Furthermore, the tumor growth in vivo was decelerated after treatment with Notch2 plasmid in established subcutaneous xenografts of nude mice or treatment with Notch1 siRNA, but combination of these two treatments did not show more efficient than using them singly, indicating that simultaneous downregulation of Notch1 and upregulation of Notch2 had no superimposed effects on biological behaviour of GBM cells. Here, NOTCH1 is linked to glioblastoma.