The aim of this study was to investigate the contributions of 1p/19q loss typically observed in oligodendroglial tumors, and ATRX mutation and p53 expression observed in astrocytic tumors and IDH mutation, which is known to have prognostic value in glial tumors and to rediagnose cases according to the new classification. The gene discussed is TP53; the disease is oligodendroglial tumor.