Barrett食管中环氧合酶-2表达和逆转的研究进展

Barrett食管（Barrett’s esophagus）是指食管下段的正常鳞状上皮被一种特殊肠化生的柱状上皮所取代的病理现象。传统Barrett食管定义中这种黏膜化生必须达到或超过3cm．而目前认为食管黏膜发生任何长度的肠化生均可定义为Barrett食管。这种特殊的肠化生可以一定模式（肠化生-不典型增生-腺癌）进展为食管腺癌。有文献报道约5％的Barrett食管患者发生癌变，较正常人群高出40～100倍。     

急性白血病p16基因微卫星不稳定性及杂和性缺失的研究

目的分析急性白血病（AL）患者p16基因连锁的微卫星不稳定性（MSI）和杂和性缺失（LOH），了解p16基因改变与AL发生的关系。方法采用多重PCR方法检测53例AL患者骨髓及口腔黏膜细胞标本的p16基因连锁的3个微卫星位点（D9S162、D9S1748、D9S171），观察其MSI及LOH情况。结果53例AL患者中，MSI检出率为43．4％（23／53）；位于9p21的p16基因连锁的微卫星D9S162、D9S1748、D9S171的LOH发生率分别为0（0／53）、5．7％（3／53）和9．4％（5／53），MSI发生率分别为13．2％（7／53）、7．6％（4／53）和7．6％（4／53）。结论AL患者p16基因连锁微卫星均可检测到高频率的MSI和LOH，说明p16基因突变与AL发生、发展有关。     

食管癌组织微卫星DNA序列不稳定性和杂合性缺失及预后的研究

目的探讨微卫星DNA序列不稳定性（MSI）和杂合性缺失（LOH）与人食管癌发生、临床病理特征及预后的关系。方法应用聚合酶链反应（PCR）和变性聚丙烯酰胺凝胶电泳技术,对30例人食管癌中MSI及LOH阳性情况进行研究,术后随访5年,了解预后。结果D3S1067位点MSI发生检出频率较高,为26.7%;D18S58位点MSI阳性率为20%。MSI的发生在食管小细胞癌中较食管鳞癌为高（P〉0.05）;MSI、LOH与肿瘤的病理分级、PTNM分期、有无区域淋巴结转移和浸润深度无关（P〉0.05）。结论食管癌在3p和18q染色体位点均存在微卫星不稳定现象;D3S1067和D18S58二个位点上MSI与食管癌的临床病理类型均相关;研究未发现这两个位点MSI、LOH与食管癌的临床分期、细胞分化程度、癌组织浸润深度和有无区域淋巴结转移等参数相关;3p位点基因的改变在食管鳞癌发生过程中具有较重要意义。     

肝癌患者血浆循环DNA杂合性缺失的检测及其临床意义

目的检测HCC患者血浆循环DNA杂合性缺失（LOH），并探讨将其作为有关临床预测标记的可能性。方法选择位于染色体8p上3个具有高度多态性的微卫星标记D8S277、D8S298和D8S1771，对62份HCC患者血浆循环DNA进行LOH检测，并进一步探讨LOH与患者HBsAg表达、是否肝硬化、血清AFP水平、肿瘤大小及细胞分化程度和有无肝内转移等临床病理特征之间的关系。结果在62份HCC患者血浆循环DNA标本中，36份（58．1％）在1个或多个位点发生LOH，D8S277、D8S298和D8S1771位点杂合度分别为74．2％（46／62）、75．8％（47／62）和69．4％（43／62），LOH频率分别为32．6％（15／46）、44．7％（21／47）和46．5％（20／43）。D8S298位点有肝内转移患者血浆循环DNA标本的LOH频率（62．5％）明显高于无肝内转移者（26．1％），差异有统计学意义（P〈0．05）；其他临床病理特征与3个位点上的LOH频率无明显相关。结论血浆循环DNA中D8S298位点LOH有可能成为HCC术后转移复发及预后的一个潜在的预测标记。     

