Seeking to further understand the biology of JHDMs in Ewing sarcoma, we noted the JHDMs KDM5A (JARID1A/RBBP2) and PHF2 (KDM7C/JHDM1E) to be consistently upregulated in expression in patient-derived Ewing sarcoma cell lines, relative to mesenchymal stem cells, the putative disease cell of origin (Figure 1A). This evidence concerns the gene KDM5A and Ewing sarcoma.