CA9 and neoplasm: Notably, the gold accumulation was higher in the GNR/anti-CAIX group (9.3 ± 0.8% ID/g), than the GNR-PEG group (5.6 ± 1.4% ID/g), indicating efficient targeting as seen with preferential accumulation of radiolabeled anti-CAIX mAb in xenografted HT29 tumor at 24 h [39–41].