Centre de protéomique clinique, CRP-Santé, Luxembourg
Development of Proteomic Clinical Assays Based on High-Resolution / Accurate Mass Spectrometry
Targeted proteomics experiments applied to biomarker evaluation are routinely performed on triple quadrupole mass spectrometers in selected reaction monitoring (SRM) mode. However, the low resolution of quadrupole mass filters has limited selectivity for complex samples, such as bodily fluids, characterized by a high biochemical background. Hybrid mass spectrometers with high resolution and accurate mass (HR/AM) capabilities overcome this limitation, and have opened new avenues in quantitative proteomics. The analyses of clinical samples using parallel reaction monitoring (PRM) on a quadrupole-orbitrap mass spectrometer showed significant gain in selectivity, while increasing the confidence in the measurements by identifying the fragments by accurate mass.
Furthermore, immuno-affinity isolation of proteins combined with a fast LC-MS technique has allowed the detailed characterization peptide isoforms of diagnostic cancer markers. More specifically, the approach was applied to quantitatively profile EGFR and RAS protein isoforms, which both are predictive markers for targeted therapy.