ERBB2 and cancer: Probes, which are based on DARPin, affibody and anticalin scaffolds, have been proposed for the radionuclide imaging of cancer-associated targets such as epithelial cell adhesion molecule (EpCAM) [33], check point protein B7-H3 [34], programmed death ligand 1 (PD-L1) [35], prostate-specific membrane antigen (PSMA) [36], insulin-like growth factor-1 receptor (IGF-1R) [37] and HER2 [38] during the last two years.