CCL3 and glioma: The predominance of M2 macrophages in the glioma microenvironment has been described to be associated with poor survival and resistance to radiotherapy, whereas M1 macrophages have been reported to be less abundant in high-grade glioma and expression of M1 marker C–C motif chemokine ligand 3 (CCL3) was further associated with a good survival (47, 48).