RCOR1 and breast neoplasm: Components of the CoREST complex are known to be deregulated and/or over-expressed in human breast tumours, resulting in the repression of epithelial pro-differentiation genes such as p21WAF1/CIP1 (22), E-cadherin (23), Grainyhead-Like 2 (GRHL2) and FOXA1 (24) to promote a malignant mesenchymal state.