CD81 and glioblastoma: In order to assess the FASN positivity of single EVs in relation to their respective tetraspanin profiles, we performed multiplex IFCM analysis for FASN, CD9, CD63 and CD81 on EVs collected from the blood of patients with glioblastomas (n = 22), anaplastic astrocytomas (n = 7) and healthy donors (n = 17), (Figure 4A).