Estrogen profiles in young women: effect of maternal history of breast cancer.

To examine the hypothesis that familial breast cancer risk is related to estrogen metabolism, we analyzed urines of daughters of breast cancer patients and their matched controls for estrone (E1), estradiol (E2), and estriol (E3). From this, we computed estriol proportions (E3/E1 + E2 + E3). "Patient-daughters" and the matched controls showed no differences in estriol proportions. Our results failed to support the hypothesis that high-risk women (those with a family history of breast cancer) have relatively lower estriol proportions, and we concluded that whatever family history contributes to breast cancer risk, that risk is not likely to be transmitted by the estrogen profile.