CXCL12 and neoplasm: One such mechanism involves the production of chemokines (e.g. SDF-1, CSF-1, IL-8) that either drive angiogenesis directly or recruit macrophages and other myeloid lineage cells, including CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs), from the bone marrow into tumor tissue [5-11].