Clinical StudiesStudy on the Expression Levels and Clinical Significance of PD-1 and PD-L1 in Plasma of NSCLC PatientsHe, Jiabei*; Pan, Yuanqing†; Guo, Yang‡; Li, Baolan‡; Tang, Yu*Author Information *Cancer Hospital of China Medical University/Liaoning Cancer Hospital & Institute, Shenyang †College of Humanities and Management, Guilin Medical University, Guilin ‡General Department, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, People’s Republic of China B.L. and T.Y.: have contributed equally and share senior authorship. J.H., Y.P.: have contributed equally to the work, mainly responsible for the experiments, data analysis, and article writing. Y.G.: was responsible for assisting J.H. and Y.P. in the experiment. Reprints: Yu Tang, Cancer Hospital of China Medical University/Liaoning Cancer Hospital & Institute, 44 Xiaoheyan Road, Dadong District, Shenyang 110042, Liaoning Province, China (e-mail: firstname.lastname@example.org). Journal of Immunotherapy: June 2020 - Volume 43 - Issue 5 - p 156-164 doi: 10.1097/CJI.0000000000000315 Buy Metrics Abstract As new members of the CD28/B7 costimulatory superfamily, PD-1 (programmed cell death 1) and its ligand PD-L1 (programmed cell death ligand 1) mediate a negative costimulatory signal, which inhibits functioning and proliferation of T and B cells, and reduce interleukin-2, interleukin-10, and interferon-γ secretion. This inhibitory pathway plays an important role in immune escape and the microenvironment of the tumor, and closely related to tumor progression. sPD-1 and sPD-L1 are the soluble form of PD-1 and PD-L1 in peripheral blood, which had not been well investigated. In this study, sPD-1 and sPD-L1 level in peripheral blood of non–small cell lung cancer (NSCLC) patients were determined, and their correlation to clinicopathologic features and long-term survival of these patients were analyzed, so as to provide references for further investigations. Plasma sPD-1 and sPD-L1 levels in 88 NSCLC patients and 40 healthy controls were determined by enzyme-linked immunosorbent assay, and their correlation to clinicopathologic features and long-term survival of these patients were analyzed. Our study showed that the plasma sPD-1 and sPD-L1 were higher in NSCLC patients than in healthy controls, and plasma sPD-L1 and sPD-L1/sPD-1 ratio independently and positively correlated with overall survival of NSCLC patients. This study provides a reference for the assessment of prognosis and risk stratification for NSCLC patients, as well as for immune treatment of cancer. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.