89Zr-labeled pertuzumab (89Zr-pertuzumab) has been used to detect HER2-positive breast cancer in small human cohorts [42,43] and to delineate tumors and show treatment effects from trastuzumab-emtansine (T-DM1) in HER2-positive breast cancer xenografts [44]. The gene discussed is ERBB2; the disease is breast carcinoma.