Loss of tumour suppressor p16 expression in initial stages of oral oncogenesis.

Background: The p16 tumour suppressor gene is known to be involved in regulation of the cell cycle. p16 expression in sequential histological stages of oral squamous cell carcinoma (OSCC) formation was investigated using an experimental model of induced oral carcinogenesis in Syrian golden hamsters.

Materials And Methods: Thirty-seven animals were divided into one control group (N = 7) and three experimental groups (N = 10 each) which were treated with a carcinogen and sacrificed at 10, 14 and 19 weeks after treatment. Tumour sections were studied immunohistochemically using monoclonal antibodies against p16 protein.

Results: p16 was found significantly increased in hyperplasia, sharply decreased in dysplasia and in the subsequent stages of oral carcinogenesis.

Conclusion: Inactivation of p16 occurs at the early stage of oral mucosal dysplasia in the multistep process of oral tumourigenesis. Therefore, p16 may be considered as a useful prognostic marker for the progression of oral cancer.