Molecular Pathogenesis, Epidemiology, Risk Factors & Prognosis of Head and Neck Cancers in Relation to Human Papilloma Virus Infection

Human papillomavirus (HPV) is well known to cause cervical cancer and has now been increasingly implicated as a risk factor for head and neck squamous cell carcinoma (HNSCC). More than 100 types of HPV have been identified but HPV type 16 genome is the one most commonly detected in head and neck cancers, followed by HPV type 18. Two viral oncoproteins E6 and E7 are implicated to play an important role in promoting tumorogenesis by degrading p53 and Rb gene products respectively and thus disrupting the cell cycle. The HPV positive HNSCC patients tend to be younger, non smokers and non drinkers. Oral sex is thought to be the probable mode of transmission for the HPV infection. Patients with HPV positive tumors have at least 50 percent reduced risk of death from HNSCC when compared with HPV-negative patients. Understanding the molecular biology of HPV-positive tumors could lead to the development of diagnostic, therapeutic, preventive and screening measures for HNSCC in the future.