肺癌中结肠多发性腺瘤样息肉基因启动子1A序列甲基化模式的研究

目的 探寻结肠多发性腺瘤样息肉（APC）基因启动子1A序列中肺癌甲基化位点及其存在模式。方法 用甲基化序列特异性引物，对阳性控制样品（CB＋）、阴性控制样品（CB-）、13份正常肺组织及19份肺癌组织进行APC基因启动子1A序列甲基化特异性扩增（MSP），其扩增产物直接测序和进行克隆测序分析。结果 在19份肺癌组织中，APC基因启动子1A序列的707、714、719和726位点发生高甲基化，甲基化率分别为95％（18／19）、74％（14／19）、74％（14／19）和74％（14／19），与正常肺组织比较，差异均有统计学意义（P〈0．001）。而679和687位点甲基化发生率均为11％（2／19），与正常肺组织甲基化发生率（0／13）接近（P〉0．05）。结论 在APC基因启动子1A序列中存在CpG胞嘧啶二核苷酸特定甲基化模式，其对肺癌早期诊断可能有重要意义。

Study of the methylated CpG status of adenomatous polyposis coli gene promoter 1A sequence on lung cancer

Objective To analyze the CpG methylation status of adenomatous polyposis coli (APC) gene promoter 1A in human lung cancer.Methods Methylation specific PCR was used to amplify the DNA template from tissues of 19 cases of lung cancer patient and 13 cases of normal lung of health person.The MSP products were sequenced directly and cloned for sequencing.Results In CpG rich region of APC gene promoter 1A, four connected CpG sites which coded 707, 714, 719 and 726 were appeared in high methylation status with the methylation rate of 95%, 74%, 74% and 74% respectively in tumor tissues of 19 lung cancer cases. The high methylation status of lung cancer showed very high significant difference to that of health person (P<0.001). While other two connected CpG sites, 679 and 687, were both in the same lower methylation rate (11%), similar to that of normal lung tissues (0/13).Conclusion There is a special CpG methylation pattern of APC gene promoter 1A which may closely relate to human lung cancer.