Investigation into the identities of circulating exosomes

Exosomes are membrane vesicles approximately 100 nm in diameter, present in a wide range of body fluids, including blood, cerebrospinal fluid, urine and saliva. Exosomes reflect the physiological state of their cells of origin and cancer cell-derived exosomes carry pathogenic components, such as proteins, messenger RNA (mRNA), microRNA (miRNA), and DNA. Thus, exosomes in body fluids provide a rich source of potential biomarkers. However, the use of exosomes as biomarkers to improve patient care has been limited by their small size and the extensive sample preparation required for their isolation and measurement. In this review, we describe a new liquid biopsy technique designed to sensitively detect disease specific circulating exosomes. We also provide perspectives in translational medicine from the standpoint of diagnosis and therapy.