The gastrin-releasing peptide receptor (GRPR) is a G protein-coupled receptor aberrantly expressed in some cancers, including prostate, colon and lung (Jensen et al. 2008), and numerous [18F]AlF-based radioligands have been developed based around bombesin (BBN) analogues (Fig. 10), either full-length or truncated sequences, which bind to GRPR with a high selectivity and affinity. Here, GRPR is linked to cancer.