肝癌组织中DNA甲基转移酶基因表达的分析

摘要

目的 分析肝癌患者癌组织、癌旁组织、肝硬化组织中甲基转移酶(DNMT)基因的表达情况.方法 应用荧光定量PCR(FQ-PCR)检测44例分期及分化程度不同的肝癌患者癌组织、癌旁组织和35例肝硬化组织中DNMT基因mRNA的表达水平.不同组间DNMT表达水平的差异采用ANOVA分析.结果 与癌旁组织相比,癌组织及肝硬化组织中4种DNMTs mRNA表达水平均高于相应癌旁组织；肝硬化组织及癌组织中DNMT1的平均表达水平明显高于癌旁组织(癌组织P＜0.01、肝硬化组织P=0.02)；DNMT2水平虽比相应组织高,但没有统计学意义(癌组织P=0.12、肝硬化组织P=0.35)；DNMT3A与DNMT3B的表达水平也明显高于相应癌旁组织(DNMT3A:癌组织P＜0.01、肝硬化组织P=0.01；DNMT3B:癌组织P=0.03、肝硬化组织P＜0.05).不同年龄、性别、分化程度和分级肝癌中DNMT1、DNMT2、DNMT3A、DNMT3B表达水平差异无统计学意义(P=0.23、0.45、0.32、0.36).结论 肝癌患者癌组织及硬化组织中DNMT1、DNMT3A和DNMT3B mRNA明显高于癌旁组织；DNMT表达与肝癌发生或发展可能有关.%Objective To investigate the differential expression of DNA methyltransferase (DNMT) in hepatocellular carcinoma (HCC).Methods DNMT mRNA expression was measured by fluorescence quantitative-PCR in specimens of cancerous tissues (n =44) and case -matched cirrhotic (n =35) and non-cancerous,non-cirrhotic (normal; n =44) liver tissues from 44 HCC patients with different tumor stages.Results The mean mRNA levels of the four DNMT types tested (1,2,3A,3B) were higher in cancerous and cirrhotic tissues than in adjacent normal tissues.The DNMT1 elevated expression reached statistical significance (vs.adjacent normal tissues,P ＜0.01 for cancerous tissue and P =0.02 for cirrhotic tissue),unlike the DNMT2 elevated expression which did not reach statistical significance (vs.adjacent normal tissues,P =0.12 for cancerous and P =0.35 for cirrhotic tissues).Both DNMT3 isoforms,A and B,were significantly higher than the levels detected in the adjacent healthy tissues (DNMT3A:P ＜ 0.01 for cancerous and P =0.01 for cirrhotic tissue; DNMT3B:P =0.03 for cancerous and P ＜ 0.05 for cirrhotic tissue).Stratification analysis of the four DNMTs mRNA expression levels according to patient sex,tumor staging,and tumor differentiation revealed no correlations (DNMT1:P =0.23; DNMT2:P =0.45; DNMT3A:P =0.32; DNMT3B:P =0.36).However,trends were found for increased DNMTs mRNA expression levels and male sex,poor tumor differentiation,and high tumor stage.Conclusion The mRNA expressions of DNMT1,DNMT3A,and DNMT3B are higher in cancerous and cirrhotic tissues from HCC patients than in their adjacent non-cancerous,non-cirrhotic liver tissues.Expression of DNMTs may be associated with pathogenesis of HCC or HCC associated with cirrhosis.