内源性端粒酶抑制基因遗传不稳定性与胃癌进展的关系

目的 研究8号染色体上D8S277位点的杂合性缺失(LOH)和微卫星不稳定性(MSI)对内源性端粒酶抑制基因(PINX1)蛋白表达的影响,阐明PINX1基因遗传不稳定性与胃癌进展的关系. 方法采用石蜡包埋组织抽提DNA,聚合酶链-单链构象多态性(PCR-SSCP)分析,常规银染检测D8S277位点的LOH和MSI,采用Envision免疫组织化学染色和Leica-Qwin计算机图像分析等方法. 结果 D8S277位点的LOH发生率在淋巴结转移组(21.15%)明显高于无淋巴结转移组(0,P<0.05);在胃癌TNM Ⅲ Ⅳ期(24.39%)显著高于Ⅰ Ⅱ期(3.33%,P<0.05).PINX1蛋白阳性率在无淋巴结转移组(78.95%)明显高于有淋巴结转移组(48.08%,P<0.05);TNM分期Ⅰ Ⅱ期(73.33%)明显高于Ⅲ Ⅳ期(43.90%,P<0.05);蛋白表达阴性组LOH阳性率为32.28%,明显高于蛋白阳性组的2.50%(P<0.01). 结论 PINX1基因的遗传不稳定性可能导致该抑癌基因突变,是肿瘤发生发展的一个因素,LOH和MSI通过不同的途径调控胃癌的发生和发展.     

CDH1基因遗传不稳定性与胃癌临床病理特征的相关性分析

目的探讨胃癌上皮钙黏蛋白(cadherin 1, CDH1)基因的遗传不稳定性与临床病理特征的相关性。方法制作120例胃癌石蜡包埋组织标本并提取DNA, 采用免疫组化、银染PCR-单链构象动态性等方法分析CDH1基因的遗传不稳定性。结果检测出98例胃癌CDH1基因D16S752位点信息个体数(杂合子数), 其中微卫星不稳定性(microsatellite instability, MSI)检出率、杂合性缺失(loss of heterozygosity, LOH)检出率和CDH1蛋白阳性率分别为19.39%(19/98)、16.33%(16/98)与51.02%(50/98);TNM分期Ⅰ、Ⅱ期的MSI检出率显著高于Ⅲ、Ⅳ期(P<0.05), LOH检出率显著低于Ⅲ、Ⅳ期(P<0.05), TNM分期Ⅲ、Ⅳ期的CDH1蛋白阳性率显著低于Ⅰ、Ⅱ期(P<0.05);有淋巴结转移的MSI检出率显著低于无淋巴结转移(P<0.05), LOH检出率显著高于无淋巴结转移的(P<0.05), CDH1蛋白阳性率显著低于无淋巴结转移(P<0.05);MSI阳性组的C...     

胃肠癌nm23H1基因遗传不稳定性及其与临床病理特性的关系

目的： 研究中国人17号染色体D17S396位点微卫星不稳定性（MSI）和杂合性缺失（LOH），对胃肠癌nm23H1蛋白表达的影响，阐明nm23H1基因遗传不稳定性与胃癌、结肠癌进展的关系，为临床治疗提供实验依据。方法: 采用石蜡包埋组织抽提DNA、PCR-单链构象多态性（SSCP）、常规银染、Envision免疫组织化学和Leica-Qwin计算机图像分析等方法，对40例石蜡包埋胃癌标本和30例石蜡包埋结肠癌标本及其相应的正常组织，进行D17S396位点MSI、LOH的检测和nm23H1蛋白表达研究。 结果: D17S396位点MSI检出率在胃癌、结肠癌的TNM Ⅰ+Ⅱ期高于Ⅲ+Ⅳ期，并且胃癌MSI发生率随着淋巴结转移的发生而降低。LOH检出率在胃癌、结肠癌的TNM Ⅲ+Ⅳ期高于Ⅰ+Ⅱ期，并随淋巴转移的发生而增高。nm23H1蛋白阳性率在胃癌、结肠癌的TNMⅠ+Ⅱ期显著高于Ⅲ+Ⅳ期，无淋巴结转移组显著高于淋巴结转移组。 结论: MSI和LOH通过相互独立的途径调控胃癌、结肠癌的进展。MSI是胃癌、结肠癌的早期分子标志,LOH多发生于胃癌、结肠癌的晚期阶段并赋予癌细胞高侵袭、预后差的表型。     

