FOLH1 and prostate cancer: A synthetic urea-based ligand, 2-[3-(1,3-dicarboxypropyl)-ureido] pentanedioic acid (DUPA) is known to selectively bind to PSMA with a high affinity (Ki = 8.0 nM, IC50 = 47 nM) [27,28] and has been successfully employed to PET imaging, therapeutics, and theranostics in prostate cancers [18,29,30,31].