Exosomes as critical mediators of cell-to-cell communication in cancer pathogenesis and their potential clinical application

Exosomes are small membrane vesicles that measure 20 to 100 nm in diameter and are released by many cell types, including lymphocytes, dendritic cells (DCs)and tumor cells. As efficient messengers in cell-to-cell communication, exosomes released by tumors play an important role in regulating tumor malignancy. Tumor-derived exosomes contain proteins, mRNAs, and miRNAs, which can be delivered between different types of cells and even transferred to distant locations to influence the biological activities of tumors, such as proliferation, invasion and metastasis, immunoregulation, generation of a premetastatic niche and stimulation of angiogenesis. This review highlights advances in the understanding of exosome secretion and the role of exosomes in cancer molecular behavior. Moreover, we also discuss the potential clinical application of exosomes as biomarkers and therapeutic tools. Tumor-derived exosomes may represent a target for therapeutic intervention and for the development of early diagnostic biomarkers.