As reported in our previous work, these biphenyl-basedPD-L1 radioligandsexhibit high albumin binding, which could contribute to the bindingpattern through a low fraction of free radioligand and high amountof radioligand bound to albumin.45 Presumably, the tumor uptake at 24 h may notbe attributed to the free radioligand but to the radioligand-albumincomplex, resulting in a loss of specificity between both tumors. This evidence concerns the gene ALB and neoplasm.