title: The prevalence and clinicopathological features of programmed death-ligand 1 (PD-L1) expression: a pooled analysis of literatures.
abstract: OBJECTIVE
  Programmed death-ligand 1 (PD-L1) has been recognized as a critical and promising target in therapies that direct immune escape of cancers. However, its association with aggressive clinicopathological features in solid tumors remains unclear. We investigated this question by synthesizing published articles.
  
  
  METHODS
  Electronic databases were searched for relevant studies. Outcomes of interest included age, gender, tumor size, tumor size, lymph node metastasis and tumor cell differentiation.
  
  
  RESULTS
  A total of 61 studies involving 17 types of malignancies were included. The overall expression rate of PD-L1 was 44.5% (95% CI, 37.5% to 51.6 %). Patients with regional lymph node metastases (OR 1.38; P < 0.01), large size tumor (OR 1.89; P < 0.01) or poor differentiated tumors (OR 1.71; P < 0.01) were associated with higher PD-L1 expression rate. However, no significant association was observed between young and elder patients (OR 1.04; P = 0.58), or male and female patients (OR 1.13; P = 0.06). A numerically higher PD-L1 expression rate was detected in polyclonal antibodies (57.2%) than monoclonal antibodies (39.6%). In addition, the PD-L1 expression rate reported by studies from Asian areas (52.3%) was numerically higher than those from non-Asian areas, namely Caucasians (32.7%).
  
  
  CONCLUSIONS
  This meta-analysis indicated that patients with larger tumors, regional lymph node metastases, or poor-differentiated tumors were associated with a higher PD-L1 expression rate; in addition the expression rate of PD-L1 in Asians might be higher than that of Caucasians. This information might be useful in screening candidates for relevant tests and treatments.
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.|Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.
authors.forename: Ziying
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.|Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yutong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.|Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.|Department of Medical Oncology of Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Yaxiong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.
authors.forename: Qihua
authors.initials: Q
authors.lastname: He
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.
authors.forename: Jianxing
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Thoracic Surgery and Oncology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.|Guangzhou Institute of Respiratory Disease & China State Key Laboratory of Respiratory Disease & National Clinical Research Center for Respiratory Disease, Guangzhou, China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Liang
mesh_terms: D060890:B7-H1 Antigen / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D006801:Humans; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology*; D011379:Prognosis
chemical_list: D060890:B7-H1 Antigen; D014408:Biomarkers, Tumor
keywords: cancer; clinicopathological features; meta-analysis; programmed death-ligand 1