肺癌癌组织标本中微卫星DNA检测及临床意义

为研究肺癌癌组织标本中微卫星DNA改变及其对肺癌的诊断价值，采用聚合酶链反应（PCR）－银染法，对43例原发性肺癌（观察组）及10例良性肺疾病患者（对照组）纤支镜活检标本的3个微卫星位点进行了检测。结果观察组微卫星不稳定（MSI）发生率47％，杂合性丢失阳性率（LOH）30％，MSI加LOH阳性率为63％；对照组未发现微卫星DNA改变。提示肺癌组织微卫星DNA检测诊断肺癌有一定价值。     

微卫星多态性分析鉴别非小细胞肺癌术后肺内转移与第二原发癌

目的 利用微卫星多态性分析探寻非小细胞肺癌（NSCLC）术后肺内复发转移与第二原发肿瘤（Second primary tumor，SPT）的分子遗传学差异以助鉴别诊断。方法 1994年1月至2002年8月接受手术治疗的21例Ⅰ-ⅢA期NSCLC患者，术后2—7年（中位2．8年）发现病理类型与原发NSCLC相同的肺内孤立肿瘤（腺癌7例，鳞癌14例），将之与相应的原发NSCLC石蜡包埋组织配对，以非恶性肺组织为对照，在显微组织切割基础上分离其DNA，应用PCR为基础的微卫星分析方法检测8个定位于染色体3p、9p及17p区域的高密度微卫星位点，确定每一位点在相应配对肿瘤组织中杂合性丢失的异同，并结合临床特点分析肺内孤立肿瘤是复发转移还是SPT。结果 根据临床及影像学特点，9例患者肺内孤立肿瘤转移的可能性较大，其中7例配对肿瘤组织在3p、9p及17p8个微卫星标志上等位基因杂合性丢失的位点相同，提示肺内孤立肿瘤与原发NSCLC具有共同的克隆起源，支持肺内转移癌的诊断。4例肺内孤立肿瘤患者的临床病理及影像学特点倾向SPT，其配对肿瘤3p、9p及17p上8个微卫星位点等位基因杂合性丢失条带不一致，表明肺内孤立肿瘤克隆起源相异于原发NSCLC，支持临床SPT的诊断。另8例肺内孤立肿瘤患者术前不能判定系SPT还是肺内转移，其中6例配对组织3p或3p与17P微卫星位点杂合性丢失模式一致，但9p或17p杂合性丢失不一致，临床随访发现该6例肺内孤立肿瘤术后6—13个月内可见肺内或远处转移，支持肺内孤立肿瘤为转移癌的诊断；2例配对肿瘤虽有一致的9p或17p微卫星位点杂合性丢失，但3p的杂合性丢失模式不一致，临床倾向SPT。结论 对NSCLC术后肺内孤立病灶，3p、9p、17p微卫星多态性分析其等位基因杂合性丢失有助于鉴别系肺内转移还是SPT，其中3p的杂合性丢失可能是鉴别诊断的重要生物学标志，需扩大样本进一步研究。     

17号染色体微卫星不稳定性和杂合性丢失与非小细胞肺癌的关系

目的　明确１７ 号染色体微卫星不稳定性（ＭＩ） 和杂合性丢失（ＬＯＨ） 与非小细胞肺癌（ＮＳＣＬＣ） 的关系。方法　对３５ 例ＮＳＣＬＣ肿瘤切除组织和肿瘤旁正常组织,采用聚合酶链反应微卫星长度多态性分析方法检测了１７ 号染色体上４ 个微卫星位点ＴＰ５３（１７ｐ１３－１）、ＴＨＲＡ１（１７ｑ１１－２１２）、Ｄ１７Ｓ５７９（１７ｑ１２２１）、Ｄ１７Ｓ８５５（１７ｑ２１） 的ＭＩ和ＬＯＨ。结果　３５ 例ＮＳＣＬＣ中,１７ 号染色体ＭＩ和（或）ＬＯＨ的发生率为６３％ （２４／３５）,其中ＭＩ为４０％ （１４／３５） ,ＬＯＨ 为３１％ （１１／３５）。同时表现有ＭＩ和ＬＯＨ 为９％ （３／３５） 。早期ＮＳＣＬＣ（ Ⅰ期和Ⅱ期） １７ 号染色体ＭＩ和（ 或）ＬＯＨ 发生率为７９％ （１５／１９）,明显大于晚期（ Ⅲ期）ＮＳＣＬＣ（４４％ ,７／１６,Ｐ＜０－０５） 。无纵隔淋巴结转移的ＮＳＣＬＣ的ＭＩ和（ 或）ＬＯＨ 发生率（８７％ ） 亦明显大于已有纵隔淋巴结转移者（４８％ ）,Ｐ＜ ０－０５。ＭＩ和（ 或）ＬＯＨ 在不同肿瘤组织类型以及不同组织细胞分化程度之间差异无显著性,Ｐ＞０．０５。结论　１７ 号染色体ＭＩ和ＬＯＨ 在ＮＳＣＬＣ的发生中可     

