Clinical correlation of p16 expression with lymphatic invasion and epithelial-mesenchymal transition (EMT) in oropharyngeal carcinomas.

Background/Aim: To examine the clinical correlation of p16 expression with Epithelial-Mesenchymal Transition (EMT) markers and lymphatic invasion in OPSCC patients in terms of clinical status at presentation, subsequent progression, and survival. Methods: Tissue blocks of biopsy-proven Oropharyngeal Squamous Cell Carcinoma were subjected to Immunohistochemistry (IHC) for evaluating the expression of p16, e-cadherin, vimentin and podoplanin. This expression pattern was correlated with the demographic details, treatment response and survival patterns. Results: 60 patients were finally available for evaluation in this study. Prevalence of HPV infection in our study was found to be 11.7%. E-cadherin expression was found in all HPV-associated patients whereas vimentin was not expressed in any of these. 71.4% patients had low Podoplanin expression and 85.7% had low lymphatic vessel count. Among the HPV- associated patients, 85.8% had T3-T4 stage, 100% had N2-N3 disease and 95% had stage IV disease. It was also found that p16-positive patients had significantly higher 1-year Overall survival (OS) (80%, p=0.045), higher 1-year Progression-free survival (PFS) (60%) and higher 1-year Locoregional recurrence-free survival (LRRFS) (75%) when compared to p16-negative patients. Conclusion: Prevalence of HPV infection was found to be similar to that of previous studies conducted in India. As previous literature suggests, the HPV-positive patients in our study presented with advanced nodal disease at presentation and thereby, an advanced overall stage. Further follow-up of these patients including their treatment details, determination of possible prognostic markers, and evaluation of their survival parameters can be done which can help in modifying the existing treatment modalities as HPV-associated OPSCC are known to have better prognosis according to literature.