Studies on models of vasogenic brain edema, including intraparenchymal fluid infusion, focal cortical freeze injury and tumor cell implantation in AQP4 knock-out mice showed increased elevations of intracranial pressure, increased brain water and worse neurological outcome, suggesting that AQP4 facilitates transcellular water movement and thereby clearance of vasogenic edema [33]. The gene discussed is AQP4; the disease is neoplasm.