PYHIN genes as potential biomarkers for prognosis of human papillomavirus-positive or -negative head and neck squamous cell carcinomas

The aim of the present study is to determine the expression levels of PYHIN (IFI16 and AIM2) and APOBEC3 (A3A, A3B, A3C, A3D, A3F, A3G, and A3H) gene family members in a cohort of patients with head and neck squamous cell carcinoma (HNSCC) and assess their potential correlation with human papillomavirus (HPV) infection status, clinical characteristics, and survival. For this purpose, 34 HNSCC tissue specimens along with healthy surrounding mucosa were collected from patients surgically treated for HNSCC. Nucleic acids were isolated to assess the presence of HPV and the expression levels of selected molecular markers. Survival analysis was carried out using the Kaplan–Meier method. In HPV-negative (HPV⁻) HNSCCs, we detected low mRNA expression levels of IFI16, A3A, and A3B, whereas these genes were upregulated of 2–100 folds in HPV-positive (HPV⁺) tumors (p < 0.05). Interestingly, AIM2 gene expression levels were predominantly unchanged in HPV⁺ HNSCCs compared to their HPV⁻ counterparts, in which AIM2 was predominantly upregulated (10% vs. 50% of patients). In HPV⁻ tumors, upregulation of TP53, NOTCH1, PD-L1, and IFI16 correlated with lower occurrence of nodal metastases. On the other hand, the expression of APOBEC family members did not correlate with clinical characteristics. Regarding survival, patients with upregulated A3F gene expression had a worse prognosis, while patients without changes in A3H expression had a lower survival rate. In conclusion, our findings indicate that the innate immune sensors IFI16 and AIM2 and some APOBEC family members could be potentially used as biomarkers for disease outcome in HNSCC patients regardless of HPV presence.