A putative ependymal differentiation was further supported by differential gene expression analysis between tumors within the novel group and a reference cohort of other glial and glioneuronal tumors, that revealed low expression levels of OLIG2 and SOX10, both suggested to distinguish astrocytic from ependymal tumors [10, 14, 21]. This evidence concerns the gene OLIG2 and mixed neuronal-glial tumor.