Within the class of polyphenols the major green tea catechin (−)-epigallocatechin-3-gallate (EGCG), the stilbene resveratrol (found in grapes and wine), several soy isoflavones and carboxylic acid derivatives such as chlorogenic acid (CGA) or caffeic acid have been extensively reported to affect HDAC activity, and all are implicated with a reduced cancer risk [2, 20–24]. This evidence concerns the gene HDAC9 and cancer.