Given that polarized AQP4 expression at astrocytic endfeet is essential for CSF–interstitial fluid exchange (Simon et al., 2022; Peng et al., 2023) its disruption in GBM likely compromises glymphatic transport not only within the tumor core but also in surrounding brain tissue, thereby promoting peritumoral fluid accumulation and impaired metabolic waste clearance. Here, AQP4 is linked to neoplasm.