CCL5 and cancer: M1 exert an anti-tumor effect via direct cancer cytotoxicity through production of reactive oxygen and nitrogen species and/or indirectly via the production of pro-inflammatory cytokines, e.g. interleukin (IL)-12, IL-23 and tumor necrosis factor-α (TNFα), and chemokines [e.g. CCL5, C-X-C Motif Chemokine Ligand (CXCL)5, CXCL9, and CXCL10] and activation of other effector cells (10).