VCAM1 and neoplasm: SPION/MSN composites have also been functionalised with tumour-targeting peptides with Xu et al. tethering VHPKQHR (Val-His-Pro-Lys-Glu-His-Arg) to the MSN shell for targeting of vascular cell adhesion molecule-1 (VCAM-1), providing direct negative contrast MRI reporting on atherosclerotic plaque in vivo [104].