Progesterone receptor activation: an alternative to SERMs in breast cancer

Data regarding the effects of progesterone and a progestagen on human norma l breast epithelial cell proliferation and apoptosis are presented here. In postmenopausal women, adding progesterone to percutaneously administrated oestradiol significantly reduces the proliferation induced by oestradiol. I n vitro and in premenopausal women, stopping the administration of nomegest rol acetate triggers a peak of apoptosis. Fibro-adenoma and cancerous cells do not show this regulation of apoptosis. Progesterone seems to be importa nt in normal breast homeostasis. (C) 2000 Elsevier Science Ltd. All rights reserved.