人胰腺癌组织3、5、7、9和18号染色体部分位点的杂合性丢失

目的了解人胰腺癌组织３、５、７、９和１８号染色体部分位点的杂合性丢失的状况。方法选择来自３、５、７、９和１８号染色体不同位置的９对多态性引物，对４５例胰腺癌存档石蜡标本经显微镜下剥离后，以ＰＣＲ－ＳＳＬＰ－银染法检测胰腺癌中这些位点的杂合性丢失。结果胰腺癌组织在１８ｑ２１．１、３ｐ１４．２、３ｐ２１．１和９ｑ２２－３１等处存在较高频率的杂合性丢失。结论胰腺癌的发生和发展可能涉及这些部位基因的改变     

喉鳞状细胞癌组织中9号染色体的杂合性丢失分析

为探讨喉鳞状细胞癌组织中９号染色体杂合性丢失的意义，应用聚合酶链反应（ＰＣＲ），检测了５８例喉鳞状细胞癌组织中９号染色体上３个座位ＤＮＡ微卫星多态标记的杂合性丢失。结果发现，３例可提供信息的原位癌中２例发生杂合性丢失，５１例可提供信息的浸润期喉癌中ＬＯＨ频率为６５％（３１／５１）。研究表明，喉癌中染色体９ｐ缺失区域在Ｄ９Ｓ３２４（９ｐ２１－ｐｔｅｒ）和Ｄ９Ｓ３１９（９ｐ２１）之间，即在此区域上存在与喉癌发生发展密切相关的抑癌基因，它的失活是喉癌发生发展的早发事件。     

用Amp—FLP技术研究中国汉族群体D4S95和DXS52位点的遗传多态性

为研究汉族群体Ｄ４Ｓ９５和ＤＸＳ５２位点的遗传多态性，应用改进的Ｄ４Ｓ９５和ＤＸＳ５２位点的增片段欧态性分析技术，检测了中国汉族个体共２２２名。结果分别为，（１）Ｄ４Ｓ９５位点：在１０８名无关个体中发了７个等位基因，１８种基因型，杂合性为０．７６，个人鉴别为０．８７；（２）ＤＸＳ５２位：在１１４名无关个体中发现了１４个等位基因，在４４名女性个体中发现了２２种基因型，杂合性为０．７７。     

用PCR法分析中国汉族群体D17S30位点遗传多态性

用聚合酶链式反应对中国汉族群体１２２名无关个体Ｄ１７Ｓ３０位点扩增片段长度多态性进行分析研究，发现１０个等位基因，片段大小为１６８－７９８ｂｐ，基因频率为０．００８２－０．２５８２，杂合性为７８％。５５种可能基因型中发现了２７种，对基因型的观察值和期望值进行Ｘ＾２检验，符合Ｈａｒｄｙ－Ｗｅｉｂｅｒｇ平衡定律。     

Rb基因在鼻咽癌中存在状态的研究

首次应用生物素－１４－ｄＵＴＰ标记Ｒｂ３．８ｋｂ探针，结合亲合素－碱性磷酸酶发光及自显影法，对Ｒｂ基因在鼻咽癌中存在状态进行了研究。杂交结果表明，３例正常胎儿鼻咽组织出现分子量为１２．８、１０．２、８．０、６．２、５．６、５．２及４．８ｋｂ的７条杂文区带，１１例鼻咽癌组织均发现有Ｒｂ基因缺失或失活，其中４例为５．６ｋｂ片段缺失，４例为４．８ｋｂ缺失并有２例伴５．６ｋｂ减弱，２例为１０．２ｋｂ缺失，１例为５．６及５．２ｋｂ片段显著减弱，说明在上述１１例鼻咽癌中均有Ｒｂ基因的改变。这种高频率的异常变化，提示Ｒｂ基因的缺失或失活，与鼻咽癌的发生有密切关系。     

人恶性肿瘤中染色体9p21—p22区带的杂合性丢失

人类恶性肿瘤中常发生染色体杂合性丢失,从而丢失抑癌基因的某一个等位基因。人类９号染色体特别是该染色体的９ｐ２１－ｐ２２区带,在多种肿瘤中都存在着染色体和杂合性丢失。在定位克隆抑癌基因的过程中,对肿瘤中高频率染色体杂合性丢失的分析是对抑部基因进行定位并最终发现和克隆该类基因的先决条件之一。     

