VPS4A and glioblastoma: Studies have shown that exosomes from mouse glioblastoma (GBM) cells are enriched in active Ras and that Ras also co-precipitates with the ESCRT-associated exosomal proteins Vps4a and Alix in lysates of EVs derived from both human and mouse GBM cells, suggesting that Ras is involved in exosome sorting [146].