Of note, Notch1 signaling has furthermore been shown to have an essential role in apoptosis resistance in glioma initiating cells.13, 57, 63 Here, we report that inhibition of the Notch1 pathway also increased susceptibility of glioma initiating cells to TRAIL-mediated apoptosis besides sensitizing conventional glioblastoma cell lines. The gene discussed is NOTCH1; the disease is glioblastoma.