Under the sphere culture conditions, protein expression of SOX2 was decreased, whereas the expression of OLIG2 and POU3F2 was increased in PTPRZ-knockdown C6 and U251 cells compared with the corresponding parental cells (Fig. 2), suggesting a contribution by PTPRZ to stem cell signaling in glioblastoma cells. Here, OLIG2 is linked to glioblastoma.