It is well recognized that astrocytomas and oligodendrogliomas harboring the IDH mutation demonstrate a better response to chemoradiation therapy, and these patients generally demonstrate better survival outcomes than those with glioblastomas harboring IDH wild-type alleles [3,4], thus emphasizing the importance of non-invasive identification of IDH mutant gliomas. The gene discussed is IDH2; the disease is astrocytoma (excluding glioblastoma).