Approximately half a million women in the United States alone currently take the drug tamoxifen, either as an adjuvant therapy for preinvasive or invasive breast cancer, or as a chemopreventive agent for those at high risk of the disease.

Now, a new study led by Dr. Matthew Goetz, an investigator for the Breast Cancer Specialized Program of Research Excellence (SPORE) at the Mayo Clinic, has shown that up to 10 percent of women taking the drug may not receive the intended benefit due to genetic differences in the way tamoxifen is metabolized. Additionally, a larger percentage of women may be at increased risk of treatment failure because of drug interactions. Read more  

NCI is moving on a number of fronts to harness the power of new genomic technology through epidemiologic studies designed to uncover gene variants that contribute to cancer susceptibility. Findings from NCI's portfolio of family studies have formed the basis for our understanding of many high-penetrant cancer-causing mutations. These rare mutations give unprecedented insights into carcinogenic mechanisms, but are responsible for only a small proportion of all cancer. Most cancer risk is believed to be due to gene-environment interactions involving low-penetrant but common genetic variants or single nucleotide polymorphisms (SNPs). Read more  

The NCI Cancer Bulletin is produced by the National Cancer Institute (NCI). NCI, which was established in 1937, leads the national effort to eliminate the suffering and death due to cancer. Through basic, clinical, and population-based biomedical research and training, NCI conducts and supports research that will lead to a future in which we can identify the environmental and genetic causes of cancer, prevent cancer before it starts, identify cancers that do develop at the earliest stage, eliminate cancers through innovative treatment interventions, and biologically control those cancers that we cannot eliminate so they become manageable, chronic diseases. For more information on cancer, call 1-800-4-CANCER or visit http://www.cancer.gov. NCI Cancer Bulletin staff can be reached at ncicancerbulletin@mail.nih.gov.