AQP4 and brain neoplasm: Also, in 3 different models of brain edema such as a freeze-injury model of cerebral vasogenic edema [31], a brain tumor model of edema [31] and a model of edema following subarachnoid haemorrhage (SAH) [32], AQP4-deficient mice displayed increased CNS water accumulation, deteriorated neurological outcome and increased ICP when compared to those of wild type control mice [31-33].