The relationship of colonic carcinogenesis and hepatic vascular tumors induced by subcutaneously injected-1,2-dimethylhydrazine dihydrochloride in specific pathogen free mice.

1,2-Dimethylhydrazine dihydrochloride (DMH) is one of the most reliable carcinogens for experimental colonic carcinogenesis. In order to evaluate the biological significances of target organ specificity of DMH-induced carcinogenesis, specific pathogen free (SPF) BALB/c mice were injected subcutaneously with DMH for 30 weeks, and were studied pathologically for tumor development of various organs. The data showed that colon tumor developed only at 2% of these mice. However, it produced 100% incidence of malignant endotheliomas and angiosarcomas of blood vessels and these tumors selectively appeared in the liver. There were no overt foci of primary vascular tumors in the heart, lung, kidney, muscle as well as spleen. This tumor model may reveal that the organ specificity of the carcinogenic activity with DMH could be converted, possibly depending upon the bacterial flora in the intestines, and very suitable for the investigation of implications of intestinal bacteria on the colonic and vascular tumorigenesis.