Since circulating levels of progesterone deeply fluctuate throughout life, and even drop following the menopausal transition, we can hypothesize that the silencing of proliferative genes by unliganded PRs and coregulators, including PRMT1, is a crucial process acting as a break to limit the development of breast cancer especially in post-menopausal women. The gene discussed is PRMT1; the disease is breast carcinoma.