||P.31 left column top paragraph: "Exosomes are small vesicles (40–150 nm in diameter) released from cells after fusion of the multivesicular bodies (MVBs) with the plasma membrane [primary sources 1, 2]. The biogenesis of exosomes can be regarded as a three-step process: (a) biogenesis of MVBs, (b) transport of MVBs to the plasma membrane, and (c) release of the intraluminal vesicles of the MVBs as a consequence of fusion of MVBs with the plasma membrane. Exosomes are considered as one of three main types of extracellular vesicles (Fig. 1). The other types of extracellular vesicles are considered to be larger than exosomes, i.e. vesicles budding off from the plasma membrane (typically in the size range 100–1000 nm) and apoptotic bodies (500–2000 nm) formed by blebbing of membranes of apoptotic cells [primary sources 3, 4]. Exosomes have a complex composition including proteins, nucleic acids, lipids and other metabolites [refs 5, 6]."