Inhibitory effect of fumaric acid on hepatocarcinogenesis by thioacetamide in mice.

The inhibitory effect of fumaric acid (FA) on hepatocarcinogenesis was examined in mice fed thioacetamide (TAA). A group of male ICR mice was fed TAA at a level of 0.035% in the diet for 40 weeks and then fed a basal diet for 48 weeks. Hepatic tumors developed in 11 of the 24 animals of this group and they were diagnosed as hepatocellular carcinomas. However, cirrhotic lesions and the enlargement of hepatocyte nucleoli were not as marked in mice as in previous findings in rats fed TAA. The effect of FA on the carcinogenesis was examined in a group of mice fed this compound at a level of 1% in a basal diet after ingestion of TAA. The inhibitory effect of FA on TAA carcinogenesis was so marked that no hepatic carcinomas were found in any of the 15 animals fed FA in combination with TAA.