EXPRESSION OF C-ERBB-2 ONCOPROTEIN IN PRIMARY HUMAN TUMORS - AN IMMUNOHISTOCHEMISTRY STUDY

An immunohistochemical study was performed with 130 primary malignant human tumors of breast(n=55)..colon/rectum (n=16), stomach (n=19), eso phagus(n=14), lung (n=15) and liver(n=11) using the 21N c-erbB-2 speci fic monoclonal antibody to identify the tumors that over-expressed the c-erbB-2 oncoprotein. Positivity appeared as an intense brown granula r staining located predominantly at the cell membrane. This occurred i n 41.8 % of breast carcinomas, 12.5% of colorectal adenocarcinomas. No ne of the gastric adenocarcinomas, squamous cell carcinomas of the eso phagus, small cell lung carcinomas or hepatocellular carcinomas were p ositive for the oncoprotein. The result of this study suggests that ov er-expression of the c-erbB-2 oncoprotein is common in breast cancer a nd relatively rare in other malignancies examined.