Gastrin-releasing peptide, a 27-amino acid peptide isolated from the gut, stimulates the release of Gastrin, and shares a common C-terminal decapeptide homology with bombesin. Gastrin-releasing peptide is an important growth-modulating factor in developing lung epithelium. It is used as a tumor marker in the diagnosis of small-cell lung carcinoma, since it is known to be produced by these cancer cells.
