Breast cancer cells were cultured and harvested for proteomic analysis. Cells were lysed using a buffer containing 8 M urea, and proteins were extracted by sonication. The lysate was centrifuged to remove debris, and the supernatant was collected. Protein concentration was determined using the BCA assay. Samples were then reduced with DTT, alkylated with IAA, and digested overnight with trypsin. Peptides were desalted using C18 columns before mass spectrometry analysis.