CXCR4 and plasma cell myeloma: Two multicenter, randomized, double-blinded, placebo-controlled phase III studies recently confirmed that plerixafor combined with G-CSF is superior to G-CSF alone in NHL and myeloma patients.10, 11Several new hematopoietic stem cell mobilization pathways are currently being explored, including drugs targeting the SDF-1/CXCR4 axis,12S1P agonists,13and VCAM/VLA-4 inhibitors.14