Ewing's sarcoma (ES) and desmoplastic small round cell tumor (DSRCT) are small cell sarcomas characterized by the translocation of chromosome 22 to chromosome 11, resulting in fusion of the EWSR1 gene to the FLI1 gene (and several rarer fusion partners) [1], [2] in the case of ES (EWSR1-FLI1), and to the WT1 gene in the case of DSRCT (EWSR1-WT1) [3], [4], [5]. This evidence concerns the gene WT1 and Ewing sarcoma.