HDAC1 and breast cancer: Increased the expression of BRCA1, p53, and p21Decreased the expression of protein arginine methyltransferase 5 (PRMT5) and enhancer of Zeste homolog 2 (EZH2) in both breast cancer cellsDecreased the lysine deacetylase (KDAC) activity and expression of KDAC1-3Increased the expression of lysine acetyltransferase KAT2A/3BIncreased the global level of H3K9ac and H3K27ac marksReduced the enrichment of repressive histone marks (H4R3me2s and H3K27me3)Increased the abundance of activating histone marks (H3K9/27ac) within the proximal promoter region of BRCA1, p53, and p21