The first US Food and Drug Administration (FDA)-approved acetylating modifier, vorinostat (also known as suberanilohydroxamic acid (SAHA)), was initially identified as a drug that induces tumor cell differentiation in vitro and was subsequently identified as an HDAC inhibitor (Richon et al., 1998; Mann et al., 2007). This evidence concerns the gene HDAC9 and neoplasm.