Autografting colonic adenocarcinomas into the colonic submucosa in rats

After inducing colonic tumors in 47 rats by weekly subcutaneous injections of 1,2-dimethylhydrazine, all rats were laparotomized and tumors were autotransplanted to tumor-free areas of the transverse colon. True autotransplants were considered to be tumors occurring in the grafted areas, which were covered by normal colonic mucosa. The frequency of auto-grafted tumors was 35.5%. In a previous work, a low incidence of 1,2-dimethylhydrazine-induced tumors was found in the transverse colon of the rat. The present results suggest that the failure of tumor growth in the transverse colon may be unrelated to an intrinsic natural "resistance" of that segment of the colon to tumor growth.