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, loss of heterozygosity, and loss of hMLH1 and hMSH2 protein expression in endometrial carcinoma

Microsatellite instability (MSI) due to replication errors occurs frequently in hereditary tumors. Association with functional inactivation of the mismatch repair (MMR) genes and lack of protein expression has been described. In endometrial carcinoma (EC), the prevalence and clinical significance of these phenomena are not well known. Therefore, DNA samples from 89 EC and 5 metachronous tumors were analyzed with polymerase chain reaction, using 5 microsatellite markers and a DNA sequencer for amplicon detection. The results were correlated with immunohistochemistry of hMLH1 and hMSH2. MSI at >or=2 loci (MSI-H) was detected in 10/89 EC (11%); 1 of 10 showed loss of both hMLH1 and hMSH2, and 5 of 10 showed loss of hMLH1 (P < 0.0001). MSI-H was observed frequently in tumors with mucinous differentiation (P = 0.048), >10% of solid-cribriform pattern (P = 0.037), International Federation of Obstetrics and Gynecology (FIGO) stage III to IV (4 of 13; P = 0.016), and necrosis >5% (P = 0.07). Loss of heterozygosity (LOH) in >or=1 loci was found in 17 of 156 (11%). Survival (Kaplan-Meier) was longer for patients with endometrioid tumors with predominant glandular pattern, <5% necrosis, low FIGO stage and grade, superficial myometrial infiltration, no lymph-vascular invasion (LVI), and loss of hMLH1 expression (all P 相似文献   

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 and loss of heterozygosity in primary and secondary proliferative lesions of the parathyroid gland.

Clonality and genetic abnormalities were evaluated to characterize proliferative lesions of the parathyroid gland. Fourteen lesions from patients with single-gland proliferation (adenomas [PA]), 6 lesions from patients with multiple-gland proliferation (primary hyperparathyroidism [PHPT]), and 47 lesions from 16 patients with secondary hyperparathyroidism (SHPT) were examined. Based on the X chromatin inactivation pattern, which was revealed by a HUMARA assay of lesions from female patients (n = 34; 24 informative cases), monoclonality was demonstrated in 6 of 10 PA (60%), 2 of 5 PHPT (40%), and 6 of 9 SHPT lesions (14 of 27 lesions, 52%). By PCR analysis using 17 microsatellite markers on eight chromosomes (chromosomes 1, 2, 3, 5, 6, 11, 13, and 17), loss of heterozygosity was sporadically observed in 4 of 14 PA, 3 of 6 PHPT, and 7 of 47 SHPT lesions, in most cases on a single locus of chromosome 11. On the other hand, microsatellite instability was observed more frequently: ie, in six PA, five PHPT, and nine SHPT lesions. The profile of microsatellite instability depended on the type of proliferation: microsatellite instability (MI) seemed to cluster in the region of chromosome 11 in PA. Microsatellite instability on TP53 was observed in 3 of 6 PHPT lesions and in 2 of 47 SHPT lesions but in no PA lesions. Microsatellite instability on Mfd47 was observed in only some cases of SHPT. Although no significant correlation was identified among histologic features, clonality, and genetic abnormalities in cases of primary proliferation, genetic abnormalities were more frequently observed in SHPT lesions that lacked fat tissues. Thus, genetic instability might be important in proliferative disorders of the parathyroid gland, either with or without uremia. However, genetic instability seems to be induced by different mechanisms in the three types of proliferation studied. In SHPT, the absence of fat tissues may indicate that the proliferation is accompanied by genetic changes.     