浸润性乳腺癌及乳腺增生细胞3p、9p上5个微卫星位点的杂合性缺失观察

目的探讨乳腺浸润性导管癌及乳腺增生细胞中染色体3p、9p上5个微卫星位点（MS）杂合性缺失（LOH）模式。方法显微分离技术分离病变细胞,PCR．微卫星技术分析18例乳腺单纯性导管增生（UDH组）、15例不典型导管增生（ADH组）和35例乳腺浸润性导管癌（IDC组）细胞的3p、9p上D3S1447、D3S1612、D3S1597、D9S171及D9S1748位点的LOH模式。结果UDH组中仅1例D3S1447位点发生LOH（10％）,ADH组5个位点均发生一定频率的LOH（10％-22％）,IDC组5个位点均发生高频LOH（19％～48％）。至少1个位点发生LOH者,UDH组为6％、ADH组为33％、IDC组为71％,三组相比,P〈0．05;2个或以上位点发生LOH者,UDH组为0、ADH组为13％、IDC组为40％,UDH组、ADH组与IDC组相比,P均〈0．05。IDC组中D3S1612发生高频LOH者在有淋巴结转移组为63％,无淋巴结转移组为19％,两组相比,P〈0．05。结论UDH组的D3S1447位点发生的LOH和ADH组的5个位点发生的LOH有作为癌变风险预测分子标记的可能性,分析多个MS的LOH模式对于乳腺癌的早期预测和早期诊断有一定参考价值,D3S1612位点的LOH可能是IDC发生淋巴结转移的重要分子机制。     

遗传性非息肉性结直肠癌患者腺瘤和癌组织微卫星基因型分析

背景：遗传性非息肉性结直肠癌（HNPCC）是一种由错配修复基因种系突变引起的常染色体显性遗传病，高度微卫星不稳定（MSI—H）为其分子生物学特征之一。目的：利用5个微卫星位点建立正常结直肠黏膜、结直肠腺瘤和癌组织的微卫星基因型，探讨HNPCC的MSI发生情况和MSI检测的临床意义。方法：纳入源自33个HNPCC家系的腺瘤28例和腺癌14例，其中4例为同步腺瘤-癌；以32例散发性结直肠腺瘤和24例散发性结直肠癌作为对照。选用BAT25、BAT26、D2S123、D5S346、D17S250五个微卫星位点行荧光标记聚合酶链反应（PCR），以GeneMapper软件分析PCR产物。通过与正常黏膜微卫星序列PCR片段长度进行比较，判定腺瘤和癌组织的MSI情况。结果：HNPCC腺瘤和癌组织MSI-H发生率分别显著高于散发性结直肠腺瘤和结直肠癌（64-3％对3．1％，71.4％对12．5％，P〈0．05）。4例同步腺瘤-癌均表现为MSI—H．其腺瘤和癌组织的MSI类型不同。结论：HNPCC腺瘤和癌组织MSI—H发生率高。同步腺瘤一癌来源于不同克隆。MSI检测可作为HNPCC的临床初筛方法。     

老年Barrett食管

Barrett食管（Barrett’s esophagusBE）是指食管下段的复层鳞状上皮被化生的单层柱状上皮所替代的一种病理现象，它是反流性食管炎常见并发症之一，正常人群BE发生率仅1％左右，而有反流性食管炎患者发生率高达10％～15％。BE与食管腺癌发生关系密切，较正常人群发生几率高40～100倍。平均5％～10％BE遵循肠化——不典型增生——腺癌规律逐渐进展为食管腺癌，80％食管腺癌发生于BE，40％贲门腺癌与BE有关。     

