Genetic alterations in head and neck squamous cell carcinomas

The genetic alterations observed in head and neck cancer are mainly due to oncogene activation (gain of function mutations) and tumor suppressor gene inactivation (loss of function mutations), leading to deregulation of cell proliferation and death. These genetic alterations include gene amplificati on and overexpression of oncogenes such as myc, erbB-2, EGFR and cyclinD1 a nd mutations, deletions and hypermethylation leading to p16 and TP53 tumor suppressor gene inactivation. In addition, loss of heterozygosity in severa l chromosomal regions is frequently observed, suggesting that other tumor s uppressor genes not yet identified could be involved in the tumorigenic pro cess of head and neck cancers. The exact temporal sequence of the genetic a lterations during head and neck squamous cell carcinoma (HNSCC) development and progression has not yet been defined and their diagnostic or prognosti c significance is controversial. Advances in the understanding of the molec ular basis of head and neck cancer should help in the identification of new markers that could be used for the diagnosis, prognosis and treatment of t he disease.