Subchromosomal Mapping of a Putative Transformation Suppressor Gene on Human Chromosome 1

We previously reported that the introduction of a normal human chromosome 1 via microcell-mediated chromosome transfer suppressed the transformed phenotypes, including anchorage-independent growth, of Kirsten murine sarcoma virus-transformed NIH3T3 (DT) cells. Soft-agar clones derived from DT-#1 cells (DT cells with an intact transferred human chromosome 1) exclusively failed to retain an intact form of this chromosome. Thus, a gene(s) with a suppressive activity on this chromosome had probably been lost. We therefore attempted to identify a commonly deleted region on human chromosome 1 in these soft-agar clones. Although eight of the 9 soft-agar clones examined still contained regions on this chromosome, to a greater or lesser degree, four loci on 1q21 and 1q23-q24 were commonly lost in all of them. Furthermore, the soft-agar clones had growth properties similar to those of DT cells. Thus, chromosome and DNA analyses suggested that human 1q21 and/or 1q23-q24 carries a transformation suppressor gene(s) which controls the transformed phenotypes of DT cells.     

Loss of 22q Chromosome is Related to Glioma Progression and Loss of 10q

Summary Loss of heterozygosity (LOH) of chromosome 22q has been investigated in 160 gliomas. LOH at one or more microsatellite increased with increasing grade of the tumor (P < 0.01). LOH22q was more frequent in astrocytic tumors (37%) compared to mixed or oligodendroglial tumors (21%) (P = 0.02). LOH22q was correlated to 10q loss but not to 1p or 9p loss. Taken together, these data suggest that LOH22q is an alteration associated with malignant progression of gliomas.     

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     

Deletion Mapping of Chromosome 1p and 22q in Pheochromocytoma

To identify the localization of tumor suppressor genes, 22 pheochromocytomas (9 hereditary and 13 sporadic) were examined for loss of heterozygosity (LOH) on the short arm of chromosome 1 and on the long arm of chromosome 22 by using 11 polymorphic DNA markers on each chromosome arm. LOH on 1p was observed in 12 of 22 informative cases (55%) and on 22q in 8 of 20 informative cases (40%). There was no significant difference in the frequency of LOH on 1p or 22q between hereditary and sporadic cases. We could localize the commonly deleted regions as distal to D1S73 and proximal to D1S63 on 1p and distal to D22S24 and proximal to D22S1 on 22q. In addition, the relationship between LOH on 1p and 22q was studied in 20 pheochromocytomas which were informative for probes on both chromosome arms. Of eight tumors that showed LOH on 22q, allelic loss on 1p was also detected in seven. Thus, LOH on 22q was correlated significantly with LOH on 1p ( P = 0.0249; Fisher's exact test). These results suggest that inactivation of multiple tumor suppressor genes may be required for development and progression of hereditary and non-hereditary pheochromocytoma.     

Detailed Deletion Mapping of Chromosome 9p21-22 in Nasopharyngeal Carcinoma

Previous studies have showed that Epstein-Barr virus (EBV) infection, certain environmental factors and genetic factors were found to be closely associated with nasopharyngeal carcinoma. The rates of NPC in southern China and southeast Asia are 25 times higher than that of in western countries. The statistic analysis revealed 5%-10% NPC patients have family history, there, genetic susceptibility might be an important factor in the pathogenesis of NPC. Unfortunately the alterations of com…     

A Novel Renal Carcinoma Predisposing Gene of the Nihon Rat Maps on Chromosome 10

A novel rat model of hereditary renal cell carcinoma (RC) was found in a rat colony of the Spra-gue-Dawley (SD) strain in Japan, and named the "Nihon" rat in 2000. This study was designed to map the RC susceptibility gene in the Nihon rat using 113 backcross annuals. Our present data clearly show that the Nihon gene is genetically linked to interleukin-3 (IL3 ) gene (χ²=93.6, Lod score=25.16), lethal (2) giant larvae (LLGL1 ) locus (χ²=109.0, Lod score=31.56) and myosin heavy chain, embryonic skeletal muscle (MYHSE ) gene (χ²=90.6, Lod score=23.87), which are located on the distal part of rat chromosome 10. The order of the genes is the Eker (Tsc2 ) gene (located on the proximal part of rat chromosome 10; human chromosome 16p 13.3)–21.3 cM– IL3 gene (human 5q23-31)–4.4 cM– Nihon gene–0.9 cM–LLGL1 locus (human 17p11.2)-4.4 cM– MYHSE gene (human 17pl3.1). We also detected loss of the wild-type allele at the MYHSE locus, fitting Knudson's "two hit" model. Thus, the Nihon rat should have a mutation of a novel tumor suppressor gene related to renal carcinogenesis.     

