CXCR4 and leukemia: To tackle leukemia CSC, neutralizing antibodies to autocrine signaling mediators important for CSC growth such as CD123 [29], antagonist for leukemia CSC localization in the bone marrow niche such as CXCR4-inhibitor AMD-3100 and CD44 antibodies [30], and inhibitors of signaling pathways specifically upregulated in CSCs that are important for the self renewal such as NFκ-β inhibitor parthenolide [31], have been shown to have efficacy in AML or CML.