It is well known that tumor cells or stromal cells in the tumor microenvironment secrete chemokines such as C-C motif chemokine ligand 2 (CCL2), C-X-C motif chemokine ligand 1 (CXCL1), CXCL2, and CXCL5 [183,184,185]. This evidence concerns the gene CCL2 and neoplasm.