Gaykema et al. evaluated 89Zr-trastuzumab-PET to determine alteration of HER2 expression after anti-angiogenic treatment with the novel heat shock protein 90 (HSP90) inhibitor NVP-AUY922 in 10 patients with HER2-positive breast cancer (Gaykema et al., 2014). Here, ERBB2 is linked to breast cancer.