Normal Human Chromosome 1 Carries Suppressor Activity for Various Phenotypes of a Kirsten Murine Sarcoma Virus-transformed NIH/3T3 Cell Line

In order to identify chromosomes that carry putative tumor-suppressor genes for the various phenotypes of Kirsten sarcoma virus-transformed NIH/3T3 (DT) cells, we performed microcell-mediated chromosome transfer into DT cells. We first isolated mouse A9 clones, containing a single human chromosome 1, 11 or 12 tagged with pSV2- neo plasmid DNA. Then, chromosome 1, 11 or 12 was transferred from the A9 clones into DT cells by microcell fusion. The growth rate, colony-forming ability in soft agar and tumorigenicity of the DT cells were controlled by chromosome 1, but not by chromosome 11 or 12, indicating that normal human chromosome 1 carries a putative tumor-suppressor gene(s) that affects various transformed phenotypes of DT cells.     

前列腺肿瘤高密度allelotype初步分析

目的：探讨原发性前列腺癌及高级别前列腺上皮内肿瘤（PIN）22条常染色体等位基因杂合性缺失及其意义采用显微切割技术提取前列腺癌及高级别前列腺上皮内肿瘤各10例的DNA，然后采用PCR及微卫星多态性技术，对22条常染体上的382个微卫星标志位点进行高密度allelotype分析。结果：10例原发性前列腺癌在染色体1p,1q,2p,2q,6q,8p,8q,10q,11q,13q,16p,17p等部位存在高频杂合性缺失（LOH），前列腺上皮内肿瘤则在染色体2p,2q,6q,8p,10q,1q等区易检测到LOH.结论：前列腺癌患者2q14,8p12-21,10q23-24,13q14等区域存在高频的LOH，位于这些区域的抑癌基因在前列腺癌发生，发展过程中起着重要作用。     

胶质细胞瘤染色体1p杂合性缺失：14例研究分析

背景与目的:少突胶质细胞瘤是胶质瘤中的一种独立类型,近年来的研究显示少突胶质细胞瘤存在着不同于其它胶质瘤类型的分子遗传学改变。其中最显著的就是在大多数少突胶质细胞瘤中出现染色质1p和19q的缺失。同时还发现,有染色质1p及19q缺失病例,对化疗药物敏感性增强,生存期延长,反之预后差。本研究旨在研究胶质细胞瘤染色体1P杂合性缺失的特点。方法:本文使用荧光原位杂交(FISH)技术检测了我院脑外科手术的7例少突胶质细胞瘤及7例其他颅内肿瘤病例的染色体1p。结果:7例少突胶质细胞瘤中4例有1p杂合性缺失,而其他颅内胶质瘤病例中仅有2例出现1p杂合性的缺失。另外1p杂合性缺失的4例病变均为单侧,3例为颞叶,1例为额叶;肿瘤级别上3例为少突胶质细胞瘤(WHOⅡ级),1例为间变性少突胶质细胞瘤(WHOⅢ级)。结论:本研究提示1p杂合性缺失的发生率在少突胶质细胞瘤(4/7)比其它类型胶质瘤(2/7)为高。     

Aggressive oligodendroglioma predicted by chromosome 10 restriction fragment length polymorphism analysis. Case study

Summary Oligodendrogliomas are indolent brain tumors with mean postoperative survival of about 5 years. However, the range of postoperative survivals is wide, suggesting that these tumors are heterogeneous in their biologic behavior. Using restriction fragment length polymorphism (RFLP) analysis, we studied a case of an oligodendroglioma with loss of chromosome 10 sequences, a finding that has only been reported in glioblastoma multiforme and anaplastic astrocytomas. Four and a half months after the initial surgery the patient returned with a recurrent tumor having classic radiologic and pathologic features of glioblastoma multiforme. Loss of chromosome 10 alleles in oligodendroglioma may be predictive of aggressive biologic behavior, even in the absence of recognized histopathologic characteristics of anaplasia, and may enable us to select more appropriate treatments for this group of patients.     

