Hello Everybody!!! Here is some interesting info I got from Dr John R. Lee's research assistant and author in her own right Virginia Hopkins who writes: "The earliest clinical study that we know of on progesterone and breast cancer was done at Johns Hopkins University back in 1981 (Cowan et al, American Journal of Epidemiology). They measured estrogen and progesterone in a group of women, then divided them into two groups: those with normal progesterone levels and those with low progesterone levels. They followed these women for 20 years and found that in the women with low progesterone, the incidence of breast cancer was over 80 percent greater than those with normal progesterone, and the incidence of all cancers was ten times higher than in women with normal progesterone. In 1996, researchers measured women’s progesterone before breast cancer surgery and found that those with normal progesterone levels had an 18-year survival rate—twice that of women with low progesterone at the time of surgery. (Mohr et al, British Journal of Cancer) Three studies in particular have shown progesterone’s effect on breast cells. One, by Foidart et al and published in the journal Fertility and Sterility in 1998 concluded, “Exposure to progesterone for 14 days reduced the estradiol-induced proliferation of normal breast epithelial cells in vivo.” Another, by Malet et al and published in the Journal of Steroid Biochemistry and Molecular Biology, in 2000 concluded, “Cells exhibited a proliferative appearance after E2 [estradiol] treatment, and returned to a quiescent appearance when Progesterone was added to E2. Progesterone appear(s) predominantly to inhibit cell growth, both in the presence and absence of E2.” The third study tested the effects of transdermal (rubbed into the skin) hormones in healthy young women planning to undergo minor breast surgery for aesthetic reasons or for benign breast disease. Ten to 13 days before surgery, four groups of women applied either estradiol cream, progesterone cream, a combination of estradiol and progesterone or a placebo cream (with no hormones in it). At surgery, biopsies were done to measure estrogen and progesterone levels, and the level of cell proliferation rates. (High levels of cell proliferation is a marker for breast cancer.) The study demonstrated that both hormones were well absorbed through the skin into the breast tissue. But even more significant, estradiol increased cell proliferation by 230 percent, whereas progesterone decreased it by more than 400 percent. The estradiol-progesterone combination maintained the normal proliferation rate. (Chang et al, Fertility and Sterility) In 2002, a French study of HRT in 3,175 women was released. This was particularly interesting because it was a large study, and because, to quote the study, “...the main specificity of the French cohort is that 83% of the combined HRT users were receiving mostly or exclusively a transdermal estradiol gel formulation, and the progestin was oral micronized progesterone in 58%, while MPA users were less than 3%.” Oral micronized progesterone is bioidentical, natural progesterone, which is what most French women use, rather than the synthetic progestins. The conclusion of the study was that, “When both duration of use and the last period of use were analyzed together, no significant increase in breast cancer incidence was observed in any of the four subgroups considered,” and “From internal analysis, there was no significant increase in the risk of breast cancer related to use of the specific type of HRT most prescribed in France.” Moderation and Common Sense are the Keys to Optimal Health