CCL2 and neoplasm: Similar to MDSCs, TAMs and TANs are recruited to tumor sites by tumor-derived chemokines and growth factors, including CCL2/MCP-1, CXCL1/Gro-a, CCL7/MCP-3, CCL5/RANTES, CXCL8/IL-8, VEGF, PDGF, and M-CSF/CSF-1 [26].