IDH1 and glioblastoma: Furthermore, pediatric GBM demonstrate decreased expression of EGFR and reduced mutation rate of IDH1 and TP53 compared to adult GBM, whereas other molecular markers of poor prognosis such as MGMT overexpression and Akt activation remain similar (Pollack et al., 2001, 2006, 2010; Hegi et al., 2005; Paugh et al., 2010; MacDonald et al., 2011).