IDH1 and astrocytoma (excluding glioblastoma): Gliomas which bear no mutation in the IDH1 or IDH2 gene (called ‘wild‐type’ gliomas) are classified as glioblastoma (Grade 4), while IDH‐mutant gliomas are classified as either astrocytoma (Grade 2–4) or oligodendroglioma (Grades 2 and 3) depending on other genetic/molecular markers (e.g., 1p/19q codeletion status) [2, 7].