Increased expression of Aquaporin-4 and its correlation with contrast enhancement and perilesional edema in brain tumors

Introduction. Aquaporins and astrocytes are important in maintaining water hemostasis in brain. Upregulation of AQP-4 has been described in conditions associated with brain edema. Aims: To study the expression of aquaporin-4 in brain tumors and its correlation with contrast enhancement and perilesional edema. Material and methods. 30 cases of brain tumors, both benign and malignant were included in the study to look for expression of AQP-4. Results. AQP-4 expression was increased in brain tumors compared to normal brain but distribution and intensity of expression depend upon the type of tumor. A trend toward increased AQP-4 expression in enhancing lesions with perilesional edema was noticed. Conclusion. AQP-4 expression was seen in tumor tissue and perilesional reactive astrocytes in primary brain tumors, however only perilesional astrocytes showed positivity in secondary brain tumors. AQP-4 could be playing a role in alteration of blood-brain barrier leading to contrast enhancement and perilesional edema. Increased knowledge of Aquaporins may open new targeted therapy for brain edema.