The clinicopathological significance of PD-L1 expression assessed by the combined positive score (CPS) in head and neck squamous cell carcinoma

Abstract

The expression of programmed cell death-ligand 1 (PD-L1) is being used as a predictive biomarker for immunotherapy in head and neck squamous cell carcinoma (HNSCC). Our study was a retrospective cohort that assessed PD-L1 expression levels through immunohistochemistry (IHC) in 119 surgical specimens from HNSCC patients. The expression of PD-L1 was evaluated by IHC staining using the monoclonal antibody 22C3 (Dako) and the combined positive score (CPS). The relationship between the PD-L1 expression and clinicopathologic features was analyzed. 107 cases (89.9%) and 52 cases (43.7%) were positive for PD-L1 expression when the CPS cutoff value was set at 1 and 20 respectively. The tumor stage (P = 0.022) and tumor site (P = 0.004) were significantly correlated with the PD-L1 expression (CPS ≥ 1). Non-diabetic patients (P = 0.046) were corelated to positive PD-L1 expression (CPS ≥ 20). When evaluating PD-L1 expression in 40 laryngeal squamous cell carcinomas (LSC), the nodal stage was found to be significantly associated with high expression of PD-L1 (CPS ≥ 20) (P = 0.042). As for 36 patients with hypopharyngeal squamous cell carcinomas (HPSC), the positive PD-L1 expression (CPS ≥ 1) were typically younger (P = 0.030) and patients without type II diabetes (P = 0.040). We evaluated all possible clinical prognostic factors in the univariate Cox model, and there was no significant correlation between clinical characteristics and survival. The results of our findings may help to understand the association between the PD-L1 expression and clinicopathological characteristics, and it showed no significant correlation between the expression of PD-L1 and OS in HNSCC.