燃煤型砷中毒患者皮损PTCH基因D9S287和D9S180位点微卫星不稳定性的观察

目的观察燃煤型砷中毒患者皮损组织中PTCH基因微卫星DNA不稳定性及杂合性丢失与临床病理、临床分度之间的关系。方法选取D9S287、D9S180两个微卫星多态性标记,采用PCR扩增-变性聚丙烯酰胺凝胶电泳-银染法检测不同病理类型的燃煤型砷中毒患者的微卫星的改变。结果34例患者皮损组织PTCH基因微卫星不稳定性的发生率为29.41%(10/34),杂合性丢失的发生率为14.7%(5/34),微卫星的改变与病理分型相关(P<0.01),与临床分度无关(P>0.05)。结论PTCH基因微卫星不稳定性和杂合性丢失可能在砷中毒患者皮损癌变的发生发展中起重要作用。     

肺癌组织频繁出现FHIT基因转录本的缺失

目的研究肺癌组织中脆性组氨酸三位体（ＦＨＩＴ）基因的改变。方法采用逆转录聚合酶链反应（ＲＴＰＣＲ）和逆转录聚合酶链反应单链构象多态性（ＲＴＰＣＲＳＳＣＰ）方法分析４７例肺癌组织和其中１６例相应的转移性肺门淋巴结。结果６８％（３２／４７）肺癌原发灶（包括２例肺鳞状细胞原位癌）和９４％（１５／１６）转移性肺门淋巴结出现ＦＨＩＴ转录本缺失,二者统计学差异有显著性（Ｐ＜０．０５）。ＦＨＩＴ基因转录本缺失主要发生于编码区。ＲＴＰＣＲＳＳＣＰ分析未发现突变。结论（１）在肺癌组织中ＦＨＩＴ基因转录本缺失是频发事件,且可能为早期事件;（２）ＦＨＩＴ基因突变可能是少见事件;（３）转移性肺门淋巴结ＦＨＩＴ基因转录本缺失频率与肺癌原发灶相比差异有显著性,提示具有ＦＨＩＴ转录本缺失的肺癌细胞具有更明显的恶性表型和恶性行为     

血清三项糖类抗原联合测定对肺癌的诊断评价

血清三项糖类抗原联合测定对肺癌的诊断评价李坚张蓝石胡盛莉孙丽萍李龙我们测定了６２例肺癌患者血清的糖类抗原５０（ＣＡ５０），糖类抗原１９９（ＣＡ１９９），糖类抗原１２５（ＣＡ１２５）水平，并与良性肺病患者比较，评价其对肺癌的临床诊断价值。对象与方法...     

肺癌组织的端粒酶活性表达及意义

应用ＰＣＲ－端粒重复序列扩增法（ＴＲＡＰ）检测３１例肺癌、４例癌旁及２６例肺良性肿瘤患者肿瘤组织的端粒酶活性表达。结果显示，肺癌组织中端粒酶活性表达率为８０．６％（２５／３１）、癌旁组织无表达、肺良性肿瘤组织表达率为７．７％（２／２６）。端粒酶活性表达与肺癌分化程度呈负相关，与肺癌分期无关。有及无淋巴结转移者的端粒酶活性表达率有显著性差异。提示端粒酶在肺癌的发生、发展及转移过程中皆起重要作用；其在肺癌组织中的高表达有望成为肺癌诊断、鉴别诊断的一项强有力的生物学指标。     

老年吸烟者肺癌H-ras基因突变的研究

目的探讨老年吸烟者肺癌Ｈｒａｓ基因变化的意义。方法对３３例吸烟肺癌和２２例不吸烟肺癌患者采用纤维支气管镜毛刷刷取支气管脱落细胞,应用ＰＣＲＲＦＬＰ方法进行Ｈｒａｓ基因突变检测。结果肺癌中Ｈｒａｓ基因总突变率为５２７％（２９／５５）,其中吸烟组肺癌Ｈｒａｓ基因突变率为６６７％,不吸烟组肺癌为３１８％,二者差异有显著性（Ｐ＜００５）,吸烟组肺鳞癌患者Ｈｒａｓ基因突变率为７００％,明显高于不吸烟组肺鳞癌患者的１６７％（Ｐ＜００５）。结论提示Ｈｒａｓ基因可能是被烟草激活的一个特殊位点,吸烟是导致Ｈｒａｓ基因突变的重要因素。     

