Prognostic value of programmed death-ligand 1 in sarcoma: a meta-analysis

// Zhenhua Zhu 1 , Zheng Jin 2 , Mei Zhang 3 , Yajun Tang 3 , Guang Yang 1 , Xiaowei Yuan 1 , Jihang Yao 1 and Dahui Sun 1 1 Department of Orthopaedic Trauma, The First Hospital of Jilin University, Changchun, China 2 Department of Immunology, College of Basic Medical sciences, Jilin University, Changchun, China 3 College of Chemistry, Jilin University, Changchun, China Correspondence to: Dahui Sun, email: sundahui1971@sina.com Keywords: programmed death-ligand 1, sarcoma, prognosis, survival, meta-analysis Received: May 23, 2017      Accepted: June 30, 2017      Published: July 11, 2017 ABSTRACT Background: The prognostic role of programmed death-ligand 1 (PD-L1) in sarcoma remains controversial. We performed a meta-analysis so as to investigate the impact of PD-L1 on clinicopathlogical findings and survival outcomes in sarcoma. Materials and Methods: A comprehensive search in PubMed, Embase and the Cochrane Library was conducted for relevant studies. The odds ratios or hazard ratios, at 95% confidence intervals were used as measures for investigation of the correlation between PD-L1 expression and clinicopathlogical features or survival outcomes. Results: Fourteen eligible studies comprising 868 patients were selected for analysis. Pooled hazard ratios indicated that the association of PD-L1 expression with overall survival in bone sarcoma (osteosarcoma and chondrosarcoma) patients was statistically significant (1.987, 95% CI: 1.224–3.224, p = 0.005), as was its association with event-free survival in bone and soft-tissue sarcoma patients (3.868, 95% CI: 2.298–6.511, p = 0.000). Additionally, the expression of PD-L1 was positively correlated with the infiltration of programmed death 1 (PD-1) positive T-lymphocytes (OR: 4.012, 95% CI: 2.391–6.733, p = 0.000). Conclusions: Our meta-analysis indicated that high PD-L1 expression is likely to be a negative factor for patients with sarcomas and that it predicts worse survival outcomes.