Distribution of colon-ovarian tumor antigen in adenocarcinomas. An immunohistochemical study of 501 cases.

To determine the distribution of colon-ovarian tumor antigen in adenocarcinomas, the authors studied formalin-fixed, paraffin-embedded tissue from 501 cases of adenocarcinoma from a variety of primary sites using a monoclonal antibody to colon-ovarian tumor antigen and an avidin-biotin immunohistochemical technique. Positive reactivity was seen in some tumors from all sites, except from the thyroid and kidney (renal cell carcinoma). Immunoreactivity was infrequent in adenocarcinomas of the breast (12%) and in hepatocellular carcinomas (14%). However, positive staining was seen in more than 60% of the adenocarcinomas from the colon, ovary, endometrium, endocervix, lung, prostate, pancreas, distal esophagus/stomach, and bile ducts. Colon-ovarian tumor antigen is present in a wide variety of adenocarcinomas. Immunostaining for colon-ovarian tumor antigen may be helpful in ruling out renal cell carcinoma and thyroid carcinoma in certain clinical settings.