Progastrin-releasing peptide as a diagnostic and therapeutic biomarker of small cell lung cancer

BACKGROUND Progastrin-releasing peptide (proGRP) is a recently identified biomarker of small cell lung cancer (SCLC). We evaluated the usefulness of plasma proGRP level as a tumor marker for diagnosis and treatment monitoring in patients with SCLC. METHODS Plasma samples were collected prospectively from 452 [212 non-small cell lung cancer (NSCLC), 105 SCLC, and 135 other diseases] patients who visited the hospital for tissue diagnosis. Plasma proGRP levels were measured using a two-step automated immunoassay. RESULTS The median proGRP level was significantly higher in patients with SCLC (892.7 pg/mL) than those with NSCLC (32.6 pg/mL, P