IDH1 and glioblastoma: PDGFRA positive glioblastoma cases showed a trend towards IDH1 mutation (7/8, 87.5% IDH1 mutant tumours positive for PDGFRA vs 135/263, 51.3% IDH1 wild-type, p = 0.068, Fishers exact test), and exhibited a similar distribution of predominant glioblastoma morphologies as for PDGFRA gene amplification (Figure 4B).