The role of WT1 gene in neuroblastoma.

The oncogenic properties of the Wilms' tumor gene (WT1) have recently been reported in various malignancies. However, the role of WT1 in pediatric tumors is unclear. To elucidate the role of WT1 in the development of neuroblastoma (NB), we examined the WT1 expression in NB and the effect of WT1 suppression on NB cell proliferation. We examined the expression of the WT1 protein in 20 NBs and 5 ganglioneuromas (GNs) by performing immunohistochemical analysis. We determined WT1 messenger RNA expression in 22 NBs, 5 GNs, and 4 NB cell lines by real-time reverse transcription polymerase chain reaction. We studied the effects of WT1 suppression on cell proliferation using small interfering RNA against WT1. Expression of WT1 was higher in mature ganglionic cells, and in the immunohistochemical analysis, the WT1 positivity for GNs was significantly higher than that for NBs (P < .01). The level of WT1 messenger RNA expression did not correlate with histologic grade, clinical stage, and prognosis of the tumor. Knockdown of WT1 gene promoted the proliferation of NB69 cells (P < .01). The WT1 may govern cell differentiation and suppress cell proliferation in NB. The WT1 does not act as an oncogene, but it may participate in the maturation of NB.