CD274 and glioblastoma: Interestingly, glioblastomas with high PD-L1 expression showed global hypomethylation in differentially methylated probes, i.e., 68% hypomethylation of all differentially methylated probes, 83% of tiling regions, 83% of promoter regions, 76% of genes, and 60% of CpG islands (Figure 3b).