Immunohistochemical characterization of a new anti-carcinoembryonic antigen monoclonal antibody.

A novel anti-CEA monoclonal antibody C234 with no cross-reactivity to other members of CEA gene family was produced by immunization with heat-treated CEA. The immunoreactivity of C234 was tested on formalin fixed normal and neoplastic tissues by peroxidase/anti-peroxidase technique. None of normal tissues from healthy or diseased individuals, except for normal colonic mucosa were stained. On the other hand, all 26 colorectal adenocarcinomas, 8 gastric adenocarcinomas, 3 of 7 pancreatic adenocarcinomas, and one small bowel duodenum carcinoma were immunoreactive. None of primary hepatocellular carcinomas expressed CEA. However, only 40 of 87 neoplasms of non-gastrointestinal origin were stained. Thus, the antibody can recognize gastrointestinal tumors and differentiate them from neoplasms of other histological origin.