CD274 and glioblastoma: Studies in glioblastoma cells revealed that FKBP51s, a spliced isoform of glucocorticoid receptor co-chaperone FK506-binding protein 51 (FKBP51), upregulates the association with glycosylated PD-L1 by catalyzing PD-L1 folding essential for glycosylation and stabilizes PD-L1 in the ER [46].