Tumours with isocitrate dehydrogenase (IDH) mutations are associated with a better survival outcome than those with wild-type IDH genes, independent of pathological grade [4, 5], and patients with grade III gliomas with wild-type IDH may even have a worse prognosis than those with grade IV gliomas with IDH mutations [6]. The gene discussed is IDH2; the disease is central nervous system cancer.