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.