High PD-L1 expression is associated with stage IV disease and poorer overall survival in 186 cases of small cell lung cancers.
BACKGROUND
Small cell lung cancer (SCLC) is an aggressive malignancy with a distinct natural history and dismal prognosis. SCLC is characterized as a recalcitrant neoplasm with limited therapeutic options and platinum-based chemotherapy is the treatment of choice. Programmed cell death-ligand 1(PD-L1)-mediated immune escape may be a suitable target for specific therapy, but its role in SCLC is unclear.


METHODS
In total, 186 SCLC cases were investigated. Paraffin-embedded tumor sections were stained with a PD-L1 antibody. PD-L1 overexpression was denoted by moderate-to-strong PD-L1 membrane staining in ≥ 5% of tumor cells. Tumor cells and infiltrating lymphocytes were scored separately.


RESULTS
The overall frequency of PD-L1 overexpression, in tumor cells and tumor infiltrating lymphocytes (TILs) was 78.0% and 54.3%, respectively. High tumor PD-L1 expression was significantly correlated with high TIL PD-L1 expression (P=0.001) and stage IV disease (P=0.048). Multivariate analysis revealed that high tumor PD-L1 expression and stage IV disease were two independent risk factors for poor overall survival.


CONCLUSIONS
High PD-L1 expression was observed in SCLCs compared with their expression in conventional NSCLCs. The aggressive behavior of SCLC could be partially related to PD-L1-mediated immune escape. High PD-L1 expression correlated with poor prognosis and may provide a rationale for immunotherapy for high-grade SCLC.
Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 10002, Taiwan.|Graduate Institute of Pathology, National Taiwan University College of Medicine, Taipei 10002, Taiwan.
Yih-Leong
YL
Chang
Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 10002, Taiwan.|Graduate Institute of Pathology, National Taiwan University College of Medicine, Taipei 10002, Taiwan.
Ching-Yao
CY
Yang
Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 10002, Taiwan.
Yen-Lin
YL
Huang
Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 10002, Taiwan.|Graduate Institute of Pathology, National Taiwan University College of Medicine, Taipei 10002, Taiwan.
Chen-Tu
CT
Wu
Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 10002, Taiwan.|Graduate Institute of Pathology, National Taiwan University College of Medicine, Taipei 10002, Taiwan.|National Taiwan University, Taipei 10617, Taiwan.
Pan-Chyr
PC
Yang
D000328:Adult; D000368:Aged; D060890:B7-H1 Antigen / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D016246:Lymphocytes, Tumor-Infiltrating / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D055752:Small Cell Lung Carcinoma / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D019139:Tumor Escape / Q000276:immunology
D060890:B7-H1 Antigen; D014408:Biomarkers, Tumor; C423236:CD274 protein, human
immunotherapy; overall survival; programmed cell-death ligand 1; small cell lung cancer; stage