OLIG2 and ependymal tumor: Expression of particular markers differentially expressed in astrocytic and in ependymal neoplasms [10, 14, 21] revealed low OLIG2 and SOX10 expression (adjusted p = 3.89e − 26 and adjusted p = 7.75e − 65) within the novel group, with similar expression of GFAP (Fig. 3d–f and Supplementary Fig. 2, online resource).