4 Nitroquinoline 1-oxide-induced carcinogenesis in the rat palate.

Most reported studies of experimental oral cancer have been carried out in the hamster. This animal is not available in certain countries and there is controversy regarding its suitability as a model for experimental oral carcinogenesis. An attempt was made to reproduce an experimental oral cancer model in rats, using a protocol based on that described by Lekholm and Wallenius (1976). The carcinogen 4 nitroquinoline 1-oxide was applied to the palates of rats for periods of up to 24 weeks. Macroscopic and microscopic examination of carcinogen-treated palatal mucosa was carried out during the experimental period. Verrucous carcinoma-like lesions of the mid-palate and squamous carcinomas of the gingival mucosa were produced, beginning at 16 and 20 weeks respectively. A variety of other macroscopic and microscopic mucosal changes were also observed during the experimental period. The findings are discussed in relation to the work of others.