[1696] Immunohistochemical Expression of WT1 in Gliomas

N Schiavo, G Martignoni, M Brunelli, F Menestrina, F Lupidi, C Dell'Agnola, T Sava, M Frizziero, C Ghimenton. University of Verona, Verona, Italy; Ospedale Civile Maggiore, Verona, Italy

Background: WT1 was initially described as a tumour suppressor gene associated with nephroblastoma and interaction of this molecule with p53, Bcl-2, IGF1R, CMYC genes have been described with oncogenic-oncosuppressor effects. WT1 target therapies have been proposed in various type of neoplasms and its inhibition on glioblastoma culture cells determines regression of proliferation.WT1 immunoexpression is observed in neoplastic astrocytes and correlates with grading of gliomas. Little is known among WT1 immunoexpression in oligodendroglial neoplasms.
Design: 83 glial neoplasms (30 oligodendrogliomas,13 astrocytomas, 8 oligoastrocytomas, 32 glioblastomas) fixed in FineFIX-paraffine embedded have been tested with Monoclonal WT1, Clone 6F-H2. Glioblastomas included also 7 glioblastoma with oligodendroglioma component, 2 gliosarcomas, 3 small cell glioblastomas and 6 giant cell glioblastomas. Scoring immunoexpression was evaluated as follows: 1+= 0-30%; 2+= 31-60%; 3+= 61-100%.
Results: 88% of glioblastomas, 70% of grade III astrocytomas showed score 3+. Gliosarcomas presented a lower expression in the sarcomatous component (less than 10% of positivity). 100% of low grade and 68% of high grade oligodendroglioma and 87% of oligoastrocytomas scored 1+. Aforementioned WT1 positive immunoexpression is observed in the cytoplasms. Gemistiocytes, minigemistiocytes, perivascular, perinecrotic and subpial neoplastic astrocytes display strong immunoexpression.

Conclusions: WT1 is a useful diagnostic marker to distinguish astrocytic and oligodendroglial tumors. WT1 immunoexpression correlates with grading of the neoplasm among astrocytic neoplasms (astrocytomas and glioblastoma). WT1 helps to evaluate astrocyitic component in oligoastrocytomas respect to oligodendroglial proliferation.
Category: Neuropathology

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 229, Tuesday Afternoon


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