Targeting of EWS/FLI-1 by RNA interference attenuates the tumor phenotype of Ewing's sarcoma cells in vitro.

The defining cytogenetic abnormality of Ewing's sarcoma is the presence of a balanced t(11;22) translocation expressing the EWS/FLI-1 chimeric fusion protein. The effect of EWS/FLI-1 appears to be dominant negative since over-expression of EWS does not overcome the sarcoma phenotype. Previous studies have shown that EWS/FLI-1 as well as related sarcoma fusion proteins are necessary and sufficient to induce transformation both in vitro and in vivo.