To investigate the prognostic relationship between HDAC-related genes and COAD, univariate Cox analysis was used to identify prognostic genes based on the expression levels of HDAC-related genes (Fig. 2A), and the results showed that the predictors of TAF1, HDAC7, and BRD3 were associated with poorer survival. The gene discussed is HDAC9; the disease is colon adenocarcinoma.