肝细胞癌肿瘤抑制基因的杂合性缺失和微卫星不稳定性研究

目的　了解肿瘤抑制基因(TSG)杂合性缺失(LOH)与微卫星不稳定性(MSI)在肝细胞癌发生机制中的作用,并探讨其临床病理学意义。方法　采用显微组织切割基础上的DNA直接测序法,从92例手术切除肝细胞癌中筛选出36例信息性肝细胞癌进行6种TSG(APC、DCC、MCC、OGG1、p53和RB1)的LOH检测,对其中15例肝细胞癌进行13个多态性微卫星位点的LOH和MSI检测,并与临床病理学参数的相关性进行统计学分析。结果　TSG的LOH总发生率为41 .7% (15 /36),仅MCC基因未出现LOH。15例肝细胞癌中有9例(60% )发生微卫星LOH,占检测微卫星的46 .2% (6 /13),但无1例肝细胞癌出现MSI。若将APC、OGG1和DCC基因LOH作为Ⅰ型(n=7 ),将p53和RB1基因LOH作为Ⅱ型(n=8)进行统计学处理,则两组肝细胞癌的平均瘤体直径分别为( 2. 9 ±1 .7)cm和(7 .2 ±3 .4)cm (P<0 .01),两组患者术后平均生存期分别为( 72. 0 ±38 6 )个月和(51 .0±30. 4)个月(P<0 .05 )。肝细胞癌基因变异型与患者的年龄、性别、血清甲胎蛋白水平、HBsAg阳性率、合并肝炎/肝硬化、肝细胞癌分化程度和组织学类型之间无明显相关性。结论　在肝细胞癌发生的多阶段演进与多基因变异过程中,LOH路径所起的作用要比MSI路径更大。Ⅰ型基因变异(APC、OGG1和DCC)主要在肝细胞癌早期阶段起作     

Microsatellite instability in adenocarcinomas of the upper gastrointestinal tract. Relation to clinicopathological data and family history.

We analyzed 66 adenocarcinomas arising in the upper gastrointestinal tract for microsatellite instability at eight microsatellite loci to investigate the role of these genetic alterations in the etiology of these tumors. We identified alterations in at least one locus in 11/46 adenocarcinomas of the stomach, in 2/15 adenocarcinomas arising in Barrett's esophagus, and in 1/5 adenocarcinomas of the duodenum and jejunum. Microsatellite instability in gastric tumors was found in 5/22 of intestinal, 1/3 of mixed, and 5/21 of diffuse type tumors. No relationship to the tumor stage (TNM), age, and survival time of the patients was observed. One patient had two synchronous gastric tumors both exhibiting microsatellite instability at multiple loci. His family history revealed four individuals in the maternal line afflicted with gastric carcinoma in three generations. Our data show that microsatellite instability is a genetic event in 11 to 24% of tumors of the upper gastrointestinal tract. The observation of microsatellite instability and a familial clustering of gastric tumors may suggest a genetic predisposition for a subset of gastric tumors, which may be identified by microsatellite analysis.     

Microsatellite instability in gastric MALT lymphoma.

The role of microsatellite instability and defects in DNA mismatch repair mechanism in the pathogenesis of gastric lymphoma of mucosa-associated lymphoid tissue (MALT) type is still controversial, as both negative and positive findings have been reported. This may be explained mainly by arbitrary selection of the tested loci, the use of various techniques of microsatellite instability analysis and by different definitions of replication error positive phenotype. The aim of our study was to evaluate the instability at selected microsatellite markers using the GeneScan Analysis Software. DNA from paraffin-embedded tissue blocks of 13 previously untreated patients with localized gastric MALT lymphoma was extracted. Five microsatellite markers, which are located in hMSH2, hMLH1, P16, APC and MLL loci, were selected from the genetic database. We found genetic instability in tumors of 9/13 patients with gastric MALT lymphoma (69%). Seven of them had replication-error-positive phenotype (54%). Microsatellite instability was found in 39% of the samples in the MLL locus, 39% in the APC, 46% in the P16, 23% in the hMLH1 and none in the hMSH2. This study demonstrates that microsatellite instability has more prominent role in pathogenesis of gastric MALT lymphoma than reported to date. We suggest that microsatellite instability should be analyzed with markers adjacent to chromosomal loci that are involved in lymphomas. Our findings support the 'Real Common Target genes' theory of high rate of microsatellite instability in specific genes, which are associated with related tumors.     

