CCL2 and neoplasm: In the tumor microenvironment (TME), circulating monocytic precursors in blood are recruited to tumor site by the growth factors, such as vascular endothelial growth factor (VEGF), transforming growth factor beta (TGF-β), granulocyte-macrophage colony stimulating factors (GM-CSF) and M-CSF and the chemokines CCL2 and CCL5 [1,2].