CSPG4 and glioblastoma: Previous studies indicated that chondroitin sulfate proteoglycan 4 (CSPG4, also known as NG2) a surface type I transmembrane core proteoglycan [79] being involved in several pathways regulating cell survival, angiogenesis, and migration [80], is highly expressed on glioblastoma cells (67%) with restricted intratumoral heterogeneity [81].