Cytogenetic analysis of oral and cutaneous squamous cell carcinomas in the rat.

Chromosomes of induced carcinomas in the oral mucosa and epidermis of rats were studied in vitro. The tumours were induced by repeated applications of one of two carcinogens: the fat-soluble 7,12-dimethylbenz (a) anthracene (DMBA) or the water-soluble 4-nitrochinoline N-oxide (4NQO). Non-random chromosomal patterns, different for each carcinogen, were revealed, irrespective of the location of the tumour. The DMBA-induced carcinomas showed the same karyotypic deviations as those in leukemias and sarcomas induced in the rat by the same carcinogen. The 4NQO-induced carcinomas displayed chromosome features similar to those previously observed in embryonic rat tissue subjected to malignant transformation by the same agent.