SOX2 and ependymoma: In the adult nervous system, SOX2 is expressed in NSCs and undifferentiated precursor cells (Wegner and Stolt, 2005), and in cancer SOX2 serves as a marker of proliferating or undifferentiated cells in human malignant gliomas, including pediatric gliomas, and ependymomas (Ferletta et al., 2007; Phi et al., 2008; Annovazzi et al., 2011).