The significance of programmed cell death ligand 1 expression in resected lung adenocarcinoma

Abstract

// Shafei Wu 1, * , Xiaohua Shi 1, * , Jian Sun 1 , Yuanyuan Liu 1 , Yufeng Luo 1 , Zhiyong Liang 1 , Jinghui Wang 2 , Xuan Zeng 1 1 Department of Pathology, Peking Union Medical College Hospital, Beijing, China 2 Department of Medical Oncology, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University, Beijing, China * These authors are co-first authors Correspondence to: Xuan Zeng, email: zengxuan88@yahoo.com Keywords: lung adenocarcinoma, programmed cell death ligand 1, immunohistochemistry, in situ hybridization Received: October 11, 2016      Accepted: January 16, 2017      Published: January 27, 2017 ABSTRACT Background: Lung adenocarcinoma (AD) is a common variant of non-small cell lung cancer (NSCLC). Programmed cell death protein 1/programmed cell death ligand 1 (PD1/PD-L1) are promising immunotherapy targets and its expression may be an important biomarker of predicting clinical response. In this study, we evaluated PD-L1 expression in conjunction with clinicopathological characteristics and outcomes in resected lung adenocarcinoma. Results: This study included 133 cases of lung adenocarcinoma. PD-L1 expression rate in lung adenocarcinoma was 16.5% at the mRNA level and 13.5% at the protein level, and the kappa coefficient of the two examination methods was 0.824 ( P = 0.219, highly correlated). PD-L1 was highly expressed in male patients and smokers with lung adenocarcinoma ( P = 0.019 and 0.002, respectively), while no associations were identified between PD-L1 expression and age, tumor size, clinical stage, positive pleural invasion, lymph node metastasis, or therapy methods. Overexpression of PD-L1 was a significant indicator of shorter recurrence free survival time and overall survival ( P = 0.000 and 0.000, respectively). Multivariate analysis revealed that PD-L1 expression was an independent risk factor for poor recurrence free survival and overall survival ( P = 0.009 and 0.016, respectively). Materials and Methods: Expression of PD-L1 was examined with immunohistochemistry, using the VENTANA PD-L1 (SP263) rabbit monoclonal antibody. mRNA levels of PD-L1 were evaluated using in situ hybridization. Conclusions: PD-L1 overexpression is more frequently observed in male patients and smokers in lung adenocarcinoma. PD-L1 expression is an indicator of worse prognosis in surgically resected lung adenocarcinoma patients.