A high accumulation of [89Zr]GPC1 mAb was observed in the tumor xenograft 1 d after administration (SUVmax, 3.85 ± 0.10), and this level then gradually decreased until day 7 (SUVmax, 2.16 ± 0.30; Figs. 2A and 2B). This evidence concerns the gene GPC1 and neoplasm.