Tumor-derived extracellular vesicles: Regulators of tumor microenvironment and the enlightenment in tumor therapy

In recent decades, extracellular vesicles (EVs) have been proven to establish an important bridge of communication between cells or cells and their microenvironment. It is well known that EVs play crucial roles in many human diseases, especially in tumors. Tumor-derived EVs (TEVs) are not only involved in epithelial-mesenchymal transition and extracellular matrix remodeling to promote the invasion and metastasis, but also contribute to the suppression of antitumor immune responses by carrying different inhibitory molecules. In this review, we mainly discuss the effects of TEVs on the remodeling of tumor microenvironment through immune and non-immune associated mechanisms. We summarize the latest studies about utilizing EVs in clinical diagnosis and therapeutic drug delivery as well. In addition, the perspective of tumor therapy by targeting EVs is discussed in this review.