Plerixafor was also shown to prevent B- and T-ALL cell transendothelial migration and homing into the BM (Figure 2), as well as their extramedullary infiltration in liver, lung and CNS (121–123), highlighting the key role of the CXCL12-CXCR4 module in malignant cell trafficking. This evidence concerns the gene CXCL12 and acute lymphoblastic leukemia.