FOLH1 and prostate cancer: PET imaging of PSMA expression is a crucial biomarker in metastatic castrate resistant prostate cancer and a variety of radiopharmaceuticals for imaging and molecular radiotherapy have been developed.13 The Lys-urea-Glu motif is a simple ligand, which effectively targets PSMA and has been utilised in a variety of applications from radiopharmaceutical development to drug delivery.14,15 A SO3F-bearing Lys-urea-Glu dipeptide was synthesised following Scheme 1.