CanAg^® ProGRP EIA

GRP (Gastrin Releasing Peptide) is a hormone that is secreted from Small Cell Lung Cancer (SCLC) cells. Although detection of serum GRP has been expected to be useful for diagnosis of SCLC, determination of serum GRP has not been feasible owing to its instability in blood^1,2. The precursor Pro Gastrin Releasing Peptide (ProGRP) however, is more stable and can be used as a serological marker for GRP³. The CanAg ProGRP EIA kit measures ProGRP (31-98) a carboxy-terminal region common to human ProGRP splice variants. 

ProGRP is expressed in neuroendocrine-derived tissues and tumors, including small cell lung cancer carcinoids, undifferentiated large cell carcinoma of the lung with neuroendocrine features, medullary thyroid carcinoma, and other neuroendocrine malignancies. Serum levels of ProGRP have been shown to be elevated in a high proportion of patients diagnosed with SCLC while normal levels are found in patients with benign disease^4-10. 

Due to its high sensitivity and specificity for SCLC, ProGRP has shown clinical utility in the differential diagnosis of lung cancer. Additive information in the diagnosis of SCLC is provided by the combined measurement of ProGRP and NSE^8,10,11,14. ProGRP is also useful in monitoring the response to therapy and for the detection of recurrent disease^11-13.

Elevated levels of ProGRP may be detected in early stage small cell lung cancer⁹. However, as the incidence of SCLC in the general population is low the ProGRP assay should not be used as a screening test.

References

1. Knigge U, Holst JJ, Knuhtsen S, Petersen B, Krarup T, Holst-Pedersen J, Christiansen PM. Gastrin-releasing peptide: pharmacokinetics and effects on gastro-entero-pancreatic hormones and gastric secretion in normal men. J Clin Endocrinol Metab. 1984;59:310-5
2. Yamaguchi K, Abe K, Kameya T, Adachi I, Taguchi S, Otsubo K, Yanaihara N. Production and molecular size heterogeneity of immunoreactive gastrin releasing peptide in fetal and adult lungs and primary lung tumors. Cancer Res. 1983 Aug;43(8):3932-9.
3. Holst JJ, Hansen M, Bork E, Schwartz TW. Elevated plasma concentrations of C-flanking gastrin-releasing peptide in small-cell lung cancer. J Clin Oncol. 1989;7(12):1831-8.
4. Aoyagi K, Miyake Y, Urakami K, Kashiwakuma T, Hasegawa A, Kodama T, Yamaguchi K. Enzyme immunoassay of immunoreactive progastrin-releasing peptide(31-98) as tumor marker for small-cell lung carcinoma: development and evaluation. Clin Chem. 1995;41(4):537-43.
5. Miyake Y, Kodama T, Yamaguchi K. Pro-gastrin-releasing peptide(31-98) is a specific tumor marker in patients with small cell lung carcinoma. Cancer Res. 1994;54(8):2136-40.
6. Yamaguchi, K., et al., Enzyme-linked immunosorbent assay of pro-gastrinreleasing peptide for small cell lung cancer patients in comparison with neuronspecific enolase measurement. Jpn J Cancer Res, 1995. 86: 698 – 705
7. Stieber P, Dienemann H, Schalborn A, Schmitt UM, Reinmidl J, Hofmann K, Yamaguchi K. Pro gastrin-releasing peptide (ProGRP)—a useful marker in small cell lung carcinoma. Anticancer Res 1999;19: 2673-78
8. Molina R, Filella X, Augé JM. ProGRP: a new biomarker for small cell lung cancer. Clin Biochem. 2004;37(7):505-11. Review.
9. Molina R, Auge JM, Alicante J, Filella X, Vinolas N, Ballesta AM. Pro-gastrinreleasing peptide in patients with benign and malignant diseases. Tumor Biol. 2004, 25:56-61
10. Stieber P, Yamaguchi K. ProGP enables diagnosis of small-cell lung cancer. In: Diamandis EP, Fritsche HA, Lilja H, Chan DW, Schwarz MK. (eds): Tumor markers, Physiology, Pathobiology, technology and Clinical Applications. AACC Press, Washington, 2002, pp 517-521. 31
11. Niho S, Nishiwaki Y, Goto K, Ohmatsu H, Matsumoto T, Hojo F, Ohe Y, Kakinuma R, Kodama T., Significance of serum pro-gastrin-releasing peptide as a predictor of relapse of small cell lung cancer: comparative evaluation with neuron-specific enolase and carcinoembryonic antigen. Lung Cancer. 2000 Mar;27(3):159-67.
12. Sunaga N, Tsuchiya S, Minato K, Watanabe S, Fueki N, Hoshino H, Makimoto T, Ishihara S, Saito R, Mori M. Serum pro-gastrin-releasing peptide is a useful marker for treatment monitoring and survival in small-cell lung cancer. Oncology. 1999;57(2):143-8
13. Okusaka T, Eguchi K, Kasai T, Kurata T, Yamamoto N, Ohe Y, Tamura T, Shinkai T, Saijo N. Serum levels of pro-gastrin-releasing peptide for follow-up of patients with small cell lung cancer. Clin Cancer Res. 1997 Jan;3(1):123-7.
14. Molina, R., ProGRP: A new biomarker for small cell lung cancer. ECJMO 2009, 1(2):25-32.