CCL2 and cancer: Cancer-associated fibroblasts secrete high levels of pro-inflammatory cytokines, including IL-1β, IL-8, IL-10, tumor necrosis factor-alpha (TNFα), monocyte chemoattractant protein-1 (MCP-1/CCL2), SDF-1/CXCL12 and interferon-beta (IFN-β), which have a range of effects on the immune system [7].