CCL5 and central nervous system cancer: Glioma-associated microglia and macrophages are attracted to the tumor,76 where they are polarized into M2-like cells that suppress tumor immunity and support tumor growth.77,78 Activated microglia secrete cytokines and growth factors that promote the growth and angiogenesis of tumor cells, such as IL-10, epidermal growth factor (EGF), and vascular endothelial growth factor (VEGF).76 Microglia can also express the chemokine CCL5, which facilitates the proliferation and survival of oligodendrocyte precursor cells (OPCs), thereby supporting tumor formation and growth.