 2010. [PUBMED Abstract]
- Paulsson K, Johansson B: High hyperdiploid childhood acute lymphoblastic leukemia. Genes Chromosomes Cancer 48 (8): 637-60, 2009. [PUBMED Abstract]
- Aricò M, Valsecchi MG, Rizzari C, et al.: Long-term results of the AIEOP-ALL-95 Trial for Childhood Acute Lymphoblastic Leukemia: insight on the prognostic value of DNA index in the framework of Berlin-Frankfurt-Muenster based chemotherapy. J Clin Oncol 26 (2): 283-9, 2008. [PUBMED Abstract]
- Synold TW, Relling MV, Boyett JM, et al.: Blast cell methotrexate-polyglutamate accumulation in vivo differs by lineage, ploidy, and methotrexate dose in acute lymphoblastic leukemia. J Clin Invest 94 (5): 1996-2001, 1994. [PUBMED Abstract]
- Moorman AV, Richards SM, Martineau M, et al.: Outcome heterogeneity in childhood high-hyperdiploid acute lymphoblastic leukemia. Blood 102 (8): 2756-62, 2003. [PUBMED Abstract]
- Sutcliffe MJ, Shuster JJ, Sather HN, et al.: High concordance from independent studies by the Children's Cancer Group (CCG) and Pediatric Oncology Group (POG) associating favorable prognosis with combined trisomies 4, 10, and 17 in children with NCI Standard-Risk B-precursor Acute Lymphoblastic Leukemia: a Children's Oncology Group (COG) initiative. Leukemia 19 (5): 734-40, 2005. [PUBMED Abstract]
- Harris MB, Shuster JJ, Carroll A, et al.: Trisomy of leukemic cell chromosomes 4 and 10 identifies children with B-progenitor cell acute lymphoblastic leukemia with a very low risk of treatment failure: a Pediatric Oncology Group study. Blood 79 (12): 3316-24, 1992. [PUBMED Abstract]
- Heerema NA, Harbott J, Galimberti S, et al.: Secondary cytogenetic aberrations in childhood Philadelphia chromosome positive acute lymphoblastic leukemia are nonrandom and may be associated with outcome. Leukemia 18 (4): 693-702, 2004. [PUBMED Abstract]
- Nachman JB, Heerema NA, Sather H, et al.: Outcome of treatment in children with hypodiploid acute lymphoblastic leukemia. Blood 110 (4): 1112-5, 2007. [PUBMED Abstract]
- Raimondi SC, Zhou Y, Shurtleff SA, et al.: Near-triploidy and near-tetraploidy in childhood acute lymphoblastic leukemia: association with B-lineage blast cells carrying the ETV6-RUNX1 fusion, T-lineage immunophenotype, and favorable outcome. Cancer Genet Cytogenet 169 (1): 50-7, 2006. [PUBMED Abstract]
- Attarbaschi A, Mann G, König M, et al.: Incidence and relevance of secondary chromosome abnormalities in childhood TEL/AML1+ acute lymphoblastic leukemia: an interphase FISH analysis. Leukemia 18 (10): 1611-6, 2004. [PUBMED Abstract]
- Lemez P, Attarbaschi A, Béné MC, et al.: Childhood near-tetraploid acute lymphoblastic leukemia: an EGIL study on 36 cases. Eur J Haematol 85 (4): 300-8, 2010. [PUBMED Abstract]
- Harrison CJ, Moorman AV, Broadfield ZJ, et al.: Three distinct subgroups of hypodiploidy in acute lymphoblastic leukaemia. Br J Haematol 125 (5): 552-9, 2004. [PUBMED Abstract]
- Holmfeldt L, Wei L, Diaz-Flores E, et al.: The genomic landscape of hypodiploid acute lymphoblastic leukemia. Nat Genet 45 (3): 242-52, 2013. [PUBMED Abstract]
- Rubnitz JE, Wichlan D, Devidas M, et al.: Prospective analysis of TEL gene rearrangements in childhood acute lymphoblastic leukemia: a Children's Oncology Group study. J Clin Oncol 26 (13): 2186-91, 2008. [PUBMED Abstract]
- Kanerva J, Saarinen-Pihkala UM, Niini T, et al.: Favorable outcome in 20-year follow-up of children with very-low-risk ALL and minimal standard therapy, with special reference to TEL-AML1 fusion. Pediatr Blood Cancer 42 (1): 30-5, 2004. [PUBMED Abstract]
- Aldrich MC, Zhang L, Wiemels JL, et al.: Cytogenetics of Hispanic and White children with acute lymphoblastic leukemia in California. Cancer Epidemiol Biomarkers Prev 15 (3): 578-81, 2006. [PUBMED Abstract]
