Introduction Predictive biomarkers are still missing in sinonasal cancer. In other malignancies checkpoints like programmed death ligand 1 (PD-L1) are already established as predictive. In this study we analyzed possible prognostic relationships between PD-L1 expression and clinicopathological factors in sinonasal cancer.
Methods We performed immunhistochemical staining for PD-L1 expression on paraffin-embedded slides of sinonasal cancer tissues. In this study we included squamous cell carcinomas (SCC) and adenocarcinomas of the sinonasal tract which were treated between 2004 and 2017 in the Department of Otorhinolaryngology of the University Hospital Münster.
Conclusions In our study we included 95 patients of which 61 patients suffered from a squamous cell carcinoma and 34 from an adenocarcinoma. Tissue samples were available for immunhistochemical staining of every patient. Membrane PD-L1 expression in cancer cells (TPS score ≥ 1 %) was detected in 30 tissue samples (31,6 %). We noticed a significant higher expression of PD-L1 in cancer cells of squamous cell carcinoma (25 cases vs. 5 cases, p = 0,008). Membrane PD-L1 expression did not have a statistical impact on overall- or progression free survival. Furthermore there was no correlation between membrane PD-L1 expression and tumor size, recurrence or lymph node metastasis of sinonasal cancer.
Discussion Our study showed that PD-L1 is not a predictive biomarker in sinonasal cancer. However higher expression rates of PD-L1 in squamous cell carcinoma could potentially be a promising indicator for successfull immun therapy in future. This has to be confirmed in larger cohorts and examined prospectively in patients with sinonasal cancer under immun therapy.
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