In GBM, loss of AQP4 polarity and disruption of its perivascular organization correlate with increased blood–brain barrier permeability, as demonstrated by elevated sodium fluorescein leakage and higher MRI-derived edema indices in patient specimens (Valente et al., 2022; Solar et al., 2022; Abbrescia et al., 2024). Here, AQP4 is linked to glioblastoma.