PDCD1 and neoplasm: They evaluated [64Cu]Cu-DOTA-pembrolizumab in two different mouse tumour models, one bearing hPD-1-expressing 293 T stable cell line xenograft (NSG/293 T/hPD-1) and the other bearing A375 tumour that does not express hPD-1 but in which some infiltrating TILs do express hPD-1 (hNSG/A375), to observe tracer retention time in clearance organs and predict human equivalents dosimetry.