Measurement of a pancreatic cancer-associated antigen (DU-PAN-2) detected by a monoclonal antibody in sera of patients with digestive cancers.

DU-PAN-2 is a high-molecular-weight glycoprotein defined by a murine monoclonal antibody (MAb) against a pancreatic ductal adenocarcinoma cell line. In order to evaluate the usefulness of this antigen as a tumor marker, we determined the serum level of the antigen by competitive inhibition radioimmunoassay in sera from 139 patients with various malignant tumors, chiefly digestive cancers, 98 patients with different benign diseases and 11 healthy subjects. Values in the healthy subjects were less than 100 U/ml. Levels above 100 U/ml were frequently observed in sera from benign diseases, but levels above 400 U/ml were found in only 6 of the patients with benign diseases. In contrast, levels exceeding 400 U/ml were detected in 72% of patients with pancreatic cancer, 44% of patients with hepatocellular cancer and 40% of patients with biliary tract cancer. The positivity was low in other cancers such as gastric cancer (19%) and colorectal cancer (7%). Serum levels of CEA and CA 19-9 were also determined in cancer patients. Among the pancreatic cancer patients studied, values above 400 U/ml were found in 5 of the 8 CEA-negative patients (less than 5 ng/ml) and 2 of the 3 CA 19-9 negative patients (less than 37 U/ml). These results indicate that determination of the serum DU-PAN-2 can aid in serological diagnosis of cancer of the digestive tract, more particularly of the pancreas.