J Neurol Neurosurg Psychiatry 72:262-265 doi:10.1136/jnnp.72.2.262
  • Short reports

Aquaporin-4 expression is increased in oedematous human brain tumours

  1. B A Bell3
  1. 1Department of Anatomy and Developmental Biology, St George's Hospital Medical School, London SW17 0RE, UK
  2. 2Department of Infectious Diseases
  3. 3Department of Neurosurgery, Atkinson Morley's Hospital, London SW20 0NE, UK
  1. Correspondence to:
    Dr D C Davies, Department of Anatomy and Developmental Biology, Cranmer Terrace, Tooting, St George's Hospital Medical School, London SW17 0RE, UK;
  • Received 26 January 2001
  • Revised 23 July 2001
  • Accepted 23 July 2001


Aquaporin-4 (AQP4) is a highly conserved water channel protein. In rats, AQP4 is expressed in astrocyte foot processes and is important in brain water homeostasis. AQP4 expression has not been investigated in non-neoplastic human brain or oedematous brain tumours, where water homeostasis is disrupted. Therefore, immunohistochemistry was used to study AQP4 expression in non-neoplastic and neoplastic human brain and blood-brain barrier permeability was assessed using contrast enhanced computed tomograms. AQP4 was present around microvessels in five specimens of non-neoplastic brain and five low grade (Daumas-Duport I or II) astrocytomas. AQP4 was massively upregulated in four and absent in one high grade (Daumas-Duport III or IV) astrocytoma. Massive upregulation of AQP4 was also found in reactive astrocytes in five metastatic adenocarcinomas. There was significant (p<0.0001) correlation between blood-brain barrier opening and upregulated AQP4 expression. Increased AQP4 expression in high grade astrocytomas and adenocarcinomas may facilitate the flow of oedema fluid.

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