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 transi tional cell carcinomas, formalin-fixed paraffin-embedded tissue from 5 27 cases of these tumors was studied using a monoclonal antibody to CA 19-9 and an avidin-biotin immunohistochemical technique. Positive rea ctivity was seen in some tumors of all types except hepatocellular car cinoma. Positive reactions were most common in pancreatic adenocarcino mas (94%), bile duct carcinomas (91%), and transitional cell carcinoma s (76%). The majority of tumors from the ovary, endometrium, distal es ophagus/stomach, and colon also showed positive staining. Immunoreacti vity was seen in 25-29% of carcinomas of the lung, thyroid, and endoce rvix. Few positive reactions were seen in renal cell carcinomas (2%), prostatic adenocarcinomas (3%), and breast carcinomas (6%). It was con cluded that CA 19-9 is frequently present in several types of adenocar cinoma and transitional cell carcinoma. Immunostaining for CA 19-9 may be helpful in excluding hepatocellular carcinoma, prostatic adenocarc inoma, and renal cell carcinoma in certain clinical settings.