IDH1 and glioblastoma: Genome methylation profiling in adult patients with IDH wild-type glioblastoma allowed the definition of three epigenetic subtypes, (i) receptor tyrosine kinase (RTK) I often with PDGFR amplification, (ii) RTK II or classical often with EGFR amplification, CDKN2A/B deletion, and PTEN mutation, and (iii) mesenchymal13.