CCL2 and neoplasm: Tumor-derived soluble mediators such as chemokines (CCL2, CCL5, CXCL12), colony-stimulating factor-1 (CSF-1), TGF-β, IL-10, prostaglandin E2 (PGE2) and metabolites (lactate) likely contribute to the development of TAMs with M2-like phenotype and tumor-promoting properties [16].