IDH1 and glioblastoma: Comparing normalized expression levels, the mean MARCO expression in IDH1-wild-type GBM macrophages was 160 times higher than in IDH1-mutated GBM (p = 0.020, n = 41 patients, Mann-Whitney U test) and 64 times higher than in LGGs (p = 0.0007, Fig. 1e top, n = 49 patients).