Abstract
The effect of splenectomy on dimethylhydrazine (DMH)-induced colon cancer in rats was studied. Tumor doubling time in the splenectomy group was significantly shorter than that in the control group. The PCNA labeling index was significantly higher in the splenectomy group than in the control group. In the analysis of DNA ploidy pattern of tumor, aneuploidy appeared only in the splenectomy group. At autopsy, the incidence of early cancer in the splenectomy group was more frequent than that in the control group, although the difference was not significant. NK activity in the blood was significantly lower one week after surgery in the splenectomy group than in the control group. On the basis of these results, splenectomy may act to promote tumor growth in DMH-induced colon carcinogenesis.