Expression of estrogen receptors ! and " protein in endometrial carcinoma

Summary To investigate the significance of the expression of estrogen receptors (ER) in endometrial carcinogenesis, we evaluated the expression of ER! and " in endometrial carcinoma. The percentage and grey of ER-positive cells were quantified immunohistochemically using an image analyzer in the lesions of varying histological risks from 247 patients and compared with the adjacent normal lesions. The expression of ER! in the lesions of atypical hyperplasia and the endometrial carcinoma was not significantly different from that in the lesions of simple or complex hyperplasia (p=0.574 and p=0.821, respectively). The percentage and grey of ER" were decreased significantly in atypical hyperplasia or endometrial carcinoma as compared to simple or complex hyperplasia (p=0.001 and p=0.001, respectively); ER" levels in atypical hyperplasia and endometrial carcinoma lesions were significantly lower than those in their respective adjacent lesions (P<0.05); ER" staining was inversely correlated with Ki67 (P=0.001). The results suggest that decreased levels of ER" protein with an increasing risk of invasive cancer plays an important role in the occurrence and development of endometrial carcinoma.