Cdx2和MUC2在反流性食管炎、Barrett食管和食管腺癌中的表达

目的研究Cdx2和MUC2在反流性食管炎、Barrett食管和食管腺癌中表达，探讨3种食管黏膜疾病的内在关系。方法选取反流性食管炎30例、Barrett食管18例及食管腺癌25例作为研究对象，以正常食管上皮黏膜25例作为对照，采用免疫组化方法检测Cdx2和MUC2的表达，对结果进行统计分析。结果Cdx2和MUC2在反流性食管炎、Barrett食管及食管腺癌中的蛋白阳性表达率均较正常对照组明显增高（P〈0．05）。Cdx2在正常食管黏膜上皮中无表达，在反流性食管炎、Barrett食管及食管腺癌中的阳性表达率分别为26．7％、66．7％和28．0％，在Barrett食管中表达明显高于反流性食管炎（P〈0．05），亦明显高于食管腺癌（P〈0．05）；MUC2在正常食管黏膜上皮和反流性食管炎组织无表达，在Barrett食管及食管腺癌中的阳性表达率分别为61．1％和24．0％，Barrett食管中表达率明显高于食管腺癌（P〈0．05）。两者表达情况相似。结论Cdx2是肠上皮化生的始动因素，MUC2的表达是肠上皮化生的晚发事件。Cdx2和MUC2在反流性食管炎、Barrett食管和食管腺癌组织中的表达情况支持这3种食管黏膜疾病间有密切的关系。     

Ki-67在Barrett食管、重度反流性食管炎和食管腺癌中的表达和意义

背景：Barrett食管是一种食管腺癌癌前病变。Ki-67是一种能较准确地评估细胞增殖状态的抗原，在肿瘤进程中可能起重要作用。目的：研究Ki-67在Barrett食管、重度反流性食管炎和食管腺癌中的表达和意义。方法：应用免疫组化SP法测定59例Barrett食管、5例重度反流性食管炎、5例食管腺癌和10例正常食管黏膜组织中Ki-67的表达。结果：Ki-67在重度反流性食管炎中的阳性率为80．0％，Barrett食管阳性率为76．3％，与正常食管黏膜组织（20．0％）相比有显著差异（P〈0．05）：食管腺癌阳性率为100％。Ki-67的表达随Barrett食管肠化生程度的加重而增高（P〈0．05）；而不同长度（短段、长段）、肠化生黏膜形态（全周型、舌型和岛型）以及不同程度（轻度、中度）异型增生的Barrett食管，Ki-67的表达均无显著差异（P〉0．05）。结论：Ki-67在重度反流性食管炎和Barrett食管中表达增强，提示其在食管腺癌进程中起重要作用。     

肝细胞癌4号染色体微卫星变异的研究

目的 探讨肝细胞癌(HCC)微卫星变异的特点及其与临床病理的相关性。方法 应用聚合酶链反应-简单重复序列多态性方法,对56例患者HCC中4号染色体上10个微卫星的杂合性缺失(LOH)、微卫星不稳定性(MSI)和等位基因失衡(AI)3种变异特征进行检测。结果 56例HCC中,LOH的频率为71.4％(40/56),D4S426的LOH率最高为61.0％,其次为D4S1534(53.7％)。D4S406基因座,血清乙型肝炎表面抗原阳性患者的LOH频率高于阴性者[76.9％(20/26)与12.5％(2/16),x~2=13.999,P<0.01];在D4S426、D4S1615和D4S1652基因座,EdmondsonⅢ、Ⅳ级的LOH明显高于Edmondson Ⅰ、Ⅱ级[76.7％(23/30)与18.2％(2/11),x~2=9.242、P<0.01;53.8％(14/26)与16.7％(2/12),P<0.05;60.7％(17/28)与18.2％(2/11),P<0.051;D4S2921基因座,肝内转移者的LOH显著高于无肝内转移者[63.6％(21/33)与18.2％(2/11),x~2=5.132,P<0.05]。MSI的频率为8.9％(5/56);AI的频率为26.8％(15/56)。结论 HCC 4号染色体微卫星变异形式以LOH为主,提示LOH路径在HCC的发生和发展过程中起主要作用,MSI路径的作用次之。     

Microsatellite alterations in phenotypically normal esophageal squamous epithelium and metaplasia-dysplasia-adenocarcinoma sequence

