Indeed, Crazzolara and colleagues reported a correlation between high CXCR4 expression on leukemic cells and extramedullary organ infiltration [72], whilst Kato and colleagues, using a xenograft mouse model, have demonstrated that liver dissemination of leukemia is driven by the CXCL12/CXCR4 axis [73]. The gene discussed is CXCR4; the disease is leukemia.