CD274 and neoplasm: PD-L1-specific affibodies (three helical protein structures with specific protein affinity) have also been designed and tested in vivo in mice and rhesus monkeys and confirmed specific tracer uptake in PD-L1 positive tumours on the same day as tracer administration.128 This feature possibly overcomes practical limitations of whole antibody approaches which can take 5–7 days for sufficient blood clearance post-PET tracer administration.