Unveiling the complexity: Liquid biopsy-based proteomic exploration of triple-negative breast cancer in women.

e13138 Background: This groundbreaking study places a spotlight on breast cancer in women, with a specific emphasis on the challenging triple-negative breast cancer (TNBC) subtype. Delving into the intricate world of extracellular vesicles (EVs) from TNBC-diagnosed individuals, the research meticulously compares various conditions, including healthy controls, benign tumors, recurrent tumors, and those in remission. Employing cutting-edge techniques like liquid biopsy and LC-MS/MS, the study meticulously explores the proteomic profile of serum exosomes, aiming to pinpoint diagnostic and prognostic markers in breast cancer. Methods: In the initial phase, EVs were expertly isolated and characterized from blood plasma samples exclusively from women, utilizing state-of-the-art methods such as ultracentrifugation and nanoparticle tracking analysis (NTA). Despite applying rigorous statistical criteria, the study found no significant differences in EV concentrations and sizes among the diverse groups. However, the ensuing proteomic analysis uncovered 130 proteins, with Cystatin A and Histone H2A emerging as promising biomarkers for TNBC. To validate them, the study intricately tested tumor cell lines from distinct subtypes, representing luminal, triple-negative, and HER2 overexpressed. The examination of gene and protein expression through RT-qPCR and western blotting added a layer of depth to the research, unraveling the complexity of regulatory processes within cells and demonstrating a remarkable congruence between protein levels found in the proteomics from patients’ serum and in immortalized cell lines. Results: The proteomic analysis brought to light the absence of CSTA and HIST1H2A expression in benign tumor patients, varied levels in malignant tumor patients, and a substantial increase in TNBC patients pre-mastectomy. Validating these findings through western blotting further accentuated the potential of these proteins as distinguishing factors. Conclusions: In conclusion, this pioneering study not only underscores the immense potential of liquid biopsy-based proteomic analysis in identifying crucial diagnostic and prognostic markers in breast cancer but also sheds light on the intricate nuances of the challenging TNBC subtype. Our findings unveil valuable insights that pave the way for future personalized treatment strategies, marking a significant stride forward in breast cancer research.