Comparative analysis of the human serum N-glycome in lung cancer, COPD and their comorbidity using capillary electrophoresis

Lung cancer (LC) and chronic obstructive pulmonary disease (COPD) are prevalent ailments with a great challenge to distinguish them based on symptoms only. Since they require different treatments, it is important to find non-invasive methods capable to readily diagnose them. Moreover, COPD increases the risk of lung cancer development, leading to their comorbidity. In this pilot study the N-glycosylation profile of pooled human serum samples (90 patients each) from lung cancer, COPD and comorbidity (LC with COPD) patients were investigated in comparison to healthy individuals (control) by capillary gel electrophoresis with high sensitivity laser-induced fluorescence detection. Sample preparation was optimized for human serum samples introducing a new temperature adjusted denaturation protocol to prevent precipitation and increased endoglycosidase digestion time to assure complete removal of the N-linked carbohydrates. The reproducibility of the optimized method was 33% in relative peak areas) between the pathological and control samples. In addition to N-glycan profile changes, alterations in the individual N-glycan subclasses, such as total fucosylation, degree of sialylation and branching may also hold important glycobiomarker values.