HDAC1 and breast cancer: Conversely, silencing NKX2-8 drastically increased, but overexpressing NKX2-8 decreased, the enrichment of H3K27 acetylation (H3K27ac) on the promoter of PTHrP gene in breast cancer cells (Figure 5C), which demonstrated that NKX2-8 inhibited PTHrP expression via HDAC1 to reduce H3K27ac on the promoter of PTHrP.