Induction of nephroblastoma-like renal tumours in rats by a single dose of 1,2-dimethylhydrazine.

A single injection of 1,2-dimethylhydrazine (200 mg/kg s.c.) resulted in the development of renal tumours in 70 per cent of treated rats within 1 year. The tumours were frequently bilateral (36 per cent) and grew to a large size (up to 100 g) before causing death. Lung metastases were found in one case. Histologically, the majority of the tumours (73 per cent) exhibited the classical triphasic morphological features of nephroblastoma (Wilms' tumour) with varying proportions of epithelial (glomeruloid and tubular structures), stromal (fibrous tissue, smooth muscle, cartilage) and blastematous elements. This pathological resemblance to human nephroblastoma suggests the possibility of using dimethylhydrazine-induced renal tumours as a model of Wilms' tumour.