Exosomes in diagnostic and therapeutic applications: biomarker, vaccine and RNA interference delivery vehicle.

INTRODUCTION: Cells release extracellular vesicles to their surroundings to communicate with each other. Exosomes are a subgroup of 30 - 100-nm-sized extracellular vesicles, originating from the endocytic pathway. They contain RNA molecules, proteins and lipids that can be transferred between cells. Exosomes have been found in several body fluids, indicating that this is a frequently used and tolerated system for cells to communicate RNA molecules and proteins over distances. AREAS COVERED: It has been shown that patients with cancer have higher concentrations of exosomes in their blood and that these exosomes can carry tumor-specific molecules. Exosomes are, therefore, currently being evaluated for their potential use as biomarkers. Additionally, exosomes have been demonstrated to have the capacity to modulate immune responses. Therefore, exosomes are believed to be beneficial as a cell-free vaccine for cancer and infections. Further, as exosomes are the body's endogenous system for transport RNA, exosomes are also evaluated for their potential use as a therapeutic RNA delivery system. This review provides an overview of studies reporting diagnostic and therapeutic potential for exosomes. EXPERT OPINION: The data reviewed here suggest that exosomes have the potential to be used for both diagnosis and therapy for several diseases in the future.