Retinoids: application in premalignant lesions and oral cancer.

Squamous cell carcinoma (SCC) of the oral cavity is a multistep process, progressing through a series of discrete, irreversible and complementary alterations in genes that control cell growth, death, and differentiation. In the premalignant state, the oral mucosa progresses through various grades of epithelial dysplasia, with the potential to convert to SCC. Natural and synthetic vitamin A metabolites and analogs (retinoids) were found to suppress head and neck and lung carcinogenesis in animal models, and inhibit carcinogenesis in individuals with premalignant lesions and a high risk to develop cancer of the aerodigestive tract. Likewise, retinoids prevent the development of second primary cancers in head and neck and lung cancer patients who had been treated for the first primary. These effects are thought to result from changes in the expression of genes that regulate cell growth and differentiation. Chemopreventive strategies are designed to suppress, reverse, or prevent the formation of premalignant lesions and their subsequent progression to SCC. This is a review of the application of retinoids in the chemoprevention of head and neck cancer.