Soluble programmed death-ligand 1 (sPDL1) and neutrophil-to-lymphocyte ratio (NLR) predicts survival in advanced biliary tract cancer patients treated with palliative chemotherapy

// Hyerim Ha 1 , Ah-Rong Nam 2 , Ju-Hee Bang 2 , Ji-Eun Park 2 , Tae-Yong Kim 1 , Kyung-Hun Lee 1,2 , Sae-Won Han 1,2 , Seock-Ah Im 1,2 , Tae-You Kim 1,2 , Yung-Jue Bang 1,2 and Do-Youn Oh 1,2 1 Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea 2 Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea Correspondence to: Do-Youn Oh, email: // Keywords : soluble PDL1, PDL1, immunotherapy, biliary tract cancer, biomarker Received : April 11, 2016 Accepted : October 17, 2016 Published : October 21, 2016 Abstract Programmed death-ligand 1 (PD-L1) expression in tumor tissue is under investigation as a candidate biomarker in immuno-oncology dug development. The soluble form of PD-L1 (sPDL1) is suggested to have immunosuppressive activity. In this study, we measured the serum level of sPDL1 and evaluated its prognostic implication in biliary tract cancer (BTC). Blood was collected from 158 advanced BTC patients (68 intrahepatic cholangiocarcinoma, 56 gallbladder cancer, 22 extrahepatic cholangiocarcinoma and 12 ampulla of vater cancer) before initiation of palliative chemotherapy. Serum sPDL1 was measured using an enzyme-linked immunosorbent assay. Clinical data included neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII, neutrophil × platelet/lymphocyte). The patients were assigned to two cohorts (training and validation cohort) using a simple random sampling method to validate the cut-off value of each marker. Validation was performed using a twofold cross-validation method. Overall survival (OS) of all patients was 9.07 months (95% CI: 8.20-11.33). Median sPDL1 was 1.20 ng/mL (range 0.03-7.28, mean 1.50, SD 1.22). Median NLR, PLR and SII were 2.60, 142.85 and 584.93, respectively. Patients with high sPDL1 (≥0.94 ng/mL) showed worse OS than patients with low sPDL1 (7.93 vs. 14.10 months, HR 1.891 (1.35-2.65), p