中国人肺鳞癌nm23H1基因遗传不稳定性的研究

目的 研究nm23H1基因5'端非转录区微卫星位点的微卫星不稳定(MSI)和杂合性缺失(LOH)对肺鳞癌(SLC)nm23H1蛋白表达的影响,以探讨nm23H1基因遗传不稳定性与肺鳞癌进展的关系,为肺鳞癌临床治疗和预后提供实验依据.方法 采用新鲜组织标本抽提DNA,应用荧光PCR-单链构象多态性(FPCR-SSCP)方法、免疫组织化学染色法,Leica-Qwin计算机图像分析等方法,进行nm23H1基因遗传不稳定性的研究.结果 在能提供信息(杂合子)的44例肺鳞癌患者中,MSI、LOH检出率和nm23H1蛋白阳性表达率分别为11.36%、25.00%和50.00%.在TNM Ⅰ、Ⅱ、Ⅲ期中,MSI的检出率分别为8.70%、10.00%和18.18%,而LOH分别为30.43%、20.00%和18.18%;MSI和LOH在淋巴结转移组的检出率为10.00%和20.00%,而无淋巴结转移组则为12.50%和29.17%.然而,以上各组在统计学上均无显著差异(P＞0.05).本研究中所有MSI(共5例)全部发生在分化良好(G1为2例和G2为3例)的存活患者(1年生存率)中,但MSI的检出率与肺鳞癌分化程度及患者生存状态并无统计学上的相关性(P＞0.05).nm23H1蛋白阳性表达率在TNM Ⅰ期(65.22%)、无淋巴结转移组(66.67%)显著高于TNM Ⅲ期(18.18%)、淋巴结转移组(30.00%)(P＜0.05).另外,统计学分析表明,MSI和LOH的检出率与nm23H1蛋白表达无关(P＞0.05).计算机图像定量分析显示,在各临床病理参数影响下,各组nm23H1蛋白的表达强度也没有差异(P＞0.05).结论 nm23H1蛋白可能对抑制肺鳞癌淋巴结转移有重要作用.nm23H1基因5'端非转录区微卫星的MSI和LOH对nm23H1蛋白的表达无影响,也未发现其与肺鳞癌发生、发展具有相关性.     

散发性胆囊癌nm23-H1基因遗传不稳定性与错配修复基因hMLH1和hMSH2蛋白表达的研究

目的:研究人类17号染色体D17S396位点微卫星不稳定性和杂合性缺失,对nm23-H1蛋白表达的影响,同时检测错配修复基因hMLH1和hMSH2蛋白的表达,为揭示nm23-H1基因、hMLH1和hMSH2基因与肿瘤发生和转移机制提供实验依据.方法:采用石蜡包埋组织抽提DNA、PCR-SSCP、常规银染、Envision免疫组织化学等方法,对50例胆囊癌及其相应的正常组织,进行D17S396位点MSI、LOH的检测和nm23-H1、hMLH1和hMSH2蛋白表达研究.结果:①原发性胆囊癌D17S396位点遗传不稳定发生率为42.55%,LOH的发生率与肿瘤组织分化程度差异显著(P＜0.05);在肝脏侵润和淋巴转移组高于无肝脏侵润和无淋巴转移组(P＜0.01),在NevinⅣ+Ⅴ期高于Ⅰ+Ⅱ+Ⅲ期(P＜0.01);而MSI发生率则相反;②nm23-H1蛋白阳性率为46.81%,在淋巴转移组低于无淋巴转移组(P＜0.01);NevinⅣ+Ⅴ期低于Ⅰ+Ⅱ+Ⅲ期(P＜0.05);③hMLH1和hMSH2蛋白阳性率分别为51.06%和42.55%,hMLH1蛋白表达在有无淋巴转移组和Nevin分期有显著差异(P＜0.01),肝脏侵润组低于无肝脏侵润组(P＜0.05);④MSI阳性组中hMLH1蛋白阳性率显著高于MSI阴性组(P＜0.05).LOH阳性组中nm23-H1和hMSH2蛋白阳性率显著低于LOH阴性组(P＜0.05);⑤hMSH2蛋白阳性组中nm23-H1蛋白表达明显高于hMSH2蛋白阴性组(P＜0.05).结论:nm23-H1基因的遗传不稳定性可能是胆囊癌发生、发展的一个重要分子机制.nm23-H1基因的MSI和LOH,通过相互独立的途径调控胆囊癌的发生和转移.hMLH1/hMSH2表达异常可能是胆囊癌的早期分子事件.提高胆囊癌局部nm23-H1、hMLH1和hMSH2蛋白的表达,可减缓肿瘤的侵润转移并提高预后率.     

