FAP and cancer: FAPI-PET might be seen as a target imaging, due to the fibroblast activation protein inhibitor (FAPI), a radiopharmaceutical labeled with either 68Ga (gallium-68) or 18F (Fluorine-18), targeting the fibroblast activation protein (FAP), overexpressed in cancer-associated fibroblasts (CAF) and rarely expressed in normal tissues [86].