石蜡包埋人胰腺癌组织中DPC4/SMAD4/MADH4基因的改变  

Alterations of DPC4/SMAD4/MADH4Gene Detected in Paraffin-embedded Tissues of Human Pancreatic Carcinomas

作　　者：谷丽君[1] 陈杰[1] 刘彤华[1] 崔全才[1] 卢朝辉[1] 李理[1] 高洁[1] 

机构地区：[1]中国医学科学院中国协和医科大学北京协和医院病理科,北京100730

出　　处：《中国医学科学院学报》2002年第2期165-169,共5页Acta Academiae Medicinae Sinicae

基　　金：国家教委跨世纪优秀人才计划基金;国家杰出青年科学基金(39625012)资助

摘　　要：目的研究石蜡包埋人胰腺癌组织中DPC4/SMAD4/MADH4基因的改变。方法用PCR-SSCP、PCR产物直接测序法检测46例石蜡包埋人胰腺癌组织中DPC4基因改变情况,用原位杂交(ISH)、免疫组织化学(IHC)检测56例石蜡包埋人胰腺癌组织DPC4的mRNA、SMAD4蛋白表达情况。结果胰腺癌DPC4基因第1、2、3、4、8、11外显子的纯合性缺失率为28.26%,突变率为21.74%,测序显示有3例无义突变,5例错义突变,1例插入、缺失及错义突变,1例插入突变。ISH、IHC显示胰腺癌DPC4/SMAD4阳性率分别为53.57%、58.93%,而对应正常胰腺阳性率分别为91.07%、89.29%。统计学分析表明胰腺癌与正常胰腺有显著性差异(P<0.05)。32例胰腺癌进行了PCR-SSCP、测序、ISH和IHC实验,四者结果一致者28例,符合率为87.50%,其中基因改变与ISH符合率为87.50%,基因改变与IHC符合率为96.88%。56例胰腺癌的ISH与IHC符合率为91.07%,统计学分析显示上述三组阳性率间均无显著性差异(P>0.05)。结论人胰腺癌纯合性缺失和突变是DPC4失活的主要机制,胰腺癌与正常胰腺相比,SMAD4表达明显下降,DPC4作为一种抑癌基因,其改变可能为胰腺癌的重要分子事件,在胰腺癌的形成中可能起重要作用。Objective To demonstrate the alterations of DPC4/SMAD4/MADH4gene in paraffin-embedded tissues of pancreatic carcinomas.Methods Forty-six cases of resected specimens containing carcinom-atous tissue and normal pancreatic tissue were analysed for possible DPC4gene mutations by polyme-rase chain reaction(PCR)and single-strand conformation polymorphism(SSCP).The DNA sequencing technique was applied to determine the patterns of gene mutation in the PCR-SSCP positive cases.Fifty-six cases of pancreatic carcinoma along with the specimens corresponding normal pancreatic tiss-ues were studied by in situ hybridization(ISH)and immunohistochemistry(IHC)techniques for gene expression in mRNA and protein level.Results The homozygous deletion rate of exon1,2,3,4,8,11of DPC4gene in pancreatic carcinoma was28.26%,while the mutation rate of DPC4gene was21.74%.In these tumors,there were3cases of nonsense mutation,5cases of missense mutation,1case of deletion and missense mutation,1case of insertion mutation.Positive rates of SMAD4in carcinomatous tissues detected by the ISH and IHC were53.57%and58.93%respectively,whereas they were91.07%and89.29%in the matched normal tissue respectively.There were significant diff-erence between cancer and normal tissue( P <0.05).Thirty-two cases were positive of DPC4/SMAD4with all methods mentioned above,the coincident rate was87.50%(28/32).The coincidence between gene detection and ISH of SMAD4was87.50%,and it was96.88%between gene detection and IHC of SMAD4.Of all56cases,the coincidence of the positive rates of SMAD4detected by ISH and IHC was91.07%.No significant difference among the positive rates of DPC4 / SMAD4as detected by the three different techniques ( P>0.05 ) .Conclusions The main mechanisms of inactivation of DPC4gene in pancreatic carcinoma are homozygous deletion and mutation.The product of DPC4expression is significantly decreased in cancer group compared with the normal tissues.As a tumor suppressor gene,DPC4alteration is an important molecular event

关 键 词：胰腺癌 抑癌基因 DPC4/SMAD4/MADH4 

分 类 号：R735.9[医药卫生—肿瘤] R－344.2[医药卫生—临床医学]