CD274 and neoplasm: To determine the suitable molar activity of the radiotracer for radiolabeling with a kit formulation, we first investigated the effect of excess ligands on the biological properties of [99mTc]Tc-HYNIC-WL12-tricine/TPPTS using female C57BL/6N mice bearing MC38-B7H1 tumors, which were confirmed to be PD-L1-positive tumor models by immunohistochemistry (Supplementary Information, Figure S7).