Biological distribution analysis showed that RKO xenografts have high uptake of 131I-PD-L1-Mab; LS174T xenografts showed moderate uptake, while the uptake of LoVo and SW480 was decreased significantly, and the tumor and spleen uptake of RKO tumor-bearing mice were reduced by injecting excess unlabeled anti-PD-L1-Mab. This evidence concerns the gene CD274 and neoplasm.