Reactivity of monoclonal anti-human pancreatic carcinoma antibodies AR2-20 and AR1-28 with tumors of nonpancreatic origin.

The reactivity of two IgG1 murine monoclonal antibodies, AR2-20 and AR1-28 directed against the RWP-1 and RWP-2 human pancreatic cell lines was evaluated with paraffin sections of nonpancreatic human carcinomas. These monoclonal antibodies, which are directed against a 200-kd glycoprotein, and which did not stain normal tissues, were both reactive with 6 of 116 neoplasms (6 of 103 carcinomas) by indirect immunofluorescent histochemistry. This contrasts with the positive incidence of staining obtained with 29 of 34 human pancreatic adenocarcinomas. The two antibodies have specificities different from those previously described that reacted with pancreatic neoplasms. The significance of these findings is discussed with respect to the use of these antibodies in a diagnostic panel.