Extracellular vesicle‐associated organotropic metastasis

Metastasis refers to the progressive dissemination of primary tumour cells and their colonization of other tissues and is associated with most cancer-related mortalities. The disproportional and systematic distribution pattern of distant metastasis in different cancers has been well documented, as is termed metastatic organotropism, a process orchestrated by a combination of anatomical, pathophysiological, genetic and biochemical factors. Extracellular vesicles (EVs), nanosized cell-derived membrane-bound particles known to mediate intercellular communication, are now considered crucial in organ-specific metastasis. Here, we review and summarize recent findings regarding EV-associated organotropic metastasis as well as some of the general mechanisms by which EVs contribute to this important process in cancer and provide a future perspective on this emerging topic. We highlight studies that demonstrate a role of tumour-derived EVs in organotropic metastasis via pre-metastatic niche modulation. The bioactive cargo carried by EVs is of diagnostic and prognostic values, and counteracting the functions of such EVs may be a novel therapeutic strategy targeting metastasis. Further investigations are warranted to better understand the functions and mechanisms of EVs in organotropic metastasis and accelerate the relevant clinical translation.