Tissue- and Serum-Derived Exosomal microRNAs as Predictors of Neoadjuvant Chemotherapy Response in Breast Cancer

This prospective observational study aims to evaluate whether exosomal microRNA profiles derived from tumor tissue and blood serum are associated with pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) in patients with breast cancer. Breast cancer patients with similar clinical and pathological features may respond differently to treatment, underscoring the need for reliable biomarkers that can help predict therapeutic outcomes. Exosomes are small extracellular vesicles released by tumor cells that carry molecular signals, including microRNAs, which may reflect tumor behavior and treatment sensitivity. In this study, patients with breast cancer receiving standard NAC as part of routine clinical care will be followed prospectively. Exosomal microRNA profiles obtained from tumor tissue and blood samples collected during routine diagnostic and treatment procedures will be analyzed and compared with pathological complete response (pCR) assessed after completion of neoadjuvant chemotherapy. A group of patients with benign breast disease will be included as a reference control for comparative analyses. The results of this study may contribute to the identification of minimally invasive biomarkers that support personalized treatment strategies in breast cancer.