ERBB2 and cancer: The merit of anti-proliferative drugs in the debulking of large tumours is beyond dispute, but these agents are molecularly unselective for cancer, and invariably also damage healthy tissue such as bone marrow and the colonic mucosa.1 Targeted drugs have successfully tackled this issue and facilitated cancer-predominant therapy with a superior safety profile (e.g. trastuzumab for HER2+ breast cancer,2 crizotinib for EML4-ALK+ lung cancer,3 imatinib for BCR-ABL+ leukaemia4).