Targeted Proteomics Driven Verification of Biomarker Candidates Associated with Breast Cancer Aggressiveness

Breast cancer is the most common and molecularly well-characterized malignant cancer in women; however, its progression to metastatic cancer remains lethal for 78% of patients within 5 years of diagnosis. Identifying novel markers in high risk patients using quantitative methods is essential to overcome genetic, inter-tumor, and intra-tumor variability, and to translate novel findings into cancer diagnosis and treatment. Using untargeted proteomics, we recently identified 13 proteins associated with some key factors of breast cancer aggressiveness: estrogen receptors, tumor grade, and lymph node status. Here we verified these findings in a set of 96 tumors using targeted proteomics based on selected reaction monitoring with mTRAQ labeling (mTRAQ-SRM). This study highlights a panel of gene products that could contribute to breast cancer aggressiveness and metastasis, and can help develop more precise breast cancer treatments.