Extracellular vesicles (EV) are a heterogeneous group of cell-derived membrane vesicles comprising apoptotic bodies, microvesicles, and small EVs also called as exosomes. Exosomes when initially identified were considered as a waste product but the advancement in research techniques have provided insight into the important roles of exosomes in cell–cell communication, various biological processes and diseases, including cancer. As an important component of EVs, exosomes contain various biomolecules such as miRNAs, lipids, and proteins that largely reflect the characteristics of their parent cells. Notably, cancer cells generate and secrete many more exosomes than normal cells. A growing body of evidence suggests that exosomes, as mediators of intercellular cross-talk, play a role in tumorigenesis, cancer cell invasion, angiogenesis, tumor microenvironment (TME) formation, and cancer metastasis. As we gain more insights into the association between exosomes and cancer, the potential of exosomes for clinical use is becoming more intriguing. This review is focused on the role of exosomes in breast cancer, in terms of breast cancer biology, mechanism of action, potential as biomarkers, and therapeutic opportunities.

中文翻译：

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乳腺癌中的外泌体——作用机制和临床潜力

细胞外囊泡 (EV) 是一组异质的细胞衍生膜囊泡，包括凋亡小体、微囊泡和小 EV，也称为外泌体。外泌体最初被认为是一种废物，但研究技术的进步已经深入了解了外泌体在细胞间通讯、各种生物过程和疾病（包括癌症）中的重要作用。作为 EV 的重要组成部分，外泌体含有各种生物分子，如 miRNA、脂质和蛋白质，它们在很大程度上反映了其母细胞的特征。值得注意的是，癌细胞比正常细胞产生和分泌更多的外泌体。越来越多的证据表明，外泌体作为细胞间串扰的介质，在肿瘤发生、癌细胞侵袭、血管生成、肿瘤微环境（TME）的形成和癌症转移。随着我们对外泌体与癌症之间的关联有了更多的了解，外泌体在临床上的应用潜力变得越来越有趣。这篇综述的重点是外泌体在乳腺癌中的作用，包括乳腺癌生物学、作用机制、作为生物标志物的潜力和治疗机会。