We tested the necessity of these three co-repressors in BCL11B-mediated repression in Ewing sarcoma cells by shRNA knock-down for chomodomain helicase DNA binding protein 4 (CHD4), the core component of the NuRD complex, or chemical inhibitors targeting SUV39H1 or SIRT1. The gene discussed is CHD4; the disease is Ewing sarcoma.