CD274 and neoplasm: Additionally, technetium-99m labeled peptide GX1, which specifically binds to tumor vessels of gastric, colorectal, and glioma tumors, shows promise as a new tumor imaging biomarker.87,88 Copper-64 labeled PD-L1 affinity peptide WL12,89 with PET imaging results indicating that [64Cu] WL12 can be used as a radiotracer to specifically detect tumors expressing PD-L1, providing a basis for the development of tumor immunotherapy strategies.