结直肠癌患者p16基因甲基化的检测

目的检测p16基因启动子区异常甲基化发生情况,探讨p16基因异常甲基化作为结直肠癌临床辅助诊断分子生物学标志物的可能性。方法选取2004年5月至2004年12月第三军医大学西南医院及贵州省人民医院普外科住院的结直肠癌患者53例,所有患者均经病理学诊断证实,并按Dukes病理分期分为四期,提取肿瘤组织DNA,分别应用巢式甲基化特异性PCR(nested methylation specific polymerase chain reaction,nested-MSP)及甲基化特异性PCR(methylation specific polvmerase chain reaction,MSP)方法,检测患者肿瘤组织中p16基冈的异常甲基化情况;比较MSP及nested-MSP两方法的灵敏度。结果应用MSP方法,Dukes A、B期患者和Dukes C、D期患者p16基因的甲基化率分别为23.8%和59.4%,两组比较有显著性差异(P<0.05);应用nested-MSP方法,Dukes A、B期患者和Dukes C、D期患者p16基因的甲基化率分别为52.4%和84.4%,两组比较有显著性差异(P<0.05)。应用MSP与nested-MSP方法检测肿瘤组织p16基因甲基化的阳性率分别为45.3%(24/53)、71.7%(38/53),两组比较有显著性差异(P<0.01)。结论应用nested-MSP方法检测肿瘤组织p16基因甲基化的灵敏度明显高于普通的MSP方法,分析患者DNA的p16基因异常甲基化有可能成为结直肠癌辅助诊断及预后评估的有效方法之一。

Detection of hypermethylation ofp16 gene from colorectal cancer patients

Objective To detect hypermethylation of p 16 gene in tissue DNA from patients with col- orectal cancer,and to assess its potential value as a malignant marker.Methods Fifty-three in-patients suf- fered from colorectal cancer were selected in Southwest Hospital of the Third Military Medical University and in the People's Hospital of Guizhou from May 2004 to December 2004.All patients were divided into four stages, Dukes A,B,C and D according to Dukes pathologic staging.Using methylation specific polymerase chain reac- tion (MSP) and nested methylation specific polymerase chain reaction (nested-MSP),the status of methylation of the p 16 was investigated in tumor tissues DNA from 53 colorectal cancer patients.Results The hypermethyla- tion of the p 16 was present in 23.8% in Dukes stages A and B tumors,59.4% in the stages of C and D tumors by MSP,and there was significant difference between the two groups (P<0.05);the hypermethylation of the p16 was present in 52.4% in Dukes stages A and B tumors,84.4% in the stages of C and D tumors by nested-MSP, and there was significant difference between the two groups (P<0.05).The sensitivity of MSP was 45.3% (24/ 53),and the sensitivity of nested-MSP was 71.7% (38/53),there was significant difference between the two groups (P<0.01).Conclusion The result indicates that the sensitivity of nested-MSP is higher than that of MSP significantly,and the hypermethylation of the p16 may be a useful marker in the auxiliary diagnosis and prognosis evaluation of colorectal cancers.