Epitomics: Analysis of Plasma C9 Epitope Heterogeneity in the Plasma of Lung Cancer Patients and Control Subjects

The human proteome is more complex than genetic code have predicted it. Sub-protein level provides us a more complex point of view in proteomics and an opportunity to examine epitopes biomarkers values. Epitomics is a recently emerging omics technology that monitors dynamic changes of protein details, epitopes in health and disease. In this study we examined three different complement C9 epitopes via monoclonal antibodies (BSI0449, BSI0581, BSI0639) in control and lung cancerous plasma with ELISA and LC MS/MS methods. Our results suggest that the immunoprecipitated complement C9 is structurally same but we found differences in posttranslational modification ratio and coprecipitated protein composition in control and lung cancerous plasma. We demonstrated that C9 protein heterogeneity exists and shows cancer association at the sub-molecular epitope level.