[Immunologic research on human colonic cancer].

Immunological studies on human colonic tumors were oriented in two ways according to their methodology: immunochemistry or cellular immunology methods. Immunochemical studies allowed to characterized several tumor associated antigens although no one was proved as cancer specific. The most famous of these antigens is no doubt the carcinoembryonic antigen of the digestive system or shortly CEA. This is a perchlorosoluble glycoprotein which is associated to the apical pole of glandular cells. It is found in relatively large amounts in colonic carcinomas, mainly the well differentiated ones, and in traces in non cancerous colonic mucosa. By radioimmunoassay CEA level was found elevated above 2,5 ng/ml in most of the sera of patients bearing a digestive cancer but also in a fair number of patients having non-digestive cancer or an inflammatory disease involving or not the digestive system. Morever CEA increase is noted in only one third of incipient colonic carcinomas. CEA assay is thus not reliable for diagnostic of colon cancers, specially the localized ones. On the contrary, this assay seems to be of great value in the follow-up of patients operated for colonic carcinoma. Cellular immunology methods aim to characterize the reactivity of patients lymphocytes to antigens carried by their own tumor. Results obtained by microcytotoxicity are now questioned. Migration inhibition of peripheral blood leukocytes and lymphoblastic transformation give perhaps more reliable informations. The same is likely true for skin tests made in cancerous patients with extracts of their own tumor.