ESR1 and breast carcinoma: Activation of ERα by estrogen ligation in breast cancer cell lines leads to direct repression of the Slug promoter as the liganded nuclear receptor attracts a repressor complex which includes histone deacetylase 1 and N-CoR (Nuclear Co-Repressor) but not SRC-3 (Steroid Receptor Coactivator 3) or IKKα in MCF7 breast cancer cells [89].