oa Proteomic Profiling of Lung Cancer Specific Plasma Proteins: Novel Diagnostic Strategy for Environmentally Exposed Male Lung Cancer Patients

Lung carcinomas are highly heterogeneous malignancies and the patient survival rate for lung cancer is very low. This is due to the lack of diagnostic markers for lung cancer and for predicting response or monitoring recurrence after treatments of the lung carcinomas. Human blood plasma proteomics has become one of most preferred method for cancer biomarker discovery. In this study, we used plasma for the detection of lung cancer-specific proteomic biomarker pattern by one-dimensional SDS- Polyacrylamide Gel Electrophoresis followed by nLC-MS/MS. Panels of low molecular weight proteins were found to be lung cancer specific or were not found in the parallel samples from ovarian and breast cancer plasma. To reveal the interactions of identified proteins we analyzed them by I2D - Interologous interaction software. Out of 30 identified proteins, 10 showed association with albumin. Albumin is the most abundant protein in plasma and serum and protects the smaller proteins and peptides from renal clearance. On integrating bioinformatics data with published literature 50% of identified proteins were found to be albumin associated. A list of proteins was identified such as apolipoprotein, transthyretin, haptoglobin alpha, haemoglobin, alpha-1 acid glycoprotein, zinc-alpha-2-glycoproteins known to be associated with lung cancer. To assess the potential usefulness of the identified proteomic pattern for diagnostic purpose, we raised the antibodies to the lung cancer specific proteins. Western blot analysis of lung, ovarian and breast cancer plasma samples with the lung cancer specific antibodies confirmed our findings on the specificity of the proteomic pattern to lung cancer. Validation of the lung cancer specific proteomic pattern would have significant implications for the early detection and diagnosis of lung cancer and better management of high risk patients.