Microsatellite instability is uncommon in uterine serous carcinoma.

Thirty-four uterine serous carcinomas, a type of endometrial carcinoma with aggressive behavior and a high frequency (90%) of p53 gene mutations, were analyzed for microsatellite instability (MI). Genomic DNA isolated from paired normal and tumor tissue was analyzed at eight microsatellite loci (D2S119, D2S123, D2S147, D10S197, D13S175, D18S58, D18S69, and ATn) located on four different chromosomes. All 34 tumors failed to meet the criteria for MI, defined as an alteration in the size of at least two of the microsatellite loci in tumor DNA when compared with normal DNA. Only three tumors demonstrated a shift in the size of a single microsatellite locus. Previously we reported MI in 20% of uterine endometrioid carcinomas, the most common type of endometrial carcinoma. The observed difference in the MI frequency between endometrioid and serous carcinoma is statistically significant (P = 0.003). Our data demonstrate that MI is uncommon in uterine serous carcinoma and support that different pathogenetic mechanisms are involved in the development of the two most common types of endometrial carcinoma.     

Screening for loss of heterozygosity and microsatellite instability in oligodendrogliomas

To assess the frequency of loss of heterozygosity (LOH) and microsatellite instability (MI) in oligodendrogliomas, we performed an extensive screening of 16 oligodendrogliomas and nine anaplastic oligodendrogliomas by using 132 microsatellite markers on chromosomes 1 through 12 and 15 through 21. In total, 3,135 loci were examined in 25 tumor samples. Only 33/1,965 (1.7%) of oligodendroglioma (low-grade) and 11/1,070 (1.0%) of anaplastic oligodendroglioma (high-grade) loci exhibited MI. High-frequency LOH regions were identified on chromosome arms 1p (31–73% for oligodendrogliomas and 60–100% for anaplastic oligodendrogliomas) and 19q (23–69% for oligodendrogliomas and 100% for anaplastic oligodendrogliomas). In addition, regions on chromosomes 4, 6, and 11 were found to be lost in 30–80% of both oligodendrogliomas and anaplastic oligodendrogliomas. Increased LOH frequency of chromosome 17 (38–40%) was found only in high-grade oligodendrogliomas. The differences in LOH frequencies between low-grade and high-grade oligodendrogliomas in all loci combined and at three loci (D1S447, D1S226, and D1S252) on chromosome arm 1p were determined to be statistically significant [χ²(1) = 20.2, P < 0.0001, and Fisher's exact test respective P values: 0.01, 0.03, and 0.02]. Our results provide evidence that microsatellite instability does not play an important role in the development of oligodendrogliomas. Furthermore, high LOH frequency on chromosomes 6 and 11 in addition to that identified previously on chromosomes 1, 19, and 4 suggests that multiple candidate tumor suppressor genes on these chromosomes may underlie the processes of initiation and/or progression in oligodendroglioma tumorigenesis. Genes Chromosomes Cancer 21:207–216, 1998. © 1998 Wiley-Liss, Inc.     

Microsatellite instability, mitochondrial DNA large deletions, and mitochondrial DNA mutations in gastric carcinoma

Mitochondrial DNA (mtDNA) large deletions and mtDNA mutations have been demonstrated in various types of human cancer. The relationship between the occurrence of such alterations and the nuclear microsatellite instability (MSI) status of the neoplastic cells remains controversial. In an attempt to clarify the situation in gastric carcinoma, we studied, by PCR/SSCP and sequencing, five mitochondrial genes and two D-loop regions in 32 gastric carcinomas that had been previously screened for MSI and mitochondrial common deletion. MtDNA alterations were detected in 26 carcinomas (81%). All the mtDNA mutations, which occurred mainly in the D-loop and ND1 and ND5 genes, were transitions. D-loop alterations (insertions and/or deletions) were not significantly associated with mutations in the coding regions. There was a trend towards an inverse relationship between the occurrence of mitochondrial common deletion and mtDNA mutations. No significant relationship was observed between MSI status and mtDNA mutations, whereas the mitochondrial common deletion appeared to be almost exclusively restricted to MSI-negative tumors. The latter finding--almost no gastric carcinoma with MSI-positive phenotype has large deletions of mtDNA--needs to be confirmed in a larger series and in tumors from other organs.     

