OLIG2 and glioblastoma: To confirm these data at the protein level, we demonstrated by western blotting inall the cell lines that long-term culture in SCM medium of irradiateddifferentiated GBM cells greatly enhanced the expression of Olig2, Sox2 and Nestincompared with untreated cells kept in SCM medium, which nevertheless showed aslight increase of these stem markers compared with FCS-differentiated cells(Figure 5a), as observed at the RNA level (Figure 4a).