ANPEP and breast adenocarcinoma: As expected, significant tracer accretion was observed in HT1080 human fibrosarcoma cells with APN/CD13 overexpression (1.72 ± 0.24% 2 h post-incubation), while CD13-negative MCF-7 human breast adenocarcinoma cells did not exhibit meaningful [64Cu]Cu-Sar-NGR2 uptake (0.4 ± 0.03% 2 h after incubation).