Infrequent loss of heterozygosity of APC/MCC and DCC genes in gastric cancer showing DNA microsatellite instability

AIM: To investigate the role of DNA microsatellite instability (MSI) in gastric carcinogenesis by studying associations between MSI status, clinicopathological features, and loss of genetic loci. METHODS: Six microsatellite loci and loss of heterozygosity at APC, DCC, and MCC were analysed by polymerase chain reaction based methods in 53 cases of advanced gastric cancer. RESULTS: MSI was observed in 32.1% of gastric carcinomas (17/53) and 20% of foci of intestinal metaplasia (3/15). Seven gastric carcinomas (13.7%) were MSI-high (MSI-H) (three loci or more) and 10 (18.9%) were MSI-low (MSI-L) (one or two loci). The frequency of MSI-H was higher in intestinal (25.0%) than in diffuse carcinomas (3.7%) (p < 0.05). None of the MSI-H tumours showed loss of heterozygosity at APC, MCC, or DCC loci. CONCLUSIONS: MSI may have an important and early role in a subset of gastric cancers, particularly the intestinal type. The MSI-H subset of gastric cancer has features in common with its colorectal counterpart, whereas MSI-L and microsatellite stable cancers appear to develop through the loss of heterozygosity pathway.     

Microsatellite instability in preinvasive and invasive head and neck squamous carcinoma.

To investigate the extent and significance of microsatellite instability in head and neck carcinogenesis we analyzed DNA extracted from normal squamous epithelium, severe dysplasia, and corresponding carcinoma specimens from 20 patients by multiplex polymerase chain reaction. Loci on chromosomes 3p, 5p, 5q, 8p, 9p, 9q, 11q, 17p, 17q, 18p, 18q were selected for analysis. Our results show that three of the dysplasias (15.0%) and six of the invasive carcinoma (30.0%) manifested instability at multiple loci. Two of the dysplastic lesions had identical alterations in the corresponding carcinomas and one showed instability differences in only two of eight loci. Normal squamous epithelium lacked microsatellite instability. No apparent association between smoking, alcohol use, or family history of cancer and instability was found in this small cohort. Invasive carcinomas with instability were relatively more poorly differentiated and had a higher stage and a high proliferative fraction. Our study indicates that microsatellite instability is 1) noted in a small subset of dysplastic lesions of head and neck squamous epithelium and 2) present in approximately one-third of invasive lesions, usually with aggressive characteristics, and may clinically be a late event associated with tumor progression.     

Microsatellite instability in gastric intestinal metaplasia in patients with and without gastric cancer

The role and significance of microsatellite instability (MSI) in gastric carcinogenesis remain unknown. This study determined the chronology of MSI in gastric carcinogenesis by examining intestinal metaplasia (IM) from patients with and without gastric cancer. DNA was obtained from gastric specimens of 75 patients with gastric IM (30 cancer, 26 peptic ulcer, and 19 chronic gastritis patients) and was amplified with a set of eight microsatellite markers. Eight (26. 7%) tumors and seven (9.3%) IM samples (three from cancer-free patients) displayed high-level MSI (three or more loci altered). Low-level MSI (one or two loci altered) was detected in 50% of the tumors, in 40% of IM samples coexisting with cancer, and in 38% of IM tissues of cancer-free individuals. Among the 30 cancer patients, microsatellites were more frequently altered in IM coexisting with tumors that showed MSI (P = 0.003). In addition, patients with low-level MSI in the tumor tissues were more likely to have active Helicobacter pylori infection than those with stable tumors (P = 0.02). In conclusion, this study indicates that MSI occurs not only in gastric IM of patients with gastric carcinoma, but also in IM of cancer-free individuals. These data suggest that the progressive accumulation of MSI in areas of IM may contribute to gastric cancer development, representing an important molecular event in the multistep gastric carcinogenesis cascade.     

