Abstract
Chronic obstructive pulmonary disease (COPD) patients are at higher risk of developing lung cancer and its metastasis, but no suitable biomarker has been reported for differential diagnosis of these patients. Levels of serum biomarkers (VEGF, IL-8, MMP-9 and MMP-2) were analyzed in these patients, which were compared with healthy donors (HD). Levels of VEGF (P < 0.005) and MMP-9 (P < 0.05) were significantly higher in COPD patients than HD. Compared to HD, a decrease in IL-8 (~8.1 folds; P < 0.0001) but an increase in MMP-9 (~1.6 folds; P < 0.05) levels were observed in the lung cancer patients. Cancer patients showed significantly (P < 0.005) lower levels of serum VEGF (1.9 folds) and IL-8 (~9 folds) than the COPD patients. VEGF level was significantly higher (2.6 folds; P < 0.0005) in metastatic than non-metastatic cancer patients. However, MMP-2 didn't show significant variation in these patients. The Youden's index (YI) values for lung cancer diagnosis in HD using IL-8 was 0.55 with 83.3% overall accuracy. VEGF was able to diagnose COPD in HD with better YI (0.38) and overall accuracy (70.6%). IL-8 was able to diagnose cancer in COPD patients and HD with YI values of 0.35, 0.55 with 71% and 83.3% overall accuracy, respectively.