肝癌中具有高突变率位于染色体17p13.3区的新报癌基因

目的：以往研究表明肝癌中染色体17p13.3区有高频率的杂合性缺失，其最小杂合性缺失范围已被确定在D17S643至D17S1574位点间，而且其中的D17S926位点有最高的杂合性缺失率，含有该位点的基因组克隆P579已被测序分析，在P579范围共有13个新基因，这里报告其中的一个新基因（命名为肝癌抑癌基因1，HCCS1）的克隆和特性研究结果。方法：利用直接杂交筛选方法获得基因组克隆P579中的基因克隆，根据HCCS1基因克隆的cDNA序列与基因组序列进行比较确定基因的外显子与内含子，应用RT－PCR扩增组织中的HCCS1基因，序列测定检查突变，应用免疫组化检测HCCS1在组织中的表达，应用克隆形成试验和裸鼠成瘤试验检测HCCS1的生物学功能。结果：HCCS1有18个外显子，cDNA全长约2．0kb，蛋白产物定位于线粒体，HCCS1在肝癌细胞中有高频率的突变，免疫组化检测表明HCCS1在癌旁组织的表达明显高于癌组织，HCCS1转染肝癌细胞明显抑制其克隆的形成及在裸鼠体内的成瘤，结论：上述发现表明HCCS1具有肝癌抑癌基因的作用。     

肝癌相关新基因HC6的全长cDNA克隆及分析

目的：染色体17p13.3区域内多态性位点D17S926是肝细胞肝癌（HCC）杂合性缺失热点,PAC579克隆含有D17S926位点,本实验目的在于从PAC579克隆中寻找与肝癌相关的表达序列（ESTs),对有意义的EST片段克隆其全长cDNA。方法：根据PAC579克隆中现有的9个代表新基因的 EST序列设计引物,对正常人肝cDNA文库作多聚酶链式反应（PCR）扩增检测,确定在肝组织中表达的EST,然后采用Southern杂交检测肝组织中表达的EST在27对肝癌和癌旁标本中杂合性生缺失（LOH）频率,选择缺失频率最高的EST克隆其全长cDNA,Nothern杂交验证后测序并作进一步分析。结果：PAC579现有9个代表新基因的EST中有3个在肝组织中表达,其中EST6有肝癌中LOH频率高达54．6％（6／11）,通过PACE－PCR方法,得到约1．8kb全长cDNA克隆,与Northern杂交结果一致,结构及同源性分析显示该基因是一新基因,编码一个包含134个氨基酸,分子量约为14．7kD的蛋白质,另外发现碱基序列313－592属于ALu同源序列,重新命名为肝癌相关基因6（HC6）。结论：通过定位克隆方法从肝癌杂合性缺失热点得到一个新基因HC6,该基因与肝癌的关系有待进一步研究。     

鼻咽癌染色体11q13等位基因杂合性缺失的研究

目的：对鼻咽癌中染色体11q13上的4个位点进行微卫星多态性分析,明确这些位点染色体位基因杂合性丢失的情况。方法：采用显微切割的方法获取较纯的肿瘤组织,然后用PCR的方法以PYGM、D11S4946、D11S449和INT－2为引物,对38例鼻咽癌进行微卫生序列分析。结果38例鼻咽癌组织中,至少有一个位点出现杂合性缺失者36例,占94．7％。其中D11S4946杂合性缺失的频率最高,占78．8％（26／33）,其余的引物分别为：INT－2占51．5％（17／33）,PYGM占45．5％（15／33）,D11S449占45．7％（16／35）。结论鼻咽癌染色体11q13区发生高频率杂合性缺失,提示缺失区域可能存在与鼻咽癌发生有关的抑癌基因。     

