CXCR4 and acute myeloid leukemia: The recent development of humanized IgG CXCR4 blocking therapeutic mAbs (BMS-936564/MDX-1338/ulocuplumab and PF-06747143) should overcome this drawback of small-molecule inhibitors, and these mAbs have shown promising results in multiple murine models of hematologic malignancies, including AML, non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, and MM.