Soy Food Intake, Tamoxifen Use, Estrogen Receptor Polymorphism, and Breast Cancer Survival
Annual summary rept. 30 Jun 2004-29 Jun 2005
VANDERBILT UNIV NASHVILLE TN
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There is a strong biological rationale suggesting that soy foods may be important to breast cancer survival. However, this hypothesis has not been adequately tested in epidemiological studies. Soy foods contain isoflavones, a group of phytoestrogens that compete with endogenous estrogens to selectively bind to the estrogen receptor. Tamoxifen, a commonly administered adjuvant therapy for breast cancer survivors with a known benefit to survival, also competes with estrogens to selectively bind to the estrogen receptor. There is some concern that soy foods may compete with tamoxifen. Laboratory data have been conflicting - whereas some studies indicate a competition between soy and tamoxifen, other studies indicate a synergistic effect. Given the common use tamoxifen in breast cancer survivors and the rapid increase of soy containing foods and products in the U.S. market, there is an urgent need to understand the joint effect of soy foods and tamoxifen in human studies. Using existing DNA samples from a large cohort of 1,459 breast cancer survivors living in Shanghai, China, we proposed to examine the joint effects of soy food-intake and tamoxifen use on breast cancer survival, and to determine whether this association differs according to polymorphisms in ER-alpha or ER-Beta.
- Medicine and Medical Research
- Food, Food Service and Nutrition