IDH1 and oligodendroglial tumor: We identified the IDH1 c.395G>A mutation in 14 of the 17 oligodendroglial tumors (82.4% in total, 8/9 O, 6/8 OA), including all 12 tumors with the 1p/19q co-deletion (100%) and two of the three tumors with the “astrocytic” genetic subtype (66.7%), while none of the tumors of the “other” subtype harbored this mutation.