Detection And Identification Of Serum Biomarkers Of Non-small Cell Lung Cancer

Part I Detection of Serum protein Biomarkers of Non-small Cell Lung CancerObjective To detect the specific serum protein biomarkers and establish the discriminant model for early screening and diagnosis of non-small cell lung cancer (NSCLC).Methods Serum proteomic profiles of 112 NSCLC and 123 controls were analyzed using surfaced enhanced laser desorption/ionization time of flight mass spectroscopy (SELDI-TOF-MS), combing a support vector machine (SVM) classifier to deal with the data.Results After detecting and analyzing by bioinformation,22 peaks with p value <0.01 were obtained. From the random combination of protein peaks with remakable variation, SVM screened out the combined model with maximum Youden index of the predicted value, identifying 3 markers positioned at 6628,9191 and 11412. In the NSCLC group, the 6628 Da protein was remarkably decreased while 9191 and 11412 Da proteins were significantly elevated. In addition, the levels of these proteins were associated with the clinical stages. Combining these 3 potential markers, the sensitivity, specificity and positive predictive value of the model were 96.56%,94.79% and 95.0% respectively in the blind testing set.Conclusions These proteins with m/z of 6628,9191 and 11412 could be as potential biomarks of NSCLC. SELDI-TOF-MS has been proved an effective method for serum protein biomarkers detection of NSCLC. Partâ…¡Identification of Serum protein Biomarkers of Non-small Cell Lung CancerObjective To identify the candidate protein biomarkers with m/z of 6628,9191 and 11412 using proteomics technologies.Methods The HPLC was used to purify the 3 candidate protein biomarkers, and then the MALDI-TOF-MS technology was applied to detect each fraction to trace the candidate protein biomarkers. After digestion with modified trypsin, the peptide mixture was analyzed by nano-LC-MS/MS.Results The candidate biomarker with m/z of 6628 was identified as apolipoprotein C-I, while another two biomarkers were identified as haptoglobin alpha-1 chain (9191 Da) and S100A4 (11412 Da).Conclusions An efficient strategy, including HPLC purification, MALDI-TOF-MS trace and LC-MS/MS identification, has been proved a powerful tool to identify the target proteins. The candidate biomarker with m/z of 6628,9191 and 11412 were identified as apolipoprotein C-I, haptoglobin alpha-1 chain and S100A4. Partâ…¢Confirmation of Serum protein Biomarkers of Non-small Cell Lung CancerObjective To confirm the identity of apolipoprotein C-I, haptoglobin alpha-1 chain and S100A4 with the ProteinChip-array-based immunoassay.Methods Serum samples with NSCLC and controls were analyzed using specific antibody arrays which were prepared by covalently coupling the appropriate antibodies to preactivated ProteinChip arrays.Results The anti-apolipoprotein C-I array captured apolipoprotein C-I (6628 Da), the anti-haptoglobin alpha-chain antibody specifically captured the haptoglobin alpha-chain (9191 Da) protein, and the S100A4 antibody specifically captured the S100A4 protein (11412 Da).Conclusions These 3 biomarkers could be specifically captured by the corresponding antibody arrays, which proved the reliability of results with identification. The expression of apolipoprotein C-I, haptoglobin alpha-1 chain and S100A4 in patients with NSCLC are significantly different from nomal controls, which have a good value and broad application prospects for early screening and diagnosis of non-small cell lung cancer.