CD274 and central nervous system cancer: Basing on The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) database analysis and meta-analysis, in two studies involving 976 and 1,052 glioma patients respectively, high PD-L1 mRNA expression level was found to be associated with significantly shorter overall survival (OS) of glioma patients (Wang et al., 2016; Xue et al., 2017b).