HES6 and glioma: Markers of pre-OPC (DLL1, DLL3 and HES6), OPC (PCDH15, PDGFRA and PTPRZ1), and COP (NEU4, SOX6 and VCAN), but not markers of APC (FABP7, FGFR3 and GLAST), were nearly uniformly expressed in the malignant cells in comparison with non-malignant cells from all PM gliomas analyzed, irrespective whether they harbored 1p19q co-deletion or not (Fig. 3B and D and Additional file 1: Fig. S10B and D).