HDAC9 and colonic neoplasm: Because butyrate also showed HDAC inhibitor activity similar to propionate, we hypothesized that butyrate in BT Sup might be involved in the HECTD2-EHMT2-TNFAIP1 axis for growth suppression of colon cancer cell lines via the reduction of HECTD2 by inducing H3K27 acetylation, as shown by propionate treatment.