Similarly, glioma CSCs polarize macrophages and microglia by the production of colony-stimulating factors (CSFs), transforming growth factor β (TGF-β), and macrophage inhibitory cytokine 1 (MIC-1), and glioma CSC-conditioned medium promoted the immunosuppressive properties of macrophages (25–27). Here, TGFB1 is linked to central nervous system cancer.