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Production of respiratory tract tumors in hamsters by benzo(a)pyrene.

Respiratory tumor induction was tested for the tumorigenic activity of benzo[a]pyrene alone. A group of 32 male and 28 female Syrian golden hamsters were given weekly intratracheal instillation of 1 mg of benzo[a]pyrene suspended in isotonic saline, for 30 weeks. Squamous cell carcinoma, adenocarcinoma, anaplastic carcinoma, adenoma, papilloma, and polyps were induced in the respiratory tract of hamsters. Tumor incidences were 42.3% in males and 57.7% in females. Respiratory carcinomas were inducible in hamsters by simple instillation of a low dose of benzo[a]pyrene without using a surface-active agent or carrier-dust. These findings may be useful as a standard data for cocarcinogenesis studies when using other modality combined with benzo[a]pyrene in experimental studies.