Tumor associated glycoprotein-72 is highly expressed in prostatic adenocarcinomas

We examined the expression of two well-characterized oncofetal antigens, the tumor associated glycoprotein-72 (TAG-72) and carcinoembryonic antigen (CEA), in malignant prostatic tissues. Three specific monoclonal antibodies, B72.3, CC49 and CC83, were used to examine the expression of TAG-72. Immunoreactivity was detected in 63% of the malignant specimens using B72.3. CC49 and CC83 were more sensitive than B72.3 in detecting TAG-72 expression. Immunoreactivity was detected in approximately 80% of prostatic adenocarcinomas with CC49 or CC83. The pattern and localization of TAG-72 immunoreactivity were similar for the three antibodies with most immunoreactivity observed within the cytoplasm of malignant cells and within the lumens of malignant glands. TAG-72 immunoreactivity was not detected within benign epithelium or stroma, with the exception of focal epithelial expression in areas of acute prostatitis. The COL-1 antibody to CEA did not detect CEA in benign glands, stroma, or malignant cells of prostate specimens resected for prostatic adenocarcinoma. These results demonstrate that TAG-72, but not CEA, is frequently expressed in prostatic adenocarcinomas.