Snapshot of Clinical Implications of p16 Overexpression in Carcinogenesis

Abstract

Molecular markers are needed to decide the treatment plans of certain cancer types when the histological and other clinical diagnoses are not sufficient to decide the tumor nodular metastasis (TNM) stage. The ubiquitous p16 gene is one of them gained popularity by fulfilling criteria to be a useful biomarker. Over expression of p16, to compensate the inactivity of another two tumor suppressor genes (TSG)s, pRb and p53 due to the integration of E7 and E6 high risk Human Papilloma viral oncoprotein respectively into the host keratinocytes is useful to consider the clinical impact of p16 biomarker in carcinogenesis. The p16 immunohistochemistry helps the diagnosis as well as prognosis of cervical and oropharyngeal squamous cell carcinoma, though there are ambiguities in the cutoff values of p16 positivity. There is also a re-emerging interest on clinical impact of p16 positivity in lung, breast, and colorectal cancer types. High risk HPV genotypes have been already established as the aetiological agents of cervical, other rare ano-genital and oropharyngeal (especially tonsils and base of the tongue) cancers. The HPV associated subset of head and neck cancers demonstrate a unique tumor biology, when compared with HPV non associated ones thus, most effective treatment planning including counselling is much needed to maximize the overall survival of HPV associated cancer patients, in the era of personalized precision medicine. In the shed of light, this communication glimpses on clinical implications of p16 overexpression in carcinogenesis not limiting to cervical and a subset of head and neck carcinomas (HNSCC).