We hypothesized that GFAP and Tau had potential as biomarkers for glioblastoma because 1) glioblastoma growth inevitably damages nearby astrocytes and neurons, releasing free GFAP and Tau into the surrounding tissues and fluid compartments25, and 2) GFAP and Tau are highly expressed in glioblastoma and may be enriched in their EVs26,27. Here, GFAP is linked to glioblastoma.