HDAC1 and ependymoma: We show that structural variants in supratentorial ependymomas not only lead to ZFTA-RELA fusion genes, but also result in the formation of new regulatory environments that are recurrently associated with aberrant overexpression of RCOR2. RCOR2 is the scaffold protein in the CoREST complex that further contains LSD1 and HDAC1 and HDAC2.