FSHR and breast cancer: Utilizing monoclonal antibody against FSHR (FSHR-mAb) on polyethylene-glycol- (PEG-) functionalized graphene oxide (GO) nanosheets and 64Cu as a radiolabel to visualize GO conjugate distribution via PET imaging, Yang et al. [114] showed metastatic tumor targeting of GO conjugates in breast cancer and lung metastasis mouse models and high specificity for FSHR.