The current review showed the WT1 gene was alternatively spliced at Ex4a to generate isoforms with opposing roles in apoptosis, anti-apoptotic isoforms (major WT1 isoforms) and pro-apoptotic isoform (truncated Ex4a(+)WT1 isoform). A number of other genes associated in apoptosis, this kind of as p53 [39], Survivin [40], Fas [41], and caspase-9 [42] are regarded to provide isoforms with opposing rol