MBD2 and Ewing sarcoma: Moreover, when we treated Ewing sarcoma cells with the KDM6A/KDM6B demethylase inhibitor GSK-J4, we found that the expression of EWSR1::FLI1-activated targets decreased strongly in those targets containing only KDM6B, suggesting that GSK-J4 phenocopies expression changes induced by KDM6B deletion (Supplementary Fig. S6H).