INHIBITORY EFFECT OF MEDROXYPROGESTERONE ACETATE ON ANGIOGENESIS INDUCED BY HUMAN ENDOMETRIAL CANCER

OBJECTIVE: The purpose of this study was to investigate the effect of medroxyprogesterone acetate on angiogenesis induced by endometrial cancer and to elucidate the possible mechanisms by which it inhibits the growth of the cancer. STUDY DESIGN: Tumors were obtained from 29 patients with endometrial adenocarcinoma, and angiogenesis was assayed in corneas of white rabbits. RESULTS: Transplantation of tumor tissues into rabbit corneas induced angiogenesis in 70.4% of the corneas, but their transplantation with a pellet of medroxyprogesterone acetate induced angiogenesis in only 21.5% of the corneas. This compound also inhibited angiogenesis induced by acidic fibroblast growth factor and transforming growth factor-alpha. CONCLUSION: Inhibition of angiogenesis may be one mechanism by which medroxyprogesterone acetate inhibits the growth of endometrial adenocarcinoma, and its inhibition of neovascularization induced by adenocarcinoma may be through its direct action on endothelial cells.