Circulating Estrogen Metabolites and Risk of Breast Cancer among Postmenopausal Women in the Nurses’ Health Study

Estradiol and estrone are well-established risk factors for postmenopausal breast cancer (BC). Experimental evidence suggests that specific estrogen metabolites, produced via irreversible hydroxylation of estrone and estradiol at the 2- or 16-position may independently influence carcinogenesis.