Thus, it was reported that antisense oligonucleotides and siRNA inhibited expression of EWS-FLI1, chimeric gene specific for Ewing's sarcoma, in cell cultures and in the xenograft model in vivo [27], as well as decrease of SS18-SSX1 gene expression in synovial sarcoma [28]. This evidence concerns the gene FLI1 and Ewing sarcoma.