CD34 and glioblastoma: Although some provocative studies reported that immature GBM stem-like cells are capable of differentiating into functional vascular endothelium and might contribute to tumor angiogenesis[49, 50]recent systematic studies demonstrated using chromogenic in situ hybridization on intact tissue that neoplastic cells are a rare component in human GBM microvasculature, do not incorporate into the vessel wall or express CD34 [51], Thus, blocking NG2/ CSPG4 signaling may have decreased the angiogenic capacity of the tumors mediated by pericytes.