Several reports indicate that impairing the acetylation/deacetylation balance of Notch3 using HDAC inhibitors (HDACi) that favor hyperacetylation can negatively affect the stability and function of Notch3 in cancer cells and tumor xenograft mouse models (Palermo et al., 2012; Jaskula-Sztul et al., 2015; Zhang et al., 2017; Pinazza et al., 2018). The gene discussed is HDAC9; the disease is cancer.