Distribution of monoclonal antibody-defined monosialoganglioside in normal and cancerous human tissues: an immunoperoxidase study.

The immunoreactivity of a monosialoganglioside antigen defined by monoclonal antibody 116NS19-9 (19-9) was studied in neoplastic and normal glandular and mucosal epithelia using an indirect immunoperoxidase method. In neoplastic mucosae, the antigen was detected in the majority of colorectal and endometrial carcinomas, predominantly in a focal staining pattern. A substantial proportion of gastric and pancreatic tumors and an occasional breast carcinoma also reacted with the monoclonal antibody. Expression of the monosialoganglioside in normal colonic mucosa appeared to be restricted to areas adjacent to tumor tissue. In gastric mucosa, the antigen was confined to some areas showing intestinal metaplasia. The antigen was also detected in the epithelium of normal mucosa of the gall bladder and endocervix, as well as in some ductal epithelia of the pancreas and salivary glands. Most other mucosae were negative for antigen expression.