脊肌萎缩症基因缺失的初步研究

目的为了研究中国人进行性脊肌萎缩症（ｓｐｉｎａｌｍｕｓｃｕｌａｒａｔｒｏｐｈｙ，ＳＭＡ）患者中神经元存活基因（ｓｕｒｖｉｖａｌｍｏｔｏｒｎｅｕｒｏｎ，ＳＭＮ）外显子７的缺失情况，进一步证实外显子７缺失与ＳＭＡ疾病的关系，为基因诊断和产前诊断建立切实可行的方法。方法采用ＰＣＲ－ＳＳＣＰ银染技术，对３７个ＳＭＡ患者家系及３０例正常个体的ＳＭＮ基因的外显子７区域进行检测。结果在ＳＭＮ基因的外显子７区域纯合缺失率分别为：ＳＭＡⅠ型８６．７％（１３／１５），Ⅱ型８６．４％（１９／２２），患者父母及正常个体共６７例中除一患者母亲为纯合缺失外，其余均无纯合缺失。结论中国人ＳＭＡ患者中ＳＭＮ基因外显子７的纯合缺失频率高，并与疾病发生密切相关，ＳＳＣＰ银染检测ＳＭＡ基因缺失方法快速安全，结果可靠，可诊断率高，适用于基因诊断和产前诊断     

用Amp－FLP技术研究中国汉族群体D4S95和DXS52位点的遗传多态性

为研究中国汉族群体Ｄ４Ｓ９５和ＤＸＳ５２位点的遗传多态性，应用改进的Ｄ４Ｓ９５和ＤＸＳ５２位点的扩增片段长度多态性（Ａｍｐ－ＦＬＰ）分析技术，检测了中国汉族个体共２２２名。结果分别为，（１）Ｄ４Ｓ９５位点：在１０８名无关个体中发现了７个等位基因（片段长度为９１０～１１５０ｂｐ），１８种基因型，杂合性为０．７６，个人鉴别力为０．８７１（２）ＤＸＳ５２位点：在１１４名无关个体中（男性７０人，女性４４人）发现了１４个等位基因（片段长度为６９５～２４００ｂｐ），在４４名女性个体中发现了２２种基因型，杂合性为０．７７．个人鉴别力为男性０．８９，女性０．９３１检测了两个家系两代３口之家的两位点的基因型，证明该两位点的基因按Ｍｅｎｄｅｌ定律遗传，该技术在法医科学鉴定中具有重要的应用价值。     

良,恶性卵巢肿瘤C—Ha—ras1位点的等位基因型与杂合性缺失

为了探讨Ｃ－Ｈａ－ｒａｓｌ位点的等位基因型与杂合性缺失在卵巢癌发生中的意义，应用Ｓｏｕｔｈｅｒｎ印迹技术，在１７例良、恶性卵巢肿瘤患者中研究Ｃ－Ｈａ－ｒａｓＩ位点的多态性和等位片段缺失。结果表明，在ＢａｍＨ Ｉ酶切、Ｃ－Ｈａ－ｒａｓ１探针杂交的放射自显影图上显示７．８ｋｂ（Ｌ）和６．８ｋｂ（Ｓ）两个等位片段，基因型ＳＳ的个体在恶性卵巢肿瘤组的比例（７／１１）显著高于良性肿瘤组（２／６）（Ｐ〈０．０     

喉癌p16区域的杂合性丢失和微卫星序列不稳定性分析

目的 缩小喉癌抑癌基因的寻找范围,探讨Ｐ１６基因在喉癌发生中的作用。方法 选择Ｐ１６基因附近５个微卫星多态标记对６０例喉癌进行杂合性丢失和微卫星序列不稳定性分析。结果 ５个标记在喉癌中杂合性丢失频率均不高,最高仅达２３．１％,但２个标记的微卫星序列不稳定性的频率较高,其中示记微卫星序列恶性循环频率高达４６．１％。结论 提示Ｐ１６基因在喉癌的发生中不以缺失为主,在Ｄ９Ｓ１７５２附近可能存在参与喉癌演     

A novel candidate tumour suppressor locus at 9q32-33 in bladder cancer: localization of the candidate region within a single 840 kb YAC

Loss of heterozygosity (LOH) on chromosome 9q is the most frequent genetic alteration in transitional cell carcinoma (TCC) of the bladder, implicating the presence of a tumour suppressor gene or genes on 9q. To define the location of a tumour suppressor locus on 9q in TCC, we screened 156 TCCs of the bladder and upper urinary tract by detailed deletion mapping using 31 microsatellite markers on 9q. Partial deletions of 9q were found in 10 TCCs (6%), and LOH at all informative loci on 9q was found in 77 TCCs (49%). In five low grade superficial bladder tumours, the partial deletion was localized to D9S195 located at 9q32-33, with retention of heterozygosity at all other informative loci including D9S103, D9S258, D9S275 and GSN. We constructed a yeast artificial chromosome (YAC) contig covering the deleted region in these five tumours and placed another four unmapped microsatellite markers on this contig map. Using these markers, we further defined the common deleted region to the interval between D9S1848 and AFMA239XA9. The region is covered by a single YAC (852e11), whose size is estimated to be 840 kb. Our data should expedite further fine mapping and identification of the candidate tumour suppressor gene at 9q32-33.      