- Loh ML, Goldwasser MA, Silverman LB, et al.: Prospective analysis of TEL/AML1-positive patients treated on Dana-Farber Cancer Institute Consortium Protocol 95-01. Blood 107 (11): 4508-13, 2006. [PUBMED Abstract]
- Borowitz MJ, Devidas M, Hunger SP, et al.: Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study. Blood 111 (12): 5477-85, 2008. [PUBMED Abstract]
- Madzo J, Zuna J, Muzíková K, et al.: Slower molecular response to treatment predicts poor outcome in patients with TEL/AML1 positive acute lymphoblastic leukemia: prospective real-time quantitative reverse transcriptase-polymerase chain reaction study. Cancer 97 (1): 105-13, 2003. [PUBMED Abstract]
- Bhojwani D, Pei D, Sandlund JT, et al.: ETV6-RUNX1-positive childhood acute lymphoblastic leukemia: improved outcome with contemporary therapy. Leukemia 26 (2): 265-70, 2012. [PUBMED Abstract]
- Forestier E, Heyman M, Andersen MK, et al.: Outcome of ETV6/RUNX1-positive childhood acute lymphoblastic leukaemia in the NOPHO-ALL-1992 protocol: frequent late relapses but good overall survival. Br J Haematol 140 (6): 665-72, 2008. [PUBMED Abstract]
- Seeger K, Stackelberg AV, Taube T, et al.: Relapse of TEL-AML1--positive acute lymphoblastic leukemia in childhood: a matched-pair analysis. J Clin Oncol 19 (13): 3188-93, 2001. [PUBMED Abstract]
- Gandemer V, Chevret S, Petit A, et al.: Excellent prognosis of late relapses of ETV6/RUNX1-positive childhood acute lymphoblastic leukemia: lessons from the FRALLE 93 protocol. Haematologica 97 (11): 1743-50, 2012. [PUBMED Abstract]
- Zuna J, Ford AM, Peham M, et al.: TEL deletion analysis supports a novel view of relapse in childhood acute lymphoblastic leukemia. Clin Cancer Res 10 (16): 5355-60, 2004. [PUBMED Abstract]
- van Delft FW, Horsley S, Colman S, et al.: Clonal origins of relapse in ETV6-RUNX1 acute lymphoblastic leukemia. Blood 117 (23): 6247-54, 2011. [PUBMED Abstract]
- Aricò M, Schrappe M, Hunger SP, et al.: Clinical outcome of children with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia treated between 1995 and 2005. J Clin Oncol 28 (31): 4755-61, 2010. [PUBMED Abstract]
- Schrappe M, Aricò M, Harbott J, et al.: Philadelphia chromosome-positive (Ph+) childhood acute lymphoblastic leukemia: good initial steroid response allows early prediction of a favorable treatment outcome. Blood 92 (8): 2730-41, 1998. [PUBMED Abstract]
- Ribeiro RC, Broniscer A, Rivera GK, et al.: Philadelphia chromosome-positive acute lymphoblastic leukemia in children: durable responses to chemotherapy associated with low initial white blood cell counts. Leukemia 11 (9): 1493-6, 1997. [PUBMED Abstract]
- Biondi A, Schrappe M, De Lorenzo P, et al.: Imatinib after induction for treatment of children and adolescents with Philadelphia-chromosome-positive acute lymphoblastic leukaemia (EsPhALL): a randomised, open-label, intergroup study. Lancet Oncol 13 (9): 936-45, 2012. [PUBMED Abstract]
- Schultz KR, Bowman WP, Aledo A, et al.: Improved early event-free survival with imatinib in Philadelphia chromosome-positive acute lymphoblastic leukemia: a children's oncology group study. J Clin Oncol 27 (31): 5175-81, 2009. [PUBMED Abstract]
- Johansson B, Moorman AV, Haas OA, et al.: Hematologic malignancies with t(4;11)(q21;q23)--a cytogenetic, morphologic, immunophenotypic and clinical study of 183 cases. European 11q23 Workshop participants. Leukemia 12 (5): 779-87, 1998. [PUBMED Abstract]
- Raimondi SC, Peiper SC, Kitchingman GR, et al.: Childhood acute lymphoblastic leukemia with chromosomal breakpoints at 11q23. Blood 73 (6): 1627-34, 1989. [PUBMED Abstract]
- Harrison CJ, Moorman AV, Barber KE, et al.: Interphase molecular cytogenetic screening for chromosomal abnormalities of prognostic significance in childhood acute lymphoblastic leukaemia: a UK Cancer Cytogenetics Group Study. Br J Haematol 129 (4): 520-30, 2005. [PUBMED Abstract]
