BIRC5 and glioblastoma: Intriguingly, the stem cell behavior in glioblastoma cell lines has been associated with upregulation of NOTCH and its downstream signaling pathways, as evident by increased expression of the NOTCH isoforms (NOTCH1, NOTCH2, NOTCH3, NOTCH4) and NOTCH target genes (HES1, survivin) (Figure 1) [24].