肿瘤抑制基因PTEN在胃癌中的表达及其临床意义

目的　研究第 10号染色体同源丢失性磷酸酶 -张力蛋白基因 (phosphatase and tensin homology delet-ed on chrom osom e ten,PTEN)在胃癌组织中的表达水平以及与生物学行为的关系和对预后评价的意义。方法　以免疫组化方法检测 10 6例胃癌组织中 PTEN蛋白的表达水平。结果　 10 6例胃癌中 ,PTEN表达阳性 72例(6 7.9% ) ,其中弱阳性 15例 (14 .1% ) ,强阳性 5 7例 (5 3.8% )。在胃癌组织中 ,PTEN蛋白水平与胃壁浸润深度、组织分化类型 ,临床分期等相关 (P<0 .0 5 ) ;单变量生存分析 ,PTEN蛋白阳性表达组 3、5年生存率分别为 4 8.6 %、37.5 % ,高于阴性表达组 32 .4 % ,11.8% ,但经 L og- rank时序检验示差异无显著性 (P=0 .0 72 1)。 Cox回归模型多变量分析显示 ,PTEN不是一个独立的预后指标。结论　 PTEN与胃癌的发生发展有关 ,但不是判断胃癌预后的一个独立指标     

PCR-SSCP分析法检测胃癌中p27基因突变

目的　对 5例早期胃癌组织和 32例进展期胃癌及其各自的正常胃粘膜组织 ,进行p2 7抑癌基因的突变检测。方法　应用聚合酶链式反应—单链构象多态性分析 (PCR SSCP)技术进行检测。结果　在早期胃癌组织中检出突变率为 2 0 .0 %( 1/5 ) ,在进展期胃癌组织中的突变率为 2 1.9%( 7/32 )。实验结果表明 ,p2 7基因在早期胃癌与进展期胃癌中均有较高突变频率 ,两者差异无显著性 ;p2 7基因突变在胃癌中与性别、年龄以及肿瘤的位置、组织分化程度、Borrmanm分期和有无淋巴结转移无关 ;p2 7基因外显子 1是该基因突变的集中区域 ,且以第 1-90密码子区域突变率最高 ,p2 7基因外显子 2突变率最低。结论　证实了p2 7基因突变发生于早期胃癌形成阶段 ,属于胃癌发生的早期事件。     

Mannose 6-Phosphate/Insulin-Like Growth Factor 2 Receptor, a Bona Fide Tumor Suppressor Gene or Just a Promising Candidate?

The mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R)³ is considereda candidate tumor suppressor gene. This hypothesis has been provoked by the identificationof loss of heterozygosity (LOH) at the M6P/IGF2R locus on chromosome 6q26 in breast andliver cancer, accompanied by point mutations in the remaining allele. Somatic mutations incoding region microsatellites have also been described in replication error positive (RER+)tumors of the gastrointestinal tract, endometrium and brain. These genetic data are compelling,but a tumor suppressor gene candidate has to meet functional as well as genetic criteria. Thisreview weighs the evidence and discusses the observations that are necessary to promoteM6P/IGF2R from candidate to bona fide tumor suppressor gene.     

A novel dimorphism in the human SRY gene: usefulness in human migration studies

A nucleotide polymorphism of C or T was detected at position 465 in the sex-determining region Y (SRY) gene. To evaluate the utility of this dimorphism in human population studies, the frequency and the frequency of the haplotype combined with the two polymorphic loci YAP and M9 were examined in a total of 130 unrelated Japanese and 130 unrelated German males. The T nucleotide was found in 24.6% (32/130) of the Japanese but not in any of the 130 German males. Accordingly, four of the eight possible combination haplotypes of SRY/YAP/M9 were identified in the Japanese population, but one of the four haplotypes comprising SRY(T) was absent in the German samples. This suggests that the C to T transition may be more recent than the YAP insertion or the M9 transversion and the change might have occurred in an ancestral Asian population. These results imply that the dimorphism at the SRY gene is one of the Y-linked markers useful for human population studies and also for ethnic identification of forensic samples. Received: 9 March 1999 / Accepted: 9 September 1999     

Androgen receptor gene mutation identified by PCR-SSCP and sequencing in 4 patients with complete androgen insensitivity syndrome

To study the genetic defect of the human androgen receptor (hAR) gene in the complete androgen insensitivity syndrome (CAIS), we amplified each of the eight exons by PCR in genomic DNA extracted from the paraffin blocks of the resected gonads. We analyzed using SSCP, and directly sequenced the abnormally shifted bands. Mutations were found in 4 cases of CAIS. Patient 1 carried a point mutation; a G to A transition in exon 7 resulted in a change from arginine to glutamine at codon 831. Patient 2 carried a point mutation; a C to T transition in exon 7 resulted in a change from arginine to stop at codon 831. Patient 3 carried a point mutation and deletion in exon 7. A point mutation was an A to G transition that caused a glutamine to be substituted for the asparagine present at codon 819. A deletion of a G at codon 820 resulted in a frameshift and consequently in the introduction of a premature stop at codon 821. Patient 4 carried a mutation in 5’ splice donor site of intron 7; a G to T transition might have caused an abnormal splicing of the exon 7. All of the mutations were found in exon 7. These mutations of hAR gene might be related to the pathogenesis of CAIS. Received: May 1999 / Accepted: 17 August 1999     

