A number of chemokines and cytokines mainly secreted by MSCs, including placental growth factors (PGF), macrophage inflammatory protein 1 alpha/beta (MIP-1a/b), IL-1a/b, IL-8 and TNF-α 18, are in more significant quantities in the leukemic microenvironment (LME), which can support the growth of leukemia cells. This evidence concerns the gene CCL3 and leukemia.