AQP2 and central nervous system cancer: Although it has been postulated that brain cancer cells distribute aquaporins (AQPs) between cells via EVs [43, 44], as occurs in the kidney where AQP1 and aquaporin-2 (AQP2) have been found in urinary exosomes, the presence of an AQP, namely AQP4, in EV cargoes derived from glioma cells has been reported here for the first time.