IDH1 and oligodendroglioma: Tumors with mutations in IDH1 or IDH2 and simultaneous loss of the entire chromosome arms 1p and 19q (and wildtype ATRX and TP53) are classified as ‘Oligodendroglioma, IDH-mutant and 1p/19q-codeleted’, and frequently have alterations in CIC, FUBP1, and the promoter region of TERT [50, 91, 101, 124].