The gastrin-releasing peptide receptor (GRPR) is a G protein-coupled receptor whose endogenous ligand is gastrin releasing peptide . In humans it is highly expressed in the pancreas and is also expressed in the stomach, adrenal cortex and brain .Gastrin-releasing peptide (GRP) regulates numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation and is a potent mitogen for neoplastic tissues. The effects of GRP are mediated through the gastrin-releasing peptide receptor. This receptor is a glycosylated, 7-transmembrane G-protein coupled receptor that activates the phospholipase C signaling pathway. The receptor is aberrantly expressed in numerous cancers such as those of the lung, colon, and prostate.