CXCR4 and plasma cell myeloma: AMD3100, also known as Plerixafor or Mozobil (Genzyme Corp), is the first CXCR4 antagonist that has been approved by the FDA as mobilizer of hematopoietic stem cells in combination with G-CSF in treatment of patients with non-Hodgkin's lymphoma and multiple myeloma, and many other small molecule inhibitors of CXCR4 are under investigation or in clinical trial for different pathological settings, as recently discussed in detail (Debnath et al., 2013).