%0 Journal Article %T Evidences Suggesting Involvement of Viruses in Oral Squamous Cell Carcinoma %A Kanupriya Gupta %A Rashmi Metgud %J Pathology Research International %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/642496 %X Oral cancer is one of the most common cancers and it constitutes a major health problem particularly in developing countries. Oral squamous cell carcinoma (OSCC) represents the most frequent of all oral neoplasms. Several risk factors have been well characterized to be associated with OSCC with substantial evidences. The etiology of OSCC is complex and involves many factors. The most clearly defined potential factors are smoking and alcohol, which substantially increase the risk of OSCC. However, despite this clear association, a substantial proportion of patients develop OSCC without exposure to them, emphasizing the role of other risk factors such as genetic susceptibility and oncogenic viruses. Some viruses are strongly associated with OSCC while the association of others is less frequent and may depend on cofactors for their carcinogenic effects. Therefore, the exact role of viruses must be evaluated with care in order to improve the diagnosis and treatment of OSCC. Although a viral association within a subset of OSCC has been shown, the molecular and histopathological characteristics of these tumors have yet to be clearly defined. 1. Introduction The significant role of viruses in cancer was acknowledged finally in the second half of the past century after various rodent tumorigenic viruses were discovered, and evidence had accumulated supporting an association between viruses and human cancer. Indeed, the Nobel Prize was awarded to Rous in 1966 in recognition of his seminal discovery of tumor-inducing viruses. In addition, almost at the same time, a Special Virus Cancer Program (VCP) was launched by the US Congress in 1964 providing enormous funds for intensive research into the supposed role of viruses in human cancer. This program, criticized by some investigators as being a political moonshot-style plan, failed to identify candidate human cancer-causing viruses yet generated fundamental information about the molecular biology and mechanisms underlying, in particular, virus-related animal cancer and cancer in general [1]. The strong cohort effect that accounted for the increased incidence of head and neck cancers after 1915 indicates that oral cancer is a disease largely attributable to behaviors that expose an individual to environmental carcinogens. The majority of oral cancers in individuals above and below the age of 45 can be attributed to the combined effects of alcohol and tobacco smoking. Other risk factors for oral cancers include diet, Body Mass Index, oral hygiene, and viral infections [2]. The most commonly implicated viruses in oral %U http://www.hindawi.com/journals/pri/2013/642496/