Role of Extracellular Vesicles in the Pathogenesis of Brain Metastasis

ABSTRACT Extracellular vesicles (EVs) are small particles released by various cells, including cancer cells. They play a significant role in the development of different cancers, including brain metastasis. These EVs transport biomolecular materials such as RNA, DNA, and proteins from tumour cells to other cells, facilitating the spread of primary tumours to the brain tissue. EVs interact with the endothelial cells of the blood–brain barrier (BBB), compromising its integrity and allowing metastatic cells to pass through easily. Additionally, EVs interact with various cells in the brain's microenvironment, creating a conducive environment for incoming metastatic cells. They also influence the immune system within this premetastatic environment, promoting the growth of metastatic cells. This review paper focuses on the research regarding the role of EVs in the development of brain metastasis, including their impact on disrupting the BBB, preparing the premetastatic environment, and modulating the immune system. Furthermore, the paper discusses the potential of EVs as diagnostic and prognostic biomarkers for brain metastasis.