IDH2 and glioblastoma: While certain genes/pathways such as TP53 are commonly mutated in both adult and pediatric glioblastomas, only two of the pediatric tumors contained a change in IDH1 and none harbored alterations in IDH2, PTEN or EGFR. Conversely, PGBMs had a much higher frequency of ATRX mutations when compared to primary adult glioblastoma.