title: Prognostic significance of PD-L1 expression in patients with gastric cancer in East Asia: a meta-analysis.
abstract: The overexpression of programmed cell death-ligand 1(PD-L1) has been observed in gastric cancer (GC). However, whether the expression of PD-L1 in tumor cells or blood serum is associated with the prognosis of patients with GC remains unclear. Therefore, we performed a meta-analysis to evaluate the prognostic significance of PD-L1 expression in GC. Electronic databases were searched systematically. Studies that met the inclusion criteria were included in the meta-analysis. Data concerning the hazard ratio (HR) for overall survival and disease-free survival with a 95% confidence interval (CI) according to the expression status of PD-L1 evaluated by immunohistochemistry or enzyme-linked immunosorbent assay were extracted. The data were analyzed using a random effects model. Subgroup analyses were proposed. Our results showed that eight studies with 950 patients met the inclusion criteria and were included in the meta-analysis. The pooled HR for overall survival indicated that patients with PD-L1-positive expression had significantly shorter survival time compared with the PD-L1-negative group (HR 1.60, 95% CI 1.09-2.36, P=0.012). The pooled HR for disease-free survival demonstrated that the difference between the two groups was not statistically significant (HR 1.02, 95% CI 0.32-3.20, P=0.98). In conclusion, our results indicate that the evaluation of PD-L1 overexpression in GC tissue or blood serum may be useful in the future as a novel prognostic factor.
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Yong-Xuan
authors.initials: YX
authors.lastname: Liu
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Xin-Shuai
authors.initials: XS
authors.lastname: Wang
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Wang
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Xiao-Chen
authors.initials: XC
authors.lastname: Hu
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Jun-Qiang
authors.initials: JQ
authors.lastname: Yan
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Zhang
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Rui-Jie
authors.initials: RJ
authors.lastname: Yang
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Feng
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: She-Gan
authors.initials: SG
authors.lastname: Gao
authors.affiliation: Department of Oncology, Cancer Institute, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, People's Republic of China.
authors.forename: Xiao-Shan
authors.initials: XS
authors.lastname: Feng
keywords: OS; PD-L1; gastric cancer; immunohistochemistry; meta-analysis; prognostic