ESTROGEN AND PROGESTERONE-RECEPTOR EXPRESSION IN POSTMENOPAUSAL TAMOXIFEN-EXPOSED ENDOMETRIAL PATHOLOGIES

Assessment of receptor levels in tamoxifen-exposed endometrial patholo gies may indicate endometrial cells potential for interaction with tam oxifen. To assess this assumption, we analyzed estrogen receptor (ER) and progesterone receptor (PR) expression by an immunohistochemical te chnique in endometrial specimens with benign hyperplasia, benign polyp s, and carcinoma obtained from postmenopausal breast cancer patients t reated with tamoxifen (study group) and from age-matched healthy postm enopausal women treated with estrogen replacement therapy (control gro up I) and not treated with estrogen replacement therapy (control group II). Overall gland and stromal ER expression of benign endometrial hy perplasia and of benign endometrial polyps was significantly higher in control groups I and II than that obtained from the study group (endo metrial hyperplasia: P = 0.0274 and 0.00093, respectively, and P = 0.0 0003 and 0.00001, respectively; benign endometrial polyps: P = 0.02889 and 0.00596, respectively; and P = 0.00228 and 0.00005, respectively) , while there were no differences between the two control groups. Over all gland and stromal PR expression was nearly similar in all the thre e groups (P = NS). There was no correlation between the length of tamo xifen treatment and the presence of ER and PR in various endometrial p athologies in the tamoxifen-treated patients, The significantly lower ER expression in most benign endometrial pathologies obtained from pos tmenopausal tamoxifen treated patients may further support the weak es trogen-like effect of tamoxifen on the endometrium in the menopause. ( C) 1997 Academic Press.