WT1 gene has oncogenic properties and its continuous over-expression is related to leukemia and several kinds of solid malignancies. Growth of WT1-expressing leukemia and solid tumor cells could be inhibited by the treatment with WT1 antisense oligomers. Various studies revealed WT1 expression in a considerable proportion of glial tumors and related it to high grade tumors and proliferative activity. Our study aimed to evaluate expression of WT1gene in glial tumors and to correlate its

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... n with various clinicopathological parameters and tumor angiogenesis to include or exclude WT1 as a potential prognostic factor and therapeutic target in patients with glial tumors. 50 cases of glial tumors were immunohistochemically evaluated for WT1 expression in tumor cells and for CD34 expression in intra-tumoral endothelial cells to calculate MVD. We correlated WT1 expression with tumor grade, MVD, mitotic count, tumoral necrosis and age of patients. Evaluation of WT1 immunostained sections revealed positive staining in 43 cases (86%). WT1 staining in all cases was cytoplasmic with five cases (10%) showing concomitant nuclear expression. Statistical analysis revealed significant differences between mean WT1 score among different tumor grades, strongly positive but yet non-significant correlation between mean WT1 score and each of mean MVD and mean mitotic activity, for all tumor grade groups and non-significant correlation with age of patients or extent of necrosis in grade IV tumors. The current study concluded that WT1 is expressed in a considerable percent of glial tumors and bears relation to tumor grade and thus prognosis and bears strongly a possible but yet not well established correlation with tumor angiogenesis and proliferative activity. This makes it a useful marker for prognosis and possible target for cancer therapy. However we must carry out further studies to confirm such role, declare the mechanism, which is probably related to downstream target genes. The scoring of WT1 expression is also not standardized between researches and we recommend it to be either negative (score 0), weak (scores 1-2), moderate (scores 3-4), or strong (scores 5-6) and consider positivity from scores 3 to 6 and negativity from scores 0 to 2.