It is known that the M/MΦ cell population is deeply influenced by soluble factors produced by tumor cells.9, 10 Data in Figure 1a indicate that CD11b+ cells (mainly represented by M/MΦ) isolated from the brain hemisphere ipsilateral to glioma cells injection do express typical anti-inflammatory genes (arg1, ym1, fizz1, cd163 and cd206), with pro-tumor activity that, upon TRAM-34 treatment, undergo a significant reduction of expression. Here, ARG1 is linked to central nervous system cancer.