CXCR4 and its ligand CXCL12 are important in the migration of cells to the lymph nodes in acute lymphoblastic leukemia and chronic lymphocytic leukemia [8], [9], [14], [15], they are also an important factor for migration of myeloma cells to the bone marrow [16]–[17]. The gene discussed is CXCL12; the disease is B-cell chronic lymphocytic leukemia.