RT Journal Article SR Electronic T1 Plasma Levels of Soluble PD-L1 Correlate With Tumor Regression in Patients With Lung and Gastric Cancer Treated With Immune Checkpoint Inhibitors JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 5195 OP 5201 DO 10.21873/anticanres.13716 VO 39 IS 9 A1 KIYOHIRO ANDO A1 KAZUYUKI HAMADA A1 MAKOTO WATANABE A1 RYOTARO OHKUMA A1 MIDORI SHIDA A1 RIE ONOUE A1 YUTARO KUBOTA A1 HIROTO MATSUI A1 TOMOYUKI ISHIGURO A1 YUYA HIRASAWA A1 HIROTSUGU ARIIZUMI A1 JUNJI TSURUTANI A1 KIYOSHI YOSHIMURA A1 TAKUYA TSUNODA A1 SHINICHI KOBAYASHI A1 SATOSHI WADA YR 2019 UL http://ar.iiarjournals.org/content/39/9/5195.abstract AB Background/Aim: Cancer immune therapy by immune checkpoint inhibitors (ICIs) is a promising therapeutic strategy for various cancer types. Among ICIs, anti-programmed cell death protein-1 (PD1) and anti-programmed death-ligand 1 (PD-L1) antibodies have shown a remarkable clinical benefit. The present study aimed to address the functional and clinical significance of serum levels of soluble PD-L1 (sPD-L1) in patients. Materials and Methods: A total of 21 patients, 11 with NSCLC, nine with gastric cancer and one with bladder cancer, who underwent anti-PD-1 therapy were evaluated for sPD-L1 concentration by ELISA analyses at diagnosis and after treatment. Results: Pretreatment levels of sPD-L1 in patients who received ICIs were not remarkably correlated with the overall survival of these patients (r=0.3394, p=0.1323). Reduction of plasma sPD-L1 level was significantly correlated with tumor regression in patients administered four cycles of treatment (p<0.05). Conclusion: sPD-L1 might be derived and secreted from tumors and might be useful to identify primary responders to ICIs at a relatively early treatment timepoint.