ABSTRACT
Both genetic and epigenetic changes are effective in cancer incidence and development. Epigenetic processes are alternations of DNA and histones conformations, chromatin remodeling, DNA methylation, post-translational modifications of histones and microRNAs patterns which are associated with genes expression or inhibition of them in cells. Some of reversible epigenetic changes such as DNA and histcone conformation alternations related to drug interaction, stabilization of telomeric quadruplex sequences, DNA hypermethylation and histone acetylation and phosphorylation have been recognized as promising novel therapeutic targets in various cancers. In the present review, molecular mechanisms of epigenetics, epigenetic changes in tumors, and epigenetic based treatments are discussed