CCL2 and neoplasm: This review compiles current knowledge on the significance of lesser-known chemokines in MM tumor processes, including CXCL13, CCR2 ligands (CCL2 [MCP-1], CCL7 [MCP-3]), CCL4, CCL5 (RANTES), CCL17, CCL20, CCL27, CCL28, and CX<sub>3</sub>CL1 (fractalkine).