However, only a few reports investigated the significance of CCL3 derived from inflammatory cells in a tumor microenvironment: CCL3 derived from basophils contributes to the maintenance of leukemia-initiating cells in chronic myeloid leukemia [25], and CCL3 derived from macrophages and granulocytes contributes to the accumulation of CCR5+ fibroblasts in murine colitis-associated cancer [22]. Here, CCR5 is linked to leukemia.