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Abstract

Background:  In a subgroup of patients with advanced stage lung cancer, immunotherapy that specifically targets the PD-L1/PD-1 pathway has been demonstrated to enhance survival. Expression of PD-L1 in cancer cells has been recognized as a promising biomarker for predicting the probable response of patients to anti-PD-L1 or anti-PD-1 therapy. The objective of this study is to examine the frequency of PD-L1 expression in non-small cell lung cancer (NSCLC) in Iraqi patients and its association with clinicopathological parameters that can offer useful insights for making treatment approaches more effective and enhancing clinical outcomes. Methods:  This is a cross sectional study on 94 non-small cell lung cancer tumor samples collected from teaching laboratories of Medical City Teaching Complex. The programmed cell death ligand 1 (PD-L1) expression was evaluated using immunohistochemistry. PD-L1 protein expression level is established by usage of Tumor Proportion Score (TPS). The specimen would be regarded to possess positive PD-L1expression result if the TPS ≥ 1% and to have high PD-L1 expression if the TPS ≥ 50%. PD-L1 expression is then compared with different clincopathological features. Results:  Positive PD-L1 expression (≥1%) was seen in 39 cases (41.5%) of NSCLC patients. In 12 cases (12.7%), there was high expression in ≥50% of tumor cells. of NSCLCs. A non-significant association was found between age& PD-L1 scores. While PD-L1 levels were significantly expressed with higher levels in female patients than males. Conclusions:  High levels of PD-L1 expression is observed in a significant percentage of NSCLC. Immunohistochemistry is needed to reveal cases that benefit from immunotherapy. A lower patient age was correlated with higher PD-L1 expression. Keywords:  Programmed cell death ligand 1, Non-Small Cell Lung Cancer, Tumor proportion score