- Pui CH, Gaynon PS, Boyett JM, et al.: Outcome of treatment in childhood acute lymphoblastic leukaemia with rearrangements of the 11q23 chromosomal region. Lancet 359 (9321): 1909-15, 2002. [PUBMED Abstract]
- Rubnitz JE, Camitta BM, Mahmoud H, et al.: Childhood acute lymphoblastic leukemia with the MLL-ENL fusion and t(11;19)(q23;p13.3) translocation. J Clin Oncol 17 (1): 191-6, 1999. [PUBMED Abstract]
- Pui CH, Sandlund JT, Pei D, et al.: Results of therapy for acute lymphoblastic leukemia in black and white children. JAMA 290 (15): 2001-7, 2003. [PUBMED Abstract]
- Crist WM, Carroll AJ, Shuster JJ, et al.: Poor prognosis of children with pre-B acute lymphoblastic leukemia is associated with the t(1;19)(q23;p13): a Pediatric Oncology Group study. Blood 76 (1): 117-22, 1990. [PUBMED Abstract]
- Andersen MK, Autio K, Barbany G, et al.: Paediatric B-cell precursor acute lymphoblastic leukaemia with t(1;19)(q23;p13): clinical and cytogenetic characteristics of 47 cases from the Nordic countries treated according to NOPHO protocols. Br J Haematol 155 (2): 235-43, 2011. [PUBMED Abstract]
- Jeha S, Pei D, Raimondi SC, et al.: Increased risk for CNS relapse in pre-B cell leukemia with the t(1;19)/TCF3-PBX1. Leukemia 23 (8): 1406-9, 2009. [PUBMED Abstract]
- Harvey RC, Mullighan CG, Wang X, et al.: Identification of novel cluster groups in pediatric high-risk B-precursor acute lymphoblastic leukemia with gene expression profiling: correlation with genome-wide DNA copy number alterations, clinical characteristics, and outcome. Blood 116 (23): 4874-84, 2010. [PUBMED Abstract]
- Zhang J, Mullighan CG, Harvey RC, et al.: Key pathways are frequently mutated in high-risk childhood acute lymphoblastic leukemia: a report from the Children's Oncology Group. Blood 118 (11): 3080-7, 2011. [PUBMED Abstract]
- Hunger SP, Raetz EA, Loh ML, et al.: Improving outcomes for high-risk ALL: translating new discoveries into clinical care. Pediatr Blood Cancer 56 (6): 984-93, 2011. [PUBMED Abstract]
- Chen IM, Harvey RC, Mullighan CG, et al.: Outcome modeling with CRLF2, IKZF1, JAK, and minimal residual disease in pediatric acute lymphoblastic leukemia: a Children's Oncology Group study. Blood 119 (15): 3512-22, 2012. [PUBMED Abstract]
- Pui CH, Mullighan CG, Evans WE, et al.: Pediatric acute lymphoblastic leukemia: where are we going and how do we get there? Blood 120 (6): 1165-74, 2012. [PUBMED Abstract]
- Roberts KG, Morin RD, Zhang J, et al.: Genetic alterations activating kinase and cytokine receptor signaling in high-risk acute lymphoblastic leukemia. Cancer Cell 22 (2): 153-66, 2012. [PUBMED Abstract]
- Mullighan CG: Molecular genetics of B-precursor acute lymphoblastic leukemia. J Clin Invest 122 (10): 3407-15, 2012. [PUBMED Abstract]
- Moorman AV, Richards SM, Robinson HM, et al.: Prognosis of children with acute lymphoblastic leukemia (ALL) and intrachromosomal amplification of chromosome 21 (iAMP21). Blood 109 (6): 2327-30, 2007. [PUBMED Abstract]
- Attarbaschi A, Mann G, Panzer-Grümayer R, et al.: Minimal residual disease values discriminate between low and high relapse risk in children with B-cell precursor acute lymphoblastic leukemia and an intrachromosomal amplification of chromosome 21: the Austrian and German acute lymphoblastic leukemia Berlin-Frankfurt-Munster (ALL-BFM) trials. J Clin Oncol 26 (18): 3046-50, 2008. [PUBMED Abstract]
- Mullighan CG, Goorha S, Radtke I, et al.: Genome-wide analysis of genetic alterations in acute lymphoblastic leukaemia. Nature 446 (7137): 758-64, 2007. [PUBMED Abstract]
- Schwab CJ, Chilton L, Morrison H, et al.: Genes commonly deleted in childhood B-cell precursor acute lymphoblastic leukemia: association with cytogenetics and clinical features. Haematologica 98 (7): 1081-8, 2013. [PUBMED Abstract]
