Reports of elevated H3K56ac in human tumor samples (Das et al. 2009), the potential of activated RAS-PI3K signaling to reduce H3K56ac (Liu et al. 2012), and a large number of clinical trials for HDAC inhibitors that likely increase H3K56ac levels in tumor cells (Eckschlager et al. 2017) all suggest changes in H3K56ac levels may be widespread in cancer. Here, HDAC9 is linked to cancer.