Desmoplastic small round cell tumor (DSRCT) is a rare but extremely aggressive cancer arising in young adolescents in the abdominal area. In all cases of DSRCT examined to date, a chromosomal translocation involving the Ewings Sarcoma gene (EWS) and the Wilms tumor suppressor gene, WT1, results in genesis of a novel transcription factor. Another pediatric tumor of interest is the Ewing?s sarcoma, where EWS gene is fused to the Fli1 gene. Our laboratory is focused on understanding the functions of EWS/WT1 and EWS/Fli1 gene products and how they contribute to tumorigenesis in their respective cancers.[unreadable] Towards this goal, we are currently developing mouse models of DSRCT and Ewing?s sarcoma to better understand the etiology and the development of these tumors in the context of whole organism. If successful, our animal models will be invaluable for the development of new and existing therapeutics against DSRCT and Ewing?s sarcoma.