ERBB2 and breast cancer: Recent developments have included the anti-CD30 ADC brentuximab vedotin [29, 30], which is approved in the USA and EU for the treatment of relapsed or refractory Hodgkin lymphoma and systemic anaplastic large cell lymphoma, and the human epidermal growth factor receptor 2 (HER2)-targeted ADC trastuzumab emtansine [31], which is approved in the USA and EU for the treatment of HER2-positive breast cancer.