PARP inhibition has been evaluated as an effective treatment option for Ewing’s sarcoma with EWS–FLI1 or EWS–ERG genomic fusions in xenograft models (130), and olaparib has been shown to have potent activity in cell lines with a EWS/FLI1 translocation (131). This evidence concerns the gene EWSR1 and Ewing sarcoma.