食管癌P53基因第5外显子突变分析

目的　分析不同地区食管癌组织中 p5 3基因第 5外显子的突变谱。 方法　采用PCR扩增产物纯化后直接DNA序列测定技术对陕西省西安市 4 2例和河南省林州市 4 3例食管癌标本 p5 3基因第 5外显子突变情况进行检测。结果　西安和林州市食管癌标本中 p5 3基因第 5外显子突变率分别为 14 3% (6 /42 )和 18 6 % (9/43) ,两地突变率比较差异无统计学意义 (P >0 0 5 )。西安 6个突变位点中 4个为点突变 ,2个为缺失突变 ;林州 10个突变位点中9个为点突变 ,1个为插入突变。西安市有 4例突变发生在 12 6～ 12 8位点 ,林州市仅有 2例发生在该区域 (2 /10 ) ,但两者相比差异无统计学意义 (P >0 0 5 )。结论　西安市食管癌 p5 3基因第 5外显子的突变位点相对集中 ,林州市突变位点比较分散 ,可能与该地区多种危险因素的暴露有关。     

MDM2基因启动子区309位点的多态性可抑制p53抑癌通路和加速肿瘤形成

背景和目的：在50％以上的人类肿瘤组织中均检测到p53抑癌基因的突变。因此，p53介导的通路中重要基因的遗传变异将会影响个体的肿瘤易感性。MDM2蛋白是p53通路中的一个重要的负性调节因子。本研究的目的是阐明MDM2基因启动子区309位点的多态性对家系遗传肿瘤和普通人群散发肿瘤易感性的影响，并进一步探讨了该位点变异的功能意义。方法：在66名含有1条突变p53等位基因的Li-Fraumeni综合征家系成员和41名散发肿瘤个体中探讨MDM2基因启动子区309位点的多态性与肿瘤发病年龄间的关系，     

聚合酶链反应-单链构象多态法在研究新疆地方性砷中毒患者p53基因突变中的应用

目的 探索砷致癌的基因多态性,为进一步研究砷对人体健康作用的远期影响提供科学依据.方法 于2001年采集新疆奎屯123团4例经病理诊断为皮肤癌的砷中毒患者的6份皮肤癌石蜡包埋组织及其4份血液组织;采集奎屯128团2例经病理诊断为皮肤癌的砷中毒患者和2例癌前砷中毒患者的血液组织;采集对照区新疆奎屯125团2例健康居民的血液组织.采用聚合酶链反应-单链构象多态(PCR-SSCP)银染术测定p53基因外显子(exon,E)5～9突变情况.结果 p53基因中,仅E6、E7发生突变.凝胶电泳成像显示,p53基因E6、E7有异常条带、条带缺失及条带上移现象.结论 砷对p53基因有致突变作用,突变位于E6、E7.     

林州居民食管癌p53基因突变谱分析与不同地区食管癌和其他类型肿瘤的比较

目的：分析河南省林州市与其他地区食管癌前病变和鳞状细胞癌p53突变谱,探讨食管癌变的发病因素。方法：采用生物信息学和Monte Carlo方法,依据IARC p53突变数据库、Curic研究院p53突变数据库和郑州大学医学院癌症研究所实验室的资料,用FileMark Pro3.0软件系统建立局部资料库进行分析。结果：林州食管癌高发区食管鳞癌碱基替换的发生率低于其他地区食管鳞癌的发生率（32.8 vs 39.8%),但CpG位点G：C→A：T的发生率高于其他地区食管癌（29.6% vs 16.4%)。林州食管癌突变位点具有明显的特征,主要发生在273（占所有错义突变的11.3%)、175（9.7%)、159（6.5%)和282（6.5%)位密码子的CpG位点上。林州地区食管鳞癌p53突变与其他地区食管鳞癌以及头颈部鳞癌p53突变相比,差异有显著性（P=0.02)。结论：林州食管癌p53突变具有内、外源致癌原所致突变的特征,提示慢性炎症、饮食习惯和接触致癌原,可能是林州居民发生食管鳞癌的主要危险因素。     

