Serum progastrin-releasing peptide in pneumonia, chronic obstructive pulmonary disease and early-stage primary lung cancers.

Introduction: Higher concentrations of the small-cell lung cancer (SCLC) serum marker, pro-gastrin-releasing peptide (proGRP), in lung inflammations has been indicated in literature. The objective of this study was to compare serum proGRP concentration in pneumonia, chronic obstructive pulmonary disease (COPD) and early-stage primary lung cancers. Materials and methods: An observational study was performed to assess serum proGRP against other lung cancer markers in pneumonia, COPD and in stage 1/2 carcinomas. A total of 91 cases of pneumonia or chronic obstructive pulmonary disease (COPD), with 107 cases of early-stage lung adenocarcinoma (ADC), squamous cell carcinoma (SQCC) and 14 cases of neuroendocrine tumors (NET), including SCLC, were analyzed. Serum proGRP (Roche Diagnostics, Basel, Switzerland), cytokeratin 19 fragment 21-1, carcinoembryonic antigen, neuron-specific enolase and C-reactive protein were measured and compared. For the statistical analysis, Mann-Whitney U test, Kruskal-Wallis ANOVA, multiple linear and multinomial logistic regression modeling were used. Results: Compared to the early-stage ADC and SQCC, proGRP in pneumonia, COPD and in NET was higher (P ≤ 0.011 in all comparisons). In 11 cases of pneumonia and COPD, proGRP reached cut-off for SCLC of 100 ng/L. No clinically relevant differences between pneumonia or COPD and early-stage cancer were observed for other markers. Concentration of proGRP was associated with CRP (model coefficient was 0.20; P < 0.019) and both parameters contributed to classification of cases to pneumonia/COPD, ADC/SQCC, and NET categories (P < 0.004, in all cases). Conclusions: Concentrations of proGRP in pneumonia and COPD patients were higher than in patients in the ADC and SQCC early stages and could exceed the SCLC cut-off.