CTLA4 and central nervous system cancer: In this study, some important glioma-related genes were not differentially expressed in PDGFRA-overexpressing canine gliomas, including HIF1-α, CTLA4, DLL3, and TNFRSF12A, important mediators of angiogenesis, immune evasion, self-renewal, and invasion65–68 in the tumor microenvironment.