1. Serum estrogen receptor bioactivity and breast cancer risk among postmenopausal women.
- Author
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Lim, Vanessa W., Jun Li, Yinhan Gong, Aizhen Jin, Jian-Min Yuan, Eu Leong Yong, and Woon-Puay Koh
- Subjects
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ESTROGEN receptors , *BLOOD serum analysis , *BREAST cancer risk factors , *POSTMENOPAUSE , *CANCER in women , *WOMEN - Abstract
The estrogen levels of Asian women are different from those of Western women, and this could affect estrogen receptor (ER) bioactivity and breast cancer risk. We conducted a case-control study in 169 postmenopausal breast cancer cases and 426 matched controls nested within a population-based prospective cohort study, the Singapore Chinese Health Study, to evaluate the serum levels of estrogens and their receptor (ERa and ERb)-mediated estrogenic activities in relation to breast cancer risk. Breast cancer cases had higher levels of estrogens and ER-mediated bioactivities in baseline serum than the controls. Compared with those in the lowest quartile, women in the highest quartile for estrone (E1) or ERa-mediated bioactivity had increased breast cancer risk. After additional adjustment for ERb bioactivity, free estradiol, and E1 levels, serum ERa-mediated bioactivity remained associated with increased breast cancer risk. Compared with those in the lowest quartile, women in the highest quartile for ERa-mediated bioactivity had an odds ratio of 2.39 (95% CIZ1.17-4.88; P for trendZ0.016). Conversely, the positive association between E1 and cancer risk became null after adjustment for ERa-mediated bioactivity, suggesting that the effect of E1 could be mediated through ERɑ. Factor(s) contributing to increased ERa-mediated estrogenic bioactivity in serum and its role as a predictor for breast cancer risk need to be validated in future studies. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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