No progestogen could further enhance the stimulatory effect of E2 on HCC1500 cells,all but KDG inhibited it.  MPA,  GSD,  T,  CMA and NET had an anti-proliferative effect on the mitotic GF and E2 combination.  P,  LNG, DNG and KDG had no significant effect.  So,  some progestogens may induce proliferation or inhibit growth of benign or malignant human breast epithelial cells independently of the effects of growth factors and E2 ⁽²³⁾. 

So,  choice of progestogen for hormone therapy may be important in terms of influencing possible breast cancer risk.However,clinical studies are necessary to prove these results obtained in vitro.

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Rosa Sabatini and Giuseppe Loverro
Dept. Obstetrics and Gynecology,
General Hospital Policlinico-University of Bari, Italy
—

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