Human Papillomavirus Prevalence and p16^INK4a Expression in Formalin-fixed, Paraffin-embedded Tissues of Head and Neck Squamous Cell Carcinomas: A Retrospective Study

Aim: To investigate the prevalence of human papillomavirus (HPV) in formalin-fixed, paraffin-embedded (FFPE) head and neck squamous cell carcinoma (HNSCC) tissues. Materials and methods: A total of 176 FFPE tissues of HNSCC were retrospectively collected. The integrity of DNA extracts was evaluated by polymerase chain reaction (PCR) analysis using primers specific for the β-globin gene and 54 DNA extracts were positive for further evaluation. Nested PCR analysis using consensus primers specific to the L1 region of HPV was subsequently performed. HPV typing was investigated using DNA sequencing analysis. The p16^INK4a expression was examined in HPV-positive samples using immunohistochemical staining with p16^INK4a antibody. Results: Out of 54 samples, only one sample (1.85%) was positive for HPV-DNA. DNA sequencing analysis confirmed the presence of HPV type 16. The HPV-positive sample came from a married male patient with a history of smoking and alcohol consumption. The tumor was located on the laryngeal area with the diagnosis of squamous cell carcinoma. Strongly positive p16^INK4a was detected in the HPV-positive sample. The majority of HPV-negative patients had a history of smoking, alcohol consumption, and betel nut chewing habit. Conclusion: Very low prevalence of HPV suggested that HPV might not play an important role in the etiopathogenesis of HNSCC in this group of patients. However, strong p16^INK4a expression was exhibited in the sample with the presence of a high-risk type of HPV. Clinical significance: Smoking, alcohol consumption, and betel nut chewing habit might play a more important role than HPV infection in the carcinogenesis of HNSCC in the present study. The p16^INK4a overexpression could be used to predict the presence of high-risk HPV.