Data published in several studies shows CXCR4 expression on leukemic blasts, increased CXCR4 expression on APL cells following ATRA therapy, and the demonstration of increased time-dependent mobilization of APL blasts after CXCR4 blockade in a murine model [57,58,59,60]. This evidence concerns the gene CXCR4 and acute promyelocytic leukemia.