Background: The development of both chronic obstructive pulmonary disease (COPD) and lung cancer (LC) is influenced by smoking related chronic pulmonary inflammation caused by an excessive innate immune response to smoke exposure. In addition, the smoking induced formation of covalent bonds between the carcinogens and DNA and the accumulation of permanent somatic mutations in critical genes are important in the carcinogenic processes, and can also induce inflammatory responses. How chronic inflammation is mirrored by serum markers in COPD and LC and if these markers reflect prognosis in patients with LC is, however, largely unknown.
Methods: Serum levels of 18 markers reflecting inflammation, endothelial activation and extracellular matrix remodelling were analysed in 207 patients with non-small lung carcinoma (NSCLC) before surgery and 42 COPD patients. 56% of the LC patients also suffered from COPD. The serum samples were analysed by enzyme immunoassays.
Results: Serum levels of OPG, PTX3, AXL, ALCAM, sCD163, CD147, CatS and DLL1 were significantly higher in patients with COPD as compared to patients with LC. High sTNFR1 levels were associated with improved progression free survival (PFS) and overall survival (OS) in LC patients with (PFS hazard ratio (HR) 0.49, OS HR 0.33) and without COPD (OS HR 0.30). High levels of OPG were associated with improved PFS (HR 0.17) and OS (HR 0.14) for LC with COPD. CRP was significantly associated with overall survival regardless of COPD status.
Conclusion: Several markers reflecting inflammation, endothelial activation and extracellular matrix remodelling are elevated in serum from patients with COPD compared to LC patients. Presence of COPD might influence the levels of circulating biomarkers. Some of these markers are also associated with prognosis.
Keywords: COPD; Inflammation; Lung cancer; Prognosis; Protein; Serum markers.