Correlation of immunohistopathological expression of somatostatin receptor-2 in breast cancer and tumor detection with 68Ga-DOTATOC and 18F-FDG PET imaging in an animal model

摘要

Background: Fludeoxyglucose positron emission topography ( 18F-FDG PET) is insufficiently sensitive at detecting small or low-grade breast tumors. The characterization of somatostatin receptors (SSTR) in tumors and the development of 68Ga-DOTATOC PET for imaging could be of interest. The aim of this study was to validate an animal model expressing SSTR2 and to correlate the immunohistochemical (IHC) analysis with 18F-FDG and 68Ga-DOTATOC uptake in vivo. Materials and Methods: Ten nude mice were xenografted with the ZR-75-1 breast tumor cell line. Imaging was performed with 68Ga-DOTATOC and 18F-FDG and correlated to IHC analysis of SSTR2. Results: IHC analyses showed that the tumors expressed SSTR2. On PET imaging, the tumors were barely visible with 18F-FDG, whereas with 68Ga-DOTATOC, specific two-fold higher uptake was observed (p0.005). Conclusion: Our results suggest that 68Ga-DOTATOC PET could be used for detection of breast tumors not detected with 18F-FDG. SSTR2 status should be assessed to allow for individual treatment.