FOLH1 and neoplasm: In addition, with recent developments of theranostic agents (which couple an 18F-labelled diagnostic biomarker and a radiolabelled therapeutic agent) (Bodei, Herrmann, Schöder, Scott, & Lewis, 2022) there is increasing interest in studying 18F-labelled ligands such as PSMA and FAPI as PET tracers to determine tumour growth in orthotopic tumour models, again with the potential for direct translation to the clinic (Holzgreve et al., 2021; Kirchner et al., 2021; Zhang et al., 2022).