Breast Cancer: Research On Tamoxifen Leads To Recommendation For CYP2D6 Gene Test
Posted Dec 20 2008 5:42pm
Findings from a new study have prompted Mayo Clinic researchers to recommend CYP2D6 gene testing for postmenopausal women about to begin tamoxifen therapy. This data confirms that women with an inherited deficiency in the CYP2D6 gene, which is important for the metabolism of tamoxifen, have a nearly fourfold higher risk of early breast cancer recurrence compared to women who have not inherited the deficiency.
The research findings, announced jointly by investigators from Mayo Clinic and the Austrian Breast and Colorectal Cancer Study Group (ABCSG) confirmed results from a previous study conducted by Mayo Clinic. The latest findings will be presented December 13 at the Cancer Therapy & Research Center-American Association for Cancer Research (CTRC-AACR) 31st annual San Antonio Breast Cancer Symposium.
Tamoxifen, approved by the Food and Drug Administration (FDA) to both prevent development of estrogen-receptor-positive (ER+) breast cancer and as a therapy to stop ER+ breast cancer from coming back, is a “pro-drug”; it must be metabolized in the liver to become active. Mayo researchers had previously discovered that the drug is less effective in postmenopausal breast cancer patients who had a deficiency in the CYP2D6 gene, which is key for activating tamoxifen and many other drugs. However, until now, testing for the gene has not been done routinely at most medical centers.