Expression of the Wilms' tumor gene product WT1 in glioblastomas and medulloblastomas

The Wilms' tumor gene WT1 was first identified as the gene responsible for a childhood renal tumor, Wilms' tumor. This gene encodes for a zinc finger-containing transcription factor. Although originally identified as a tumor suppressor gene, WT1 is overexpressed in a variety of hematologic malignancies and solid tumors. Recently, WT1 protein has been considered as a new molecular target of cancer immunotherapy for several solid tumors. In the present study, we investigated the expression of WT1 protein and WT1 mRNA in glioblastomas and medulloblastomas. Forty-eight of 51 glioblastoma samples (94%) showed immunohistochemically positive staining of WT1 protein, whereas all 10 medulloblastomas examined were negative. According to the immunohistochemical expression of WT1 protein, WT1 mRNA was also highly expressed in the same glioblastoma tissue. Our results suggest that the WT1 gene may play an important role in the tumorigenesis of glioblastoma, in contrast to medulloblastoma, and be integral in the development of the immunotherapy targeting WT1 protein in patients with glioblastoma.