Based on the role of CXCR4 signaling in ATLL cell maintenance and the beneficial effect of CXCR4 blockade on tumor growth reduction in vivo [164], the potential benefits of the small antagonist peptide, Motixafortide (BL-8040), targeting CXCR4 combined with Nelarabine, a nucleoside analog, is currently being tested for relapsed/refractory T-ALL (ClinicalTrials.gov: NCT02763384). This evidence concerns the gene CXCR4 and acute lymphoblastic leukemia.