CXCR4 and leukemia: For example, the CXCR4 inhibitor AMD3100 can mobilize HSCs, and inhibition of CXCR4/ CXCL12 signaling has been shown to be useful as an adjuvant in the treatment of hematological malignancies (e.g., leukemia) and solid tumors (e.g., breast cancer) [240, 241, 242, 243].