For example, transcriptional and differential repression of several transcriptional fusion proteins with key roles in the progression of acute leukemias, such as AML1/ETO, STAT5/RARa, and PLZF/RARa fusion proteins, is mediated by the aberrant recruitment of corepressor complexes in the N-CoR/mSin3/HDAC1 complex. The gene discussed is STAT5A; the disease is acute leukemia.