Frequency and clinical significance of human papilloma virus in oral cancer ‑ A study from Kerala

Abstract

Background: Oral cancer is a major health problem in India. Recently an increase in the oral cancer incidence among young individuals without any habits was observed, which may be due to Human Papilloma Virus (HPV). However, information on the prevalence of HPV in oral cancer in India is sparse. This study aims to document the frequency of HPV16 infection in oral squamous cell carcinoma (SCC) and to study its correlation with treatment outcome. Methods: Paraffin-embedded tissue blocks of 183 patients with SCC of the oral cavity were studied. HPV16 prevalence was detected by a polymerase chain reaction and expression of p16INK4a was analyzed by immunohistochemistry. This was correlated with clinical outcomes. Results: The prevalence of HPV 16 was 6.6% and all were carcinoma tongue. All HPV-positive patients showed intense expression of p16INK4a. The five-year overall survival (OS) and disease-free survival (DFS) for HPV positive patients were higher compared to HPV negative patients (100% versus 74.5% and 100% versus 70.8% respectively). The five-year OS and DFS for patients with p16INK4a intense expression were also higher compared to p16INK4a weak expression (91.2% versus 57.4% and 82% versus 22.5% respectively). Five-year OS and DFS of patients with HPV16 positivity and p16INK4a intense expression were significantly higher than patients with HPV negative and p16INK4a weak expression (100% versus 54.7% and 100% versus 22.5% respectively). Conclusion: The frequency of HPV16 positivity in oral cancer was low in this study with a site predilection to the oral tongue. p16INK4a expression did not correlate with HPV status. A better treatment outcome was observed in HPV-positive cancers. We also observed better treatment outcomes in patients with p16INK4A overexpression irrespective of HPV status.