Three New Regions on Chromosome 17p13.3 Distal to p53 with Possible Tumor Suppressor Gene Involvement in Lung Cancer

We investigated loss of heterozygosity (LOH) at the distal portion of the p53 gene on the short arm of chromosome 17 in lung cancers in order to search for new tumor suppressor genes. The roles of the putative genes were also studied in terms of pathological features. One hundred and forty-five resected non-small cell lung cancers were examined for LOH using 11 markers mapped on, and distal to the p53 locus, and deletion maps were constructed. Four commonly deleted regions were found: one from TP53 to ENO3, where the p53 gene resides, and three others from ENO3 to D17S1566, D17S379 to D17S1574 and distal to ABR, with LOH frequencies almost the same as, or higher than, at the TP53 locus. Examination of the relationship between LOH of the latter three regions and histopathological parameters of adenocarcinomas (genetically negative for p53 mutation) revealed allelic losses on D17S379 to be associated with advanced lesions, while D17S513 was more frequently deleted in poorly differentiated tumors. These results indicate that new tumor suppressor gene(s) may reside on these three distinctly deleted regions on chromosome 17p13.3 distal to the p53 gene in lung cancer, with possible roles in progression and differentiation of adenocarcinomas.     

Rare-type Mutations of MMAC1 Tumor Suppressor Gene in Human Glioma Cell Lines and Their Tumors of Origin

A total of 10 glioma cell lines were examined to evaluate the status of the MMAC1 gene, a candidate tumor suppressor gene. Six cell lines showed mutations with presumed loss of heterozygosity and 1 cell line showed no mRNA expression. The 6 mutations consisted of 3 3-bp deletions (codons 17, 101 or 199), 1 missense mutation (codon 252) and 2 truncation mutations (1 nonsense mutation at codon 233 and 1 2-bp insertion at codon 241). Among them, the 3-bp deletions, which are a rare type of mutation in MMAC1 gene, were located in the N-terminal half (codons 1–212) of the coding region, which is considered important in MMAC1 function. The missense mutation was located unusually in the C-terminal half (codons 212–403), but it was in a small region in which some other reported missense mutations are clustered. Thus, these 4 mutations were suggested to have functional effects on the MMAC1 activity, like the other 2 mutations with predicted protein truncations. By sequence analysis of cDNA clones, we confirmed that all the mutations including these 4 rare ones were in the MMAC1 gene, not in the PTH2 pseudogene. In 2 cases, we also examined the primary glioma tissues from which the cell lines had been derived and found the same mutations as in the cell lines in both cases. This suggested that the mutations in these cell lines were derived from the primary glioma tissues, but not from artifacts arising during long-term in vitro cultivation.     

Chromosome alterations and E-cadherin gene mutations in human lobular breast cancer

We have studied a set of 40 human lobular breast cancers for loss of heterozygosity (LOH) at various chromosome locations and for mutations in the coding region plus flanking intron sequences of the E-cadherin gene. We found a high frequency of LOH (100%, 31/31) at 16q21-q22.1. A significantly higher level of LOH was detected in ductal breast tumours at chromosome arms 1p, 3p, 9p, 11q, 13q and 18q compared to lobular breast tumours. Furthermore, we found a significant association between LOH at 16q containing the E-cadherin locus and lobular histological type. Six different somatic mutations were detected in the E-cadherin gene, of which three were insertions, two deletions and one splice site mutation. Mutations were found in combination with LOH of the wild type E-cadherin locus and loss of or reduced E-cadherin expression detected by immunohistochemistry. The mutations described here have not previously been reported. We compared LOH at different chromosome regions with E-cadherin gene mutations and found a significant association between LOH at 13q and E-cadherin gene mutations. A significant association was also detected between LOH at 13q and LOH at 7q and 11q. Moreover, we found a significant association between LOH at 3p and high S phase, LOH at 9p and low ER and PgR content, LOH at 17p and aneuploidy. We conclude that LOH at 16q is the most frequent chromosome alteration and E-cadherin is a typical tumour suppressor gene in lobular breast cancer.     