具有家族史鼻咽癌4p15.1-4q12区等位基因杂合性丢失分析

目的确定有家族史鼻咽癌患者4p15．1-4q12区域等位基因杂合性丢失（loss of heterozygosity，LOH）的分布和频率，为进一步缩小该区域内易感基因的范围提供新的线索和依据。方法收集具有家族史的鼻咽癌患者石蜡包埋的活检组织标本，采用显微切割的方法在肿瘤组织石蜡切片上分离肿瘤细胞和正常淋巴细胞，选定7个定位于4p15．1-4q12区域内的高密度微卫星位点，多重PCR扩增和丙烯酰胺凝胶电泳后，Genescan软件对各位点LOH进行分析。结果25例具家族史鼻咽癌患者中，23例在4p15．1-4q12区至少存在一个微卫星位点的LOH（92％）。其中D4S2382位点LOH的频率最高，达到56％；D4S350和D4S1547位点LOH频率均约为50％。最小共同缺失区位于位点D4S350和D4S1547之间。结论鼻咽癌4p15．1—4q12区域内的易感基因可能位于微卫星位点D4S350和D4S1547附近。     

THE FREQUENCY AND MECHANISM OF LOSS OF HETEROZYGOSITY ON CHROMOSOME 11q IN BREAST CANCER

Loss of heterozygosity (LOH, allele loss) occurs frequently on the long arm of chromosome 11 in breast cancer. Seventy-one paired tumour/normal DNA samples from breast cancer patients under 50 years old were studied for allele loss at four microsatellite loci on 11q: D11S29 (11q23.3), NCAM (11q22–q23), D11S968 (11qtel), and D11S1313 (11qcen). The maximum frequency of LOH (≈35 per cent) was found at the D11S29 and NCAM loci. This result is consistent with previous studies and the frequency of allele loss is moderate to high compared with the usual baseline of 0–20 per cent. In most of the cases studied, LOH on chromosome 11q could be accounted for by one of two mechanisms. Either chromosomal non-disjunction had occurred, or sequences stretching from the telomere at least as far as NCAM had undergone deletion or mitotic recombination. These results suggest that a putative tumour suppressor gene is most likely to exist near 11q22–q23. There was a very low frequency of microsatellite instability in the tumours. An association was found between lack of progesterone receptor (PgR) expression and LOH at NCAM , suggesting that deletion of sequences on 11q may prevent high levels of PgR expression in some cases.     

胶质母细胞瘤14号染色体杂合性丢失的初步研究

目的 寻找胶质母细胞瘤（glioblastoma,GBM)14号染色体上可能存在肿瘤抑制基因的杂合性丢失（loss of heterozygosity,LOH)aqfa,为发现和定位肿瘤抑制基因提供线索和依据。方法 应用聚合酶链反应方法,采用荧光标记引物和377型DNA序列自动分析仪,分析了20例GBM患者14号染色体上14个微卫星多态性标记的LOH。结果 在50％（10／20）GBM患者的14号染色体上观察到LOH,在38．2％（81／212）可提供信息位点存在LOH。14p和14q的LOH率分别为32％（6／19）、50％（10／20）。在位于14q31-32．3的D14S65位点、14q21-24.1的D14S63－D14S74位点间区域检测到了较高LOH率,分别为57．1％、46．7％－47．1％。在所测位点均未检测到微卫星不稳定（microsatellite instability,MI)。结论 染色体14q上等位基因的丢失可能在GBM分子水平发病机理中起着重要作用,14q31-32.3的D14S65位点、14q21-24.1的D14S63－D14S74位点间区域可能存在与GBM相关的肿瘤抑制基因。     

Definition of a region of loss of heterozygosity at chromosome 11q23.3-25 in head and neck squamous cell carcinoma using laser capture microdissection technique.