食管癌与p53突变和人乳头状肉瘤病毒感染

目的探讨p53基因突变与人乳头状肉瘤病毒16（HPV16）感染在食管癌发病中的作用及相互关系。方法应用病例-病例研究方法进行分析，采用聚合酶链反应（PCR）、单链构像多态性（SSCP）、测序等分子生物学技术对110例食管癌组织标本中p53基因的突变与HPV16感染进行了检测。结果110例食管癌组织标本p53基因突变率为49．1％，其中外显exon5—6，exon7，exon8—9的突变率分别为19．1％，27．3％，17．2％。食管癌组织HPV16的检出率为49．1％。吸烟患者p53基因突变率（61．4％）明显高于非吸烟患者p53基因突变率（48．2％），差异有统计学意义；淋巴结转移患者p53基因突变率（65．2％）明显高于无淋巴结转移患者p53基因突变率（37．5％）；HPV16阳性者中，p53突变率是40．7％，HPV16阴性者仅为57．1％，两者差异无统计学意义。结论HPV16感染可能是食管癌高发区的危险因素；p53基因突变与吸烟、淋巴结转移有明显相关性；HPV16感染和p53基因突变可能是2个独立的事件。     

MTHFR基因C677T和A1298C多态性与儿童孤独症的关系

探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T和A1298C多态性与儿童孤独症的关系,为相关领域的理论研究提供依据.方法 采用限制性片段长度多态性聚合酶链反应(PCR-RFLP)和基因测序方法,对200例孤独症儿童与性别年龄匹配的200例对照组儿童MTHFR基因C677T和A1298C多态性进行分析.结果 在MTHFR基因C677T位点突变中,病例组突变率为54.5%,对照组突变率为28.0%,差异有统计学意义(x2=28.97,P<0.05).病例组T等位基因频率明显高于对照组(x2 =44.90,P<0.05).对病例组和对照组的基因型突变率进行多重比较,病例组的TT基因型和CT基因型的突变率均高于对照组(x2值分别为27.00,12.89,P值均<0.012 5).在MTHFR基因A1298C位点突变中,病例组突变率为28.0%,对照组突变率为17.0%,差异有统计学意义(x2=6.94,P<0.05).病例组C等位基因频率高于对照组(x2=18.32,P<0.05).对病例组和对照组的基因型突变率进行多重比较,病例组的CC基因型的突变率高于对照组(x2=13.07,P<0.012 5),而病例组AC基因型的突变率与对照组之间差异无统计学意义(x2=0.02,P>0.012 5).在MTHFR基因两位点的联合作用中,677 CT-1298 CC两位点联合突变对孤独症的影响要比677CC-1298CC,677CT-1298AA,677TT-1298AA单独位点突变影响大.结论 MTHFR基因C677T和A1298C突变可能是儿童孤独症发病的遗传危险因素,且在两位点突变联合作用中,C677T突变对孤独症的影响比A1298C突变明显.     

前列腺癌患者解脲脲支原体感染与p53基因表达的关系

目的 检测解脲脲支原体(Uu)和p53基因在前列腺癌中的表达,并分析二者的相关性.方法 采用PCR法和免疫组化法,检测47例前列腺癌组织中Uu和p53蛋白的表达.结果 47例前列腺癌患者中,Uu感染21例占44.7％,p53蛋白阳性23例占48.9％ ;Uu与前列腺癌的肿瘤分期、肿瘤转移差异有统计学意义(P＜0.05); Uu阳性的前列腺癌组织中p53基因的表达较Uu阴性组高,Uu感染与p53蛋白表达存在相关性,差异有统计学意义(P＜0.05).结论 在前列腺癌中,Uu与前列腺癌的分期和肿瘤转移差异有统计学意义(P＜0.05),Uu可能通过诱导p53基因的突变引发前列腺癌的发生.     

p53基因在膀胱肿瘤中的研究进展

p53基因与膀胱肿瘤相关性研究很多,绝大多数研究认为p53的突变与膀胱肿瘤的发生有关。为对其做进一步深入研究,本文综述了近3年有关化学致癌物质引起p53基因突变机制、p53基因的分子生物学行为以及用于膀胱肿瘤基因治疗的最新研究进展。     

双酚A诱导斑马鱼P53基因CDS突变的RT-PCR及序列分析

目的:研究双酚A(bisphenol A,BPA)对斑马鱼肝脏p53基因编码序列(CDS)的致突变作用。方法:试验设空白对照组与BPA暴露组,连续染毒30 d后,从斑马鱼肝脏组织中提取RNA,通过RT-PCR方法扩增得到有完整编码区序列的p53基因,并进行测序分析。结果:序列分析表明,斑马鱼P53基因编码区序列长1122 bp,编码373个氨基酸,与网上已经登陆的斑马鱼p53序列有99.9%的相似系数,而与其他生物的P53序列存在一定的差异。在0.6 mg/L浓度下染毒30 d后,BPA暴露组斑马鱼p53基因序列发生了突变。直接测序证明,它们分别在135位、311位密码子发生GAG→GGG、AGG→CGG转变,使其编码的p53蛋白发生Glu→Gly变异。结论:试验结果表明BPA对斑马鱼p53基因CDS有致突变作用,采用RT-PCR技术检测BPA诱导p53基因突变是可行的。     