肝癌染色体17p13.3区的杂合性缺失分析及缺失区连续克隆群的构建

目的　检测原发性肝癌在染色体 17p13.3区的杂合性缺失状况 ,确定其共同缺失范围和最小热点缺失范围 ,并获得缺失范围内基因组克隆和构建连续克隆群。方法　应用Southern杂交分析VNTR(variablenumberoftandemrepeat,VNTR)和RFLP标志在肝癌中杂合性缺失 (LOH)状况。应用PCR扩增微卫星标志 ,变性聚丙烯酰胺凝胶电泳分析各个微卫星标志的LOH状况。以微卫星标志为引物 ,经过 3轮PCR筛选阳性基因组克隆。通过检测各位点标志对基因组克隆的反应 ,构建连续克隆群。结果　检测了 5 4份原发性肝癌样品在染色体 17p13.3区 16个位点标志和染色体 17p13.1区的p5 3基因的TP5 3位点标志的LOH情况 ,发现从D17S5位点至D17S34位点间的各个标志都有较高LOH ,频率 >6 3%。而从D17S5位点起、近着丝粒方向的 3个标志LOH率都较低或无LOH。染色体17p13.1的TP5 3标志只有 31%的LOH ,低于染色体 17p13.3区的D17S5至D17S34位点间各标志的LOH率。有 2例肝癌样品在近端粒的D17S34、D17S186 6位点和近着丝粒的D17S5、D17S15 74位点均无LOH ,但在D17S849至D17S15 74间的各位点上均呈LOH或为纯合子。在缺失范围内 ,共筛选了 18个位点的基因组克隆 ,获得了相对应的阳性基因组克隆 ,经过检测各位点对基因组克隆的反应性 ,构建了覆盖 9个标     

乳腺浸润性导管癌染色体1p36杂合性缺失的初步研究

目的 探讨染色体1p36可能存在的与非特殊类型乳腺浸润性导管癌发生、发展有关的肿瘤抑制基因,为发现和定位肿瘤抑制基因提供线索和热点位点.方法 选取1号染色体8个微卫星多态位点标志物,采用新鲜和石蜡组织基因组DNA抽提-PCR扩增-变性聚丙烯酰胺凝胶垂直电泳-银染法-全自动凝胶成像系统分析,检测80例浸润性导管癌及癌旁正常组织基因组DNA的杂合性缺失（LOH）频率.应用x2检验对实验结果进行综合分析.结果 80例浸润性导管癌中有45例（56.3％）至少在一个位点出现LOH,其中D1S1310微卫星位点频率最高,为35.7％（25/70）.结论 乳腺浸润性导管癌染色体1p36发生高频率LOH,提示1p36.23 ～ 33区间可能存在与乳腺癌发生、发展有关的抑癌基因.     

人膀胱移行细胞癌染色体9p21.3-9p23杂合性缺失作图

目的　研究并确定人膀胱移行细胞癌染色体 9p2 1.3 -9p2 3区域杂合性缺失发生率和最小缺失区域 ,为寻找与克隆膀胱移行细胞癌相关的抑癌基因提供线索。方法　选取 7个微卫星多态性标记 (其中 6个位于 9p2 1.3 -9p2 3 ,另 1个位于 9q3 4作为对照 ) ,对 2 4例膀胱移行细胞癌组织及其对应的外周血淋巴细胞进行核素标记的聚合酶链反应和聚丙烯酰胺变性凝胶电泳。分析 9p2 1.3 -9p2 3区各微卫星位点杂合性缺失的发生情况及其与病理分期分级的关系。 结果　 2 4例膀胱癌中的 2 0例 (83 .3 % )存在至少 1个微卫星位点的杂合性缺失。在 9p2 1.3 -9p2 3区域的 6个位点中 ,杂合性缺失率最高的为 9p2 3的D9S2 85 ,达66.7%(8/12 ) ;其次为 9p2 1的D9S1846,达 5 4.5 % (6/11)。位于 9q3 4.12的D9S182 1的杂合性缺失率为 5 4.5 % (6/11) ,而且在发生杂合性缺失的 6个病例中 ,有 5个被证明为部分染色体片段的缺失。结论　在 9p2 1.3 -9p2 3区域 ,可能至少存在 2个与膀胱移行细胞癌相关的候选抑癌基因 ,分别位于D 9S2 85和D9S1846附近     