To date, loss of heterozygosity (LOH) studies on HNSCC have had limited success in identifying a confined region of loss on chromosome 11q partially due to the heterogeneous nature of tumor tissue examined. Additionally, little is known about the role of the 11q allelic deletion in HNSCC tumorigenesis and current reports are conflicting. The aim of this study was to better define LOH at distal 11q by using combination of a pure cell population procured by laser capture microdissection (LCM) and subsequent sensitive PCR amplification of polymorphic microsatellites. This study analyzed HNSCC for LOH using a panel of 5 microsatellite markers spanning 11q23-25. Thirty-four paired DNA samples from tumor and autologous normal tissue were harvested by LCM technique to ensure a pure cell population for PCR amplification. Approximately 2000 to 3000 cells were procured from each sample. Twenty-one of 34 cases (62%, P < 0.001) showed LOH on at least one of the loci examined. The highest frequency of LOH was found at the 11q23.3-25 segment, with 44% at marker D11S968 and 35% at marker D11S1316. A distinct novel region of frequent LOH at 11q23.3-25, defined by D11S1316 and D11S968, was identified. No allelic loss was found in any normal squamous tissue samples. To study LOH in HNSCC, combination of pure cell population procurement by LCM and sensitive PCR provides a more accurate approach than the conventional method using a bulk of heterogeneous tissue. A novel region of LOH at 11q23.3-25 was defined. LOH in this region may harbor putative tumor suppressor gene(s) critical for HNSCC. Furthermore, these allelic losses were not found in any non-neoplastic squamous tissue samples, clarifying prior discrepant data.     

Identification of three commonly deleted regions on chromosome arm 6q in human pancreatic cancer

Pancreatic cancer has one of the poorest prognoses among malignant diseases. To understand its molecular mechanisms, we studied allelic losses on the long arm of chromosome 6. Using 55 paired DNAs of tumors and their corresponding normal tissues and 30 microsatellite markers that spanned the entire 6q chromosome arm, we found three distinct regions of common allelic loss: region A, a less than 500-kb region bordered by D6S449 and D6S283 on 6q21 with a loss of heterozygosity (LOH) frequency of 69% (38/55); region B, a 7-cM region bordered by D6S292 and D6S308 on 6q23-q24 with a LOH frequency of 60% (33/55); and region C, a 13-cM region bordered by D6S305 and D6S264 with a LOH frequency of 51% (28/55). We further focused on region A and constructed a physical map using yeast artificial chromosome (YAC) clones, their derived cosmid clones, and bacterial artificial chromosome (BAC) clones. Region A was completely covered by three overlapping BAC clones. Our results in the present study should shed light on the cloning and characterization of tumor suppressor genes in pancreatic carcinogenesis.     

Allelic loss at BRCA1, BRCA2, and adjacent loci in relation to TP53 abnormality in breast cancer

Cells with abnormal TP53 lose cell cycle checkpoints, resulting in genomic instability and neoplastic transformation. However, the evidence linking the tumor-specific targets of genomic alteration to an abnormal TP53 is limited. The present study tested the hypothesis that TP53 abnormalities are correlated with an increased frequency of deletion of breast cancer susceptibility loci (17q and 13q) in breast carcinomas. Tumors from 90 patients were examined for TP53 abnormality and loss of heterozygosity (LOH) at 11 loci on 17q (17q11.2–21) and 13q (13q12–14), including the loci for BRCA1 and BRCA2. A higher frequency of LOH was consistently found at 17q or 13q loci in tumors with an abnormal TP53. The increased LOH in relation to TP53 abnormality was statistically significant at the BRCA1, D17S588, and D13S267 loci (P < 0.05) but not at the locus for BRCA2 (P = 0.64). These observations imply a possible link between an abnormal TP53 and specific genomic deletions of breast cancer susceptibility loci, which may provide clues to the role of TP53 during breast tumorigenesis. Genes Chromosomes Cancer 20:377–382, 1997. © 1997 Wiley-Liss, Inc.     

