No effect of high-dose medroxyprogesterone acetate on the frequency of sister chromatid exchange in lymphocytes of cancer patients.

Sister chromatid exchange observed in metaphase chromosomes has been shown to be a sensitive assay for the detection of possible mutagenic and/or carcinogenic agents. The semisynthetic progestin medroxyprogesterone acetate is a drug used in high doses for the treatment of advanced breast cancer. We studied the frequency of sister chromatid exchange in PHA-stimulated peripheral lymphocytes of 11 patients who received medroxyprogesterone acetate in high doses. Overall results disclosed no significant effect of this drug on the frequency of sister chromatid exchange (SCE) and cell proliferation in sister chromatid differentiation patterns. Considering sex differences a slight tendency towards SCE increase and growth delay was observed in females.