Overexpression of CXCR4 in AML correlates with poor clinical outcome [55, 56] and hence, inhibition or blockade of the SDF-1α/CXCR4 axis has become an attractive therapeutic approach for AML [57–59] showing efficacy in preclinical studies [60] and in an ongoing clinical trial with BL-8040 [61]. The gene discussed is CXCR4; the disease is acute myeloid leukemia.