IDH1 and glioblastoma: According to the expression of these markers, gliomas of adulthood are classified into three main groups: (i) IDH-mutant, 1p19q co-deleted tumours, with a predominantly oligodendroglial morphology and favourable outcome; (ii) IDH-mutant, non-1p19q co-deleted tumours, with an astrocytic morphology and intermediate outcome; and (iii) IDH wild-type tumours, which are mostly glioblastomas, with an unfavourable prognosis [16].