**4. Conclusion**

Epigenetic modifications is observed to perform a significant role in disease occurrence and pathogenesis. DNA methylation and chromatin remodeling are the most common epigenetic mechanisms, as described as a phenomenon of modifications in gene expression caused by heritable, but reversible, alterations in the chromatin structure, DNA methylation, and post-transcriptional effects of small noncoding microRNAs (miRNAs), without changes in the DNA sequence. The relationship between epigenome, epigenetic mechanisms and gene expression form a complicated feedback network that regulates and organizes cellular functioning at the molecular level; when this regulatory circuit is disrupted by internal or external factors, normal physiological functions are affected, leading to tumor initiation process [59]. Epigenetic mechanisms represent novel targets for natural products in prevention and treatment of cancer and other diseases. The influence of various classes of diet phytochemicals on the enzymatic activities of enzymes involved in epigenetic gene regulation; such as DNA and histone methyltransferases (DNMTs and HMTs), histone acetyltransferases (HATs), histone deacetylases (HDACs), and histone demethylases (HDMs) are also emphasized.

As a conclusion, the present review provided an overview of the most frequent epigenetic alterations in cancers, then described the most studied dietary phytochemicals and their potential use in the reversion of cancer hallmarks through epigenetic mechanisms, and finally discussed their potential use as an alternative strategy for cancer therapy. Above all, this review focused on modulation of epigenetic activities by epi-drugs that will allow the discovery of novel biomarkers for cancer prevention, as a potential alternative therapeutic approach in cancer, summarizing the progress made in cancer chemoprevention with dietary phytochemicals, and challenges in the future.
