PD-L1 positivity and relation with clinicopathological characteristics in head and neck squamous cell carcinoma patients

Abstract

Programmed death ligand 1 (PD-L1) is a transmembrane protein expressed on various immune cells including antigen-presenting cells, monocytes, macrophages, activated T and B lymphocytes, as well as on different tumour cells. It plays a role in weakening the T-cell-specific immune response, thereby allowing tumour cells to evade immune surveillance. This study aimed to evaluate PD-L1 expression in tumour tissue and the tumour microenvironment in patients diagnosed with head and neck squamous cell carcinoma (HNSCC), and to explore its association with clinicopathological features. A total of 68 paraffin-embedded tumour samples from surgically treated HNSCC patients were analyzed. PD-L1 immunohistochemical staining patterns, both cytoplasmic and membranous, were assessed in tumour cells and tumour-infiltrating lymphocytes (TILs). Statistical analysis was conducted to investigate the relationship between PD-L1 expression and variables such as age, gender, smoking history, perineural and lymphovascular invasion, tumour stage, and tumour grade. No PD-L1 staining was observed in tumour cells; however, PD-L1 expression was found to be prominent in peritumoral lymphocytes. Among the evaluated clinicopathological parameters, only lymph node metastasis showed a statistically significant correlation with PD-L1 positivity. These findings suggest that while PD-L1 is not expressed in tumour cells of HNSCC, its presence in the tumour microenvironment, particularly in peritumoral lymphocytes, may have clinical relevance. Further large-scale studies are warranted to better understand the implications of PD-L1 expression in HNSCC.

Keywords

• PD-L1
• Cancer Treatment
• Prognosis
• head and neck cancer
• squamous cell carcinoma of head and neck
• larynx cancer

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