Our ChIP assay showed that HDAC inhibitors (SAHA and VPA) alone or in combination with ATRA markedly increased the enrichment of acetylated histones (H3K9ac) on the RARβ2-RARE region both in vitro and in vivo, leading to a restoration of RARβ2 and the upregulation of its downstream growth inhibitory pathways in cervical cancer. This evidence concerns the gene HDAC9 and cervical cancer.