Non-small cell lung cancer biomarkers: Discovery using mab proteomics.

Abstract

10561 Background: A challenge in the treatment of lung cancer is the lack of early, pre-symptomatic diagnosis. Here, we describe the application of monoclonal antibody proteomics approach to profile the natural plasma proteome for the discovery of lung cancer biomarkers. Methods: We produced large monoclonal antibody (mAb) libraries directed against the natural form of complex mixtures of protein antigens present in the plasma of non-small cell lung cancer (NSCLC) patients. Lung cancer specific biomarkers in the plasma were detected via high throughput ELISA with mAbs. Antigen identification and specificity of the selected antibodies was determined using immunoprecipitation followed by mass spectrometric analysis. The presence of the biomarkers in non-small cell lung cancer tissues was validated by immunohistochemistry. Results: Differential profiling of plasma proteomes of four clinical collections, totalling 301 patients with lung cancer and 235 healthy controls, identified twenty four monoclonal antibodies recognizing protein biomarkers specific for NSCLC. The majority of the selected mAbs detect antigens present in non-small cell lung cancer cells in-situ. Our study confirms previously reported circumstantial evidences for the association with lung cancer for four of the identified biomarkers and provides an independent validation in larger multi-centric clinical collection for the association of their plasma concentrations to the presence of lung cancer. Multivariate analysis of the biomarker results generated with one of these collections (214 NSCLC cases of which 128 in stage I and 169 healthy controls) yielded a five biomarkers classifier that could discriminate NSCLC cases from healthy controls with 77% sensitivity and 87% specificity. The performance of the classifier was validated in an independent collection and combination with well known a NSCLC biomarkers showed additive effect and combined performance of 84 % sensitivity at 95 % specificity. Conclusions: Using the mAb proteomics approach we have identified a panel of monoclonal antibodies associated with specific protein biomarkers that could be readily transferred to a simple screening test for the early detection of non-small cell lung cancer.