Initially (Wild et al., 2006), Wild was the first to successfully visualize insulinomas in preclinical studies utilizing Ahx as a linker between DTPA and peptide by c-terminal extension of the Lys side chain coupling of exendin-4 (Lys40NH2 modifies Exendin-4), a landmark for GLP-1R molecular visualization. This evidence concerns the gene GLP1R and pancreatic insulinoma.