Programmed cell death –ligand 1 (PD-L1) expression in primary tumor and metastatic lymph nodes in head and neck squamous cell carcinoma

Abstract Background Programmed cell death protein 1 (PD-1) is commonly found on T lymphocytes, while programmed cell death ligand 1 (PD-L1) is commonly overexpressed in tumor cells. Elevated levels of PD-L1 allow malignant cells to evade immune surveillance and suppress antitumor immune responses. Objective To elucidate the immunological changes that may occur in lymph nodes related to HNSCC and may contribute to distant metastasis. Also, to compare PDL-1 expression in primary tumors and lymph nodes in N0 or N+ patients. Patients and methods A prospective observational cohort study with cross-sectional analysis of surgical specimens was executed on 40 HNSCC patients exhibiting resection of both primary tumor and metastatic lymph nodes and then histopathological examination using PDL-1 staining from February 2023 until February 2025. Results There were significant differences in the combined positivity score (CPS) between N0 and N+ patients. increasing PDL-1 expression is much elevated in patients having lymph node metastasis. Conclusion A significant increase can be seen in PDL-1 expression in patients with lymph node metastasis(LNM). In comparison to N0 patients. PDL-1 can act as a reliable indicator for assessing tumor aggressiveness and metastatic potential in HNSCC.