Serum sex steroids in premenopausal women and breast cancer risk within the European Prospective Investigation into Cancer and Nutrition (EPIC).

Authors: Kaaks R, Berrino F, Key T, Rinaldi S, Dossus L, Biessy C, Secreto G, Amiano P, Bingham S, Boeing H, Bueno de Mesquita HB, Chang-Claude J, Clavel-Chapelon F, Fournier A, et al.

Publication Year: 2005

Citation: J Natl Cancer Inst 2005; 97:755-65.

In this large multicenter study, higher serum progesterone levels were associated with a significant reduction in breast cancer risk.

http://www.ncbi.nlm.nih.gov/pubmed/15900045