胃癌8号染色体等位基因杂合性缺失及其临床相关性研究

近年来，人们认为染色体上等位基因缺失或失活是肿瘤形成和演进的一个重要机制。应用从人类染色体上分离出的克隆──Ｄ８Ｓ７作为探针，采用ＳｏｕｔｈｅｒｎＢｌｏｔ方法检测了２０例胃癌病员的癌组织及其相应的癌旁组织基因组ＤＮＡ８号染色体等位基因杂合性丢失（ＬＯＨ），结果发现，２５％（５／２０）的胃癌组织以及１５％（３／２０）的癌旁组织中存在染色体８Ｐ上等位基因缺失或丢失，早期和晚期胃癌均存在这种分子遗传学改变，提示人类８号染色体短臂上存在肿瘤抑制基因，此基因正常等位基因缺失或丢失参与胃粘膜细胞癌变及其胃癌的演化和进程。     

人脑胶质瘤细胞中IL-6mRNA的表达及意义

目的观察白细胞介素－６（ＩＬ－６）ｍＲＮＡ在人脑胶质瘤细胞中的表达。方法采用逆转录聚合酶链反应（ＲＴ－ＰＣＲ）方法对２０例新鲜人脑胶质瘤标本进行了检测。结果２０例标本中有１７例表达ＩＬ－６ｍＲＮＡ，恶性程度高的肿瘤中ＩＬ－６ｍＲＮＡ的表达量明显高于恶性程度低的肿瘤。结论脑胶质瘤细胞中ＩＬ－６基因的表达与脑胶质瘤的发生发展有关。     

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.     

人脑胶质瘤中PTEN基因突变和蛋白表达的研究

目的 :研究人脑胶质瘤中PTEN蛋白表达和PTEN基因突变情况。方法 :应用免疫组化技术和聚合酶链反应 -单链构象多态性分析 (PCR SSCP)技术 ,检测 10 2例人脑胶质瘤中PTEN蛋白表达及PTEN基因突变。结果 :PTEN阳性染色主要定位于细胞质中。 10 2例中PTEN蛋白表达 5 5 / 10 2(5 3 9% ) ,高分化组 (Ⅰ级和Ⅱ级 ) 32 / 39(82 1% )与低分化组 (Ⅲ级和Ⅳ级 ) 2 3/ 6 3(36 5 % )之间差异有极显著意义 ,P <0 0 1;4 2例胶质母细胞瘤中共有 11例发生PTEN基因突变 ,突变率为 2 6 % (11/ 4 2 ) ;6 0例其他胶质瘤中仅 1例发生突变 ,胶质母细胞瘤突变率显著高于其他胶质瘤 ,χ2 =11 6 2 ,P <0 0 1。结论 :PTEN基因突变或缺失在人脑胶质瘤的发生发展中起重要作用 ,与肿瘤恶性分化程度密切相关     

Loss of Heterozygosity on Chromosome 13q: Suggestion of a Candidate Tumor Suppressor Gene in Sporadic Breast Cancer

In order to corroborate the assumption that a candidate tumor suppressor gene is located on chromosome 13q21-22 between D13S1313 and D13S162, we examined loss of heterozygosity of six microsatellite markers in this region in 98 sporadic breast tumors. Our data demonstrate that loss of heterozygosity at 13q21-22 is not solely caused by genetic changes in BRCA2, but is also attributable to another gene in this region. There is strong indication of a new tumor suppressor gene located between D13S1313 and D13S162, most probably adjacent to D13S1308, which could play a role in sporadic breast cancer.     

Mapping of a Breast Cancer Tumor Suppressor Gene Locus to a 4-cM Interval on Chromosome 18q21

DPC4 and DCC , putative tumor suppressor genes implicated in the genesis of several types of human cancer, lie on the long arm of human chromosome IS. We examined 200 primary breast cancers for allelic losses on chromosome IS, using 15 microsatellite markers distributed along the long arm. Allelic loss was detected most frequently (29–30%) at loci mapped to 18q21. Deletion mapping of the 34 tumors showing partial or interstitial deletions identified a commonly deleted region within the 4-cM interval flanked by D18S474 and D18S487 at 18q21.1-q21.3. Although this interval included the DPC4 and DCC genes, we excluded DPC4 from candidacy when polymerase chain reaction-single-strand conformation polymorphism analysis of each exon failed to detect abnormalities in any of the 54 breast cancers that exhibited loss of heterozygosity involving 18q. Allelic loss on 18q was found more frequently in tumors of the solid tubular histological type (24 of 55, 44%) than in other types (24 of 113, 21%) ( P= 0.0049). The results suggest that a tumor suppressor gene located within the 4-cM region at 18q21, either DCC or another gene not yet identified, may play a role in the development of some sporadic breast cancers, particularly those of the solid tubular type.