NCI Cancer Bulletin: A Trusted Source for Cancer Research NewsNCI Cancer Bulletin: A Trusted Source for Cancer Research News
October 5, 2004 • Volume 1 / Number 38 E-Mail This Document  |  Download PDF  |  Bulletin Archive/Search  |  Subscribe

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Cancer Research HighlightsCancer Research Highlights

Hodgkin's Survivor Gives Birth Following Ovarian Tissue Implant

For the first time, a woman who became sterile as a result of chemotherapy has given birth to a healthy baby following implantation of her own ovarian tissue, which had been cryopreserved before she underwent chemotherapy. The baby girl was born on September 23, approximately 7 years after the 32-year-old Belgian woman's initial chemotherapy treatment for Hodgkin's disease and 3 years after she had been cleared by her oncologists as disease free. "Our findings open new perspectives for young cancer patients facing premature ovarian failure," said lead investigator Dr. Jacques Donnez of the Catholic University of Louvain in Brussels. A report on the procedure that led to the birth was published on The Lancet Web site on September 24.

The patient presented with clinical stage IV Hodgkin's disease in 1997. Dr. Donnez's team took five biopsy samples via laparoscopy from the left ovary (12-15 mm long and 5 mm wide). One tissue strip was kept intact, while the remaining four were cut into smaller cubes. The tissue was frozen and stored for 7 years. Seven days before the actual tissue implantation, the team surgically created a small pocket, or "peritoneal window," near the woman's right ovary. "The goal was to induce angiogenesis and neovascularization in this area," the authors explained. A week later, some of the thawed tissue samples were implanted. The remaining samples were implanted after 4 months, with signs of ovulatory activity several months later. In early 2004, the patient became pregnant by natural means.

Although the authors acknowledged there is a chance that the pregnancy did not originate from the transplanted tissue, they offered several lines of evidence to support that it was. In addition, they stressed that the procedure presents some ethical and medical considerations that must be addressed. "One major the potential risk that the frozen-thawed ovarian tissue might harbor malignant cells, which could induce a recurrence of disease after transplantation," they wrote in the paper. "Screening methods to detect minimal residual disease must be developed to eliminate risk of cancer cell transmission with reimplantation."

Artificial Neural Networks Can Predict Clinical Outcomes of Neuroblastoma Patients

Researchers at NCI, in collaboration with colleagues from Germany and Australia, have used artificial neural networks (ANNs) to successfully predict the clinical outcomes of patients diagnosed with neuroblastoma (NB). They also used the ANNs to identify a set of 19 genes whose expression levels were closely associated with outcome. The study, which appears in the October 1 Cancer Research, suggests the predictive power of ANNs could assist physicians in the treatment of individual patients, especially those considered high risk.

Dr. Javed Khan and his team at NCI's Pediatric Oncology Branch first used cDNA microarrays containing over 25,000 genes to create gene expression profiles of primary tumors from 49 NB patients with a known clinical outcome: good (event-free survival for more than 3 years) or poor (death due to disease). Next, they adapted an ANN algorithm - a specialized pattern recognition program modeled after the human brain - to identify patterns in tumor gene expression. They found that the ANN could predict the clinical outcome from any individual gene profile with about 88 percent accuracy. The researchers then optimized the profiles and found 19 genes whose expression could act as a predictor set. Using only these 19 genes, ANN accuracy increased to 95 percent.

"What was most exciting was that we were able to predict which high-risk patients would have good or poor outcomes," said Dr. Khan. "This has major clinical implications, since we are now able to distinguish a group of ultra-high-risk patients who will not respond to conventional therapy and therefore require alternative treatment. We may also be able to reduce the intensity of the treatment regimen to high-risk patients predicted to survive based on their gene expression profiles."

"Because we are using 19 genes instead of 25,000," he added, "we can translate our findings to the clinic because simple prognostic assays can be developed quickly, based on this small number of genes."

Antioxidant Supplements May Not Prevent GI Cancers

Populations with diets rich in antioxidants from fruits and vegetables show low rates of cancer and heart disease. But in a recent analysis of studies from the last 20 years involving people considered to be at high risk for gastrointestinal (GI) cancers, there was no significant link between antioxidant nutritional supplements and the prevention of digestive cancers. The study, sponsored by Denmark's Knowledge and Research Center for Alternative Medicine and the Copenhagen Trial Unit at the Centre for Clinical Intervention Research, is published in the October 2 issue of The Lancet.

The research team, led by Dr. Goran Bjelakovic of the University of Nis in Serbia and Montenegro, and colleagues at the Cochrane Hepato-Biliary Group, looked at 14 randomized trials that jointly involved more than 170,000 participants, where the supplements beta-carotene, vitamins A, C, and E, and selenium were compared, either alone or in combination, against a placebo. The results showed no link between antioxidants and digestive cancer prevention and, in half of the trials, there was a small increase in mortality among people who took the antioxidant supplements. Four of the trials, however, did show a possible link between selenium supplements and decreased risk for digestive cancers.

In an interview with the Associated Press, Dr. Bjelakovic deemed antioxidant pills (excepting selenium) as "useless for prevention of gastrointestinal cancers." But this type of analysis can be misleading, notes Dr. Peter Greenwald, director of NCI's Division of Cancer Prevention. "Analyzing all types of GI cancers together, when they have differing etiologic factors, is an oversimplification," says Dr. Greenwald. "When you look at the studies in each organ site, the relative risk for gastric cancer suggests a slight increase in risk from supplements, while the relative risk for colorectal cancer shows a tendency toward a decrease in risk." None of the results are statistically significant, but those trends suggest that antioxidant supplements may yet be useful in some kinds of GI cancers, he notes.