THE COMBINATION OF IN-SITU HYBRIDIZATION AND IMMUNOHISTOCHEMICAL ANALYSIS - AN EVALUATION OF HER2 NEU EXPRESSION IN PARAFFIN-EMBEDDED BREAST CARCINOMAS AND ADJACENT NORMAL-APPEARING BREAST EPITHELIUM/

The combination of in situ hybridization and immunohistochemical techn iques can successfully identify viral DNA/RNA in specific subsets of c ellular populations. We recently modified this method to evaluate ampl ification of the oncogene Her2/neu and overexpression of its protein c -erbB-2 in a series of 15 breast carcinomas. This combination allows t he simultaneous evaluation of the oncogene and its corresponding prote in expression in single cells and specific cellular populations in his tologic tissue sections. Double staining demonstrated heterogeneity wi thin breast carcinomas, In addition, both nuclear and cytoplasmic sign als were often detected in morphologically normal-appearing adjacent b reast epithelium. The ability to view both the oncogene and its corres ponding protein in single cells offers a unique look at the biology of c-erbB-2.