Among these proteins, EAAT2, found in 66% and 75%, of plasma- and CSF-derived EVs, respectively (Table 3), is the dominant glutamatergic transporter in the CNS which is mainly expressed by astrocytes and involved in glutamate homeostasis dysfunction, a key feature in MS pathogenesis [20, 21]. The gene discussed is SLC1A2; the disease is myeloid sarcoma.