ERBB3 and breast cancer: Those data, together with the capability to exert anti‐tumoral action in cells made resistant to T‐DM1, lapatinib, or neratinib and even the effect of EV20/MMAF on naïve HER2+ cells offer attractive possibilities of using the anti‐HER3 ADC for several indications in the HER2+ cancer clinic, even beyond breast cancer.