老年人食管鳞状上皮化生和不典型增生及腺癌序列微卫星改变

目的评估老年人食管鳞状上皮和化生-不典型增生-腺癌的微卫星变化。方法应用稀释性聚合酶链反应（PCR）方法检测存档手术切除的食管癌标本中的D2S123、D3S1616、D3S1300、BATRII、D5S346、D17S787和D18S61位点微卫星的变化。结果在非稀释DNA中，17例食管鳞状细胞癌和12例腺癌微卫星不稳定性（MSI）的频率分别是52．9％（9例）和41．7％（5例），杂合性丢失（LOH）的频率分别是23．5％（4例）和16．7％（2例），两者差异均无统计学意义（P〉0．05）。在8例食管鳞状上皮和化生-不典型增生-腺癌组织稀释DNA中，MSI和LOH频繁出现，与其非稀释DNA的结果比较，差异均有统计学意义（P〈0．05）。结论MSI和LOH在上述组织中普遍存在，它们可能是食管腺癌发生、发展的早期事件。     

221例良性胃病中幽门螺杆菌感染与癌胚抗原表达的研究

胃镜取２２１例良性胃病的粘膜组织进行ＨＥ染色，Ｇｅｉｍｓａ染色查Ｈｐ，ＣＥＡ单克隆抗体免疫组化检查。结果：Ｈｐ感染率７７３８％（１７１／２２１），ＣＥＡ阳性率３８９１％（８６／２２１），肠化生（ＩＭ）和／或不典型增生（ＡＨ）发生率２６７％（５９／２２１），在Ｈｐ阳性与阴性病变中，ＩＭ和／或ＡＨ发生率分别为３０４１％（５２／１７１）及１４％（７／５０）（Ｐ＜００５）；ＣＥＡ的阳性率分别为４３２８％（７４／１７１）及２４％（１２／５０）（Ｐ＜００１）。提示Ｈｐ感染与胃的癌前病变的发生及ＣＥＡ的表达相关     

Microsatellite alteration in multiple primary lung cancer

Patients with pulmonary neoplasms have an increased risk for developing a second tumor of the lung, either at the same time or different times. It is important to determine if the second tumor represents an independent primary tumor or recurrence/metastasis, because it will significantly change the management and prognosis. Microsatellite instability (MSI) and loss of heterozygosity (LOH) represents molecular disorders acquired by the cell during neoplastic transformation. Both are associated with genetic instability. Functional silencing of tumour suppressor genes may be the consequence of genomic instability, particularly of the globally occurring LOH phenomenon. Numerous studies have confirmed the role of MSI/LOH at both the early and the late stages of multiple primary lung cancer. This paper reviews the published literatures focused on the role of MSI/LOH significance in multiple primary lung cancer. Additionally, a new method based on the allelic variations at polymorphic microsatellite markers was offered that it does not rely on collection of normal tissue, performed with minimal tumor sample, and will complement clinical criteria for diagnostic discrimination between multiple primary cancers versus solitary metastatic diseases.     

Loss of heterozygosity and microsatellite instabilities of fragile histidine triad gene in gastric carcinoma

AIM: To detect the loss of heterozygosity (LOH) and microsatellite instabilities (MSI) of fragile histidine triad (FHIT) gene in gastric carcinoma and to study their association with the clinical pathological characteristics of gastric carcinoma. METHODS: LOH and MSI of FHIT gene were detected at four microsaterllite loci D3SI3H, D3S4I03, D3SI48I and D3S1234 using PCR in matched normal and cancerous tissues from 50 patients with primary gastric cancer. RESULTS: The average frequency of LOH and MSI of FHIT gene in gastric cancer was 32.4% and 26.4% respectively. LOH and MSI of FHIT gene in gastric cancer had no association with histological, Borrmann, and Lauren's classification. LOH of FHIT gene in gastric cancer was related to invasive depth. The frequency of FHIT LOH in gastric cancer with serosa-penetration was obviously higher than that in gastric cancer without serosa-penetration (73.5% vs 37.5%, P < 0.05). MSI of FHIT gene in gastric cancer was associated with the lymph node metastasis. The frequency of MSI in gastric cancer without lymph node metastasis was significantly higher than that in gastric cancer with lymph node metastasis (66.7% vs 34.3%, P < 0.05). CONCLUSION: LOH of FHIT gene is correlated with invasive depth of gastric carcinoma. MSI of FHIT gene is correlated with lymph node metastases. LOH and MSI of FHIT gene play an important role in carcinogenesis of gastric cancer.     

