Fig. 1

Schematic representation of exosome biogenesis, release, and isolation from the blood. Endocytosis at the plasma membrane forms the early endosome. The inward budding of the membrane of late endosomes and subsequent pinching off of the membrane creates the exosomes, called multivesicular bodies (MVBs). Upon the fusion of MVBs with the plasma membrane, exosomes are released into the extracellular milieu, which enriched in nucleic acid and proteins. Exosomes, cell-free nucleic acid (cfNA), circulating tumor cell can be found and extracted from a blood sample. Improvement in mass spectrometry-based proteomic tools and microfluidic approaches, which coupled with improved purification schemes for exosomes, has allowed more in-depth proteome analyses. The potential of exosomal protein profiles for use as diagnostic biomarkers of disease through a non-invasive blood test