p16 Overexpression in Sinonasal Squamous Cell Carcinoma: Association with Human Papillomavirus and Prediction of Survival Outcomes.

p16 overexpression is often used as a surrogate marker for human papillomavirus (HPV) infection in oropharyngeal squamous cell carcinoma but remains an uncertain diagnostic tool for HPV-related sinonasal squamous cell carcinoma (SNSCC). Our study involved 79 consecutive SNSCC patients who were treated at a tertiary referral university hospital during 2006-2021. We retrospectively examined their clinical characteristics and conducted p16 immunohistochemistry and HPV detection. We found that 12.7% of the patients exhibited p16 overexpression, which was significantly more common in the nasal cavity and increased from 2015 onward. The HPV was a high-risk type and viral loads ranged from 4.2 to 1.6 × 106 copies/ng DNA with genome integration. Five-year overall survival (OS) and five-year relapse-free survival (RFS) rates were 74.6% and 69.9%, respectively. Our multivariate analysis showed that T category (T1-4a) and hemoglobin levels (≥13.7) were significant favorable prognostic factors for OS, while T category, performance status, and p16 overexpression were significantly associated with RFS. In patients with p16 overexpression, OS was 100% and RFS was 90%. Our findings suggest that p16 overexpression is a reliable surrogate marker for transcriptionally active HPV infection and predicts a favorable prognosis.

Coordinated Expression of HPV-6 Genes with Predominant E4 and E5 Expression in Laryngeal Papilloma.

Laryngeal papilloma (LP) associated with human papillomavirus (HPV)-6 or -11 infection shows aggressive growth. However, the detailed molecular mechanism of virus-driven tumorigenesis has not been uncovered fully. HPV-6 viral gene expression and dynamic alterations were investigated with in situ localization of viral DNA and RNA in 13 patients with HPV-6-infected laryngeal papilloma. The average viral load was 4.80 × 105 ± 1.86 × 105 copies/ng DNA. E4, E5a, and E5b mRNAs accounted for 96% of the expression of 9 mRNAs. The alteration of viral DNA load during recurrence paralleled the mRNA expression levels, and the expression of all mRNAs showed a similar curve. E4, E5a, and E5b were expressed in the middle to upper part of the epithelium and were co-expressed in the same cells. E4 immunohistochemistry demonstrated an extensively positive reaction in the upper cell layer in accordance with E4 mRNA expression. These results suggest that individual viral genes are coordinately expressed for viral replication, virus release, and immunosurveillance avoidance. The newly developed E4-specific monoclonal antibody can be applied to further functional studies and clinical applications such as targeted molecular therapies.