A total of 966 proteins were common to GBM Pre-OP and Post-OP uEVs (Fig. 3a), and levels of 72 proteins were identified to change significantly in uEVs following the total gross resection of primary GBM tumours (GBM ‘tumour burden’ proteins; p ≤ 0.05; Fig. 3b, Supplementary Table 5), including three proteins (BCAM, ITGA3, ITM2B) reduced by more than 2-fold in Post-OP relative to Pre-OP samples (adjust p-value ≤ 0.05; see Fig. 4a). Here, ITGA3 is linked to glioblastoma.