Human papilloma virus (HPV) and methods for its identification in head and neck cancers

Human papillomavirus (HPV) selectively infects the epithelium of the skin and mucous membranes. Specific HPV types are associated with squamous cell carcinoma, adenocarcinoma, and dysplasias of the cervix, penis, anus, vagina and vulva1. The term head and neck cancer includes malignancy in an area that comprises the skin, oral cavity, salivary glands, lip, pharynx, larynx, nasal cavity, paranasal sinuses and soft tissues of the neck and ear2. The first association of HPV with head and neck cancer was published in 1985 3. HPV was also shown to play a role in the pathogenesis of a subset of head and neck squamous cell carcinomas (HNSCCs)4. Almost 650,000 patients worldwide are diagnosed with head or neck cancer each year and 350,000 patients die of this disease as this cancer is the sixth most prevalent type of cancer worldwide. The ratio of males to females is approximately 2:12, 3. From the point of view of the infection, HPVs have developed several molecular mechanisms to enable infected cells to suppress apoptosis5, 6. Based on their potential for oncogenesis, HPV types can be classified both as high-risk or low-risk7. Precancerous lesions of the oral mucosa are epithelial changes that are able to undergo malignant transformation more likely than normal tissue at other mucosal sites8. A total of 150 HPV genotypes have been identified9. The HPV 16 and 18 strains, which are known to cause nearly all cases of cervical cancer, also raise the risk of developing oropharyngeal cancer10. The evident similarities between both cervical and head and neck tumors prompted the utilization of the same HPV diagnostic procedures. There is now compelling evidence that specially designed methodologies must be employed for prognosis11, 12.