Microsatellite instability and Epstein-Barr virus infection in gastric remnant cancers

Clinicopathological analysis, microsatellite analysis, detection of Epstein-Barr virus (EBV), and immunohistochemistry on p53 protein were performed in 26 cases of gastric remnant cancer (GRC). They were divided into two groups; Group A (n = 14) who had undergone a primary gastrectomy for benign gastric disease, and Group B (n = 12) who had undergone the same operation for gastric cancer. EBV infection was present in 29% of Group A, 8% of Group B and 6% of the conventional gastric carcinoma (CGC) (Group A vs CGC, P = 0.01). Microsatellite instability (MSI) was found in 7% of Group A, 25% of Group B, and 9% of the CGC (Group B vs CGC; P = 0.08). p53 Overexpression was observed in 46% of the GRC and 33% of the CGC. p53 Overexpression was observed in 90% of the intestinal type of GRC, but in only 20% of the diffuse type of GRC (P = 0.002). The cancer stage was a significant factor in the univariate analysis of survival (P = 0.04). In conclusion, GRC is different from CGC in terms of MSI or EBV association. The pathogenetic differences between the two groups require further investigation. EBV infection may have been involved in the carcinogenesis of Group A. MSI may be an important factor in the carcinogenesis of metachronous multiple gastric cancer (Group B).     

Analysis of microsatellite instability and loss of heterozygosity in uterine endometrial adenocarcinoma

Microsatellite instability (MSI) and loss of heterozygosity (LOH) were examined in 60 cases of uterine endometrial adenocarcinoma, using 13 microsatellite markers. In non-Smad-related regions, MSI and LOH were noted in 13 of 60 (21.7%) and in 20 of 60 (33.3%) cases, respectively. Genetic alternation of TGF-beta RII was noted in 1 of 60 cases (1.7%). The frequency of MSI and LOH was highest in Stages III and IV, respectively. Cases with G2 carcinoma showed the highest frequency, but LOH frequency did not differ among G1, G2, and G3 carcinoma cases. In Smad-related microsatellite regions, MSI and LOH were noted in 10 of 60 (16.7%) and in 12 of 60 (20.0%) cases, respectively. The frequency of MSI and LOH was highest in Stages III and IV, respectively. LOH was seen only in the Smad2 gene but not in the Smad4 gene. Our results suggest that the alterations in MSI and LOH were associated with middle and late stages of carcinogenesis of endometrial carcinoma. Both MSI and LOH tended to show an association with moderate to severe atypia of carcinoma. Our results also suggest that genetic alteration of the Smad2 gene is more responsible for endometrial carcinogenesis than that of the Smad4 gene. However, the TGF-beta type II receptor gene was considered a minor target of genetic instability in endometrial carcinogenesis.     

乳腺浸润性导管癌微卫星不稳定性

目的 探讨乳腺浸润性导管癌的微卫星不稳定(MSI)性及其与临床病理资料的关系。方法 选取10个微卫星位点，从石蜡包埋的存档标本中选取34例肿瘤组织和其对应的自身正常对照组织，提取DNA后用PCR扩增，6％聚丙稀酰胺凝胶电泳，银染显色后进行微卫星不稳定性分析。用免疫组化S-P法观察p53、c-erbB-2、PR、ER在乳腺癌中表达情况。结果 在34例乳腺浸润性导管癌中有9例(26．47％)至少1个位点出现MSI。MSI和病人年龄、肿瘤大小、病理分级、淋巴结转移、p53、c-erbB-2之间没有明显的相关性。但ER和PR阴性的病例出现MSI的比例远远高于ER和PR阳性病例。结论在乳腺癌的发生、发展过程中出现MSI,并可能和ER、PR的表达降低有关。     