肝细胞癌基因组5q13.2与8p23.1位点的杂合性缺失分析

[目的]分析肝细胞癌(HCC)中5q13.2和8p23.1位点的杂合性缺失(LOH)情况,以探索新的抑癌基因.[方法]应用聚合酶链反应—非变性聚丙烯酰胺凝胶电泳法对83例HCC患者基因组DNA中的5q13.2和8p23.1位点的LOH进行检测,并将其与临床参数进行关联分析.[结果] 83例HCC患者基因组中,36.1％(30例)存在5q13.2位点LOH,在该位点存在OCLN、SMN2、SERF1A、SMN1、NAIP和GTF2H2基因;8p23.1的D8S503和D8S1130位点分别存在68.4％和61.3％的LOH.[结论]HCC患者基因组中存在较高频率的5q13.2和8p23.1位点LOH,这些位点中可能存在与HCC发生密切相关的基因.     

肺癌相关基因HLCDG1的克隆和表达分析

背景与目的：比较基因组杂交和微卫星多态性位点全基因组扫描结果显示肺癌患者在染色体3p、5q、6q、9p、10q、llp、13q、17p、19p等区域存在高频率的杂合性缺失,提示可能有多个未知的易感基因或抑癌基因与肺癌的发生、发展相关。本研究选用在mRNA差异显示研究中获得的在肺癌组织中表达下调且代表新基因的表达序列标签(expressed sequence tag,EST)LXDDl为进一步研究对象,克隆其全长cDNA。方法：采用Northern杂交验证LXDDl在肺癌中的表达差异。并用MTN(Multiple Tissue Northern Blots^TM)膜检测其在正常组织中的表达及其所代表基因的转录本大小;克隆其全长cDNA,并利用生物信息学对该序列进行初步分析;用差异RT-PCR检测新基因在肺癌组织、配对癌旁非癌组织、肺癌细胞系和其它肿瘤细胞系中的表达。结果：成功地克隆了一个在肺癌中表达下调的新基因。HLCDGl(human lung carcinoma deleted gene 1),GenBank登录号为AF447582,全长cDNA为3．113kb,预测其开放阅读框编码一个含166个氨基酸的跨膜蛋白质。通过电子-聚合酶链反应(electric-polymerase chain reaction,e-PCR)将该基因定位于5q33。结论：HLCDGl基因是一个在肺癌中表达下调的新基因。这提示HLCDGl可能与肺癌的发生、发展相关。     

染色体17p13.3肿瘤杂合性缺失区域内外显子的分离

目的 在染色体１７ｐ１３．３杂合性缺失区域内进行表达的分离。方法 采用外显子搏获法对位于１７ｐ１３．３杂合性缺失区域内的ＢＡＣ基因组克隆进行外显子的分离。结果 在获得的克隆中,４个克隆为已知基因的外显子,另４个史隆属于３个上显子（２个克隆中的外显子片段序列一致）。结论 在染色体１７ｐ１３．３杂合性缺失区域内获得了一些表达序列。     

