Clinicopathological associations of PD-L1 expression and mismatch repair status in laryngeal squamous cell carcinoma
Gizem Teoman, Erdal Rahman Köprücü, Ümit Çobanoğlu, Sevdegül Aydın Mungan, Yakup Kadri Yaralı, Hatice Bengü Yaldız ÇobanoğluAbstract
Objectives
This study aimed to evaluate programmed death-ligand 1 (PD-L1) expression and mismatch repair (MMR) protein status in laryngeal squamous cell carcinoma (LSCC) and to investigate their associations with clinicopathological parameters and overall survival.
Methods
A total of 100 patients diagnosed with LSCC between 2017 and 2024 were retrospectively enrolled in this study. PD-L1 expression was evaluated using both the Tumor Proportion Score (TPS) and Combined Positive Score (CPS) scoring systems. The expression of mismatch repair (MMR) proteins, including MLH1, MSH2, MSH6, and PMS2, was assessed by immunohistochemistry. Associations between biomarker expression and clinicopathological variables were analyzed using univariate and multivariate logistic regression analyses. Overall survival was estimated using the Kaplan–Meier method, and independent prognostic factors were identified using multivariate Cox proportional hazards regression analysis.
Results
PD-L1 expression assessed by CPS was positive (CPS ≥1) in 64 % of cases, while high PD-L1 expression (CPS ≥20) was observed in 16 % of the entire cohort (16/100), corresponding to 25 % of CPS-positive cases (16/64). Using TPS, 48 % of tumors were PD-L1-positive (TPS ≥1 %). All tumors retained MLH1, MSH2, MSH6, and PMS2 expression, indicating proficient MMR. During follow-up, 40 deaths occurred; median overall survival was 74 months, with an estimated mean of 90.97 months (95 % CI: 75.07–106.87). Presenting symptoms were the only independent factor associated with PD-L1 expression (OR=0.214, 95 % CI: 0.067–0.679; p=0.009) and overall survival (HR=2.898, 95 % CI: 1.203–6.977; p=0.018). PD-L1 expression was not independently associated with survival.
Conclusions
PD-L1 expression in LSCC shows limited association with clinicopathological features and does not independently predict survival. MMR deficiency appears to be rare in this tumor type. These findings suggest that PD-L1 and MMR status alone are insufficient as standalone biomarkers, supporting the need for integrated molecular and immune profiling approaches.