CD274 and neoplasm: In contrast, small molecule-based PD-L1 radiotracers yielded fewer promising outcomes so far, mainly caused by high non-specific binding, relatively low in vivo tumor uptake, and primarily hepatobiliary clearance (Bamminger et al. 2024; Hu et al. 2023; Huang et al. 2023; Lu et al. 2024; Lv et al. 2021; Maier et al. 2022; Miao et al. 2020; Xu et al. 2023; Yang et al. 2024; Zhu et al. 2023).