Furthermore, ex vivo immunophenotyping of these tumors presented a high abundance of PD-L1-expressing TAMs and GSCs, which relates to TAM infiltration seen in human mesenchymal GBM.35 Conversely, there was only negligible uptake in the GL261PD-L1KO tumors, which appears to reflect endothelial cell PD-L1 expression as seen with IHC. This evidence concerns the gene CD274 and glioblastoma.