68Ga-OncoFAP microPET/CT imaging in different breast cancer mouse models

Abstract

BackgroundBreast cancer (BC) is currently the most common malignancy worldwide and the leading cause of cancer-related death in women. Positron emission tomography/computed tomography (PET/CT) with fluorine-18-2-fluoro-2-deoxy-glucose (18F-FDG-PET) plays an important role in staging breast cancer, and now many promising tracers for tumor imaging are striving for superior breast cancer detection and monitoring. Some studies have reported better results regarding the diagnostic and therapeutic value of FAP ligands, especially in the diagnostic evaluation of primary BC. MethodsIn this study, we have successfully radiolabeled the 68Ga-OncoFAP, which is FAP (Fibroblast activation protein) targeting tracer, and tested the imaging efficacy in both subcutaneous ER-positive MCF-7 breast cancer tumors models and orthotopic triple negative MDA-MB-231 breast cancer tumor models. ResultsMCF-7 subcutaneous tumors and MDA-MB-231 orthotopic tumors exhibited a high uptake of 68Ga-OncoFAP, which correlated with the corresponding pathological results. Between 30 and 100 min post injection, the tumor-to-background ratio (TBR) of MDA-MB-231 orthotopic tumors gradually decreased, but to a limited extent, all less than 10%. 68Ga-labeled OncoFAP could be applied for noninvasive imaging of breast cancer, and we could observe the metabolism of the probe by the MicroPET imaging. Conclusions68Ga-OncoFAP could selectively image fibroblast activation protein in mice models and is very promising for the diagnosis of different histological and molecular subtypes of breast cancer.