Abstract 4056: Correlation analysis between PD-L1 expression, TMB and clinical characteristics in Chinese non-small cell lung cancer

Background: Immunotherapy has played an increasingly important role in the treatment of non-small-cell lung cancer (NSCLC) and it was approved for the first-line treatment of advanced lung cancer. PD-L1 expression and TMB are two important immunotherapy biomarkers, however, the relationship between PD-L1 expression, TMB and clinical features is still unclear. Methods: A total of 205 Chinese NSCLC patients (pts) including 120 males and 85 females with a median age of 61.5 years (range 31-84) were enrolled. Tumor stage was evaluated according to the 8th edition of the AJCC/UICC TNM staging system for NSCLC. FFPE tumor and matched blood samples were collected for NGS based 450[[Unsupported Character - Codename s]]gene panel assay. TMB was assessed by standard NGS algorithms. TMB data (median: 5.4 muts/Mb, range 0.8-68.9 muts/Mb) from 206 lesions were provided for analysis. 172, 16 and 18 lesions tissues were analyzed for PD[[Unsupported Character - Codename s]]L1 expression by IHC with 22C3, 28-8 and ZR3 antibodies, respectively. Results: According to TNM staging system, pts were divided into stage I (44 pts), stage II (20 pts), stage III (40 pts) and stage IV (101 pts). The pathological types of pts are adenocarcinoma (69.4%), squamous cell carcinoma (18.4%) and other types (12.1%). 34.5% of lesions were positive for PD-L1 expression (TPS≥1%), including 25.7% PD-L1(TPS≥10%) and 16.5% PD-L1(TPS≥50%) respectively. Significant differences between males and females were observed in PD-L1 expression (TPS≥1%: 40.8% vs. 25.6%, p Conclusion: In this study, we found the most commonly used two biomarkers for immune checkpoint inhibitors, PD-L1 expression and TMB, may be correlated with gender, stage and pathological type of NSCLC patients. There is also a weak correlation between these two biomarkers. Exploring the relationship between immune biomarkers and clinical features may better guide in screening more suitable patients for immune checkpoint blockade. Citation Format: Yang Yu, Xinglong Fan, Yucheng Wei, Zimin Liu, Zuping Lian, Hongxia Han, Ming Yao, Kai Wang. Correlation analysis between PD-L1 expression, TMB and clinical characteristics in Chinese non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4056.