HIFs activate the expression of multiple angiogenic growth factors that contribute to intratumoral blood vessels, including vascular endothelial growth factor (VEGF), stromal-derived factor 1 (SDF1; also known as CXCL12), stem cell factor (also known as KIT ligand), placental growth factor, angiopoietin 2, angiopoietin-like 4, and other secreted factors that stimulate angiogenesis locally as well as serving to recruit bone marrow–derived angiogenic cells that participate in tumor vascularization (8, 21, 35, 46, 47). This evidence concerns the gene CXCL12 and neoplasm.