Steroid Therapy and the Endometrium: Biological and Clinical Implications

The benefits of estrogen replacement therapy in postmenopausal women include increased quality of life, relief from specific symptoms, and the prevention of osteoporosis, genitourinary atrophy, and cardiovascular diseases. Despite these advantages, this therapy has been reported to be associated with an increased frequency of endometrial hyperplasia and adenocarcinoma. In order to evaluate a possible relationship between the histological findings and stroma-derived growth regulators, 19 endometrial samples obtained from women undergoing both percutaneous (n = 11) and oral (n = 8) steroid replacement therapy were processed for histological and immunocytochemical evaluation of estrogen receptor (Er), progesterone receptor (Pr), and epidermal growth factor receptor (EGFr). Transdermal estradiol was given for 21 days and 10 mg medroxyprogesterone acetate (MAP) were added to the last 12 days; conjugated equine estrogens were given for 21 days and 10 mg MAP added to the last 12 days. Endometrial samples were obtained between days 17-18 of the sixth month of therapy. Proliferative and hyperplastic endometria showed immunoreactivity against Er, Pr, and EGFr. Atrophic endometria were always negative by immunocytochemistry. Our results suggest: 1) a relationship between histological findings and the receptor examined; 2) a crucial role for EGF in the regulation of endometrial proliferation.