AIM： To investigate the microsatellite alterations in phenotypically normal esophageal squamous epithelium and metaplasia-dysplasia-adenocarcinoma sequence.
METHODS： Forty-one specimens were obtained from esophageal cancer （EC） patients. Histopathological assessment identified 23 squamous cell carcinomas （SCC） and 18 adenocarcinomas （ADC）, including only 8 ADC with Barrett esophageal columnar epithelium （metaplasia） and dysplasia adjacent to ADC. Paraffin-embedded normal squamous epithelium, Barrett esophageal columnar epithelium （metaplasia）, dysplasia and esophageal tumor tissues were dissected from the surrounding tissues under microscopic guidance. DNA was extracted using proteinase K digestion buffer, and DNA was diluted at 1：100, 1：1000, 1：5000, 1：10000 and 1：50000, respectively. Seven microsatellite markers （D2S123, D3S1616, D3S1300, D5S346, D17S787, D18S58 and BATRII loci） were used in this study. Un-dilution and dilution polymerase chain reactions （PCR） were performed, and microsatellite analysis was carried out.
RESULTS： No statistically significant difference was found in microsatellite instability （MSI） and loss of heterozygosity （LOH） of un-diluted DNA between SCC and ADC. The levels of MSI and LOH were high in the metaplasia-dysplasia-adenocarcinoma sequence of diluted DNA. The more the diluted DNA was, the higher the rates of MSI and LOH were at the above 7 loci, especially at D3S1616, D5S346, D2S123, D3S1300 and D18S58 loci.
CONCLUSION： The sequence of metaplasia-dysplasia-adenocarcinoma is associated with microsatellite alterations, including MSI and LOH. The MSI and LOH may be the early genetic events during esophageal carcinogenesis, and genetic alterations at the D3S1616, D5S346 and D3S123 loci may play a role in the progress of microsatellite alterations.     

Loss of heterozygosity in multistage carcinogenesis of esophageal carcinoma at high-incidence area in Henan Province, China

AIM:Microsatellites are the repeated DNA sequences scattered widely within the genomes and closely linked with many important genes. This study was designed to characterize the changes of microsatellite DNA loss of heterozygosity (LOH) in esophageal carcinogenesis. METHODS: Allelic deletions in 32 cases of matched precancerous,cancerous and normal tissues were examined by syringe microdissection under an anatomic microscope and microsatellite polymorphism analysis using 15 polymorphic markers on chromosomes 3p, 5q, 6p, 9p, 13q, 17p, 17q and 18q. RESULTS: Microsatellite DNA LOH was observed in precancerous and cancerous tissues,except D9S1752. The rate of LOH increased remarkably with the lesions progressed from basal cell hyperplasia (BCH) to squamous cell carcinoma (SCC) (P<0.05).Three markers,D9S171, D13S260 and TP53, showed the highest incidence of LOH (>60%).LOH loci were different in precancerous and cancerous tissues. LOH in D3S1234 and TP53 was the common event in different lesions from the same patients. CONCLUSION: Microsatellite DNA LOH occurs in early stage of human esophageal carcinogenesis, even in BCH. With the lesion progressed, gene instability increases, the accumulation of this change may be one of the important mechanisms driving precancerous lesions to cancer.     

Early genetic instability of both epithelial and stromal cells in esophageal squamous cell carcinomas, contrasted with Barrett's adenocarcinomas

Background We have shown previously that stromal genetic alteration may make a greater contribution to early genesis of ulcerative colitis-associated tumors than sporadic colon cancers. We assessed whether similar differences in genetic alteration might exist between squamous cell carcinomas (SCCs) and Barrett's adenocarcinomas (BACs) of the esophagus. Methods We investigated epithelial and stromal genetic instability with five National Cancer Institute standard (NCI), four chromosome 17 (Chr. 17), and six tumor suppressor gene (TSG) microsatellite markers in 26 SCC and 12 BAC cases and in 11 normal controls, using a novel combination of microdissection, polymerase chain reaction, and GeneScan. Results Frequency of epithelial loss of heterozygosity (LOH) increased in the order background mucosa, to precursor lesions, to tumors with both types of carcinoma, especially for the Chr. 17 and TSG markers, while stromal LOH was relatively high but consistent from background mucosa to carcinoma. Epithelial LOH of D17S796 demonstrated a significantly higher frequency in SCCs than in BACs, without significant variation in p53 overexpression. The frequency of microsatellite instability (MSI) showed constant high levels in both epithelium and stroma of background, dysplasia, and carcinomas in the SCC series, and rather low frequencies in the BAC series. Although epithelial hMLH1 and hMSH2 expression decreased with tumor progression, no correlation was found with the individual MSI status. Conclusions Although epithelial LOH exists similarly in both lesion types, whereas epithelial and stromal MSI may occur in a relatively early phase of SCC development, stromal MSI is rare in BACs, strongly suggesting differences in tumorigenesis between the two types.     

