CXCR4 and leukemia: In our view, by far targeting chemokines and adhesion factors represented by CXCL12/CXCR4 axis and E-selectin to mobilize leukemic cells from their protective niche tend to be one of the most successful strategies for targeting resting leukemia cells, with emerging clinical trials demonstrating the effectiveness of this strategy in conjunction with circulating cell-targeted traditional chemotherapy regimens.