Effect of Genistein on DMBA-induced Oral Carcinogenesis in Hamster

Objectives: to investigate to the putative chemopreventive effect of genistein in oral carcinogenesis in hamster cheek pouch. Methods: 60 male Syrian golden hamsters were randomly divided into 4 groups, with two of 20 and two of 10. DMBA solution (0.5% in acetone) was applied topically to the left cheek pouch of male Syrian golden hamsters in group A and B, while animals in group C were painted with acetone, 3 times a week for 6 weeks. Animals in group D received neither DMBA nor acetone in the first 6 weeks. Two days after the last treatment of DMBA, animals in group B and D received genistein suspended in distilled water (10mg/kg /d) by gavage, animals in group A and C received same volume of saline, for the next 12 weeks. At the end of the experiment, animals were sacrificed and tissue samples were collected for histopathological examination. Results: The genistein treatment decreased the visible oral tumor incidence to 40.7% (11/27) from 53.6% (15/28) of the positive control, but the difference was not statistically significant (P = 0.34). And no significant difference in the average number of tumors/tumor-bearing hamster, the average tumor volume and latency was observed between the control and genistein treated group. The cheek pouch mucosa of the animals in Group C and Group D appeared normal. Conclusion: No inhibitory effect of genistein on chemically induced oral tumor was observed in hamster. The exact mechanism behind this needs further investigation.