FGF2 and neoplasm: In the present study, we utilized SPIONs to target FGF2 to tumor stroma, as benefits of using SPIONs are manifold, including large surface area and surface functionalization allowing easy conjugation of ligands/proteins on the surface, small size evading reticuloendothelial system and better tumor penetration 44, 45, improved targeting efficiency using external magnetic field and detection by MRI 46.