Identification of serum proteome components associated with progression of non-small cell lung cancer

The aim of the present study was to perform comparative analysis of serum from patients with different stages of non-small cell lung cancer (NSCLC) using the three complementary proteomic approaches to identify proteome components associated with the progression of cancer. Serum samples were collected before any treatment from 200 patients with NSCLC, including 103 early stage, 64 locally advanced and 33 metastatic cancer samples, and from 200 donors without malignancy. The low-molecular-weight fraction of serum proteome was MALDI-profiled in all samples. Serum proteins were characterized using 2D-PAGE and LC-MS/MS approaches in a representative group of 30 donors. Several significant differences were detected between serum samples collected from patients with early stage cancer and patients with locally advanced cancer, as well as between patients with metastatic cancer and patients with local disease. Of note, serum components discriminating samples from early stage cancer and healthy persons were also detected. In general, about 70 differentiating serum proteins were identified, including inflammatory and acute phase proteins already reported to be associated with the progression of lung cancer (serum amyloid A or haptoglobin). Several differentiating proteins, including apolipoprotein H or apolipoprotein A1, were not previously associated with NSCLC. No significant differences in patterns of serum proteome components were detected between patients with adenocarcinoma and squamous cell carcinoma. In conclusion, we identified the biomarker candidates with potential importance for molecular proteomic staging of NSCLC. Additionally, several serum proteome components revealed their potential applicability in early detection of the lung cancer.