p33生长抑制基因1b甲基化在结直肠癌组织及粪便中的检测

Detection of p33 inhibitor of growth gene 1b methylation in tissue and fecal DNA of colorectal cancers

目的 检测散发性结直肠癌患者癌组织及其配对的粪便DNA中p33生长抑制基因1b（p33ING1b）启动子甲基化,探讨其在两种标本中检测的一致性及其意义.方法 收集散发性结直肠癌组织及其配对的粪便标本及对照组粪便标本,采用巢式甲基化特异性聚合酶链反应（nMSP）检测p33ING1b基因启动子甲基化状况.结果 37例散发性结直肠癌组织、粪便中p33ING1b启动子甲基化阳性检出率分别为83.78％、78.38％,检测结果符合率为94.60％,具有明显相关性（r=0.838,P＜0.01）.粪便DNA中p33ING1b启动子甲基化率明显高于对照组（P＜0.01）,与癌组织临床病理特征无明显相关（P＞0.05）.结论 检测粪便DNA中p33ING1b启动子甲基化能反映其在肿瘤组织中甲基化状况.

Objective The aim of this study was to detect the promoter methylation status of p33 inhibitor of growth gene 1 b （p33ING1b） in tissue and the matched fecal DNA of sporadic colorectal cancers,and evaluate the consistency of the assays in the two samples and the clinical value.Methods Tissues with matched fecal samples and control group were collected from 37 patients of colorectal cancer.The promoter methylation status of p33ING1 b was detected by the nested methylation specific polymerase chain reaction （nMSP）.Results Out of 37 cases,83.78% and 78.38% exhibited p33ING1b methylation in the tissue and matched fecal samples,respectively.The coincident rate of p33ING1 b methylation status in the two groups was 94.6%,with significant correlation （R =0.838,P 〈 0.01）.The methylated rate of p33ING1b in fecal samples of colorectal cancers （CRCs） was significantly higher than control group （P 〈 0.01）,and there was no significant relationship with clinical pathological factors of CRCs （P 〉 0.05）.Conclusion The p33ING1b methyaltion test in fecal DNA may reflect the real methylation status in CRCs and as a noninvasive test for screening CRCs.