GRP and cancer: The bombesin (Bn) receptor family [Gastrin-releasing peptide (GRPR/BB2R) and Neuromedin B receptors (NMBR/BB1R)] are G-protein coupled receptors (GPCR’s) with potent growth effects on normal tissues/numerous cancers, often by transactivating the ErbB receptor-tyrosine kinase (RTK) family.