Polymerase chain reaction-based methods of DNA methylation analysis
Section snippets
PCR-based methods of DNA methylation analysis
Cytosines located 5′ to guanines, called CpG dinucleotides, are present in the regulatory regions of many genes. In normal cells, CpG dinucleotides in gene transcriptional promoter regions are generally unmethylated. However, in the promotor sequences of genes associated with certain cancers or inherited diseases these cytosines are methylated. The methylation status of some of these promoter regions can provide important information with respect to the nature of a tissue or cellular specimen.
Critical note to these analytical approaches with respect to clinical application
PCR-based sensitive detection methods made it possible to assess methylation changes in cancer cells. These PCR-based strategies to assess methylation changes in minute quantities of biological materials raise the possibility that this type of analysis could facilitate risk assessment or early diagnosis strategies [29]. This strategy is further enhanced by three facts: (1) the PCR signal is a positive signal that cannot be masked through contamination by normal cells, (2) promoter
Conclusions
As the number of genes known to be hypermethylated in cancer is growing, the detection of aberrant promoter region methylation will be a promising approach for using DNA-based markers for the early detection of human cancers. Many techniques to make methylation detection possible have been developed over the years [34], [35]. New methods and approaches to avoid certain limitations or to be more practical are developed continually [36], [37], [38], [39], [40]. Therefore, so many techniques
Acknowledgements
This study was supported in part by the Japan–China Sasakawa Medical Fellowship.
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