The presence of GRP in lung cancer samples was identified in 1983.[5] In pathological situations, GRP has mitogenic activity in vitro in many cancers including pancreatic cancer, small cell lung carcinoma, prostate cancer, kidney cancer, breast and colorectal cancer.[6][7][8][9] GRP could operate as an autocrine growth factor. In cancers, GRP induces cell growth and inhibits apoptosis by shutting down the endoplasmic reticulum stress pathway.[10] The mechanisms of the impacted signal pathways have not been established.[11] As early as 1994, research on Pro-GRP as a biomarker for small-cell lung carcinoma began.[12] Because of the very short half-life of GRP (2 minutes), the Pro-GRP is used for measurements and analysis. Since then, Pro-GRP has been used as a tumor marker for patients with small-cell lung carcinoma in limited and extended stages.[13]
^Patel, Oneel; Dumesny, Chelsea; Giraud, Andrew S.; Baldwin, Graham S.; Shulkes, Arthur (2004). "Stimulation of proliferation and migration of a colorectal cancer cell line by amidated and glycine-extended gastrin-releasing peptide via the same receptor". Biochemical Pharmacology. 68 (11): 2129–2142. doi:10.1016/j.bcp.2004.08.009. PMID15498503.
^"Gastrin-releasing peptide gene-associated peptides are expressed in normal human fetal lung and small cell lung cancer: A novel peptide family found in man". Lung Cancer. 5: 10. 1989. doi:10.1016/0169-5002(89)90319-x. ISSN0169-5002.
^"Pro-gastrin-releasing peptide (PROGRP) as a specific tumor marker in patients with small cell lung carcinoma (SCLC)". Lung Cancer. 11: 45. 1994. doi:10.1016/0169-5002(94)93944-6. ISSN0169-5002.