中国人肝癌分泌型卷曲相关蛋白1基因遗传的不稳定性

目的 研究8号染色体上D8S532位点的杂合性缺失(LOH)和微卫星不稳定性(MSI)对分泌型卷曲相关蛋白1基因(sFRP1)蛋白表达的影响,阐明 sFRP1 基因遗传不稳定性与肝癌进展的关系,为揭示sFRP1 基因作用机制和肿瘤发生发展机制提供实验依据. 方法 采用石蜡包埋组织抽提DNA,聚合酶链-单链构象多态性(PCR-SSCP)分析,常规银染检测D8S532位点的LOH和MSI,采用Envision免疫组织化学染色,Leica-Qwin计算机图像分析系统采图和Image-Pro P1uS(IPP)Version5.0专业图像分析软件分析蛋白表达. 结果 在36例肝癌中,D8S532位点LOH和MSI检出率分别为11.11%(4/36)和8.33%(3/36),D8S532位点MSI发生率在60岁以上年龄组(≥60) 26.67%(4/15),高于60岁以下年龄组(<60)0.00%(0/21, P <0.05).相比较于正常组织,86.11%(31/36)的sFRP1蛋白有不同程度表达下降,在肝癌组织中,sFRP1表达阳性率为52.78%(19/36),蛋白表达阴性组LOH阳性率为23.53%(4/17),明显高于蛋白阳性组的0.00%(0/19)( P <0.05). 结论 在中国人肝癌发生进展中,sFRP1蛋白表达下降甚至缺失是普遍现象, sFRP1 基因的遗传不稳定性可能是导致该抑癌基因突变、肿瘤发生的一个机制,LOH在sFRP1表达缺失的过程中起了重要作用.     

肝细胞癌nm23H1基因遗传不稳定性与临床病理特征的相关性研究

目的： 研究人类17号染色体D17S396位点微卫星不稳定性和杂合性缺失，对肝细胞癌nm23H1蛋白表达的影响，阐明nm23H1基因遗传不稳定性与肝细胞癌及临床病理特征的关系，为揭示nm23H1基因作用机制和肿瘤发生、转移机理提供实验依据。方法： 采用石蜡包埋组织抽提DNA，PCR-单链构象多态性（PCR-SSCP），常规银染，Envision免疫组织化学和Leica-Qwin计算机图像分析等方法进行nm23H1基因遗传不稳定性研究。 结果： ① 48例肝细胞癌D17S396位点遗传不稳定性的发生率为35.42%。LOH的发生率在有无淋巴结或远处转移和有无肝内转移或门静脉栓的癌组织中有显著差异（P<0.01），临床TNM分期Ⅲ期LOH的发生率显著高于Ⅰ、Ⅱ期（P<0.01）。此外，在侵袭转移高危组LOH的发生率显著高于侵袭转移低危组 (P<0.01)。MSI检出率与肝细胞癌临床病理参数均无关。② nm23H1蛋白阳性率为56.25%，nm23H1蛋白阳性率在Edmondson分级Ⅲ +Ⅳ组低于Ⅰ+ Ⅱ组（P<0.01） ，在有淋巴或远处转移组显著低于无淋巴或远处转移组（P<0.01）,TNM分期Ⅲ期显著低于Ⅰ+Ⅱ期（P<0.01）；在侵袭转移高危组中nm23H1蛋白阳性率显著低于侵袭转移低危组 (P<0.01)。此外，计算机图像定量分析显示，在各临床病理参数影响下，nm23H1蛋白的表达强度没有差异。③ LOH阳性组中nm23H1蛋白阳性率为27.27％，显著低于LOH阴性组64.86％，两者差异显著（P<0.05）。结论： nm23H1基因的MSI和LOH通过相互独立的途径调控肝细胞癌的发生和转移，后者可抑制肝细胞癌局部nm23H1蛋白的表达，并赋予肝细胞癌高转移、预后差的特性。提高肝细胞癌局部nm23H1蛋白的表达，可减缓肿瘤的侵袭转移倾向，并改善预后。     

