SEQUENTIAL CYTOGENETIC ALTERATIONS IN HAMSTER ORAL KERATINOCYTES DURING DMBA-INDUCED ORAL CARCINOGENESIS

Using the hamster cheek pouch oral cancer model, we have performed a c omprehensive analysis of the cytogenetic changes in hamster oral kerat inocytes during 7,12-dimethylbenz[a]anthracene (DMBA)induced carcinoge nesis. Tumour induction in the hamster cheek pouch required repeated a pplication of the carcinogen for 14 weeks. We have found that this ham ster oral cancer model to be suitable for cytogenetic studies. Unlike human oral cancers where chromosome breaks have been shown, this is on ly infrequently observed in DMBA-treated hamster oral keratinocytes. O f importance is the finding that at the beginning of the second week o f DMBA treatment, there is a significant increase of karyotypes demons trating tetraploid or near-tetraploidy. We propose that the significan t increase in hamster oral keratinocytes exhibiting tetraploidy be fur ther evaluated as a marker of premalignancy/malignancy.