Actions of medroxyprogesterone acetate on the efficacy of cytotoxic drugs: Studies with human breast cancer cells in culture

Abstract

Human breast cancer cells (MCF-7) showed increased responses to methotrexate and vincristine after a 48-hr pre-treatment with medroxyprogesterone acetate. The effect of the hormone, which was detectable at concentrations of between 10 and 100 nM, was independent of its growth-inhibitory action. These findings confirm a previous clinical study and have important implications with regard to the management of advanced breast cancer.