These monocyte-derived macrophages are attracted by several chemotactic cues produced by the tumor, including CCL2/MCP1 (monocyte chemotactic protein-1), CCL3/MIP-1α (macrophage inflammatory protein-1alpha), CCL4/MIP-1β (macrophage inflammatory protein-1beta), and CCL5/RANTES (regulated on activation, normal T cell expression and secretion). Here, CCL2 is linked to neoplasm.