肝癌抑制基因-1与转运功能相关的451 bp序列区的确定

背景与目的:肝癌抑制基因-1(HCCS1)是一种潜在的肝癌抑制基因,并且在细胞内蛋白分拣运输中也发挥着重要作用,其抑癌作用有可能是通过其蛋白转运的功能而发挥的,本文以寻找HCCS1序列中与转运相关的最小功能序列区域为目的.方法:通过亚克隆技术,构建以pEGFP-C2为载体的含不同长度HCCS1cDNA片段的亚克隆,将构建的亚克隆转染子宫颈癌HeLa细胞,通过免疫荧光共聚焦显微镜观察不同长度HCCS1蛋白的分布,以及与6-磷酸甘露糖受体(M6PR)的共定位.结果:成功构建了以pEGFP-C2为载体的10个含有不同长度HCCS1片段的亚克隆;HCCS1cDNA从3'端向5'端逐渐缺失的片段中:2 100 bp片段至778 bp片段编码的不同长度HCCS1蛋白呈颗粒状分布于核周的胞质内,其中2 100 bp片段至1 571 bp片段编码的不同长度HCCS1蛋白均呈颗粒状、极性分布于核周的胞质内,且与M6PR有共定位;而1 120 bp片段至778 bp片段编码的不同长度HCCS1蛋白虽然也呈颗粒状分布于核周,但极性分布消失,且与M6PR共定位消失;HCCS1cDNA片段678 bp片段至339 bp片段编码的不同长度HCCS1蛋白呈散点状弥散分布于胞质以及胞核内.结论:确定了HCCS1cDNA 1 571 bp片段的3'端451 bp的序列为与HCCS1转运功能相关的最小区域范围.     

A novel growth suppressor gene on chromosome 17p13.3 with a high frequency of mutation in human hepatocellular carcinoma

Previous studies have shown that there is a high frequency of loss of heterozygosity (LOH) on chromosome 17p13.3 in hepatocellular carcinoma [HCC (M. Fujimori et al., Cancer Res., 51: 89-93, 1991; H. Nagai et al., Oncogene, 14: 2927-2933, 1997; V. Boige et al., Cancer Res., 57: 1986-1990, 1997; Z. Piao et al., Int. J. Cancer, 75: 29-33, 1998; and B. Charroux et al., J. Cell Biol., 148: 1177-1186, 2000)]. The minimum region of LOH on chromosome 17p13.3 in HCC has been defined within the region between D17S643 and D17S1574. Moreover, D17S926 in the minimum region of LOH has the highest frequency of LOH, and its sequencing analysis has been accomplished. In this region, 6 of 13 novel genes have been characterized (X. Zhao, D. Wan, M. He, Yu. Ye, Yi. He, L. Han, M. Guo, Y. Huang, W. Qin, M-W. Wang, W. Chong, J. Chen, L. Zhang, N. Yang, B. Xu, M. Wu, L. Zuo, and J. Gu. A high frequency LOH region on chromosome 17p13.3 in human HCC with densely clustered genes identified, submitted for publication). Here we describe the cloning and characterization of one of these novel genes, designated HCC suppressor 1 (HCCS1), located at this region. HCCS1 had 18 exons, and its full-length cDNA was 2.0 kb. The protein expression product of HCCS1 was located in mitochondria. HCCS1 had a high frequency of mutations in HCC samples, whereas no alteration has been found in matched noncancerous liver tissues. Immunohistochemistry revealed a significantly higher expression of HCCS1 in the noncancerous liver tissues (33 of 35 samples) than in the HCC samples (2 of 35 samples). Transfection of HCCS1 cDNA into the HCC cell line remarkably reduced the efficiency of its colony formation and inhibited tumor growth in nude mice. Taken together, these findings strongly suggest a potential role of HCCS1 as a HCC putative suppressor gene.     

肝癌染色体17p13.3区的杂合性缺失分析及缺失区连续克隆群？…

目的 检测原发性肝癌在染色体１７ｐ１３．３区的杂合性缺失状况,确定其共同缺失范围和最小热点缺失范围,并获得缺失范围内基因组克隆和构建连续克隆群。方法 应用Ｓｏｕｔｈｅｍ杂交分析ＶＮＴＲ（ｖａｒｉａｂｌｅ ｎｕｍｂｅｒ ｏｆ ｔａｎｄｅｍ ｒｅｐｅａｔ,ＶＮＴＲ）和ＲＦＬＰ标志在肝癌中杂合性缺失（ＬＯＨ）状况。应用ＰＣＲ扩增微卫星标志,变性聚丙烯酰胺凝胶电泳分析各个微卫星标志的ＬＯＨ状况。以微卫星标     

