We employed IHC and flow cytometry because the M2 and M1 markers are also ubiquitous enzymes (iNOS and ARG1) and cytokines (IL10 and IL12) which can be expressed by other Iba1(−) cell types (non-TAM, including other immune cells) in the GBM tumor microenvironment. This evidence concerns the gene ARG1 and glioblastoma.