Evaluation of DNA methylation in the human genome: Why examine it and what method to use

Purpose: Since its discovery 50 years ago, DNA methylation has been found to be an important part of gene regulation. Newer methods of analysis over the last decade have helped further the understanding of this epigenetic phenomenon. The purpose of this article is to describe current methods of analysis and discuss advantages and disadvantages of each and their possible roles in gynecologic malignancies.

Results: The methods for analysis of DNA methylation are divided into two major categories: 1) methods which utilize chemical methods or restriction enzymes to differentially cleave at cytosine versus 5-methylcytosine sites, 2) methods which utilize sodium bisulfite (NaHSO3) to specifically convert unmethylated cytosines to uracil (thymine after PCR). This recently developed method appears to be more sensitive and allows the investigator to specifically delineate the study site(s).

Conclusion: DNA methylation is important in the human genome. Its role in tumorigenesis is just beginning to be understood. While relying upon newly designed methods of analysis, further understanding of this epigenetic phenomenon and its role in gene expression and tumorigenesis will be forthcoming.

Methylation; Tumor suppressor genes; CpG; Mutation

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