[Immunologic results obtained with an experimental system oftransplantable colonic tumors. Possible applications of these results to human intestinal tumors].

Intestinal cancers, morphologically very close to human colo-rectal adeno-carcinoma, have been induced by dimethylhydrazine in inbred rats. Graftable lines have been obtained from 5 primary intestinal tumors, and 3 cell lines have been cultivated from the grafts. This model was used to demonstrate carcinofetal antigen(s) on the surface of the intestinal cancer cells. Circulating antibodies against tumor-associated antigen(s) have been found in tumor-bearing rats. Cancer enhancement was regularly observed when specific (tumor cells) and non-specific (B.C.G.) immunologic treatments were used to prevent or cure rat intestinal tumors. These results suggest that immunotherapy of human colo-rectal cancer might be hazardous.