Studies performed with AQP null mice have revealed an important role of aquaporin‐4 (AQP4) for the migration of astrocytes forming the glial scar in the central nervous system 9 and of aquaporin‐1 (AQP1) for the migration of endothelial cells in tumour angiogenesis 10, 11. Here, AQP1 is linked to neoplasm.