Importantly, the prognosis of most patients with IDH-wildtype astrocytic gliomas corresponding histologically to WHO grades II or III has been found to be comparable to that of patients with glioblastoma (GBM) of WHO grade IV, suggesting that genotype is prognostically more important than phenotype in these most common group of gliomas [10, 11]. The gene discussed is IDH2; the disease is glioblastoma.