IDH3A and anaplastic astrocytoma: Based on the mutation of isocitrate dehydrogenase (IDH) and the codeletion of chromosome 1p/19q, AGs can be divided into three main distinct subgroups: 1) anaplastic astrocytoma, IDH-mutant (AAmut); 2) anaplastic astrocytoma IDH-wild-type (AAwt); and 3) anaplastic oligodendroglioma, IDH-mutant and 1p/19q codeletion (AOD) (3).