To date, most clinical data on
pro-gastrin-releasing
peptide (
proGRP) have been based on serum concentrations. This study evaluated the agreement between
proGRP levels in fresh serum and plasma in patients with various
lung diseases. Pairs of serum and
EDTA plasma were collected from 49 healthy individuals. At the same time,
EDTA plasma of 118
lung cancer patients and 23 patients with benign
pulmonary diseases were prospectively collected. Compared to serum, plasma
proGRP concentrations were higher by an average of 103.3%. Plasma
proGRP was higher in
malignancy (336.4 ± 925.4 pg/mL) than in benign conditions (40.1 ± 11.5 pg/mL).
Small cell lung cancer (SCLC) patients showed higher levels of
proGRP (1,256.3 ± 1,605.6 pg/mL) compared to other types of
lung cancer. Based on the ROC curve analyses at a specificity of 95%, the diagnostic sensitivity of plasma
proGRP was estimated to be 83.8% in distinguishing SCLC from all the other conditions, and 86.5% for discriminating SCLC from the nonmalignant cases. Among the SCLC cases, limited stage disease had lower levels of plasma
proGRP than extensive disease. When measuring circulating levels of
proGRP, the use of plasma is preferred over serum. Plasma
proGRP has a potential marker for discriminating SCLC from nonmalignant conditions or
non-small cell lung cancer.