Gastrointestinal carcinoma-associated antigen defined by a murine monoclonal antibody

A murine monoclonal antibody, CHIP, has been prepared against a human pancreatic carcinoma cell line, SHAW. With the use of the avidin-biotin immunoperoxidase technique, the CHIP antibody detected an antigen found in 11 of 20 fixed tissue sections of tumors obtained from patients with pancreatic carcinoma. The antibody also detected the antigen in 25 of 26 colon carcinoma specimens, 4 of 6 gastric carcinoma specimens, and 1 of 2 esophageal adenocarcinoma specimens. The antigen was also found in normal proximal jejunum and colon and in small amounts in pancreatic islets and parathyroid. There was no reactivity with normal pancreatic ductal or acinar cells or with mesenchymal tissues.