CXCR4 and neoplasm: Homing of WM cells to the bone marrow is regulated, in part, by the BMSC-secreted chemokine SDF-1 (stromal cell-derived factor 1 that is officially designated chemokine [C-X-C motif] ligand 12 or CXCL12), which binds to the CXCR4 receptor (CD184, fusin) on the tumor cells.