However, few insights on the role of FAPI PET/CT imaging are currently available in diseases that are known to overexpress FAP on the malignant cell membrane itself [91], like certain sarcomas, or on the cell membrane of activated fibroblasts within the microenvironment of salivary gland cancer, cholangiocarcinoma, breast cancer, and others. Here, FAP is linked to cholangiocarcinoma.