IDH1 G394T and IDH2 A514G mutants exhibited the same characteristics, except that they were differentiated from each other by the presence of MGMT methylation in the 5–10% region in the former and not the latter.89,91,92 IDH2 G515T mutants exhibited the previously reported93 association with 1p/19q codeletions, as well as ATRX retention, no EGFR amplification, and unmethylated MGMT, in oligodendroglioma. The gene discussed is EGFR; the disease is oligodendroglioma.