Loss of heterozygosity on chromosome 22q in gastrointestinal stromal tumors (GISTs): a study on 50 cases

Mutational activation of KIT or PDGFRA is considered an early step in pathogenesis of gastrointestinal stromal tumors (GISTs); however, other nonrandom genetic changes have also been identified. At least three common regions of deletions on chromosome 22q, which may harbor putative tumor suppressor genes, have been defined. However, mapping of these regions has been inconsistent. It has also been speculated that GI autonomous nerve tumors (GANTs), GISTs with ultrastructural features suggestive of autonomic nerve differentiation, are characterized by a specific deletion involving 22q13 cytogenetic region. This study was undertaken to evaluate loss of heterozygosity (LOH) on chromosome 22q in 50 GISTs, including 10 GANTs. Four tumors were incidental minimal lesions 相似文献   

Endometrial glandular dysplasia: a putative precursor lesion of uterine papillary serous carcinoma. Part II: molecular features

Endometrial glandular dysplasia (EmGD) may be a newly defined precursor lesion of uterine papillary serous carcinoma (UPSC) by morphology. In this report, we studied molecular changes present in EmGD by the loss of heterozygosity (LOH) approach using laser capture microdissected tissue samples. Nineteen uteri showing at least 1 focus of EmGD by morphology were selected. These cases were 12 UPSC, 2 clear cell carcinomas, 1 mixed uterine papillary serous and endometrioid carcinoma, 1 uterine carcinosarcoma, 1 serous endometrial intraepithelial carcinoma (EIC), and 2 EmGD involving endometrial polyps. Seven microsatellite polymorphic DNA markers (TP53 at 17p, D1S211, and D1S162 at 1p32, D17S1323 at 17q21, D17S1330 at 17q25, D5S346 at 5q, and D2S123 at 2p) were utilized. A total of 123 laser-captured microdissection samples from 19 cases was studied with LOH method. The frequencies and patterns of LOH were analyzed and compared among benign resting endometrium (RE), EmGD, serous EIC, and UPSC. LOH was observed for at least 1 of the 7 markers in all categories of lesions, EmGD, serous EIC, and UPSC. The frequency of LOH for EmGD ranged from 4.2% to 31.3%; the range for serous EIC was 5.9% to 78.6%; and that for UPSC was 7.7% to 62.5%. The most frequent LOH in the 3 above-cited categories of lesions was identified at 17p (TP53) and 1p (D1S162). The frequency of LOH in EmGD with markers of TP53 and D1S162 was significantly higher than in RE (p < 0.05). With markers of D1S211 and D2S123, LOH in EmGD was higher than RE, approaching to a statistically significant level. Compared with foci of serous EIC and UPSC, however, the rate of LOH in EmGD was significantly lower only with TP53 locus (31.3% vs more than 60%, p < 0.05). The difference of LOH frequency with other chromosomal markers between EmGD and serous EIC/UPSC did not reach a statistically significant level. A significantly high concordant LOH pattern was found between foci of EmGD and serous EIC/UPSC (p = 0.05). We conclude that EmGD frequently shows LOH at multiple chromosomal loci, particularly at 17p and 1p. Significantly high concordant LOH frequency between EmGD and paired serous EIC or UPSC strongly suggests that EmGD is a noncancerous precursor lesion of UPSC, probably also of serous EIC. The clinical significance of EmGD needs further studies.     

Genetic Changes in Chromosomes 1p and 17p in Thyroid Cancer Progression

Little is known about the genetic alterations that occur during the progression of thyroid neoplasms. To understand better the biology of thyroid tumors, we investigated several genetic loci in benign and malignant thyroid neoplasms. Forty-one thyroid tumors (6 adenomas, 16 papillary, 14 follicular, and 5 anaplastic carcinomas) were studied. Normal and tumor cells were microdissected from paraffin-embedded tissues. DNA was used for polymerase chain reaction-based loss of heterozygosity (LOH) analysis with the following markers: D1S243 (1p35–36), D1S165 (1p36) and D1S162 (1p32), TP53 (17p13), and INT-2 (11q13). Immunohistochemistry for Ki-67 was performed. The Ki-67 labeling index (LI) was the percentage of positive tumor cells. LOH at 1p was seen in 2 of 5 (40%) informative cases of anaplastic carcinoma (2 of 2 at D1S162 and 1 of 2 at D1S165) and in 2 of 11 (18%) informative cases of follicular carcinoma (2 of 7 at D1S243, 2 of 7 at D1S165, and 1 of 6 at D1S162). One anaplastic (20%) and two follicular carcinomas (14%) had LOH in at least two of the 1p loci analyzed. None of the adenomas and papillary carcinomas had LOH at these loci. LOH at 17p and 11q13 were infrequent. Ki-67 LI was 1.4, 7, 16, and 65% in adenomas, papillary, follicular, and anaplastic carcinomas, respectively. Allelic loss at 1p may occur in aggressive types of thyroid carcinoma and may be a marker of poor prognosis. LOH at 1p may represent a late genetic event in thyroid carcinogenesis. LOH at 17p and 11q13 (MEN gene locus) is uncommon in thyroid neoplasms.