FLT1 and neoplasm: In order to promote tumor growth and survival, the activation of HIF-1α enhances the expression of many proangiogenic factors, including VEGF, VEGF receptors FLT-1 and FLK-1, plasminogen activator inhibitor-1 (PAI-1), angiopoietins (ANG-1 and ANG-2), platelet-derived growth factor B (PDGF-B), and matrix metalloproteinases MMP-2 and MMP-9, that support tumor vascular remodeling and O2 and nutrients delivery [153, 154, 156, 157].