These gene sets were derived from global gene expression profiling comparisons between Ewing family tumors and normal tissues [29], before and after EWS/FLI1-induced expression in either neural crest cells [6] or mesenchymal stem cells [5], or before and after RNAi-mediated EWS/FLI1 knockdown in Ewing sarcoma cells [30]. Here, FLI1 is linked to Ewing sarcoma.