Histopathological changes induced in the urinary bladder and liver of female BALB/c mice treated simultaneously with 2-naph-thylamine and cyclophosphamide.

The effect of 2-naphthylamine and cyclophosphamide on the urinary bladder and liver of female BALB/c mice was investigated. The bladder mucosa of mice treated with 2-naphthylamine alone for 40 weeks showed diffuse hyperplasia. Oral administration of 2-naphthylamine for 40 weeks plus injections of cyclophosphamide produced bladder carcinomas in 30.8 approximately 35.7% of all animals, associated with downward growth of the bladder epithelium. All the bladder carcinomas were of the transitional cell type and most of them contained pseudoglandular areas. Hepatomas seemed to develop in higher incidence in mice treated with 2-naphthylamine plus cyclophosphamide than in mice treated with 2-naphthylamine alone. Most of the hepatomas were solitary and showed a trabecular pattern. Cyclophosphamide seemed to have a summative or promoting effect on carcinogenesis of the bladder mucosa and liver induced by 2-naphthylamine in female BALB/c mice.