When a journal article reads, “Progesterone, the Ultimate Endometrial Tumor Suppressor,” it’s time for a small celebration. This study was done with actual bioidentical progesterone and confirms, from a biochemistry point of view what we already know, which is that the production of progesterone during the menstrual cycle is what keeps the uterus healthy and free of cancer.

If the adrenal glands are healthy enough at menopause to produce some progesterone, (which they are not in most women in industrialized countries), and estrogen levels are allowed to drop far enough to stop the buildup of the uterine lining (which they often aren’t because we are awash in a sea of petrochemical xenoestrogens), then endometrial cancer is not an issue when women are menopausal.

Women who have estrogen dominance, which is to say a low ratio of progesterone to estrogen, are undoubtedly at higher risk of endometrial cancer.

Now it would be great if these researchers would do similar research for progesterone and breast cancer.

Here’s the abstract/reference for the article (my emphasis added):

Yang S, Thiel KW, Leslie KK, “Progesterone: the ultimate endometrial tumor suppressor,” Trends Endocrinol Metab. 2011 Feb 24.

The uterine endometrium is exquisitely sensitive to steroid hormones that act through well-described nuclear receptors. Estrogen drives epithelial proliferation, and progesterone inhibits growth and causes cell differentiation. The importance of progesterone as a key inhibitor of carcinogenesis is reflected by the observation that women who ovulate and produce progesterone almost never get endometrial cancer. In this review we describe seminal research findings that define progesterone as the major endometrial tumor suppressor. We discuss the genes and diverse signaling pathways that are controlled by progesterone through progesterone receptors (PRs) and also the multiple factors that regulate progesterone/PR activity. By defining these progesterone-regulated factors and pathways we identify the principal therapeutic opportunities to control the growth of endometrial cancer.