Ovarian cancers can also arise from mutations in p53, BRAF, β-catenin, Rb, BRCA1, BRCA2, MSH2 and MLH1 and overexpression of epithelial growth factor receptor (EGFR), Akt and HER2. HDAC inhibitors are promising drugs for ovarian cancer treatment, and there are several currently in clinical trials. This evidence concerns the gene HDAC9 and ovarian cancer.