1102P Genomic alterations correlated with the expression of PD-L1 based on the next-generation sequencing in Chinese non-small cell lung cancer

Abstract

Blockade of programmed cell death protein-1 (PD1)/programmed cell death ligand-1 (PD-L1) interaction is one of important immunotherapies in lung cancers. Current research also focused on the relationship between genomic alterations and the expression of PD-L1. Therefore, we analyzed the molecular characteristics and its correlation with the expression of PD-L1, which may help to establish a reasonable tumor classification strategy to improve immunotherapy. Tissue specimens were obtained from 391 cases suffered from lung cancer. Frequencies of gene alterations were detected and analyzed using next-generation sequencing(152 or 603 genes). All specimens were also performed for PD-L1 (22C3) by immunohistochemistry (IHC) with PD-L1 tumor proportion score (TPS) reported for further analysis. In 391 lung cancer samples, 113 (28.9%) cases had comutations in both TP53 and EGFR, 110 (28.1%) cases had alterations in EGFR only, 94 (24.0%) cases had alterations in TP53 only, and 74(18.9%) cases were wild-type of TP53 and EGFR. Two major alterated genes were TP53 (57.0%) and EGFR (52.9%), both of whose frequencies were significantly higher than the other tested genes (P < 0.05). Groups with alterations in EGFR, APC (3.3%) or RBM10 (4.1%) were significantly associated with the decreased expression of PD-L1 (P < 0.05), while alterations in TP53 were significantly associated with the increased expression of PD-L1 (P < 0.05). Comparative analysis revealed that alterations (single or compound mutation) occured in either EGFR or TP53 affect the PD-L1 expression in this Chinese cohort. Although alterations in either EGFR or TP53 has independent and synergistic effects on the PD-L1 expression, there is limited evidence for those alterations serving as predictive biomarkers for the PD-L1 status. Furthermore, whether patients with both high PD-L1 expression and alterations in EGFR or TP53 can benefit from immunotherapies is still in question, and this subgroup is still worthy of clinical molecular recognition by further study.