Exosomes are small vesicles secreted by cells with a diameter of 30-150 nm. They contain proteins, mRNA, microRNA and other molecules. Exosomes can circulate in various body fluids and reach other cells and tissues, where they regulate physiological and pathological processes. The surface of exosomes contains tetraspanins, integrins and other proteins. Tetraspanins, such as CD9, CD81, CD63, are common markers that can be used for exosome identification and detection