EXPRESSION OF C-ERBB-2 PROTEIN AND EPIDERMAL GROWTH-FACTOR RECEPTOR IN ENDOMETRIAL CARCINOMAS - CORRELATION WITH CLINICOPATHOLOGICAL AND SX STEROID-RECEPTOR STATUS

Background. The c-erbB-2 (HER-2/neu) protein is a membrane glycoprotein growth factor receptor showing molecular homology with the epidermal growth factor receptor (EGFR). In endometrial carcinomas, little is known about the relationship between the expression of c-erbB-2 protein and that of EGFR. Methods. The immunohistochemical reactivity of monoclonal antibodies against both of these proteins was examined in 34 endometrial carcinomas, and the presence or absence of correlation with the clinicopathologic features or with the immunohistochemical expression of sex steroid receptors (estrogen receptor [ER] and progesterone receptor [PR]) was analyzed. Results. Of the 34 patients, 22 (64.7%) had c-erbB-2 protein-positive and EGFR-negative tumor, and 8 (23.5%) had tumor positivity for both proteins. Four patients had tumors negative for both proteins. ER or PR positivity was found in 24 (70.6%) of the 34 patients. Intense immunostaining for c-erbB-2 protein was found in 5 (14.7%) of the 34 patients but was not correlated with the stage or grade of differentiation in endometrial carcinoma. However, expression of EGFR in addition to c-erbB-2 protein was more frequently observed with advancing stage of disease and was inversely correlated with the grade of differentiation and with the expression of ER or PR of the tumor. Conclusion. The expression of EGFR, in addition to that of c-erbB-2 protein, is an important event that presumably is linked with progression or with a poorly differentiated state of endometrial carcinomas.