PIK3CA and glioblastoma: The frequency of driver alterations in our dataset recapitulates trends seen in other large genomic studies of GBM and corroborates previous reports of intratumoral heterogeneity of driver alterations including in EGFR, CDKN2A, PTEN, TP53, PDGFRA, BRAF, NF1, PIK3CA, and KIT, among others (Fig. 3b; Supplementary Data 1)32,33.