一种新的 GPⅡb基因540A缺失移码突变引起的血小板无力症

目的:为了明确1例血小板无力症患者发生的分子机制.方法:用40对引物对血小板无力症患者GPⅡ/皿a (αⅡbβ3)基因的45个外显子序列及其剪切点进行全长扩增,用SSCP-聚丙烯酰胺凝胶电泳技术对扩增产物进行基因突变筛选,将筛选出的PCR产物进行直接测序.结果:患者GPⅡb基因Exon4的PCR产物经SSCP-聚丙烯酰胺凝胶电泳后出现异常条带,PCR产物直接测序显示GPⅡb基因540A缺失导致后面的氨基酸编码发生移码突变.结论:GP Ⅱb基因540A缺失发生移码突变是GP Ⅱb基因的一种新突变,是血小板无力症发病的分子基础之一.     

1例X连锁型视网膜色素变性家系的分子遗传学研究

目的 对1例来自云南省的X连锁型视网膜色素变性家系进行相关分子遗传学研究.方法 在本研究小组前期工作中对该家系已初步确定的X连锁型遗传位点--RP2和RP3处选取具有高信息量的9个微卫星位标进行精细单倍型分析.在定位的候选基因RP3基因即RPGR基因上,使用构象敏感凝胶电泳(conformation sensitive gel electrophoresis, CSGE)的方法对其1～14号外显子进行突变筛选的同时对已有报道的突变热点区--外显子ORF15进行直接测序以寻找致病突变.结果 通过精细定位扫描及相关单倍型分析,将该例家系的致病基因定位在RP3位点.RPGR基因1～14号外显子经CSGE的方法进行突变筛选,未发现有异常电泳条带;通过直接对突变热点区外显子ORF15的测序,在该例家系中检测到1个在国内外均有报道的热点突变:g.ORF15 483_484delGA.结论 g.ORF15 483_484delGA移码突变导致了该家系产生X连锁型视网膜色素变性.     

EGFR基因在肺腺癌中突变的研究

目的:探讨表皮生长因子受体(EGFR)基因酪氨酸激酶域体细胞在肺腺癌患者中突变的相关因素。方法:分析和检测64例肺腺癌石蜡包埋标本EGFR基因突变状况,采用PCR和序列分析技术进行EGFR基因18、19和21外显子突变分析。结果:64例PAC患者中有16例(25%)酪氨酸激酶域存在体细胞突变。其中2例(3.1%)为18外显子,7例(10.93%)为19外显子,7例(10.93%)为21外显子。结论:肺腺癌(PAC)患者肿瘤组织中EGFR基因突变主要集中于19、21外显子突变,女性高于男性。     

中国东乡族、保安族、裕固族儿童口腔细菌学检测分析

目的了解东乡族、保安族、裕固族儿童龋齿的流行情况,并分析导致龋齿的细菌因素,为进一步预防及控制龋齿提供依据。方法选取3个民族的100名5岁儿童和165名12岁儿童,由口腔专业医师按照世界卫生组织的诊断标准及方法进行龋齿检查、测定唾液和牙菌斑中变异链球菌水平以及对牙菌斑的细菌学涂片进行分析。结果东乡族、保安族、裕固族儿童龋齿患病率的差异无统计学意义(P>0.05)。5岁儿童唾液中的变异链球菌水平东乡族以2级(32.0%)和3级(56.0%)为主,裕固族以0级(60.0%)和1级(32.0%)为主,两者间的差异有统计学意义(P<0.05);12岁儿童唾液中的变异链球菌水平东乡族以3级为主(48.0%),保安族以2级(27.3%)和3级为主(38.2%),裕固族以0级(48.3%)和1级为主(33.3%),3组间的差异均有统计学意义(P<0.05)。同一民族12岁儿童4个牙菌斑部位的变异链球菌分布及程度较一致,但东乡族儿童牙菌斑的变异链球菌水平以2级和3级为主,保安族和裕固族儿童均以0级和1级为主,不同民族间4个牙菌斑部位变异链球菌水平的差异均有统计学意义(P值均<0.05)。各族5岁儿童与12岁儿童正常牙的牙菌斑细菌含量球菌和杆菌比例的差异均无统计学意义(P值均>0.05),但龋齿的牙菌斑细菌含量为球菌比例升高、杆菌比例下降,其中5岁儿童正常牙与龋齿的球菌和杆菌比例的差异均有统计学意义(P值均<0.05)。结论东乡族、保安族、裕固族儿童的龋齿患病率较低,东乡族儿童唾液和正常牙的牙菌斑中变异链球菌数量较多,各族儿童患龋后口腔细菌中球菌和杆菌的数量发生明显变化。