- Mullighan CG, Miller CB, Radtke I, et al.: BCR-ABL1 lymphoblastic leukaemia is characterized by the deletion of Ikaros. Nature 453 (7191): 110-4, 2008. [PUBMED Abstract]
- Den Boer ML, van Slegtenhorst M, De Menezes RX, et al.: A subtype of childhood acute lymphoblastic leukaemia with poor treatment outcome: a genome-wide classification study. Lancet Oncol 10 (2): 125-34, 2009. [PUBMED Abstract]
- Mullighan CG, Su X, Zhang J, et al.: Deletion of IKZF1 and prognosis in acute lymphoblastic leukemia. N Engl J Med 360 (5): 470-80, 2009. [PUBMED Abstract]
- Krentz S, Hof J, Mendioroz A, et al.: Prognostic value of genetic alterations in children with first bone marrow relapse of childhood B-cell precursor acute lymphoblastic leukemia. Leukemia 27 (2): 295-304, 2013. [PUBMED Abstract]
- Feng J, Tang Y: Prognostic significance of IKZF1 alteration status in pediatric B-lineage acute lymphoblastic leukemia: a meta-analysis. Leuk Lymphoma 54 (4): 889-91, 2013. [PUBMED Abstract]
- Cario G, Zimmermann M, Romey R, et al.: Presence of the P2RY8-CRLF2 rearrangement is associated with a poor prognosis in non-high-risk precursor B-cell acute lymphoblastic leukemia in children treated according to the ALL-BFM 2000 protocol. Blood 115 (26): 5393-7, 2010. [PUBMED Abstract]
- Ensor HM, Schwab C, Russell LJ, et al.: Demographic, clinical, and outcome features of children with acute lymphoblastic leukemia and CRLF2 deregulation: results from the MRC ALL97 clinical trial. Blood 117 (7): 2129-36, 2011. [PUBMED Abstract]
- Harvey RC, Mullighan CG, Chen IM, et al.: Rearrangement of CRLF2 is associated with mutation of JAK kinases, alteration of IKZF1, Hispanic/Latino ethnicity, and a poor outcome in pediatric B-progenitor acute lymphoblastic leukemia. Blood 115 (26): 5312-21, 2010. [PUBMED Abstract]
- Loh ML, Zhang J, Harvey RC, et al.: Tyrosine kinome sequencing of pediatric acute lymphoblastic leukemia: a report from the Children's Oncology Group TARGET Project. Blood 121 (3): 485-8, 2013. [PUBMED Abstract]
- Palmi C, Vendramini E, Silvestri D, et al.: Poor prognosis for P2RY8-CRLF2 fusion but not for CRLF2 over-expression in children with intermediate risk B-cell precursor acute lymphoblastic leukemia. Leukemia 26 (10): 2245-53, 2012. [PUBMED Abstract]
- Davies SM, Bhatia S, Ross JA, et al.: Glutathione S-transferase genotypes, genetic susceptibility, and outcome of therapy in childhood acute lymphoblastic leukemia. Blood 100 (1): 67-71, 2002. [PUBMED Abstract]
- Krajinovic M, Costea I, Chiasson S: Polymorphism of the thymidylate synthase gene and outcome of acute lymphoblastic leukaemia. Lancet 359 (9311): 1033-4, 2002. [PUBMED Abstract]
- Krajinovic M, Lemieux-Blanchard E, Chiasson S, et al.: Role of polymorphisms in MTHFR and MTHFD1 genes in the outcome of childhood acute lymphoblastic leukemia. Pharmacogenomics J 4 (1): 66-72, 2004. [PUBMED Abstract]
- Schmiegelow K, Forestier E, Kristinsson J, et al.: Thiopurine methyltransferase activity is related to the risk of relapse of childhood acute lymphoblastic leukemia: results from the NOPHO ALL-92 study. Leukemia 23 (3): 557-64, 2009. [PUBMED Abstract]
- Relling MV, Hancock ML, Boyett JM, et al.: Prognostic importance of 6-mercaptopurine dose intensity in acute lymphoblastic leukemia. Blood 93 (9): 2817-23, 1999. [PUBMED Abstract]
- Stanulla M, Schaeffeler E, Flohr T, et al.: Thiopurine methyltransferase (TPMT) genotype and early treatment response to mercaptopurine in childhood acute lymphoblastic leukemia. JAMA 293 (12): 1485-9, 2005. [PUBMED Abstract]
- Yang JJ, Cheng C, Yang W, et al.: Genome-wide interrogation of germline genetic variation associated with treatment response in childhood acute lymphoblastic leukemia. JAMA 301 (4): 393-403, 2009. [PUBMED Abstract]
