both the dimer and the monomer specifically target APN/CD13 overexpressing HT1080 tumour xenografts, improved tumour accumulation and retention were found for the dimeric compound compared to the monomer, and dimeric [64Cu]Cu-DOTA-NGR2 is a better PET imaging probe for the in vivo visualisation of the APN/CD13 pattern. The gene discussed is ANPEP; the disease is neoplasm.