NGR-peptide targeting is of further interest, since NGR peptides undergo a non-enzymatic, slow asparagine deamidation to isoaspartate-glycine-arginine (isoDGR) generating a further ligand for alphaV integrins [37, 38], which are also upregulated on tumor endothelial cells [37, 39–41]. Here, RTN4R is linked to neoplasm.