Proteomics-driven approach for the detection of breast cancer biomarkers

Breast cancer (BC) is the most often diagnosed cancer entity of women worldwide. No molecular biomarkers are usable in the clinical routine for the early detection of BC. Proteomics is one of the dynamic tools for the successful examination of changes on the protein level. In this thesis different proteomics-based investigations were performed for the detection of protein and autoantibody biomarkers in serum samples of BC and healthy (CTRL) subjects. First, protein levels of candidates from previous profiling studies were investigated via antibody-microarray platform. Three proteins were found in distinct levels in both groups: secretoglobin family 1D member 1, alpha-2 macroglobulin and inter-alpha-trypsin inhibitor heavy chain family member 4. The second part was dedicated to the de novo exploration of potentially immunogenic tumor antigens (TA’s) with immunoprecipitation and Western immunoblotting followed by identification over mass spectrometry. Autoantibody levels were verified in individual serum profiling via the protein microarray platform. Two autoantibody’ cohorts (anti-Histone 2B and anti-Recoverin) were found in different levels in both groups. The findings of this PhD thesis underline deregulated serum protein and autoantibody levels in the presence of BC. Further investigations are needed to confirm the results in an independent study population.