GFAP expression in brain tumors: an immunohistochemical study

ABSTRACT

To identify the Immunohistochemical expression of glial fi-brillary acidic protein [GFAP] in different types of brain tumors, and to correlate the results with patient's age and sex, and with tumor type, site and grade. During the two year period, from July 2007 to June 2009, 52 cases of neuroepithelial tumors were collected from Rizgari Teaching Hospital, and private labs in Hawler city. Typing and grading of tumors were done according to the World Health Organization [WHO] classification system. Immunohistochemical staining was done for GFAP using polyclonal antibodies and chromogen visualizing system. A semi quantitative histochemical score was applied to the GFAP staining. Of the 52 collected cases, 36 were astrocytoma, 6 meduiloblastoma, 5 oligoden-droglioma, 3 ependymoma, 1 oligoastrocytoma, and 1 ganglioglioma. GFAP was expressed in 86.5% of neuroepithelial tumors. Higher positivity was found in gliomas than in other neuroepithelial tumors [p < 0.001]. A significant correlation between GFAP expression with the patient's age and site of the tumor was found. It was inversely correlated with the grade of glioma. GFAP expression is helpful in identification of glial from non-glial neuroepithelial tumors. It is of a great use to highlight the tumor grade particularly if the scoring system is applied