Abstract:

Objective To assess the performance of pro-gastrin-releasing peptide （ProGRP） assay by electrochemiluminescence immunoassay. Methods A total of 127 lung cancer patients [48 small-cell lung cancer （SCLC）patients and 79 non-small-cell lung cancer （NSCLC）patients],40 benign lung disease patients,60 other tumor patients,20 autoimmune disease patients and 120 healthy subjects （healthy control group） were enrolled. Serum levels of ProGRP were determined by electrochemiluminescence immunoassay,chemiluminescence microparticle immunoassay and enzyme-linked immunosorbent assay（ELISA）. The precisions,accuracies,linearities and reference intervals of the 3 methods were assessed. Receiver operating characteristic（ROC）curve was used to evaluate the diagnostic efficiency of ProGRP determination independently and ProGRP determination combined with carcinoembryonic antigen（CEA）,neuron specific enolase（NSE）and cytokeratin 19-fragment（CYFRA21-1）. The diagnostic efficiency of the 3 methods was compared. Results The within-run and between-run precisions of high-level and low-level ProGRP were 0.8%,1.2% and 0.9%,2.2%,respectively. The recoveries were 99.86% and 98.32%,respectively. There was a good linear range of 33.13-4 796.00 pg/mL. For healthy control group,the reference interval was 0-69.2 pg/mL. Pearson correlation analysis showed that there was a correlation among the 3 methods. Bland-Altman analysis showed a good consistency in low-level region among the 3 methods,but the bias was increased with the increasing results. The level of ProGRP in SCLC group was higher than those in the other groups （P<0.05）,and there was no statistical significance among the other groups （P>0.05）. The optimal cut-off value was 66.65 pg/mL. The sensitivity and specificity were 79.2% and 95.3%,respectively. The sensitivity and specificity increased to 83.3% and 96.2% for the combined determination with NSE （P<0.05）,and there was no statistical significance compared with those for the combined determination with CEA,NSE and CYFRA21-1（P>0.05）. The diagnostic efficiency of the 3 methods for SCLC had no difference（P>0.05）.Conclusions The performance of ProGRP assay by electrochemiluminescence immunoassay is accordance with expected requirements. ProGRP can be as a reliable marker for the diagnosis of SCLC.

Key words: Pro-gastrin-releasing peptide, Electrochemiluminescence immunoassay, Small-cell lung cancer