The minimum LOH region defined on chromosome 17p13.3 in human hepatocellular carcinoma with gene content analysis

Hepatocellular carcinoma (HCC) is one of the most common human cancers in Asia. Previous studies have shown that in addition to aberrations of the p53 gene on chromosome 17p13.1, other gene(s) on chromosome 17p13.3 may also play a role in HCC. To detect the status of loss of heterozygosity (LOH) in HCC and to determine the minimum region of LOH on 17p13.3, we analyzed 22 paired HCC and non-cancerous liver samples with 14 polymorphic markers plus TP53 (p53 gene) as a comparison. The data revealed a high level of LOH (>68%) in a minimum region between D17S1866 and D17S1574, spanning over a 1.5 Mb region. Genomic library screening using markers in the region has resulted in the isolation of a cluster of BAC/PAC clones. We created a physical map in this region. Using large-scale genome sequencing, gene annotation, cDNA screening, and exon trapping, we identified 17 known genes and 13 novel genes in the minimum region. The function of these genes was analyzed and the possibility of several putative tumor suppressor genes was discussed.     

PTEN/MMAC1 Mutation and Frequent Loss of Heterozygosity Identified in Chromosome 10q in a Subset of Hepatocellular Carcinomas

Frequent allelic losses on chromosome 10q have been reported in several types of cancers, suggesting the presence of a putative tumor suppressor gene(s) on the chromosomal arm. We examined loss of heterozygosity (LOH) on chromosome 10q in 37 hepatocellular carcinomas (HCC) using eleven dinucleotide microsatellite markers, spanning the entire chromosome arm of 10q. Twelve (32%) out of 37 informative cases showed allelic losses of at least one locus on 10q and eight tumors showed a partial deletion of 10q. Analysis of deletion mapping of these eight cases identified two commonly deleted regions within the distal part of 10q (10q24-q26), a 20-cM interval flanked by D10S597 and D10S216 and a 24-cM interval flanked by D10S216 and D10S590. Moreover, we detected a somatic missense mutation (Met→Val) of a candidate tumor suppressor gene PTEN/MMAC1, located at 10q23.3, in one HCC with LOH of 10q. Our findings indicated the presence of putative tumor suppressor gene(s) in the distal region of 10q that might be involved in the development and progression of HCC. Inactivation of PTEN/MMAC1 gene located outside the commonly deleted region of 10q might also play an important role in a subset of HCCs.     

PTEN / MMAC1 mutation and frequent loss of heterozygosity identified in chromosome 10q in a subset of hepatocellular carcinomas.

Frequent allelic losses on chromosome 10q have been reported in several types of cancers, suggesting the presence of a putative tumor suppressor gene(s) on the chromosomal arm. We examined loss of heterozygosity (LOH) on chromosome 10q in 37 hepatocellular carcinomas (HCC) using eleven dinucleotide microsatellite markers, spanning the entire chromosome arm of 10q. Twelve (32%) out of 37 informative cases showed allelic losses of at least one locus on 10q and eight tumors showed a partial deletion of 10q. Analysis of deletion mapping of these eight cases identified two commonly deleted regions within the distal part of 10q (10q24-q26), a 20-cM interval flanked by D10S597 and D10S216 and a 24-cM interval flanked by D10S216 and D10S590. Moreover, we detected a somatic missense mutation (Met --> Val) of a candidate tumor suppressor gene PTEN / MMAC1, located at 10q23.3, in one HCC with LOH of 10q. Our findings indicated the presence of putative tumor suppressor gene(s) in the distal region of 10q that might be involved in the development and progression of HCC. Inactivation of PTEN / MMAC1 gene located outside the commonly deleted region of 10q might also play an important role in a subset of HCCs.     