焦炉工人痰细胞p53基因外显子突变检测

目的 探讨焦炉工人痰细胞p53基因突变与焦炉暴露关系.方法 选取某焦化厂125名焦炉作业工人(炉底38人,炉侧45人,炉顶42人)作为暴露组,同时选取同厂37名材料管理工人作为对照组;个体采样法对作业环境进行监测;高渗盐水超声雾化法诱导取痰,分离痰细胞;高效液相色谱法检测环境空气样本B[a]P和尿中1-羟基芘的水平;聚合酶链式反应-单链构象多态性方法(PCR-SSCP)检测痰细胞p53基因突变的情况.结果 暴露组中炉顶工人组痰细胞p53基因6、7外显子和p53基因5、6、7外显子总突变率分别为14.3%,21.4%,33.3%,明显高于对照组(0%,5.4%,5.4%),差异有统计学意义(P＜0.05),且总突变率有随外暴露水平升高而升高的趋势(x2=7.457,P＜0.01);经多元Logistic回归分析,焦炉暴露、炉顶暴露、炉底暴露和年龄的调整OR值(95% CI)分别为25.278(3.461～184.625)、7.359(1.017 ～53.267)、22.228(3.146 ～ 157.082)、1.106(1.011 ～1.211),是焦炉工人痰细胞p53基因突变率升高的主要危险因素.结论 焦炉逸散物可诱发焦炉工人的痰细胞p53基因突变率升高,且与暴露水平有关.     

p53蛋白在联苯胺接触人群和膀胱癌患者血清中的表达

目的研究职业性联苯胺接触者和膀胱癌患者突变型p53蛋白的表达。方法用免疫PCR法测定职业性联苯胺接触人群和膀胱癌患者血中突变型p53蛋白,用巴氏分级法对尿脱落细胞进行分级。结果随着联苯胺接触强度指数的增高,人群突变型p53蛋白的阳性率不断增加,膀胱癌患者组突变型p53蛋白的阳性率(83.3%)高于接触强度指数1组(33.3%)。PCR扩增条带经扫描积分后,膀胱癌患者组和接触强度指数2组的平均扫描积分(24016.11±2979.99、12960.79±903.27)高于1组(9231.58±1140.74),差异有统计学意义(P<0.01,P<0.05)。在联苯胺接触人群的各组中以巴氏分级作为组内分层因素,接触强度指数2组中,巴氏2、3级层PCR扩增条带平均扫描积分(12960.79±903.27、13612.78±1697.38)高于1级层(9231.58±1140.74),差异有统计学意义(P<0.05)。接触强度指数3组中,巴氏3级层的突变型p53蛋白的阳性率(46.9%)高于1级层(33.3%),差异有统计学意义(P<0.05)。结论在联苯胺接触强度较低的范围内,随着接触强度的增加,接触工人血清中p53突变蛋白的阳性表达不但更频繁,而且更加强烈;但接触强度超过了这个范围,工人血中p53突变蛋白的阳性率以及表达量将不再随着接触强度的上升而增高,而尿脱落细胞病变程度在联苯胺接触强度较高的情况下与p53基因突变率     

Detection of mutant p53 protein in workers occupationally exposed to benzidine

To investigate the expression of mutant p53 protein in workers occupationally exposed to benzidine, we detected mutant p53 protein by immuno-PCR assay in the serum of 331 benzidine-exposed healthy workers, while we classified exfoliated urothelial cells in urine samples with Papanicoloau's grading (PG). The Papanicoloau's grading classified exfoliated urothelial cells of the subjects from grade I (normal cells) to grade III (suspicious malignant cells). The subjects were also divided into high, medium and low exposure groups according to the exposure intensity index. The results revealed that mutant p53 protein in the medium and high exposure groups were significantly higher than the in low exposure group (p<0.05), and in PG II and III were significantly higher than in the PG I (p<0.05). There was no significant differences among Papanicoloau's gradings strata in the low exposure group on the incidence and quantity of mutant p53 protein. In the medium and high exposure groups, the incidence and/or quantity of mutant p53 protein in the stratum of PG II and/or III were significantly higher than that of PG I (p<0.05). Detection of mutant p53 protein in conjunction with benzidine exposure level and Papanicoloau's gradings of exfoliated urothelial cells could provide more information to help us elevate surveillance efficiency and diagnose bladder cancer in the early period.     