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.     

外阴鳞癌组织中HPV检测及FHIT基因杂合性缺失、微卫星不稳定性观察

目的 观察外阴鳞癌( VSCC)组织中HPV感染情况及脆性组氨酸三联体(FHIT)基因的杂合性缺失(LOH)、微卫星不稳定性(MSI),并探讨其意义.方法 选取VSCC组织24例、外阴尖锐湿疣(VCA)42例、正常外阴组织20例,用PCR法检测上述组织中的HPV6、11、16、18、31、33亚型,用PCR-单链构像多态性分析(PCR-SSCP)法检测FHIT基因D3S1300位点的LOH和MSI.结果 在正常外阴、VCA、VSCC组织中低危型HPV( HPV6/11)阳性分别为2、38、21例,高危型HPV(HPV16/18/31/33)阳性分别为0、13、10例;VCA、VSCC组织与正常外阴组织比较,P均＜0.05.在正常外阴、VCA、VSCC组织中,FHIT基因D3S1300位点上LOH、MSI阳性分别为0、9、13例,VSCC与VCA、正常外阴组织比较,P均＜0.05.VSCC组织中HR-HPV感染与FHIT基因D3 S1300位点LOH/MSI相关(r =0.438,P＜0.05).结论 VSCC组织中存在较高的低危型、高危型HPV复合感染及FHIT基因LOH和(或)MSI;二者在VSCC的发生发展中发挥重要作用.     

Prognostic significance of microsatellite alterations at tp36 in cholangiocarcinoma

AIM: To investigate loss of heterozygosity (LOH) and microsatellite instability (MSI) on the chromosomal region 1p36-pter in cholangiocarcinoma (CCA) patients and determine the association between microsatellite alterations and clinicopathological parameters.METHODS: Ten polymorphic microsatellite markers were determined for LOH and MSI using GS-3000 gel scan fragment autoanalyzer.RESULTS: Sixty-eight out of 90 cases (75.6%) showed LOH in one or more loci. LOH was found most frequently at D1S199 (40.0%), D1S507 (34.6%), D1S2845 (30.5%),and D1S2734 (30.1%). MSI was found in 34 of 90 cases (37.8%) at one or more loci. Fine mapping at 1p36 showed two distinctive regions of common loss, which were D1S2845 and the 25.5-cM region between D1S507and D1S2734, indicating the existence of putative tumor suppressor genes that is likely to play important roles in the development of CCA. Patients with LOH at D1S234 showed less lymphatic invasion (P = 0.017),whereas patients with LOH at D1S2676 exhibited more lymphatic invasion than those without (P = 0.031).LOH at D1S2845 showed a significant correlation with nerve invasion (P = 0.029). Moreover, patients who demonstrated MSI at D1S228 showed a poor prognosis (P = 0.0026).CONCLUSION: Allelic loss plays a major role in microsatellite alterations at chromosome 1p36, which may contribute to carcinogenesis and pathogenesis of liver fluke related CCA and these alterations can be used as molecular prognostic indicators for CCA patients.     

