Differential prognostic value of PD-L1 expression in oropharyngeal squamous cell carcinoma based on HPV status

OBJECTIVE: To investigate the correlation between PD-L1 expression and HPV status in oropharyngeal squamous cell carcinoma (OPSCC) and evaluate their prognostic implications. METHODS: We retrospectively analyzed 131 OPSCC patients treated at the Affiliated Hospital of Qingdao University. PD-L1 and p16 expression were evaluated via immunohistochemistry, and HPV status was determined via PCR. Between-group differences in baseline characteristics were analyzed using ANOVA, t-test, chi-square, or Fisher's exact test. Survival outcomes were evaluated via Kaplan-Meier and Cox proportional hazards models. RESULTS: HPV-associated OPSCC was identified in 51.1 % (67/131) of patients. PD-L1 expression was prevalent (89.3 %), with 47.3 % (n = 62) showing low and 42.0 % (n = 55) showing high expression (p < 0.001), though no correlation with HPV status was found (p = 0.954). While high PD-L1 expression predicted favorable survival in the overall cohort, its prognostic value was most pronounced in HPV-negative (HPV-) patients (p < 0.05), and it was attenuated and not statistically significant in the HPV-positive (HPV+) subgroup. The HPV+/PD-L1-high group achieved the longest PFS and OS (p < 0.001). Multivariate analysis confirmed HPV+ and high PD-L1 expression as independent protective factors. CONCLUSION: PD-L1 expression is prevalent in OPSCC independent of HPV status. Notably, PD-L1 expression serves as a strong independent prognostic marker specifically in HPV- OPSCC, while its prognostic value is limited in HPV+ OPSCC. This combined stratification facilitates more precise risk assessment, highlighting the clinical potential of biomarker-driven therapeutic strategies.