Expression of heat shock proteins HSP70 and HSP90 in endometrial carcinomas. Correlation with clinicopathology, sex steroid receptor status, and p53 protein expression.

Abstract

It has been suggested that heat shock proteins HSP70 and HSP90 are involved in the functional modulation of sex steroid receptors and are expressed in normal endometrium. However, little is known about the expression of HSP70 and HSP90 in endometrial carcinomas. The immunohistochemical reactivity of monoclonal antibodies against HSP70 and HSP90 was examined in 42 endometrial carcinomas, and the presence or absence of correlation with the clinicopathologic features, sex steroid receptor status, and p53 protein expression was analyzed. Expression of HSP70 was found in 52% of endometrial carcinomas and was correlated with nonendometrioid histology (P < 0.05), a poorly differentiated state (P < 0.01), p53 protein expression (P < 0.01), and absence of sex steroid receptors (P < 0.001) in the tumor. By contrast, strong expression of HSP90 was observed in 29% of endometrial carcinomas, and occurred more frequently in well-differentiated carcinomas that were positive for sex steroid receptors. Both HSP70 and HSP90 are significantly correlated with the histology and the sex steroid receptor status of endometrial carcinomas. Expression of HSP70 may be associated with a loss of sex steroid receptors in either nonendometrioid or poorly differentiated carcinoma of the endometrium, which frequently exhibits p53 protein expression. Conversely, strong expression of HSP90 may indicate high levels of sex steroid receptors in the tumor cells.