Additional file 3: of Immunotherapy of triple-negative breast cancer with cathepsin D-targeting antibodies

Figure S2. Schematic overview of the biotinylation method used for the identification of accessible proteins in TNBC samples.The technique involves the biotinylation of TNBC biopsies by immersion in the chemically modified biotin solution. Proteins are then solubilized and biotinylated proteins are captured on the streptavidin material. After their enrichment, these proteins can be analyzed using HPLC chromatographic separation, MS analysis, selection of a particular mass (peptide), and fragmentation (MS/MS). MS/MS yields a pattern that delivers the sequence of the peptides and contributes to protein identification. The putative biomarkers discovered by this method require subsequent validation, for instance by immunohistochemistry. (PPTX 42 kb)