Histochemical studies on nuclease activity and neoplastic transformation in rat liver during diethylnitrosamine carcinogenesis.

The distribution of RNase activity and the occurrence of hyperbasophilic foci and tumors have been examined in rat liver during diethylnitrosamine carcinogenesis. A focal loss of RNase activity was found to occur in the hyperplastic liver nodules prior to the development of hy perbasophilic foci and hepatomas. The RNase-negative areas were widely distributed in livers of rats treated with diethylnitrosamine and so were the hyperbasophilic foci and the tumors. The results indicate that temporal and topographic correlations exist among these phenomena and suggest that a deficiency of RNase activity may play a role in the development of hyperbasophilic foci and hepatomas.