Theranostics targeting fibroblast activation protein in the pan-cancer field

Fibroblast activation protein (FAP), a membrane-bound glycoprotein overexpressed in cancer-associated fibroblasts (CAFs), is a promising target for diagnostic and therapeutic interventions in oncology. Its elevated expression correlates with tumor progression and metastasis, with minimal presence in normal tissues. Recent advancements in FAP-targeted theranostics have focused on positron emission tomography/computed tomography (PET/CT), fluorescence imaging, and targeted radionuclide therapy (TRT). FAP-targeted PET/CT (using FAPI) shows superior sensitivity and specificity over conventional FDG PET/CT, while TRT demonstrates promising clinical efficacy. This review highlights the translational potential of FAP-based theranostics in solid tumor management and proposes an integrated framework for clinical applications.