CCR2 and breast neoplasm: Studies have shown that various cytokines, chemokines, growth factors, and their receptors such as vascular endothelial growth factor (VEGF), VEGF Receptor (22), CXC receptor 1(CXCR1), CCL2 receptor (CCR2) (23), colony-stimulating factor-1 (CSF-1) (24) and toll-like receptors (TLRs) (25) are essential for breast tumor proliferation and metastasis.