CCL2 and neoplasm: TAMs participate in tumor angiogenesis by secreting pro-angiogenic factors, including tumor necrosis factor-alpha (TNF-α), Interleukin-1β(IL-1β), C-C motif chemokine ligand 2 (CCL-2), and matrix metalloproteases (MMPs) (5), which are essential for metastasis and development of late-stage cancers (6).