Kidney tumors induced in rats by the antischistosomal drug niridazole.

An increased incidence of kidney tumors was found in MRC rats fed the antischistosomal drug niridazole at four dose levels in the diet. Histologically, the adenomas and adenocarcinomas were solid papillary, clear cell, and tubular types, with the latter type predominating. Seven mesenchymal tumors were found among the 107 renal epithelial neoplasms. Severe nephrosclerosis occurred in both treated and control rats and has been suggested as important in renal carcinogenesis. Niridazole is considered a potent inducer of epithelial kidney tumors.