We have previously reported on gold nanoparticles (AuNPs) functionalized with a macrocyclic thiol-DO3A derivative and with a bombesin peptide analog, which have shown a favorable affinity towards gastrin-releasing peptide receptor (GRPR), remarkably high internalization into human pancreatic PC3 cancer cells, T1/T2 MRI properties and promising properties as radiosensitizers [16,17,18,19]. This evidence concerns the gene GRPR and cancer.