TAMs promote migration of tumor cells via several mechanisms, including the enhancement of endothelial permeability via the release of interleukin-6 (IL-6), C-C motif chemokine ligand 2 (CCL2), and matrix metalloproteinases (MMPs), attaching to VCAM-1 on tumor cells, and suppressing anti-tumor immune cell infiltration [125]. This evidence concerns the gene CCL2 and neoplasm.