Extracellular Vesicles Derived from Breast Cancer Cells: Emerging Biomarkers of Tumor Progression and Metastasis.

Breast cancer (BC) remains one of the most prevalent and life-threatening malignancies worldwide, marked by significant heterogeneity and complex mechanisms of progression. Despite major advances in understanding its molecular and cellular basis, the processes driving tumor progression and metastasis continue to challenge effective treatment. Among the emerging research areas, extracellular vesicles (EVs) have gained considerable attention for their key role in intercellular communication and their contribution to cancer biology. In BC, tumor cell-derived EVs are implicated in multiple processes that promote disease progression, including tumor growth, remodeling of the tumor microenvironment, and facilitation of metastasis. By transferring oncogenic signals to recipient cells, EVs critically shape the metastatic niche and support the spread of cancer cells to distant organs. Recent studies highlight the diverse functions of BC-derived EVs in modulating immune responses, inducing angiogenesis, and enhancing cancer cell invasiveness. This review explores the role of BC-derived EVs in tumor progression and metastasis. We discuss their molecular composition, mechanisms of action, and impact on the tumor microenvironment, aiming to provide insights into their role in BC pathophysiology and discuss potential clinical applications. A deeper understanding of the complex interplay between EVs and cancer progression may pave the way for innovative strategies to combat BC and improve patient outcomes.