CA9 and neoplasm: In vivo, 99mTc-(HE)3-ZCAIX:1 showed efficient and specific targeting of CAIX-expressing SK-RC-52 xenografts, since the tumor uptake was reduced from 9.7±0.7 to 0.4±0.1% ID/g (P<5×10−7) by pre-saturation of CAIX in vivo (Fig. 2).