Therefore the parental Wilms tumor cell line with a novel and unusual chromosome 11 alteration and the immortalized derivative with a homozygous deletion of the entire WT1 gene will be useful for further studies on the function of WT1 in Wilms tumor development, to further explore the origin of WT1 mutant tumors as well as for the analysis of activated signaling pathways. This evidence concerns the gene WT1 and Wilms tumor.