FLI1 and Ewing sarcoma: While this strategy has been unable to eradicate leukemia stem cells in chronic myelogenous leukemia, a study by Awad et al. (2010) found that Ewing sarcoma CSCs were sensitive to inhibition by the small molecule YK-4-279 that targets the EWSR1-FLI1 fusion protein (Graham et al., 2002).