Synergistic Effects of Benzo(a)pyrene and N-Methyl-N-Nitrosourea on Respiratory Carcinogenesis in Syrian Golden Hamsters
Sequential intratracheal administrations of benzo(a)pyrene plus ferric oxide and N-methyl-N-nitrosourea to Syrian golden hamsters resulted in a greater tumor response than that expected as the additive effect of tumor responses induced by each carcinogen alone. Mortality was accelerated in groups receiving both carcinogens. The extents of the synergistic tumor responses and the increased mortality rates related to the specific sequence of carcinogen administrations. Squamous cell carcinoma was the predominant type of tumor induced; the average latency of these tumors was reduced by the sequential carcinogen treatments. The high mortality and rapid tumor development resulted in numerous early deaths of hamsters bearing a spectrum of epithelial lesions. A sequence of stages in the histogenesis of squamous cell carcinomas is suggested based on these observations.
KeywordsBasal Cell Ferric Oxide Tumor Incidence Bronchogenic Carcinoma Intratracheal Instillation
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