CCL2 and breast cancer: In this respect, the chemokine (C-C motif) ligand 5 (CCL5/RANTES), the monocyte chemotactic protein-1 (MCP-1/CCL2), interleukin 17B (IL17B) and the chemokine (C-X-C motif) ligand 10 (CXCL10) are known to be involved in the cross-talk between MSCs and breast cancer cells and to favour the development of metastases [2–5].