Fu X, Liu Z, Xiang L, et al. - In surgically resected limited stage-small-cell lung cancer (LS-SCLC), researchers here explored the expression and prognostic role of programmed death 1 (PD-1) and its ligand (PD-L1), delta-like ligand-3 (DLL-3), and poly ADP-ribose polymerase (PARP). From the First Affiliated Hospital of Xi’an Jiaotong University, 404 SCLC patients from 2011 to 2018 were retrospectively reviewed and 43 surgically resected LS-SCLC samples with adequate materials containing abundant tumor cells were collected. Immunohistochemistry staining of PD-L1, DLL-3, and PAPR1 by anti-PD-L1 (22C3/Dako), anti-DLL-3, and anti-PAPR1 antibodies, respectively, revealed 63.04% patients as positive for PD-L1, 65.12% as positive for DLL-3, and 20.93% as positive for PARP1. Multivariate analysis revealed independent and significantly negative predictive value of both PD-L1 and TNM stage for OS, while there appeared an independent positive prognostic value of adjuvant treatment for OS.