Prognostic significance of microsatellite alterations at 1p36 in cholangiocarcinoma

AIM: To investigate loss of heterozygosity (LOH) and microsatellite instability (MSI) on the chromosomal region 1p36-pter in cholangiocarcinoma (CCA) patients and determine the association between microsatellite alterations and clinicopathological parameters. METHODS: Ten polymorphic microsatellite markers were determined for LOH and MSI using GS-3000 gel scan fragment autoanalyzer. RESULTS: Sixty-eight out of 90 cases (75.6%) showed LOH in one or more loci. LOH was found most frequently at D1S199 (40.0%), D1S507 (34.6%), D1S2845 (30.5%), and D1S2734 (30.1%). MSI was found in 34 of 90 cases (37.8%) at one or more loci. Fine mapping at 1p36 showed two distinctive regions of common loss, which were D1S2845 and the 25.5-cM region between D1S507 and D1S2734, indicating the existence of putative tumor suppressor genes that is likely to play important roles in the development of CCA. Patients with LOH at D1S234 showed less lymphatic invasion (P = 0.017), whereas patients with LOH at D1S2676 exhibited more lymphatic invasion than those without (P = 0.031). LOH at D1S2845 showed a significant correlation with nerve invasion (P = 0.029). Moreover, patients who demonstrated MSI at D1S228 showed a poor prognosis (P = 0.0026). CONCLUSION: Allelic loss plays a major role in microsatellite alterations at chromosome 1p36, which may contribute to carcinogenesis and pathogenesis of liver fluke related CCA and these alterations can be used as molecular prognostic indicators for CCA patients.     

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。     

Somatic DNA alterations in lung epithelial barrier cells in COPD patients

BackgroundInstability of the Microsatellite DNA Instability (MSI) and Loss of Heterozygosity (LOH) have been previously detected in sputum cells of COPD patients. However, the particular cell subpopulation exhibiting genetic instability in COPD was uncertain. The aim of this study was to determine which cell type expresses Microsatellite DNA Instability in sputum and BALF samples from COPD patients.MethodsThirty-five COPD patients and 30 non-COPD smokers were studied. Sputum was induced from 20 COPD patients and 20 non-COPD smokers and BALF was obtained from 15 COPD patients and 10 non-COPD smokers. The sputum cell pellet and BALF samples were processed using immunomagnetic technology to separate antibody-specific cell subpopulations, using CD45 + for leukocytes, Epithelial enrich (MACS) for sputum epithelial cells and HEA-human epithelial antigen-(Dynal) for BAL epithelial cells. Microsatellite DNA amplification was performed using specific primers, namely G29802, D6S2223, D6S344, D6S263, D5S207, D13S71, RH70958, and D17S250. The presence of MSI and/or LOH was analyzed with LI-COR Saga GT Microsatellite Analysis Software.Measurements and main resultsNone of the non-COPD smokers exhibited any genetic alteration. MSI and LOH were found in 15 cases (8 MSI and 7 LOH) in sputum and BAL samples. MSI and/or LOH were revealed only in the epithelial barrier cells. LOH was detected in D5S207, D6S344, G29802 and D17S250 microsatellite markers, while MSI in D13S71, D5S207 and D6S344. The entire leukocyte subpopulation exhibited no genetic alteration.ConclusionsOur results support the hypothesis that chronic inflammation and oxidative burden in COPD can lead to DNA damage of the lung epithelial barrier cells, detected at the Microsatellite DNA level. Further studies are required to investigate the significance of these findings in the pathogenesis of COPD.     

慢性白血病微卫星不稳定性和杂合性缺失的研究

应用PCR扩增技术检测17例慢性白血病患者不同染色体上8个微卫星位点的微卫星不稳定性（MSI）和杂合性缺失（LOH）,同时检测11例健康志愿者的MSI和LOH,以作对照。结果发现,健康对照组所选微卫星位点均未发生MSI或LOH;9例处于慢性白血病加速期的人中有7例发生至少一个位点的MSI,8例慢性期患者中仅1例发生一个位点的MSI,慢性白血病加速期的MSI发生率明显高于其慢性期（P＜0.05>,提示微卫星的遗传不稳定性可能与慢性白血病的病情进展有关。17例慢性白血病中只有1例在急变后出现LOH,提示所选位点的LOH可能不是慢性白血病的多发事件。