CXCL13 and neoplasm: CCR5 binds many ligands which are overexpressed in the tumor microenvironment including CXCL13 (BCA-1), CCL3 (MIP1α), CCL3L1, CCL4 (MP-1β), CCL8 (MCP2), CCL11 (eotaxin), CCL13 (MCP-4), and CCL16 (HCC-4).