p53、malat1、ki-67和β-catenin基因mRNA检测在大肠癌分子诊断中的意义

Detection of p53,malat1,ki-67 and β-catenin mRNA expression and its significance in molecular diagnosis of colorectal carcinoma

目的:初步研究多个大肠癌相关基因p53、malat1、ki-67和β-catenin在大肠癌分子诊断中的意义.方法:收集手术切除的新鲜大肠癌组织标本47例、大肠腺瘤组织标本13例,以及分别和大肠癌、大肠腺瘤对应的正常大肠黏膜组织标本53例,用实时荧光定量RT-PCR方法检测各基因的Ct值.结果:p53、malat1在大肠癌组表达量均高于大肠腺瘤组(P=0.026,P=0.034),但是p53在正常大肠黏膜组、大肠腺瘤组和大肠癌组中表达依次增高,而malat1在大肠腺瘤组、正常大肠黏膜组和大肠癌组中表达量依次增高,大肠腺瘤组mRNA表达最低.ki-67在大肠癌组的表达量是正常黏膜组表达量的1.42倍(P=0.007).β-catenin基因在三组间的表达差异无统计学意义.各基因的表达量均和大肠癌的分期无关.经ROC曲线分析,p53的曲线下面积是0.755(P<0.05),在大肠腺瘤组和大肠癌组的最佳Cut-off值分别是2.585、3.215,malat1的曲线下面积是0.748(P<0.05),在大肠腺瘤组和大肠癌组的最佳Cut-off值分别是0.925、1.395;二元Logistic回归分析,p53和malat1进入回归模型(P<0.05).联合检测p53和malat1在大肠腺瘤组和大肠癌组的ROC曲线下面积为0.785(P=0.01),在大肠腺瘤组的和大肠癌组的最佳Cut-off值分别是0.750、0.790.p53和malat1联合检测的ROC曲线下面积均高于单独检测的ROC曲线下面积.结论:p53和malat1在大肠癌的分子诊断中有一定的应用价值,可为鉴别大肠腺瘤和大肠癌提供有效的参考;和单独检测相比,二者联和检测的准确性高于单独检测的准确性.

AIM： To detect p53, malat1, ki-67 and β-catenin mRNA expression in colorectal carcinoma and to evaluate its significance in molecular diagnosis of colorectal carcinoma. METHODS： Real-time RT-PCR was used to detect p53, malat1, ki-67 and β-catenin mRNA expression in samples from 47 colorectal carcinomas, 13 colorectal adenomas and 53 normal colorectal tissues. RESULTS： The expression levels of p53 and malat1 were significantly different between colorectal carcinoma, colorectal adenoma and normal colorectal tissue （P 〈 0.05）. p53 expression levels showed an average 1.61-fold （P = 0.000） and 2.62-fold （P = 0.000） increase in colorectal adenoma and colorectal carcinoma tissues when compared with normal colorectal tissues respectively, and 1.77-fold （P = 0.026） increase in colorectal carcinoma compared with colorectal adenoma. Similarly, malat1 expression levels were 0.55-fold （P = 0.001）, 1.48-fold （P = 0.002） and 1.78-fold （P = 0.034） respectively. However, there were no significant differences among colorectal carcinoma, colorectal adenoma and normal colorectal tissues in ki-67 and β-catenin. The expression levels of p53, malat1, ki-67 and β-catenin mRNA were not associated with the staging of colorectal carcinoma. The AUC （area under curve） of p53 and malat1 were 0.755 and 0.748, respectively. The cut-off value for p53 in colorectal adenoma and colorectal carcinoma was 2.582 and 3.215 respectively; for malat1, 0.925, 1.395 respectively. Logistic regression analysis showed that p53 and malat1 entered the regression equation （P 〈 0.05）. The combined determination showed, the AUC were 0.785, the cut-off values in colorectal adenoma and colorectal carcinoma were 0.750, 0.790 respectively. Thus, the AUC of combined determination was larger than that of single detection for p53 and malat1. CONCLUSION： The present study demonstrates that p53 and malat1 have certain application value in molecular diagnosis of colorectal carcinoma to identify colorectal carcinoma and colorectal adenoma. Furthermore, the accuracy in diagnosis of colorectal cancer is improved by combined assaying of p53 and malat1.