Expression of neural cell adhesion molecule in normal gastric mucosa and in gastric carcinoid tumors

Expression of neural cell adhesion molecule (NCAM) in the digestive system was studied with NE-150 monoclonal antibody, together with those against Lewis blood group antigens. NE-150 did not react with any of 32 cell lines tested derived from digestive tract cancers. In gastric adenocarcinomas NCAM was not expressed regardless of its differentiation status, while in gastric carcinoids and in other carcinoid tumors of different organs, it was present in all the specimens tested. Among normal tissues, it reacted with the deep gastric gland and the islets of Langerhans. These results suggest that NCAM is one of the most specific markers for gastric carcinoid tumors. It was also suggested that the gastric carcinoid tumor might be derived from NCAM-positive cells in the deep gastric gland. These findings should be exploitable in subgrouping gastric tumors in terms of antigen expression.