Epigenetic impact of dietary polyphenols in cancer chemoprevention: lifelong remodeling of our epigenomes.

Cancer, as one of the non-communicable diseases, remains one of the leading causes of death around the world. Recently, epigenetic changes in DNA methylation patterns at CpG sites (epimutations) or deregulated chromatin states of tumor promoting genes and noncoding RNAs emerged as major governing factors in tumor progression and cancer drug sensitivity. Furthermore, various environmental factors such as nutrition, behavior, stress, and toxins remodel our epigenomes lifelong in a beneficial or detrimental way. Since epigenetic marks (epimutations) are reversible in contrast to genetic defects, chemopreventive nutritional polyphenols (soy, genistein, resveratrol, catechin, curcumin) are currently evaluated for their ability to reverse adverse epigenetic marks in cancer (stem) cells to attenuate tumorigenesis-progression, prevent metastasis or sensitize for drug sensitivity. Although polyphenols in fruit and vegetables may help to reduce the risk of cancer, few protective effects have been firmly established, presumably because of inappropriate timing or dosing of diet exposure or due to confounding factors such as smoking and alcohol. In this review will discuss the possible epigenetic contributions of dietary polyphenols in cancer chemoprevention.