Fibroblast activation protein (FAP) plays an important role in changing the situation of the tissue and helps the tumor cells to attack the surrounding tissues. FAP receptor-defined tumors and cancer-associated fibroblasts (CAFs) play an important role in various aspects of malignant tumors such as migration, metastasis, resistance to chemotherapy, and immunosuppression. Therefore, targeting these cells might be useful for both imaging and treatment purposes. This receptor is expressed in various cancers such as bone, brain, breast, colon, esophagus, stomach, liver, lung, mouth, ovary, pancreas, kidney, etc.
The Lu-177-FAPI theranostic radiopharmaceutical, produced by labeling the FAPI 46 peptide with Lutetium-177, intelligently detects FAP receptors, and using the PRRT (Peptide Receptor Radionuclide Therapy) technique, Lu-177-FAPI causes the death of tumor cells in which this type of receptor is expressed. Moreover, being a gamma emitter, it can be used for imaging purposes and following up of the treatment.