PDGFRA and glioblastoma: While PDGFRA alterations were also present in a subset of the conventional glioblastomas (48/450, 11%), activating missense mutations in PDGFRA occurring in the absence of focal PDGFRA amplification were rare (2/450, < 1%), with the vast majority of conventional glioblastomas harboring focal high-level PDGFRA amplification (46 of the 48 altered tumors).