Loss of heterozygosity on chromosome 10q23 and mutation of the phosphatase and tensin homolog deleted from chromosome 10 tumor suppressor gene in Korean hepatocellular carcinoma patients

Loss of heterozygosity (LOH) in the 10q23 chromosomal region was analyzed in 18 tissue samples from Korean hepatocellular carcinoma (HCC) patients. LOH at the phosphatase and tensin homolog deleted from chromosome 10 (PTEN) region (D10S215, AFMa086wg9 and D10S541) was found in 8 of the 18 (44.4%) HCCs. LOH (20%) and microsatellite instability (26.7%) were also frequently found at the D10S2177 locus, which is located on the telomere side of the PTEN region. LOH was found in other loci, such as AFM280we1 and D10S2281. The presence of LOH in regions other than the PTEN region on chromosome 10q23 suggested the presence of additional tumor suppressor gene(s). PTEN mutation was found in only a subset of HCCs: A single base insertion at the end of the 5'-end splice signal (AG-GUAAGUU) in intron 5 and a silent mutation in exon 6 (codon 188, CTG-Val to CTA). Our data collectively suggest that the genetic alterations of chromosome 10q23, including the PTEN gene, could be important in hepatocarcinogenesis in the Korean population.     

原发性肝癌8号和16号染色体杂合子丢失的研究

目的:分析人肝细胞肝癌(HCC)组织中染色体8和16部分染色体片段的杂合子丢失及与临床病理关系,初步筛选HCC相关的抑癌基因,为HCC的早期诊断、预后预警提供可能的新分子标记物.方法:应用聚合酶链反应-变性聚丙烯酰胺凝胶-银染法分析45例HCC组织标本中分别位于染色体8和16上的具有高度多态性微卫星位点的杂合性丢失(LOH)状态.结果:发生LOH的总频率为68.89％ (31/45),其中D16S511位点的LOH发生率最高为53.33％ (24/45),其次是D8S261( 39.02％,16/41)和D8S499(34.88％,15/43).结论:染色体16q23、8p22-21.3及8p12区域的LOH发生频率高,可能存在与HCC发生发展相关的新的抑癌基因,特定位点的遗传变异可能与HBV感染、临床病理恶性程度等预后因素相关.     

Frequent allelic loss on chromosome 9 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignancy worldwide and highly associated with chronic virus-B or -C infection and cirrhosis. Molecular studies have shown high frequency of loss of heterozygosity (LOH) in some specific chromosome regions, but LOH on chromosome 9 in HCC has not been thoroughly investigated. In our investigation of chromosome 9 with 19 polymerase-chain-reaction (PCR)-based polymorphic microsatellite markers, 30 of 48 HCC tissue samples (63%) had LOH, and a distinct common deletion region and a region of loss were identified. The first region was located at the 9p21 region and the minimal deletion region was located between loci D9S1747 and D9S1748. This is a region of approximately 200 kb which includes the p16 tumor-suppressor gene. A region of loss was located on 9p13 to 9q33. The putative tumor-suppressor gene for nevoid-basal-cell-carcinoma syndrome (NBCCS) at 9q22.3 resides within this region. In addition to LOH, 4 HCC cases showed possible homozygous deletions at 9p21 with markers D9S1748, D9S1752 and D9S171 by multiplex PCR analysis. In 3 cases, the minimal region of possible homozygous deletion was approximately 300 kb and was defined between markers D9S1747 and D9S1752. Since this deletion region includes both the p15 and the p16 tumor-suppressor genes, these genes were possibly inactivated by homozygous deletion in HCC. In addition, a second region of possible homozygous deletion was present on the centromeric side of 9p21. However, these changes are not associated with age, gender, size or tumor-cell differentiation. Our data also suggest that inactivation of the p16 and the p15 genes and the possibility of other unknown tumor-suppressor genes located on these defined deleted regions of chromosome 9 may be involved in the pathogenesis of HCC.