CSPG4 and cancer: As neuro-glial antigen2 (NG2/CSPG4) is a specific biomarker of oligodendrocyte progenitor cells (OPCs) and glioma cancer stem cells (CSC) (26), indirect data on the changes in NG2 expression upon irradiation could be deducted from the changes of OPC cells, which are characterized by high NG2 content.