- Gregers J, Christensen IJ, Dalhoff K, et al.: The association of reduced folate carrier 80G>A polymorphism to outcome in childhood acute lymphoblastic leukemia interacts with chromosome 21 copy number. Blood 115 (23): 4671-7, 2010. [PUBMED Abstract]
- Relling MV, Dervieux T: Pharmacogenetics and cancer therapy. Nat Rev Cancer 1 (2): 99-108, 2001. [PUBMED Abstract]
- van Dongen JJ, Seriu T, Panzer-Grümayer ER, et al.: Prognostic value of minimal residual disease in acute lymphoblastic leukaemia in childhood. Lancet 352 (9142): 1731-8, 1998. [PUBMED Abstract]
- Zhou J, Goldwasser MA, Li A, et al.: Quantitative analysis of minimal residual disease predicts relapse in children with B-lineage acute lymphoblastic leukemia in DFCI ALL Consortium Protocol 95-01. Blood 110 (5): 1607-11, 2007. [PUBMED Abstract]
- Coustan-Smith E, Sancho J, Hancock ML, et al.: Use of peripheral blood instead of bone marrow to monitor residual disease in children with acute lymphoblastic leukemia. Blood 100 (7): 2399-402, 2002. [PUBMED Abstract]
- Yamaji K, Okamoto T, Yokota S, et al.: Minimal residual disease-based augmented therapy in childhood acute lymphoblastic leukemia: a report from the Japanese Childhood Cancer and Leukemia Study Group. Pediatr Blood Cancer 55 (7): 1287-95, 2010. [PUBMED Abstract]
- Conter V, Bartram CR, Valsecchi MG, et al.: Molecular response to treatment redefines all prognostic factors in children and adolescents with B-cell precursor acute lymphoblastic leukemia: results in 3184 patients of the AIEOP-BFM ALL 2000 study. Blood 115 (16): 3206-14, 2010. [PUBMED Abstract]
- Stow P, Key L, Chen X, et al.: Clinical significance of low levels of minimal residual disease at the end of remission induction therapy in childhood acute lymphoblastic leukemia. Blood 115 (23): 4657-63, 2010. [PUBMED Abstract]
- Basso G, Veltroni M, Valsecchi MG, et al.: Risk of relapse of childhood acute lymphoblastic leukemia is predicted by flow cytometric measurement of residual disease on day 15 bone marrow. J Clin Oncol 27 (31): 5168-74, 2009. [PUBMED Abstract]
- Panzer-Grümayer ER, Schneider M, Panzer S, et al.: Rapid molecular response during early induction chemotherapy predicts a good outcome in childhood acute lymphoblastic leukemia. Blood 95 (3): 790-4, 2000. [PUBMED Abstract]
- Coustan-Smith E, Sancho J, Behm FG, et al.: Prognostic importance of measuring early clearance of leukemic cells by flow cytometry in childhood acute lymphoblastic leukemia. Blood 100 (1): 52-8, 2002. [PUBMED Abstract]
- Schrappe M, Valsecchi MG, Bartram CR, et al.: Late MRD response determines relapse risk overall and in subsets of childhood T-cell ALL: results of the AIEOP-BFM-ALL 2000 study. Blood 118 (8): 2077-84, 2011. [PUBMED Abstract]
- Biojone E, Queiróz Rde P, Valera ET, et al.: Minimal residual disease in cerebrospinal fluid at diagnosis: a more intensive treatment protocol was able to eliminate the adverse prognosis in children with acute lymphoblastic leukemia. Leuk Lymphoma 53 (1): 89-95, 2012. [PUBMED Abstract]
- Vora A, Goulden N, Wade R, et al.: Treatment reduction for children and young adults with low-risk acute lymphoblastic leukaemia defined by minimal residual disease (UKALL 2003): a randomised controlled trial. Lancet Oncol 14 (3): 199-209, 2013. [PUBMED Abstract]
- Gaynon PS, Desai AA, Bostrom BC, et al.: Early response to therapy and outcome in childhood acute lymphoblastic leukemia: a review. Cancer 80 (9): 1717-26, 1997. [PUBMED Abstract]
- Borowitz MJ, Wood BL, Devidas M, et al.: Assessment of end induction minimal residual disease (MRD) in childhood B precursor acute lymphoblastic leukemia (ALL) to eliminate the need for day 14 marrow examination: A Children’s Oncology Group study. [Abstract] J Clin Oncol 31 (Suppl 15): A-10001, 2013. Also available online. Last accessed November 26, 2013.
