BRCA1/2 and Effect of Mifepristone on the Breast

Overview

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.

Objectives • Research objective To study the safety and effect of treatment with mifepristone, a progesterone receptor modulator, on epithelial cell proliferation in human breast tissue in women with BRCA-1 or -2 mutations prior to protective mastectomy. Project description • Hypothesis/ Theory Mifepristone treatment exerts an antiproliferative, protective effect on breast tissue in women with BRCA-1 or -2 mutations Study Design Randomized, double blind, placebo controlled trial. Women will be recruited among patients with BRCA-1 or -2 mutations scheduled for prophylactic mastectomy. Included women will be randomized to a 3-month treatment with mifepristone, 50 mg (Mifegyne, Exelgyn, Paris, France) or placebo taken orally every second day. Breast biopsies will be obtained in the luteal phase prior to start of treatment and again during surgery.