Extracellular vesicles in cancer diagnostics and therapeutics

Cancer promotion, development, and malignant transformation is greatly influenced by cell-to-cell interactions in a complex tissue microenvironment. Cancer and stromal cells secrete soluble factors, as well as deport membrane-encapsulated structures, which actively contribute and mediate cell-to-cell interaction within a tumor microenvironment (TME). These membrane structures are recognized as extracellular vesicles (EVs), which include exosomes and microvesicles. They can carry and transport regulatory molecules such as oncogenic proteins, coding and non-coding RNAs, DNA, and lipids between neighboring cells and to distant sites. EVs mediate crucial pathophysiological effects such as the formation of premetastatic niches and the progression of malignancies. There is compelling evidence that cancer cells exhibit a significant amount of EVs, which can be released into the surrounding body fluids, compared with nonmalignant cells. EVs therefore have the potential to be used as disease indicator for the diagnosis and prognosis of cancers, as well as for facilitating research into the underlying mechanism and biomolecular basis of these diseases. Because of their ability to transport substances, followed by their distinct immunogenicity and biocompatibility, EVs have been used to carry therapeutically-active molecules such as RNAs, proteins, short and long peptides, and various forms of drugs. In this paper, we summarize new advancement in the biogenesis and physiological roles of EVs, and underpin their functional impacts in the process of cancer growth and metastasis. We further highlight the therapeutic roles of EVs in the treatment, prevention, and diagnosis of human malignancies.