CD274 and glioblastoma: Consistent with previous reports that GBM expresses high levels of PD-L1 [35,36,37], the transcriptomic analysis demonstrated that the level of PD-L1 in mGBM was noticeably higher than in benign tissue, while GBM and the other GBM subtypes displayed a tendency for increased levels of PD-L1 relative to the corresponding controls (Figure 1E).