散发性胆囊癌nm23-H1基因遗传不稳定性与错配修复基因hMLH1和hMSH2蛋白表达的研究

目的： 研究人类17号染色体D17S396位点微卫星不稳定性和杂合性缺失，对nm23-H1蛋白表达的影响，同时检测错配修复基因hMLH1和hMSH2蛋白的表达，为揭示nm23-H1基因、hMLH1和hMSH2基因与肿瘤发生和转移机制提供实验依据。方法: 采用石蜡包埋组织抽提DNA、PCR-SSCP、常规银染、Envision免疫组织化学等方法，对50例胆囊癌及其相应的正常组织，进行D17S396位点MSI、LOH的检测和nm23-H1、hMLH1和hMSH2蛋白表达研究。结果: ①原发性胆囊癌D17S396位点遗传不稳定发生率为42.55%，LOH的发生率与肿瘤组织分化程度差异显著（P <0.05）；在肝脏侵润和淋巴转移组高于无肝脏侵润和无淋巴转移组(P <0.01)，在NevinⅣ+Ⅴ期高于Ⅰ+Ⅱ+Ⅲ期(P <0.01)；而MSI发生率则相反；②nm23-H1蛋白阳性率为46.81%，在淋巴转移组低于无淋巴转移组(P <0.01)；NevinⅣ+Ⅴ期低于Ⅰ+Ⅱ+Ⅲ期(P <0.05)；③hMLH1和hMSH2蛋白阳性率分别为51.06%和42.55%，hMLH1蛋白表达在有无淋巴转移组和Nevin分期有显著差异(P <0.01)，肝脏侵润组低于无肝脏侵润组(P <0.05)；④MSI阳性组中hMLH1蛋白阳性率显著高于MSI阴性组(P <0.05)。LOH阳性组中nm23-H1和hMSH2蛋白阳性率显著低于LOH阴性组（P <0.05）；⑤hMSH2蛋白阳性组中nm23-H1蛋白表达明显高于hMSH2蛋白阴性组（P<0.05）。结论:nm23-H1基因的遗传不稳定性可能是胆囊癌发生、发展的一个重要分子机制。nm23-H1基因的MSI和LOH，通过相互独立的途径调控胆囊癌的发生和转移。hMLH1/hMSH2表达异常可能是胆囊癌的早期分子事件。提高胆囊癌局部nm23-H1、hMLH1和hMSH2蛋白的表达，可减缓肿瘤的侵润转移并提高预后率。     

人肝癌P57~(kip2)基因失表达的遗传不稳定性

目的探讨肝细胞癌(HCC)P57kip2mRNA表达与遗传不稳定性之间的相互关系,以探索P57kip2基因失表达的机制。方法用原位分子杂交技术检测肝癌组织中P57kip2mRNA表达,用PCR-聚丙烯酰胺凝胶电泳-银染法检测LOH和MSI。结果在正常肝组织未见P57kip2mRNA表达,癌周肝硬化组与肝癌组阳性表达率均为26.7%(8/30)。3个位点均未发生LOH;在2个微卫星位点发生MSI,MSI总阳性率为16.7%。D11S1760位点发生MSI与P57kip2mRNA表达有关联性(P<0.05)。结论P57kip2mRNA表达异常提示其可能在HCC发生过程中起重要作用。MSI可能是肝癌发生过程中P57kip2mRNA表达异常的原因之一。     

头颈部鳞癌的微卫星不稳定性和杂合性丢失的初步研究

目的:探讨头颈部鳞癌的微卫星不稳定性(MSI)及杂合性丢失(LOH)。方法:选择来自3、5、6、8、9、13、17和18号染色体的15个微卫星标志对36例头颈部鳞癌标本和相应的外周血进行微卫星分析。结果:36例头颈部鳞癌中,27.8%(10/36)分别有1-8个位点存在MSI,MSI发生率较高的位点为:D17S520(22.9%)、D6S105(16.7%)和D8S264(13.9%)。在9p21-p22和3p14等处存在一定的LOH。微卫星异常的检出率与肿瘤分期、分级无相关性。结论:提示MSI是头颈部鳞癌中较为常见的遗传学变化,染色体9p21-p22和3p14区域可能存在与头颈部鳞癌有关的抑癌基因。     

