EP300 and breast cancer: Likewise, 31.8% (556/1748) and 30.2% (528/1748) of genes downregulated by EP300 knockdown in MCF-7 cells are upregulated in luminal A and B BC, respectively (Figure S5B), and again the Estrogen Response Early and Estrogen Response Late Hallmark Gene Sets are the top two enriched pathways for the overlapping genes (Figure S5B).