Exosomes as “translational” cancer promoter organelles

The term Exosome has come into use to define nano-vesicles contained in multivesicular endosomes (MVE), secreted by fusion of MVE with the plasma membrane (1-3). Exosomes are secreted in vivo by almost any cell type and can be isolated from body fluids (4-6). Indeed, circulating vesicles account for both exosomes and microvesicles (MVs), which can be purified by various purification methods and fully discriminated according to their shape, size and CD-markers (7,8). Due to their protein and RNA content, once internalized, exosomes have the potential to act as “translational” organelles, altering the expression pattern of recipient cells, their growth, and fate. In fact, exosomes are involved in many of physio-pathological processes, thereby including cancer (9).