Impact of copy number variant and single nucleotide polymorphism of the programmed death‑ligand 1 gene, programmed death‑ligand 1 protein expression and therapy regimens on overall survival in a large group of Caucasian patients with non‑small cell lung carcinoma
Anna Grenda, Paweł Krawczyk, Tomasz Kucharczyk, Justyna Błach, Katarzyna Reszka, Izabela Chmielewska, Jarosław Buczkowski, Robert Kieszko, Jan Siwiec, Tomasz Kubiatowski, Aleksandra Bożyk, Kinga Krukowska, Bożena Jarosz, Iwona Paśnik, Juliusz Pankowski, Daria Świniuch, Katarzyna Stencel, Michał Gil, Kinga Lew, Rodryg Ramlau, Aleksandra Szczęsna, Sebastian Fidler, Andrzej Sieracki, Andrzej Każarnowicz, Piotr Serwatowski, Tomasz Grodzki, Janusz Milanowski
Abstract
Anti‑programmed death‑1 or anti‑programmed death‑ligand 1 (PD‑L1) blockade may be ineffective in some patients with non‑small cell lung cancer (NSCLC) with high percentage of tumor cells with PD‑L1 expression. In addition, immunotherapy may provide great benefits in patients without PD‑L1 expression. The present study assessed PD‑L1 protein expression by immunohistochemistry, copy number variation (CNV) of <em>PD‑L1</em> and two single nucleotide polymorphisms (SNPs), rs822335 and rs822336, in the promoter of <em>PD‑L1</em> by quantitative PCR in 673 patients with NSCLC. Overall survival time of patients with NSCLC depending on the assessed predictive factors (<em>PD‑L1</em> CNV or SNP) and the treatment methods (immunotherapy in first/second line of treatment or chemotherapy) was analyzed. The present study revealed significantly higher <em>PD‑L1</em> copies number in patients with ≥10% and ≥50% of tumor cells with PD‑L1 expression compared to patients with lower percentage of PD‑L1‑positive tumor cells (P=0.02 and P=0.0002, respectively). There was a significant positive correlation (R=0.2; P=0.01) between number of PD‑L1 copies and percentage of tumor cells with PD‑L1 protein expression. Percentage of tumor cells with PD‑L1 expression was lower in patients with TT genotype of the rs822335 polymorphism compared to those with CC genotype (P=0.03). The present study observed significantly higher risk of death in patients treated with chemotherapy compared to those treated with immunotherapy (P<0.0001; hazard ratio=2.4768; 95% confidence interval, 2.0120‑3.0490). The present study demonstrated a close relationship between <em>PD‑L1</em> copies number, genotype of rs822335 <em>PD‑L1</em> polymorphism and PD‑L1 protein expression on tumor cells. However, the impact of CNV and SNPs of <em>PD‑L1</em> on overall survival of patients with NSCLC requires further investigation.