IDH1 and oligodendroglioma: Characteristic molecular alterations include IDH1/2 mutations, TP53 mutations and ATRX loss in astrocytomas; IDH1/2 mutations and chromosome 1p/19q codeletions in oligodendroglioma; and TERT promoter mutations, EGFR amplification and chromosome 7 gain/10 loss in glioblastoma (GBM) [86].