Epigenetic alterations and their clinical implications in esophageal squamous cell carcinoma

Alterations in the regulation of gene expression that do not involve a change in the DNA sequence have been increasingly recognized as an important key event of carcinogenesis, referred to as epigenetic'' changes. Major epigenetic mechanisms include the methylation of cytosines in DNA, changes of histone and chromatin structure by covalent posttranslational modifications of histone proteins and alterations in the expression of microRNAs. These epigenetic alterations have also been identified in esophageal squamous cell carcinoma (ESCC). In this brief review, we will discuss DNA hypermethylation of the tumor suppressor gene promoters, histone modifications including histone acetylation/deacetylation and histone methylation and microRNAs in ESCC. Clinical implications of these epigenetic alterations in ESCC will be also discussed.