Further decisions on therapeutic modalities are then based on the biomarkers of the tumor and, according to the 5th Edition of the World Health Organization Classification of Tumors of the Central Nervous System (WHO CNS5), particularly the mutational status of isocitrate dehydrogenase (IDH) and the methylation status of methylguanine methyltransferase (MGMT) gene [28]. The gene discussed is IDH3A; the disease is neoplasm.