Use of a monoclonal anti-estrogen receptor antibody in the immunohistochemical evaluation of human tumors.

A monoclonal antibody to human estrogen receptor protein (H222 Sp gamma), amplified via immunoperoxidase techniques, was used in the analysis of estrogen receptor in 452 breast carcinomas, 100 endometrial carcinomas, and 15 melanomas. Immunohistochemical evaluation incorporated both intensity and distribution of staining (HSCORE). Quantitative estrogen receptor content was determined by dextran-coated charcoal analysis and sucrose density gradient analysis. In all cases H222 Sp gamma localized in the nucleus of target cells. A semiquantitative correlation existed between HSCORE and biochemical assays for breast and endometrial tissues. The sensitivities and specificities for HSCORE as compared to the biochemical assays ranged from 80 to 95% and from 74 to 94%, respectively. HSCORE correlated with tumor grade for breast and endometrial carcinoma. Immunohistochemical evaluation showed no specific staining in melanomas. The data suggest that immunohistochemical receptor localization provides information complementary to standard biochemical assays in the tissues studied.