ERBB2 and breast cancer: For example, T-DXd was the first ADC approved for HER2-low breast cancer based on immunohistochemical weak positivity [110, 133], while sacituzumab govitecan (Trodelvy®) showed remarkable activity in heavily pretreated triple-negative breast cancer (TNBC), supporting the value of ADCs in patient populations with limited therapeutic options [134, 135].