The validation qRT‐PCR of selected M/M polarization markers (CCL2, TLR2, IL1B, MRC1, CD14, CD163, PTGS2, MSR1, CD163L) in GAMs from eight GBM patients (n = 7 IDH1R132H‐non‐mutant, n = 1 IDH1R132H‐mutant) and one exemplary patient with IDH1R132H‐mutant anaplastic astrocytoma WHO grade III as compared to three different samples of WM microglia (Figure 1C) largely confirmed the microarray data. Here, PTGS2 is linked to glioblastoma.