CD274 and glioblastoma: However, in two studies on glioblastoma multiforme (GBM), one study by Ricklefs et al. found that mesenchymal subtypes with higher expression of exosomal PD-L1 were more likely to inhibit T cells [38], while the other study by Himes et al. found that GBM derived exosomal PD-L1 did not significantly inhibit T cells [39].