Exosomes: Current knowledge of their composition, biological functions, and diagnostic and therapeutic potentials

► Exosomes are microvesicles containing nucleic acid and protein, secreted by all cells. ► Exosomes are found in abundance in all body fluids including blood, saliva, urine. ► Exosomes most intriguing role is intercellular communication. ► We describe exosomes composition, functions, and pathways. ► We discuss exosomes potential for diagnostic and therapeutic applications.