胃癌及肠化组织微卫星不稳定性

目的研究微卫星不稳定性（ＭＳＩ）在胃癌发生、发展中的作用。方法采用聚合酶链反应（ＰＣＲ）方法检测了５０例手术切除胃癌标本及１５例肠化标本的ＭＳＩ。结果５０例胃癌中有２７例检出１个以上位点ＭＳＩ,总阳性率为５４０％;高中分化腺癌ＭＳＩ检出率（８６．６％）显著高于低分化腺癌（３８．７％,Ｐ＜０．０５）;肠型胃癌ＭＳＩ阳性率（７７．８％）显著高于胃型胃癌（４００％,Ｐ＜０．０５）;ＭＳＩ与胃癌发病年龄、大小、发生部位、浸润深度、淋巴结转移及临床分期无显著相关。３例早期胃癌ＭＳＩ均阳性,１５例肠化标本中有３例检出ＭＳＩ,阳性率为２０％。结论ＭＳＩ是胃癌发生过程中的早期分子标志,在胃癌的发生中可能扮演重要角色。     

Microsatellite instability in ovarian and other pelvic carcinomas

Twenty-six cases of ovarian carcinoma and six cases of other pelvic neoplasms were analyzed for microsatellite instability (MSI) using frozen specimens, fluorescence technology, and four selected markers (D2S123 on chromosome 2, D18S58 on chromosome 18, BAT26 on chromosome 2, and BAT40 on chromosome 1). This procedure also allowed the detection of loss of heterogeneity (LOH) at the four selected loci. One of the cases of ovarian carcinoma exhibited MSI and this was evident at three loci. Of 44 informative loci, 7 exhibited LOH representing 3 cases of ovarian carcinoma, 3 of 4 cases of primary peritoneal carcinoma, and one case of unknown primary. These data support other findings that MSI is not a frequent occurrence in ovarian cancer; however, LOH is a more frequent event and may be a target for the development of diagnostic/prognostic procedures for ovarian and primary peritoneal carcinoma.     

Methylation of the hMLH1 promoter in multiple gastric carcinomas with microsatellite instability

Hypermethylation of the hMLH1 promoter is observed in the majority of sporadic gastric carcinomas with high frequency microsatellite instability (MSI), and it contributes to the genesis of MSI-positive gastric carcinoma. Multiple gastric carcinoma is known to have a higher frequency of MSI positivity than single gastric carcinoma. However, the molecular basis of MSI in these tumors remains obscure. We investigated the role of hMLH1 promoter hypermethylation in the genesis of multiple gastric carcinoma with MSI. We analyzed 33 tumors from 15 patients with multiple gastric carcinoma (12 double tumors and three triple tumors) for MSI, expression of hMLH1 and hMSH2, and hypermethylation of hMLH1 and hMSH2 promoters. High frequency MSI was found in seven out of 33 tumors (21%) in five out of 15 patients (33%). All of the tumors with high frequency MSI had a lack of hMLH1 expression, with the presence of hMSH2 expression, while all the tumors with no MSI or low frequency MSI were positive for both hMLH1 and hMSH2. All of the tumors with no expression of hMLH1 had hMLH1 hypermethylation, whereas hMLH1 hypermethylation was observed in two out of 26 (8%) tumors with no or low frequency MSI. None of the tumors showed hMSH2 hypermethylation. These results suggest that epigenetic changes in the hMLH1 promoter account for the genesis of multiple gastric carcinoma with high frequency MSI.     