Plasma p53 protein and anti-p53 antibody expression in vinyl chloride monomer workers in Taiwan.

Vinyl chloride (VC) workers are known to be at risk for development of angiosarcoma of the liver (ASL), a rare tumor. Previously, a study of p53 gene mutations in tumors of VC-exposed workers found that 50% of liver angiosarcomas contained such mutations. Mutant p53 oncoprotein and anti-p53 antibodies can also be found in the sera of ASL patients and VC-exposed workers without cancer. Workers in Taiwan have also been exposed to VC, and some have contracted liver tumors. In this study, we used enzyme-linked immunosorbent assays to detect mutant p53 protein and anti-p53 antibodies in the plasma of VC-exposed workers in Taiwan. Thirty-three of 251 (13.2%) VC-workers tested positive for the p53 overexpression (10% with positive mutant p53 protein and 3.6% with positive anti-p53) in their plasma, but only 2 of 36 controls (5.6%) tested positive (2.8% with positive mutant p53 protein and 2.8% with positive anti-p53). There was a significant association between cumulative VC exposure concentration and positive p53 expression (P = 0.032) among VC workers after we adjusted for age, hepatitis, drinking, and smoking status. In summary, P53 overexpression (mutant p53 protein or anti-p53 antibody) can be found in the plasma of VC workers in Taiwan, and a significant dose-response relationship exists between plasma p53 overexpression and VC cumulative exposure concentration.     

生存素、bcl-2及p53在卵巢上皮性肿瘤的表达及意义

目的:探讨具有调节细胞凋亡作用的生存素、bcl-2和p53蛋白在卵巢上皮性肿瘤中表达及意义。方法:用免疫组织化学方法检测该院2002～2007年卵巢良性上皮性肿瘤(22例)、交界性肿瘤(19例)以及恶性肿瘤(34例)中生存素、bcl-2及突变型p53蛋白的表达情况,并以正常卵巢组织(12例)作为对照。结果:生存素及突变型p53在卵巢良性上皮性肿瘤中表达的阳性率低于恶性肿瘤组,而bcl-2在3组中的表达则无统计学意义。生存素、bcl-2及p53的表达强度与恶性肿瘤的临床期别无相关性,但随肿瘤恶性程度升高,多个标记物同时表达的现象增加。生存素的表达和突变型p53表达有关。结论:生存素、bcl-2及突变型p53与卵巢上皮性肿瘤形成有关,其中生存素及突变型p53与恶性肿瘤发生有关,且二者表达有相关性。恶性卵巢上皮性肿瘤的发生可能是多基因共同作用的结果。     

金雀异黄素诱导人胃癌细胞凋亡的机制研究

采用 4’ ,6 二乙酰基 2 苯基吲哚染色、琼脂糖凝胶电泳实验观察了金雀异黄素 (Gen)对体外培养的人胃癌SGC 790 1细胞的凋亡诱导作用 ,并采用WesternBlot法检测Gen对人胃癌细胞p5 3、Caspase 3蛋白的表达情况。结果显示 ,Gen诱导了胃癌细胞凋亡 ,并抑制突变型p5 3蛋白表达 ,增加Caspase 3蛋白表达。结果提示 ,Gen抑制突变型p5 3蛋白表达 ,增加Caspase 3蛋白表达 ,可能是其诱导胃癌细胞凋亡的机制之一     

DNA-protein crosslinks and p53 protein expression in relation to occupational exposure to formaldehyde

Background: Formaldehyde (FA) is classified as a probable human carcinogen. Aims: To examine DNA protein crosslinks (DPC) and p53, which are generally known to be involved in carcinogenesis, in peripheral blood lymphocytes of workers exposed to FA. Methods: DPC and p53 ("wild type" and mutant) were examined in peripheral blood lymphocytes of 186 workers exposed to FA (mean years of exposure = 16) and 213 unexposed workers. Every worker completed a questionnaire on demographic data, occupational and medical history, smoking, and hygiene. Results: The adjusted mean level of DPC in the exposed and the unexposed workers differed significantly. Adjustment was made for age, sex, years of education, smoking, and origin. Exposure to FA increased the risk of having a higher level of pantropic p53 above 150 pg/ml (OR 1.6, 95% CI 0.8 to 3.1). A significant positive correlation was found between the increase of pantropic p53 protein and mutant p53 protein, as well as between pantropic p53 >150 pg/ml and mutant p53 protein. In the exposed group a significantly higher proportion of p53 >150 pg/ml was found among workers with DPC >0.187 (55.7%) (0.187 = median level of DPC) than among workers with DPC ⩽0.187 (33.3%). The risk of having pantropic p53 protein >150 pg/ml was determined mainly by levels of DPC. Workers with DPC above the median level had a significantly higher risk of having pantropic p53 >150 pg/ml (adjusted OR 2.5, 95% CI 1.2 to 5.4). Conclusions: Results suggest that DPC and mutation in p53 may represent steps in FA carcinogenesis and a possible causal relation between DPC and mutation in p53. These biomarkers can be applied in the assessment of the development of cancer due to FA exposure.     

