Abstract: BACKGROUND ＆ AIM: The preventive effects of curcumi on 7,12-dimethylbenz(a)anthracene (DMBA)-induced oral carcinogenesis in golden syrian hamster were studied. MATERIALS AND METHODS: The hamsters were divided into four groups, i.e. the positive control group (the left buccal pouches of animal were topically treated with 0.5 ％ DMBA in mineral oil three times per week for 14 weeks) ,two curcumin treated groups and the negative control group (mineral oil applied topically). The animals in curcumin treated groups received 5 and 10 μmol/L curcumin applied topically 3 times per week before starting the DMBA treatment and until the end of the experiment. RESULTS: Ten μmol/L curcumin significantly decreased the oral visible tumor incidence from 95.0 ％ to 60.0 ％ (P<0.01) and the squamous cell carcinoma (SCC) incidence from 85.0 ％ to 55.0 ％(P<0.01). Five μmol/L curcumin significantly decreased the number of visible tumors, the tumor volume, as well as the numbers of dysplasic lesions and SCC by 21.0 ％, 36.3 ％, 29.9 ％ and 29.3 ％, respectively. Ten μmol/L curcumin decreased significantly by 36.8 ％,63.8 ％,37.2 ％ and 44.4 ％, respectively. Curcumin also decreased the frequency of micronucleated cells in hyperlasis, dysplasia and bromodeoxyuridine (BrdU)-labeling index in hyperlasis, dysplasia and Carcinoma, but do not have effect on cell apoptosis. CONCLUSIONS: The results suggested that curcumin could effectively inhibit DMBA-induced oral carcinogenesis in hamsters and such inhibition may be related to protecting DNA damage, the suppression of cell proliferation.

Key words: curcumin, oral cancer, chemoprevention