Immunohistochemical studies on the localization of cancer associated antigens DU-PAN-2 and CA19-9 in carcinomas of the digestive tract.

The immunohistochemical localization of DU-PAN-2 antigen and CA19-9 antigen in carcinomas of the digestive tract was studied using an immunoperoxidase technique. Staining for DU-PAN-2 antigen and CA19-9 antigen was observed in 104 (79%) and 96 (73%) of 131 carcinomas of the digestive tract, respectively. Diffuse staining (more than 20% of carcinoma cell stained) for DU-PAN-2 was detected in 14 of 21 (67%) pancreatic carcinomas and 11 of 19 (58%) carcinomas of the biliary tract (including cholangiocarcinoma). Diffuse staining for CA19-9 was detected in 15 (71%) of pancreatic carcinomas and nine (47%) of the carcinomas of the biliary tract. In colon carcinomas, no diffuse staining for DU-PAN-2 was observed, whereas diffuse staining for CA19-9 was found in 41%. There was a positive correlation between the differentiation degree (or grade) of the adenocarcinomas of the colon and the expression of CA19-9, but not that of DU-PAN-2. These immunohistochemical studies showed that DU-PAN-2 antigen is expressed diffusely in most cases of adenocarcinoma of the pancreas and biliary tract and is more specific for adenocarcinomas of the pancreas and biliary tract than CA19-9.