The initiation, progress, and diagnosis of dog bladder cancer induced by 4-aminobiphenyl

24 beagles received 4-aminobiphenyl orally 5 days a week for 3 years. The dogs were examined cytoscopically at frequent intervals. Biopsy and surgery were performed according to predetermined criteria. Three basic patterns of carcinogen responses were seen. Negative or minimal disease was seen in four dogs. Of these, two remained completely free of neoplasia. Eleven dogs progressed slowly in their development of neoplasia with minor fluctuations in development. A rapidly progressive pattern was observed in the remaining nine dogs. A large variance in the time of onset of the first positive diagnosis of neoplasia was seen. Eleven dogs underwent surgery ranging from tumor sampling to cystectomy plus ureterosigmoidostomy. Histologic types and grades and patterns of metastasis as well as several other characteristics seemed to parallel closely human bladder cancer.