Esophageal squamous cell carcinomas with DNA replication errors (RER+) are associated with p16/pRb loss and wild-type p53

PURPOSE: Microsatellite instability (MSI) as a determinant of propensity to esophageal squamous cell carcinoma (ESCC) at seven microsatellite markers at 2p (2p15-16), 3p (3p13, 3p14.1-3, 3p25, and 3p26) and 16q (16q12.1-3) was investigated to analyze their putative role as indicators of predisposition to esophageal malignancies. METHODS: Seven microsatellite loci were amplified by polymerase chain reaction, from surgically resected tumor tissues from 30 ESCC patients from Indian population, to assess the loss of heterozygosity (LOH) and replication error repeats (RER) and to correlate these alterations with aberrations in major cell cycle regulatory proteins and histopathological parameters. RESULTS: LOH and RER analyses at these loci demonstrated moderate microsatellite alterations, suggesting the involvement of MSI in esophageal tumorigenesis in a subset of the Indian population. MSI, defined as RER in at least two or more of the loci studied, was observed in ten of 30 (33%) patients. Twenty-two of 30 patients (73%) showed LOH at one or more loci, while 17 of the 30 patients (60%) showed RER in at least one of the loci studied. RER-positive patients showed a trend towards better prognosis when compared to RER-negative patients. MSI demonstrated a significant association with concomitant loss of p16 and pRb (p16-/pRb- phenotype) (P=0.046). Interestingly, we observed an inverse correlation between MSI and p53 mutations (P=0.03) suggesting that MSI may provide a p53-independent pathway for esophageal tumorigenesis in RER+ patients. MSI showed a trend towards longer survival and absence of distant organ metastasis (P=0.06). CONCLUSIONS: The present study demonstrates the probable role of MSI in esophageal squamous cell carcinoma in the Indian population. Instability associated with the repetitive sequences--the revealing marks of loss of DNA replication fidelity may serve as an indicator of predisposition to esophageal cancer.     

Approaches to identification of HNPCC suspected patients in Slovak population

Patients with hereditary non-polyposis colorectal cancer (HNPCC) have a DNA mismatch repair defect (MMR) in their tumor tissue that results in instability of microsatellite DNA sequences (MSI). Thus, MSI analysis may effectively indicate this form of cancer that should be then proved by analysis of germline mutations in MMR genes. The aim of this study was to identify HNPCC suspected patients in the Slovak population by investigating microsatellite instability in colorectal tumor tissues. MSI was studied at 5-11 loci in matched tumor and normal DNA using radioactively labeled PCR products separated on sequencing gels. High microsatellite instability (MSI-H) was present only in patients younger than 50 years, in 100% of patients having two affected relatives by colorectal cancer and in 67% of patients with only one affected relative. In both groups of patients colorectal cancer was present in two successive generations. No MSI-H was found in the group of patients older than 50 years, even if they had positive family history for colorectal cancer. Among all markers used, the BAT26 mononucleotide repeat (100%), DI0S197 and D13S175 (62.5%) dinucleotide repeats were the most frequently altered in the tumor tissues. Retrospective analysis revealed that some of the patients having MSI-H tumors have had clinicopathological characteristics frequently reported to HNPCC. The family members of those patients with MSI-H are enrolled in preventive health care program until mutational analyses will enable to select carriers from non-carriers of mutated MMR genes.     

Telomere erosion is independent of microsatellite instability but related to loss of heterozygosity in gastric cancer

