We utilized RCC cell lines with high CAIX (SKRC-09, Fig. 1a), moderate CAIX (SKRC-52, Fig. 1b), or no CAIX expression (SKRC-59, Fig. 1c), and found that all five antibodies mediate ADCC in accordance with the relative expression level of CAIX on RCC lines (Fig. 1 and Additional file 1: Figure S1A) [28]. Here, CA9 is linked to renal cell carcinoma.