POU5F1 and glioblastoma: Both NANOG and POU5F1 are well-known master regulators of pluripotency; specifically, NANOG is implicated in both normal neural stem cell self-renewal and tumorigenesis in glioblastoma multiforme (GBM), while OCT4 functions in the differentiation of neural stem cells into neurons (Po et al. 2010; Zbinden et al. 2010; Deleidi et al. 2011).