Review
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World J Gastroenterol. Mar 7, 2012; 18(9): 882-888
Published online Mar 7, 2012. doi: 10.3748/wjg.v18.i9.882
DNA methylation and microRNAs in cancer
Xiang-Quan Li, Yuan-Yuan Guo, Wei De
Xiang-Quan Li, Yuan-Yuan Guo, Wei De, Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
Author contributions: De W conceived the review; Li XQ and Guo YY analyzed the data; and Li XQ wrote the review.
Correspondence to: Wei De, Professor, Head of the Department of Biochemistry and Molecular Biology of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China. njmu2011@163.com
Telephone: +86-25-86862895 Fax: +86-25-86863202
Received: May 14, 2011
Revised: September 9, 2011
Accepted: January 18, 2012
Published online: March 7, 2012
Abstract

DNA methylation is a type of epigenetic modification in the human genome, which means that gene expression is regulated without altering the DNA sequence. Methylation and the relationship between methylation and cancer have been the focus of molecular biology researches. Methylation represses gene expression and can influence embryogenesis and tumorigenesis. In different tissues and at different stages of life, the level of methylation of DNA varies, implying a fundamental but distinct role for methylation. When genes are repressed by abnormal methylation, the resulting effects can include instability of that gene and inactivation of a tumor suppressor gene. MicroRNAs have some aspects in common with this regulation of gene expression. Here we reviewed the influence of gene methylation on cancer and analyzed the methods used to profile methylation. We also assessed the correlation between methylation and other epigenetic modifications and microRNAs. About 55 845 research papers have been published about methylation, and one-fifth of these are about the appearance of methylation in cancer. We conclude that methylation does play a role in some cancer types.

Keywords: Methylation gene expression; Transcriptional control; Cancer; MicroRNA; Gastric cancer