Since 2016, the histological method of subtype classification has been changed to one based on molecular parameter standards, according to which, lower-grade gliomas with the IDH1 mutation and TP53 mutation or ATRX loss are classified as diffuse astrocytoma (IDH1 mutant), gliomas with the IDH1 mutation and 1p/19q co-deletion are classified as oligodendroglioma, and those with IDH1 wild-type are classified as diffuse astrocytoma [10]. The gene discussed is IDH1; the disease is oligodendroglioma.