The M2 macrophages, in addition to producing vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), transforming growth factor β (TGF-β), and hepatocyte growth factor (HGF), also enhance the maturation of regulatory T cells via TGF-β and the infiltration of the tumor by M2 TAMs via chemokine (C-C motif) ligand 2 (CCL2) and colony-stimulating factor 1 (CSF-1). Here, CCL2 is linked to neoplasm.