Distribution of CA 19-9 in adenocarcinomas and transitional cell carcinomas. An immunohistochemical study of 527 cases.

To determine the distribution of CA 19-9 in adenocarcinomas and transitional cell carcinomas, formalin-fixed paraffin-embedded tissue from 527 cases of these tumors was studied using a monoclonal antibody to CA 19-9 and an avidin-biotin immunohistochemical technique. Positive reactivity was seen in some tumors of all types except hepatocellular carcinoma. Positive reactions were most common in pancreatic adenocarcinomas (94%), bile duct carcinomas (91%), and transitional cell carcinomas (76%). The majority of tumors from the ovary, endometrium, distal esophagus/stomach, and colon also showed positive staining. Immunoreactivity was seen in 25-29% of carcinomas of the lung, thyroid, and endocervix. Few positive reactions were seen in renal cell carcinomas (2%), prostatic adenocarcinomas (3%), and breast carcinomas (6%). It was concluded that CA 19-9 is frequently present in several types of adenocarcinoma and transitional cell carcinoma. Immunostaining for CA 19-9 may be helpful in excluding hepatocellular carcinoma, prostatic adenocarcinoma, and renal cell carcinoma in certain clinical settings.