宫颈癌基因组HLA-Ⅰ类基因微卫星不稳定和杂合性缺失的研究

目的　探讨人白细胞抗原 Ⅰ类基因在宫颈癌中微卫星不稳定和杂合性缺失的情况 ,并构建宫颈癌基因组在该区域的精细缺失图谱。方法　应用聚合酶链反应 单链长度多态性 银染技术 ,对 3 0例宫颈癌活检标本进行杂合性缺失和微卫星不稳定的检测。结果　在 3 0例宫颈癌活检组织中 ,有 2 3例( 76.7% )存在有 1个或多个位点的杂合性缺失 ,微卫星位点C3 2 11的杂合性缺失频率最高 ,可达5 0 % ( 15 /3 0 )。微卫星不稳定的发生率为 66.7% ( 2 0 /3 0 ) ,其中位点D6S2 5 8发生微卫星不稳定频率最高 ,达 40 % ( 12 /3 0 )。结论　人白细胞抗原 Ⅰ类基因的微卫星不稳定和杂合性缺失在宫颈癌的发生和发展过程中起着重要作用 ,同时发现位点C12 5～C3 2 11之间是宫颈癌患者的一个最小的共同缺失区域 ,该区域可能存在有与宫颈癌相关的抑癌基因。     

Microsatellite instability in gastric cancer is closely associated with hMLH1 hypermethylation at the proximal region of the promoter

Most sporadic gastric cancer with the microsatellite instability (MSI) phenotype is linked with hypermethylation (HM) of hMLH1. However, a part of gastric cancer with hMLH1 HM does not show MSI, suggesting a region-specific effect of hMLH1 promoter methylation on developing MSI. To test this possibility, we measured the methylation level in 3 distinct areas of hMLH1 promoter and compared them with MSI in 129 sporadic gastric cancer patients. Three areas of hMLH1 promoter, from distal toward proximal, were designated as hMLH1-A, hMLH1-B, and hMLH1-C, respectively. The methylation level was measured by fluorescence-based real-time methylation specific PCR. MSI status was tested using a panel of 5 microsatellite markers (BAT25, BAT26, D2S123, D5S346, and D17S250). Gastric cancers with no HM in hMLH1-A (n=105, 81.4%) also showed no HM in 2 other regions of hMLH1 promoter. On the other hand, the cancers with HM in hMLH1-A (n=24, 18.6%) showed various levels of methylation in 2 other regions. In most cases, the methylation value was the highest in hMLH1-A and the lowest in hMLH1-C. We found the MSI phenotype in 12 cancers (13%) of 92 tested cases and these cancers were all associated with HM in the region of hMLH1-C. A third of hypermethylated cancers in the hMLH1-A region did not show the MSI phenotype. The survival of the patients with HM in hMLH1-C was significantly better than that of patients without HM (P<0.05). These results suggest that HM in the proximal region of hMLH1 promoter, hMLH1-C in this study, plays a critical role in the progression of gastric cancer with MSI. The complete association between HM in hMLH1-C and MSI phenotype with gastric cancer provides an alternative diagnostic tool for detecting a favorable prognostic subgroup with MSI by using simple methylation analysis.     

Methylation profile of the MLH1 promoter region and their relationship to colorectal carcinogenesis

Methylation of the MLH1 promoter region has been suggested to be a principal mechanism of gene inactivation in sporadic microsatellite instability (MSI)-positive colorectal carcinoma. Recently, we have shown a novel methylation profile of the MLH1 promoter region (i.e., full, partial, and no methylation), among which full methylation was strongly associated with MSI. In this study, to confirm whether methylation requires the involvement of both alleles, we studied the MLH1 promoter region concerning the methylation profile and allelic loss. Furthermore, we studied correlations of methylation profiles with genetic alternations such as loss of heterozygosity (LOH) of the TP53 locus and KRAS mutation. Eighty-eight tumors were classified as full (n = 14), partial (n = 26), and no methylation (n = 48). Full methylation was observed in 78% (14/18) of high-frequency MSI, in which all CpG sites in the promoter region were methylated. Full methylation differed significantly from partial methylation regarding absence of TP53 LOH (0/12) and KRAS mutation (0/14). In cases with full methylation, we could show biallelic methylation by use of a single-base nucleotide polymorphism in the promoter. However, this did not accompany LOH of the MLH1 locus. In contrast, there were no significant differences in molecular features between partial and no methylation, except for low frequencies of LOH of the MLH1 locus (P = 0.02). In conclusion, biallelic extensive methylation of the MLH1 promoter region plays a significant role in gene inactivation and is independent of KRAS mutation and TP53 LOH.