Cai et al. (2015) identified six cytokine signatures among a group of glioma patients with poor survival prognosis. Additionally, the authors related those cytokines with the M2-like phenotype, such as high levels of mRNA encoding IL-10 and TGF-β1, with the glioma progression (Cai et al., 2015). Altogether, it has been suggested that GAMs release MMPs related to tumor invasion, specifically the MMP-2 and membrane type-1 (MT1)-MMP (Osenkowski et al., 2004; Mayes et al., 2006). Here, MMP2 is linked to central nervous system cancer.