Lower-grade gliomas with both an IDH mutation (a mutation in either IDH1 or IDH2) and deletion of chromosome arms 1p and 19q (1p/19q codeletion), which occurs most often in oligodendrogliomas, had better responses to radio chemotherapy and were associated with longer survival than diffuse gliomas without these alterations (56). The gene discussed is IDH1; the disease is oligodendroglioma.