Microsatellite instability in ductal carcinoma in situ of the breast

Microsatellite instability (MI⁺) is associated with defects in mismatch repair, resulting in a ‘mutator’ phenotype and the development and progression of cancer. MI⁺ has been documented in invasive breast carcinomas. This study was undertaken to determine whether MI⁺ is found in the early non-invasive form of breast cancer, ductal carcinoma in situ(DCIS). We examined microdissected ducts from 23 cases of DCIS with 11 markers comprising mono-, di-, and trinucleotide repeats from six chromosomal regions. Five tumours (22 per cent) displayed MI⁺ at two or more loci, in all ducts examined. A further seven (30 per cent) tumours showed alterations at a single locus (the DM-1 trinucleotide), and for two of these, heterogeneity between ducts was observed. Alterations at microsatellite repeat motifs in the coding regions of four cancer-associated genes (TGFβRII, IGFIIR, BAX, and E2F-4) were not observed. Immunohistochemistry revealed that there was no loss of reactivity for the mismatch repair proteins, MLH1, MSH2, and PMS2, in the DCIS cases. In general, MI⁺ tumours and those with alterations at the DM-1 microsatellite were predominantly of higher nuclear grade and expressing c-erbB-2, suggesting that aberrations in DNA repair functions may lead to the acquisition of a more aggressive phenotype in breast cancer. © 1998 John Wiley & Sons, Ltd.     

Analysis of microsatellite instability and loss of heterozygosity in human aortic atherosclerotic lesions

The aim of the present study is to investigate whether microsatellite instability (MSI) and loss of heterozygosity (LOH) are involved in atherogenesis. Paraffin-embedded tissues of thoracic and abdominal aortas were collected from 29 non-neoplastic autopsied cases. We selected two types of atherosclerotic lesions including fibrocellular intimal thickening and uncomplicated atheromatous lesions, and analyzed two sites such as the aortic tunica intima and tunica media in each case. The frequencies of MSI and LOH were highest in the aortic tunica intima of atheromatous lesions and lowest in the aortic tunica media of fibrocellular intimal thickening lesions. Our results suggest that genetic instabilities such as MSI and LOH may be involved in the development of atherosclerotic lesions.     

Prognostic implications for gastric carcinoma based on loss of heterozygosity genotypes correlation with clinicopathologic variables

In this study we used polymorphic DNA markers to examine 38 patients with gastric carcinoma for loss of heterozygosity (LOH) on five chromosomal arms. The aims were to compare LOH genotyping with the clinicopathologic variables and to identify some genetic differences between early (EGC) and advanced gastric carcinoma (AGC). The frequency of LOH was found in 27 of 38 (71.1%) cases with a low-level LOH in 17 (44.7%) and a high-level LOH (LOH-H) in 10 (26.3%). There was statistical significance found in the differentiation of cells (WD/MD vs. PD [well or moderately differentiated vs. poorly differentiated]), metastasis (absent vs. present), and tumor-node-metastasis stage (I/II vs. III/IV) based on LOH genotyping. The frequency of LOH in the markers of chromosome 6 revealed a significant difference between the early and advanced stages (P=0.043). However, there were no differences in each chromosome or in the number of affected chromosomes with an allelic loss between the histologic types EGC and AGC, except for the frequency of the markers on chromosome 22.These findings suggest that LOH genotyping may be another independent prognostic indicator in gastric carcinoma, that LOH-H, particularly the LOH on chromosome 6, could be associated with an unfavorable prognosis, while the LOH on chromosome 22 may be related to the histologic progression of gastric carcinoma.