CCL2 and neoplasm: Moreover, tumor cells and GAMs secrete chemokines (e.g., monocyte chemotactic protein-1; CCL2) capable of attracting MDSCs – immature macrophages, granulocytes, dendritic cells, and myeloid progenitors (212) – to the tumor site, where they can further promote tumor growth via release of anti-inflammatory cytokines (e.g., TGF-β, IL-10) (209).