Ovarian steroids, as well as their synthetic counterparts gestagens and estrogens have a role
in breast cell proliferation and the development of breast cancer. Here, the effect of a
progesterone receptor modulator, mifepristone, on cell proliferation in human breast tissue
in vivo will be studied in women with BRCA-1 or -2 mutations. Our preliminary results
implicate a possible protective effect of mifepristone in breast epithelium. The ability of
mifepristone to block breast epithelial cell proliferation may prevent tumorigenesis and may
also prove beneficial when used for contraceptive purposes and on other indications. The
proposed project concerns a Randomized Controlled Trial on mifepristone versus placebo
treatment of women with BRCA-1or -2 mutations with a high risk/incidence of breast cancer and
ovarian cancer.