Quantitative Detection Of Methylated E-cad, A Gastric Cancer Supressor Gene, By Uantitative Realtime Methylation-specific PCR

Object:The hypermethylation of promoter CpG islands has a important rolein tumorigenesis and regulation of tumor suppressor genes. The methyla-tion amounts of promoter CpG islands may be more and more in tumorigenesis,so it is essential to detect methylated DNA quantitatively. In thisstudy, we quantified methylated E-cadherin (E-cad), a gastric cancersuppressor gene, by quantitative real time methylation-specific PCR usingSYBR Greenl and analyzed it's role in gastric cancer.Materials and Methods: Samples were in two groups, 18 gastric cancers and10 normals. CpGenome^TM Universal Methylated DNA was used to prepare theexternal standards for quantitative real time methylation-specific PCR.We detected methylated E-cad quantitatively. Meanwhile we tested thespecificity and accuracy of this experiment.Results: The coefficient correlation of standard curve was-0.99. Thespecificity of this test is 100%. The positive rate of methylationwas found to be 55.56% in gastric cancers, and 10.00% in normals. The pos-itive rate of methylation of first group was significantly higher thansecond group (p＜0.05). The logarithm mean is 4.29±4.12 in gastric can-cers and 0.29±0.91 in controls, The amounts of methylated E-cadherinin gastric cancers were also significant higher than in controls(p＜0.05).The positive rate of methylation was found to be 38.10% in≥50 ages and42.86% in＜50 ages, there was no significant relationship in ages andmethylation of E-cad(p＞0.05).Conclusion: SYBR Green quantitative real time methylation-specific PCRcan detect methylation of DNA promoter CpG islands quantitatively. It is accurate and specific. The amounts of methylated E-cad in gastric cancerswere significant higher than in controls. The quantitative detection ofhypermethylated E-cad may be useful in screening of gastric cancer.