PDL-1 expression in lung carcinoma and its correlation with clinicopathological and prognostic characteristics

Lung cancers have high incidence and high mortality rates. The immune checkpoints as programmed death ligand 1 (PDL-1) can suppress the tumor immune reaction. So, their blocking seems to be a way to treat tumors. This study assesses PDL-1 immunohistochemical expression in lung cancer, and its correlation with prognosis. It included 62 specimens of lung cancer in Hospitals of Mansoura Faculty of Medicine, Egypt. Seventy-one percent of cases showed positive PDL-1 and about 59.1% of them showed high expression. PDL-1 expression in NSCLC was significantly higher than in SCLC (P = 0.019). There were no significant associations between PDL-1 expression and other clinicopathological parameters. A significant mild positive correlation between PDL-1 and EGFR marker was found (P = 0.006). The mean overall survival in cases with positive PDL-1 was lower than negative cases (P = 0.37). Also, progression-free survival was lower among PDL-1 positive cases compared to negative cases (P = 0.5). This study reports that immune checkpoint, PDL-1 is overexpressed in lung cancer especially NSCLC. It is correlated with EGFR overexpression. PDL-1 could have potential to be an effective immune target for lung cancer immunotherapy. But the presence of PD-L1-negative tumors highlights the importance of searching for alternative or combination treatment strategies.Abbreviations: AC: Adenocarcinoma; COPD: Chronic Obstructive Pulmonary Diseases; CTLA-4: Cytotoxic T-lymphocyte-associated protein 4; EGFR: Epidermal Growth Factor Receptor; IHC: Immunohistochemical; NSCLC: Non-Small Cell Lung Cancer; OS: Overall Survival; PD1: Programmed Death 1; PDL-1: Programmed Death ligand 1; PFS: Progression Free Survival; SCC: Squamous cell carcinoma; SCLC: Small Cell Lung Cancer; SD: Standard Deviation; TCR: T-cell receptor; TPS: Tumor Proportion Score.