| Summary: | 碩士 === 國立中興大學 === 生命科學系所 === 95 === DNA methylation would appear at CpG island of promoter and exon 1 in many genes and inhibit the expression of the gene. Abnormal DNA methylation would inhibit gene expression abnormally. Many studies show that many DNA from tumor tissues had abnormal DNA methylation. Therefore, to build a new technique for DNA methylation analysis fastly becomes very important. Methylation-specific bisulfite amplicon microarray is a new type of chip, which is combined the concept of methylation-specific PCR and tissue microarray, to screen many clinical sample methylation status at once. 192 pairs of tumor samples, which were from Hepatomacarcinoma, lung cancer, colorectal carcinoma and breast cancer, were spotted on the methylation-specific bisulfite amplicon microarray. In order to make sure the quality of methylation-specific bisulfite amplicon microarray, we double check the results of the chip with MSP. The results of methylation-specific bisulfite amplicon microarray shows that there were many samples of hepatoma carcinoma have hypermethylation status. The results of MBA microarray and MSP in hepatoma carcinoma have 85% samples are the same. But only 23% of colorectal carcinoma clinical samples have the same results on MBA microarray and MSP. We also analyzed the methylation status of colorectal carcinoma on different genes, and then find the correlation between methylation status and clinical datas. Hypermethylation frequencies of the 5 genes tested in colorectal cancer tumor tissue DNA were 78% (46 of 59) for PCDH21, 63% (37 of 59) for 3OST3B, 64% (38 of 59) for CDH1, 71% (15 of 59) for p16INK4a and 23.8% (5 of 59) for DAPK. Our statistical data shows that the methylation of PCDH21 was significantly correlated with N stage (p=0.044), CEA of pre-operation (p=0.029) and treatment of CCRT (Pre-operative Combined Chemoradiotherapy) (p=0.008) at diagnosis of the patients analyzed. The methylation status of 3OST3B was significantly correlated with treatment of CCRT (p=0.018) and so was CDH1 (p=0.021). Our statistical data indicated that hypomethylation of PCDH21 correlated with metastasis in regional lymph nodes and higher value of pre-operation CEA. After we have the survival rate in the next 3 years, then we can see whether the hypomethylation of PCDH21 relate to metastasis and prognosis in colorectal cancer patients.
|
|---|
