P16 Expression Independent of Human Papilloma Virus in Egyptian Patients with Head and Neck Squamous Cell Carcinoma: A Retrospective Study

Background the prognostic role of human papillomavirus (HPV) associated p16 expression in oropharyngeal squamous cell carcinoma (OPSCC) is well established, however data are less on the prognostic significance of p16 expression independent of HPV status in non-oropharyngeal SCC (non-OPSCC). We evaluated the expression of p16 in different sites of head and neck squamous cell carcinoma (HNSCC) in Egyptian patients in correlation to the relevant clinical characteristics and treatment outcome. Methods Forty-two paraffin blocks of HNSCC were collected and immunostained for p16. Clinical data were extracted from the charts from 2011-2016, at the Clinical Oncology Department- Ain-Shams University, and analyzed for the p16 status. P16 positive case was diagnosed when there was positive diffuse nuclear and cytoplasmic staining of the majority (70 %) of tumor cells. Results Twenty-five (59.5 %) out of 42 patients were positive for p 16, while 17 were negative (40.5 %). P16 + and p16 patients had no differences in age, smoking, tumor site, tumor grade, and stage. Expression of p16 was higher in patients with Eastern Cooperative Oncology Group (ECOG) performance 1 and 2 (p 0.045). No correlation was observed between p16 status and type of treatment or recurrence. P16+ patients tended to have higher incidence of metastases (p 0.062). The p16 status did not affect the disease free survival (DFS) or the overall survival (ORS). Conclusion Most of our patients had positive p16 expression. We could not show significant correlation between p16 status and clinical characteristics, and outcome. Large studies are needed to further investigate the prognostic role of p16 as a marker of HPV infection in non-OPSCC.