Small-cell　lung　cancer　(SCLC)　is　an　aggressive　high-grade　neuroendocrine　tumor　with　limited　treatment　strategies.　Programmed　death　1　(PD-1)　and　its　ligand　(PD-L1),　delta-like　ligand-3　(DLL-3),　and　poly　ADP-ribose　polymerase　(PARP)　inhibitors　have　shed　light　on　the　treatment　of　extensive　stage-SCLC.　However,　the　expression　and　prognostic　role　of　PD-L1,　DLL-3,　and　PARP　are　barely　explored　in　surgically　resected　limited　stage-SCLC　(LS-SCLC).We　retrospectively　reviewed　404　SCLC　patients　from　2011　to　2018　in　the　First　Affiliated　Hospital　of　Xi＇an　Jiaotong　University　and　collected　43　surgically　resected　LS-SCLC　samples　with　adequate　materials　and　histological　specimens　containing　abundant　tumor　cells.　Immunohistochemistry　staining　of　PD-L1,　DLL-3,　and　PAPR1　was　performed　by　anti-PD-L1　(22C3/Dako),　anti-DLL-3,　and　anti-PAPR1　antibodies,　respectively.　Positive　expression　of　PD-L1　was　characterized　as　＞5%　tumor　cells　and/or　tumor-infiltrating　immune　cells　expressing　PD-L1.　The　correlation　between　PD-L1,　DLL-3,　PARP1,　and　clinicopathological　characteristics　of　surgically　resected　LS-SCLC　patients　was　performed　by　χ2　test.　The　survival　curves　were　calculated　by　the　Kaplan-Meier　method　and　analyzed　by　the　Log　rank　test　and　Cox　proportional　hazards　model.63.04%　patients　were　positive　for　PD-L1,　65.12%　were　positive　for　DLL-3,　and　20.93%　were　positive　for　PARP1.　DLL-3　was　significantly　overexpressed　in　SCLC　tissues,　compared　with　matched　para-noncancerous　tissues.　Male,　elder　than　60　years　old,　advanced　TNM　stage,　smoking,　and　positive　PD-L1　expression　predicted　shorter　DFS,　while　patients　received　adjuvant　therapy　performed　better　DFS.　Further　multivariate　analysis　revealed　that　TNM　stage　(HR=2.51,　95%　CI=1.31-4.78,　P=0.005)　was　an　individual　prognostic　factor　for　DFS　in　LS-SCLC.　Moreover,　advanced　TNM　stage　and　positive　PD-L1　expression　also　indicated　worse　OS,　but　adjuvant　therapy　improved　OS　in　LS-SCLC.　Multivariate　analysis　demonstrated　that　PD-L1　and　TNM　stage　were　independent　and　significant　negative　predictive　factors　for　OS　(HR=2.89,　95%　CI=1.21-6.93,　P=0.017;　HR=2.49,　95%　CI=1.25-4.94,　P=0.009　for　PD-L1　and　TNM　stage,　respectively),　while　adjuvant　treatment　was　an　independent　positive　prognostic　factor　for　OS　(HR=0.37,　95%　CI=0.17-0.81,　P=0.012).