CA9 and breast cancer: Alternatively, high affinity CAIX mAbs capable of receptor-mediated internalization have the potential to provide effective vehicles for targeted delivery of various therapeutic compounds, including cytotoxins and radionuclides, as has been demonstrated clinically for antibody-drug conjugates such as ado-trastuzumab emtansine (T-DM1) in breast cancer (Lambert and Chari, 2014).