CCR2 and plasma cell myeloma: For example, the expressions of macrophage inflammatory protein-1α (MIP-1α, CCL3) and MIP-1β (CCL4) in multiple myeloma cells were found to enhance osteolytic lesions by enhancing osteoclast formation and bone resorption, and, more recently, CCR2 was shown to increase expression of RANK and enhance RANK signaling in ovariectomized mice [23,24].