RRM2 and Ewing sarcoma: Recently, the oncogenic role of RRM2 has been linked to the EMT process in esophageal adenocarcinoma, glioma, and prostate cancers [53, 54, 72] and multiple RRM2 inhibitors have been developed and are being investigated in clinical trials as monotherapy or combinational treatment option. In particular, RRM2 inhibitors was found to be highly effective when combined with cell-cycle checkpoint inhibitors in Ewing sarcoma [73].