- Möricke A, Reiter A, Zimmermann M, et al.: Risk-adjusted therapy of acute lymphoblastic leukemia can decrease treatment burden and improve survival: treatment results of 2169 unselected pediatric and adolescent patients enrolled in the trial ALL-BFM 95. Blood 111 (9): 4477-89, 2008. [PUBMED Abstract]
- Griffin TC, Shuster JJ, Buchanan GR, et al.: Slow disappearance of peripheral blood blasts is an adverse prognostic factor in childhood T cell acute lymphoblastic leukemia: a Pediatric Oncology Group study. Leukemia 14 (5): 792-5, 2000. [PUBMED Abstract]
- Volejnikova J, Mejstrikova E, Valova T, et al.: Minimal residual disease in peripheral blood at day 15 identifies a subgroup of childhood B-cell precursor acute lymphoblastic leukemia with superior prognosis. Haematologica 96 (12): 1815-21, 2011. [PUBMED Abstract]
- Schrappe M, Hunger SP, Pui CH, et al.: Outcomes after induction failure in childhood acute lymphoblastic leukemia. N Engl J Med 366 (15): 1371-81, 2012. [PUBMED Abstract]
- Silverman LB, Gelber RD, Young ML, et al.: Induction failure in acute lymphoblastic leukemia of childhood. Cancer 85 (6): 1395-404, 1999. [PUBMED Abstract]
- Oudot C, Auclerc MF, Levy V, et al.: Prognostic factors for leukemic induction failure in children with acute lymphoblastic leukemia and outcome after salvage therapy: the FRALLE 93 study. J Clin Oncol 26 (9): 1496-503, 2008. [PUBMED Abstract]
- Moghrabi A, Levy DE, Asselin B, et al.: Results of the Dana-Farber Cancer Institute ALL Consortium Protocol 95-01 for children with acute lymphoblastic leukemia. Blood 109 (3): 896-904, 2007. [PUBMED Abstract]
- Veerman AJ, Kamps WA, van den Berg H, et al.: Dexamethasone-based therapy for childhood acute lymphoblastic leukaemia: results of the prospective Dutch Childhood Oncology Group (DCOG) protocol ALL-9 (1997-2004). Lancet Oncol 10 (10): 957-66, 2009. [PUBMED Abstract]
- Balduzzi A, Valsecchi MG, Uderzo C, et al.: Chemotherapy versus allogeneic transplantation for very-high-risk childhood acute lymphoblastic leukaemia in first complete remission: comparison by genetic randomisation in an international prospective study. Lancet 366 (9486): 635-42, 2005 Aug 20-26. [PUBMED Abstract]
- Schrauder A, Reiter A, Gadner H, et al.: Superiority of allogeneic hematopoietic stem-cell transplantation compared with chemotherapy alone in high-risk childhood T-cell acute lymphoblastic leukemia: results from ALL-BFM 90 and 95. J Clin Oncol 24 (36): 5742-9, 2006. [PUBMED Abstract]
- Ribera JM, Ortega JJ, Oriol A, et al.: Comparison of intensive chemotherapy, allogeneic, or autologous stem-cell transplantation as postremission treatment for children with very high risk acute lymphoblastic leukemia: PETHEMA ALL-93 Trial. J Clin Oncol 25 (1): 16-24, 2007. [PUBMED Abstract]