FLI1 and sarcoma: In a subsequent study by the same group, Riggi et al. (2010) expressed the characteristic Ewing sarcoma fusion oncogene EWS/FLI-1 in undifferentiated human MSCs (hMSCEWS/FLI-1) derived from pediatric bone marrow samples and demonstrated the generation of a CD133+ subpopulation of cells with stem cell properties.