The tumor-to-muscle ratio in the 1-μg group was about 2.5-fold of that in the 100-μg group, the tumor-to-lungs ratio was about 3.5-fold, and the tumor-to-other organs ratio was approximately twofold of that in the 100-μg group (Fig. 2a), indicating specific binding of the tracer to PD-L1 in humanized mice. The gene discussed is CD274; the disease is neoplasm.