CXCL12 and neoplasm: Hypoxia inducible factor (HIF)-1 stimulates the local production of factors, including stromal cell-derived factor 1 (SDF1, also known as C-X-C motif chemokine 12, (CXCL12) which promotes the recruitment of bone marrow EPC and CD45+ myeloid cells to the tumor site [21,22].