EXPERIMENTAL INTESTINAL CARCINOGENESIS

Experimental models of colo-rectal cancer have been established in rodents mimicking human large bowel cancer by their morphology, the slowness of the evolution, and the resistance to chemotherapy. They differ from human colorectal carcinoma by their multiplicity, but the number of carcinomas may be modulated with carcinogen dosage, the absence of adenoma-carcinoma sequence in the rat (de novo carcinoma), the rarity of liver metastases and the strong association with gut lymphoid tissue. Grafted tumors, serially transplanted in syngeneic animals and cancer cells in culture represent a reliable source of subcutaneous, measurable tumors and artificial metastases to lung, liver and peritoneum. These experimental models contribute to the knowledge of human colorectal cancer. They permit the development of new chemotherapeutic drugs and biological modifiers of the immune response. Prospective epidemiological studies could give more informative results on the protective and preventive effects of the supplementation of diet by calcium.