Diallyl disulfide (DADS) induces the antitumorigenic NSAID-activated gene (NAG-1) by a p53-dependent mechanism in human colorectal HCT 116 cells

Garlic is appealing as an anti-carcinogenic agent due to its ability to induce apoptosis in vitro and inhibit the formation and growth of tumors in animals in vivo. Diallyl disulfide (DADS) is a constituent of garlic that suppresses neoplastic cell growth and induces apoptosis. We examined the effects of DADS on various cancer cell lines to better understand its effect on apoptosis and apoptosis-related genes. The nonsteroidal anti-inflammatory drug (NSAID)-activated gene (NAG-1) has proapoptotic and antitumorigenic activities and is upregulated by anticancer agents such as NSAIDs. In this study, human colorectal HCT-116 (wild-type p53), HCT-15 (p53 mutant) and human prostate PC-3 (p53 mutant) cells were exposed to DADS. DADS inhibited cell proliferation in all cell lines albeit to a lesser extent in HCT-15 and PC-3 cells at 11.5 and 23 micromol/L. In HCT-116 cells, DADS induced p53 and NAG-1 in a dose-dependent manner and the induction of p53 preceded that of NAG-1. In HCT-116 cells, NAG-1 protein expression was increased 2.4-fold +/- 0.6 at 4.6 micromol/L and 6.1-fold +/- 1.7 at 23 micromol/L DADS, whereas p53 was induced 1.5-fold +/- 0.1 and 2.3-fold +/- 0.4. DADS did not induce NAG-1 or p53 in p53 mutant cell lines; however, NAG-1 expression was induced by sulindac sulfide. HCT-116 cells treated with 4.6 and 23 micromol/L DADS resulted in a 1.9- and 2.9-fold increase in apoptosis, respectively. In contrast, 23 micromol/L DADS induced apoptosis only 1.8-fold in HCT-15 cells and not at all in PC-3 cells. Thus, DADS-induced apoptosis and NAG-1 protein expression appear to occur via p53.     

Maspin蛋白在宫颈鳞癌中的表达及其与p53蛋白表达的关系

目的研究maspin蛋白在宫颈鳞癌组织中的表达及其与p53蛋白表达的相关性。方法应用免疫组化SP法检测maspin蛋白和p53蛋白在宫颈鳞癌、宫颈上皮内瘤样变、正常宫颈三种组织中的表达。分析maspin蛋白表达与宫颈鳞癌各临床病理参数之间的关系,及宫颈鳞癌组织中maspin与p53蛋白表达的相关性（本研究遵循程序符合本院人体试验委员会制定的伦理学标准,得到该委员会批准）。结果①从正常宫颈上皮组织→宫颈上皮内瘤样变→宫颈鳞癌,maspin蛋白表达逐渐下调,三者比较,差异有显著意义（P〈0．05）。②临床分期越高,分化程度越低的宫颈鳞癌组织中,maspin阳性表达越少。有淋巴结转移的宫颈鳞癌中,maspin阳性率低于无淋巴结转移者,两者比较,差异有显著意义（P〈0．05）。③Maspin与p53蛋白在宫颈鳞癌组织中的表达呈负相关（rs=-0．399,P=0．003）。结论Maspin在宫颈鳞癌的发生、发展过程中起重要的抑制作用,可作为判断宫颈鳞癌患者病情进展、恶性程度及转移潜能的指标之一。Maspin与p53蛋白表达呈负相关,MASPIN可能是P53的效应基因。     

柴油机排放颗粒物有机组份诱发细胞中p53及p21蛋白的表达

采用中国仓鼠肺成纤维细胞（Ｖ７９），对国产跃进中型柴油机排放颗粒提取物不同有机组份诱导体外培养的Ｖ７９恶性转化细胞进行ｐ５３及ｐ２１蛋白表达水平的免疫组织化学－ＡＢＣ法检测。结果表明：各组份均能引起体外培养转化的Ｖ７９细胞中ｐ５３蛋白水平的异常表达。但ｐ２１蛋白表达水平未发现有显著改变