The function of tumor-derived exosomes.

Exosomes, especially the tumor-derived exosomes (TDEs), are extracellular vesicles released by many kinds of cells, which are involved in several biological and pathological processes. Their contents mainly include DNA, RNA and proteins. The message could be transmitted in neighboring or distant cells by secreting extracellular vesicles (EVs). Exosomes are a main intercellular communication regulator because they are involved and interact with intracellular signaling pathways. Exosomes can be detected in the tumor microenvironment, and there is growing evidence that TDEs are active in tumor growth, angiogenesis, invasion and metastasis, as well as immune responses and drug resistance. All of the functions mentioned above make it clear that exosomes have an important role in tumors. This review focuses on the origin and structure of TDEs and their important biological functions in the environment due to cell-to-cell intercellular communication.