proGRP

ProGRP, short for progastrin-releasing peptide, is a peptide precursor that yields gastrin-releasing peptide (GRP). It is a neuroendocrine peptide produced by various cells, most notably in the lung and stomach, and is secreted into the bloodstream. In clinical practice, ProGRP is primarily used as a tumor biomarker.

The serum concentration of ProGRP is elevated in many patients with small cell lung cancer (SCLC) and, to a lesser extent, in some other neuroendocrine tumors. ProGRP is often more specific for SCLC than neuron-specific enolase (NSE), and it is used alongside imaging and other markers to aid diagnosis, assess tumor burden, and monitor response to therapy. It can help differentiate SCLC from non–small cell lung cancer when radiologic findings are equivocal.

Interpretation considerations include the influence of renal function and age on ProGRP levels; elevated levels may occur in nonmalignant conditions and other neuroendocrine tumors. Therefore, results are interpreted in the clinical context and with supportive diagnostic information.

Measurement is performed in serum by immunoassay, commonly using enzyme-linked immunoassay or chemiluminescent immunoassay platforms. Normal reference ranges vary by assay and laboratory.

See also: Gastrin-releasing peptide, Neuron-specific enolase, Small cell lung carcinoma, Neuroendocrine tumor.