Abstract: Purpose: To explore the carcinogenic mechanisms of oral cancer in DMBA-induced hamster. Methods: 0.5 ％ DMBA solution (in mineral oil) was applied topically to the left cheek pouch of male Syrian golden hamsters 3 times per week for 6 weeks, and the animals were observed until the 24 th week. Brdu-labelling index and vascular density were examined by immunostaining in different oral lesions including normal mucosa, hyperplasia, dysplasia, papilloma and squamous cell carcinoma(SCC) . Apoptotic cells were evaluated based on morphological features. Results: Brdu-labeling index and vascular density increased with oral carcinogenesis, and were correlated with oral histopathological grades. Apoptotic index increased from normal mucosa and hyperplasia to dysplasia, papilloma and SCC, but there was no significant difference among dysplasia, papilloma and SCC. Conclusion: Cell proliferation and angiogenesis are the important carcinogeneic mechanisms of oral cancer.

Key words: Hamster, Oral cancer, Proliferation, Apoptosis, Angiogenesis, 7, 12-dimethylbenzanthracene(DMBA)