Mayo Clinic research on tamoxifen leads to recommendation for CYP2D6...( SAN ANTONIO - Findings from a new st...)

SAN ANTONIO - 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.

VIDEO ALERT: Additional audio and video resources, including excerpts from an interview with Dr. Goetz describing the research, are available on the Mayo Clinic News Blog http://newsblog.mayoclinic.org/2008/12/11/gene-testing-may-be-key-for-treating-some-women-with-breast-cancer/, with password: sabcs08g.

The latest findings will be presented today 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.

"These new results validate our earlier findings," says the study's lead investigator, Matthew Go
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