POLE and glioblastoma: Additionally, in the TCGA dataset of astrocytoma, their expressions were significantly higher in GBM compared to lower grade astrocytoma (AGII and AGII), (p < 0.0001, Kruskal–Wallis test), except for XRCC1 and POLA1. Among them, MBD4 (methyl-CpG binding domain 4), PLAUR (urokinase plasminogen activator receptor), POLE (DNA polymerase epsilon, catalytic subunit) and RAD51 (RAD51 recombinase) expressions were significantly higher in GBM-MES subtype when compared to CS and PN subtypes (p < 0.05 Dunn test for all comparisons) (Supplementary Fig. 1).