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目的 :探讨人乳腺癌组织中微RNA-34a(micro RNA-34a,mi R-34a)的表达及其临床意义,并分析mi R-34a基因启动子甲基化状态与成熟mi R-34a表达及患者生存的相关性。方法 :采用Taq Man探针-实时荧光定量PCR法检测93例乳腺癌组织及5例良性乳腺疾病标本(作为对照)中成熟mi R-34a的表达。运用Epi Tect Fast FFPE Bisulfi te试剂盒对石蜡包埋乳腺癌组织的基因组DNA进行抽提及亚硫酸盐修饰,然后采用甲基化特异性PCR法检测mi R-34a基因启动子的甲基化状态。统计学分析mi R-34a基因启动子甲基化状态与mi R-34a表达量之间的关系,并用生存曲线分析其预后意义。结果 :乳腺癌组织中成熟mi R-34a的表达水平比良性对照组明显降低(P=0.006)。mi R-34a表达水平与肿瘤大小(r=-0.312,P=0.021)、淋巴结转移(r=-0.378,P=0.004)和肿瘤分级(r=-0.341,P=0.011)均呈负相关性,而与雌激素受体(estrogen receptor,ER)、孕激素受体(progesterone receptor,PR)和人表皮生长因子受体2(human epidermal growth factor receptor-2,HER-2)等水平均不相关(P均>0.05)。mi R-34a基因启动子非甲基化组的成熟mi R-34a表达水平明显高于甲基化阳性单一模式组和甲基化阳性混合模式组(P值均<0.001)。与非甲基化组和甲基化阳性混合模式组相比,mi R-34a基因甲基化阳性组的乳腺癌患者无复发生存期(P<0.001,P=0.019)及总生存期(P=0.002,P<0.001)均明显缩短。结论 :在部分乳腺癌患者中,mi R-34a基因甲基化可导致mi R-34a表达下调。mi R-34a基因的甲基化状态与乳腺癌的复发及不良预后相关。
Objective: To investigate the expression of micro RNA-34a (mi R-34a) and its clinical significance in human breast cancer and to analyze the relationship between the methylation status of mi R-34a promoter and the expression of mature mi R-34a And the relevance of patient survival. Methods: The expression of mature mi R-34a in 93 cases of breast cancer tissues and 5 cases of benign breast disease (as control) was detected by Taq Man probe-real-time fluorescence quantitative PCR. The genomic DNA of paraffin-embedded breast cancer tissues were extracted and sulfite-modified by using Epi Tect Fast FFPE Bisulfate kit. The methylation status of mi R-34a gene promoter was detected by methylation-specific PCR . The relationship between the methylation status of mi R-34a promoter and the expression of mi R-34a was statistically analyzed. The prognostic significance of mi R-34a gene expression was analyzed by survival curves. Results: The expression of mature mi R-34a in breast cancer tissues was significantly lower than that in the benign control group (P = 0.006). The expression of mi R-34a was negatively correlated with tumor size (r = -0.312, P = 0.021), lymph node metastasis (r = -0.378, P = 0.004) and tumor grade (r = -0.341, P = 0.011) , But not with estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2) (P> 0.05). The expression level of mature mi R-34a in the non-methylated group of mi R-34a gene promoter was significantly higher than that of methylated positive monotherapy group and methylation-positive monotherapy group (all P <0.001). There was no recurrence (P <0.001, P = 0.019) and overall survival (P <0.001) in breast cancer patients with methylation-positive mi R-34a gene compared with non-methylated and methylated positive mixed groups = 0.002, P <0.001) were significantly shorter. Conclusion: In some breast cancer patients, mi R-34a gene methylation may result in the down-regulation of mi R-34a expression. The methylation status of mi R-34a gene is associated with the recurrence and poor prognosis of breast cancer.