| Summary: | 碩士 === 國防醫學院 === 公共衛生學研究所 === 98 === The incidence of colorectal cancer in Taiwan is the second ranking, and the mortality is the third, therefore, colorectal cancer is worthy of studying. Most of colorectal cancers are evolved from adenomas. In the process, there are genetic changes and epigenetic modification. One of the epigenetic modification is DNA methylation that is the best well-known. As a result, the main purpose of this study is to evaluate the relationship between DNA methylation and the risk of colorectal cancer. A total of three candidate genes named cyclin dependent kinase inhibitor 2A(CDKN2A), human mutL homolog 1(MLH1) and O6-methylguanine-DNA methyltransferase(MGMT) have been chosen in this study.
Tissue samples of this study are from the tumor bank of Tri-Service General Hospital and we use methylation specific PCR to analyze the status of DNA methylation. The results show that the methylation frequencies of CDKN2A, MLH1 and MGMT in adenocarcinomas are 24%, 16% and 48%. The odds ratios of colorectal cancer for methylation of CDKN2A, MLH1 and MGMT are 13.7(95% confidence interval: 1.2-150.9), 0.9(95% confidence interval: 0.1-10.6) and 10.4(95% confidence interval: 2.2-48.4).
In conclusion, these results suggest that DNA methylation has the relationship with colorectal cancer and it plays a certain role in carcinogenesis.
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