Collectively, these results suggest that like CXCR4/CXCL12, the CCR2/CCL2 and CCR5/CCL4 receptor/chemokine axes contribute to leukemia-MSC interactions, and that the chemokines expressed by MSCs are regulated, at least in part, by ARC in AML cells. The gene discussed is CCR5; the disease is acute myeloid leukemia.