Research progress for the clinical application of radionuclide labeling fibroblast activation protein inhibitor in the diagnosis and treatment of liver cancer

Liver cancer has high morbidity and mortality worldwide. Traditional morphological imaging can offer crucial anatomical information for the diagnosis and treatment of liver cancer, and when combined with the functional data shown by PET imaging, the diagnostic accuracy of tumors can be further improved and assisted in treatment selection. Fibroblast activation protein (FAP), a signature protein of cancer-associated fibroblasts, is highly expressed in a variety of malignant tumors of epithelial origin and is an important target for tumor diagnosis and treatment. Compared with routinely applied 18F-fluorodeoxyglucose (FDG) PET imaging, FAP inhibitor (FAPI) PET imaging has the advantages of high image contrast and independence from blood glucose. In recent years, a variety of radiopharmaceuticals targeting FAP have been continuously expanded in the diagnosis, staging and targeted therapy of different liver cancer types, and the progress of their related applications is reviewed in this paper.