A study on H-score threshold for p16ink4a immunoperoxidase expression in squamous cell tumours of oral cavity

BACKGROUND: Validity of various detection methods used are likely contributing factor to this wide variation of prevalence of HPV (0-73%) by using GP5/GP6/MY09/MY11 (L1) primer. PCR is a sensitive method but does not identify transcriptionally active High-risk Human papillomavirus and also does not indicate whether the virus is isolated from malignant tumour cells and non-neoplastic cells. P16ink4a Immunohistochemistry is a highly sensitive and Cost-effective surrogate marker for transcriptionally active high-risk HPV for oral cancer. Objective The aim of the present study was to evaluate the H-SCORE of p16 expression in the surface epithelial tumour sites of a large cohort of squamous cell carcinoma (SCC), severe dysplasia (SD). we sought to determine whether the p16 algorithm is reliable in Oral cavity SCC and severe dysplasia (SD). MATERIALS AND METHODS: This study used Immunohistochemistry in archival Formalin-fixed paraffin embedded specimens for assessment of p16 protein expression, cytoplasmic and nuclear staining intensity was categorized based on score (range, 0-3) and presence of tumour cell staining (0-100%). RESULTS: The majority of positive cases had low H-score of p16 staining except 3/161 (1.8%) cases of tongue SCC had positive for p16 with diffuse moderate staining with ≥2 scores. There were no significant differences in the distribution of demographic, exposure and histopathological characteristics between patients with and without P16 expression. CONCLUSION: The present study demonstrated that p16 expression is a reliable HPV marker in the lateral border of the tongue with tonsil involvement but no other sites of the oral cavity. Further p16 IHC detection is required in large cohort of all sites of tongue squamous cell carcinoma studies to validate the marker of HPV.