Currently, several approaches aimed at development of anti-cancer therapeutics targeting CAIX are under evaluation, including small molecule CAIX inhibitors9,10, small-molecule-drug conjugates11,12, anti-CAIX monoclonal antibodies13,14, anti-CAIX antibody-drug conjugates15, and anti-CAIX monoclonal antibodies labeled with cytotoxic radionuclides for targeted radionuclide therapy16,17. Here, CA9 is linked to cancer.