AIM: To correlate the length of the telomere to microsatellite instability (MSI) and loss of heterozygosity (LOH) of APC, MCC and DCC genes in gastric carcinomas. METHODS: Telomeric restriction fragment (TRF) length of gastric cancer was measured with Southern blot. LOH of APC, MCC and DCC genes, microsatellite instability (MSI) and frameshift mutation of hMSH6, TGF-betaRII and BAX genes were analyzed by PCR-based methods. RESULTS: Sixty-eight cases of sporadic gastric carcinoma were studied for MSI using five microsatellite markers. MSI in at least one locus was detected in 17 (25%) of 68 tumors analyzed. Frameshift mutations of hMSH6, TGF-betaRII and BAX were detected in 2,6 and 3 of gastric carcinomas respectively showing high MSI (> or = 2 loci, n = 8), but none was found in those showing low MSI (only one locus, n = 9) or MSS (tumor lacking MSI or stable, n = 51). Thirty-five cases, including all high MSI and low MSI, were studied for TRF. The mean TRF length was not correlated with clinicopathological parameters. No association was observed between TRF length and MSI or frameshift mutation. On the contrary, LOH at the DCC locus was related to telomere shortening (P<0.01). This tendency was also observed in APC and MCC genes, although there was no statistical significance. CONCLUSION: The development of gastric cancer can arise through two different genetic pathways. In high MSI gastric cancers, defective mismatch repair allows mutations to accumulate and generate the high MSI phenotype. In gastric cancers showing either low MSI or MSS, multiple deletions may represent the LOH pathway. Telomere erosion is independent of high MSI phenotype but related to the LOH pathway in gastric cancer.     

Microsatellite instability in Ewing tumor is not associated with loss of mismatch repair protein expression

Only few clinical factors predict the prognosis of patients with Ewing tumors. Unfavorable outcome is associated with primary metastatic disease, age > 15 years, tumor volume above 200 ml, and the histological response to chemotherapy. The aim of this study was to elucidate the prevalence and clinical impact of microsatellite instability (MSI) together with the relation between MSI and mismatch repair protein expression in Ewing tumors. DNA from 61 primary Ewing tumors and 11 Ewing tumor cell lines was extracted and microsatellite analysis for the detection of instability or loss of heterozygosity was performed for the five markers of the Bethesda panel BAT25, BAT26, D5S346, D2S123, and D17S250, which represents the established marker panel for the analysis of hereditary non-polyposis colorectal carcinoma (HNPCC) patients. In addition, single nucleotide repeat regions of the two tumor genes BAX and transforming growth factor receptor II (TGFBR2) were also included. All of the 61 samples were suitable for LOH analysis and 55 for the determination of MSI-status. LOH of these microsatellite markers was detected in 9 of the 61 patients (14.8%). Over all, genetic instability, i.e. MSI and/or LOH, was detected in 17 tumors (27.9%). One out of the 11 tumor cell lines (STA ET1) was characterized by instability of all the five Bethesda markers, while from primary tumor samples, only one showed MSI in more than one microsatellite marker (D5S346 and D17S250, MSI-high). Eight of the fifty-five patients (14.5%) showed instability of one microsatellite locus (MSI-low). No instability was detected in BAT26, D2S123, BAX and TGFBR2. There was no significant correlation between MSI and loss of expression of mismatch repair proteins MLH1, MSH2, or MSH6. The impairment of the p53 signaling pathway (expression of TP53 and/or MDM2 by immunohistochemistry) was significantly associated with reduced overall survival (15 of 49 patients (30.6%), P = 0.0410, log-rank test). We conclude that MSI is not prevalent in Ewing tumor and that the nature of instability differs from the form observed in colorectal carcinoma, the model tumor of MSI. This is documented by the different pattern of MSI (no BAT26 instability) in Ewing tumors and the lack of a strict correlation between MSI-high and loss of expression of MSH2, MSH6 and MLH1. IA and KLS contributed equally to this study.     

Analysis of microsatellite instability in stool DNA of patients with colorectal cancer using denaturing high performance liquid chromatography

INTRODUCTION Colorectal cancer, one of major causes of tumor-induced death in the Western population, becomes prevalent in Korea. The mortality rate from colorectal cancer has increased rapidly from 3.9 per 100 000 individuals in 1983 to 11.4 in 2003 in K…     

Genetic instability in myelodysplastic syndrome: detection of microsatellite instability and loss of heterozygosity in bone marrow samples with karyotype alterations

Using a polymerase chain reaction (PCR)-based approach, we examined the prevalence of loss of heterozygosity (LOH) and microsatellite instability (MSI) in relation to chromosomal imbalances in myelodysplastic syndrome (MDS). Two of 26 patients displayed MSI (8%), one of them at five loci. LOH was detected in six out of 26 cases (23%), predominantly involving markers IRF1 [5q31] and WT1 [11p]. Two patients displayed a corresponding chromosomal deletion by conventional cytogenetics. Supporting the mutator phenotype hypothesis, a significant coincidence of LOH, MSI and chromosome abnormalities was observed (P < 0.025). Moreover, our data suggest that LOH represents an initial rather than a secondary genetic event in MDS, promoting genetic instability in a subset of patients.