应用PCR—SSCP银染检测膀胱癌中H—ras基因突变

目的：了解膀胱癌中H-ras基因突变情况。方法：应用PCR－SSCP银染和DNA测序技术对31例膀胱癌组织进行检测。结果：H－ras基因突变发生率为38．7％，突变位点在H－ras基因的第1外显子的第12位密码子，由GGC变为GTC。结论：H-ras基因突变与膀胱癌的发生发展存在着一定的联系，H-ras基因突变可望作为膀胱癌早期临床诊断有价值的指标。     

膀胱癌H—ras基因突变和P21蛋白表达的研究

目的 了解膀胱癌中H—ras基因突变和P21蛋白表达情况。方法 应用PCR—SSCP银染和免疫组化方法对31例膀胱癌组织分别进行检测。结果 发现H—ras基因突变发生率为38.7％,P21蛋白阳性率为71.0％。结论 二者存在一定的关联,并与临床分期、病理分级有密切联系。H—ras基因突变和P21蛋白表达可望作为膀胱癌诊断和判断预后有价值的指标。     

大肠癌Ki-ras基因突变与肿瘤复发死亡

在大肠腺癌演变为大肠癌的进程中早期就发生了Ki－ras基因的突变。为了研究Ki-ras基因突变与肿瘤的特点及与病人预后的关系，英国的H.J．N．Andreyev等研究人员对13个国家和地区、22家医院的2721名大肠癌患者进行了研究。结果发现在37．7％的肿瘤中检出Ki－ras基因12密码子或13密码子的突变。N－ras基因突变80．8％发生在第12密码子。未发现Ki－ras基因突变与性别、年龄、肿瘤部位及DubS分期之间存在着联系。分化差的肿瘤较少发生突变。多变量分析表明：有m－＿基因突变的大肠癌病人其疾病复发的危险性增加以及死亡的危险性增加。尤其…     

突变型K-ras siRNA抑制肺癌A549细胞的增殖和迁移并诱导细胞凋亡

目的:构建靶向Kras的siRNA,研究Kras siRNA对Kras基因突变型肺癌细胞A549及Kras野生型小细胞肺癌细胞NCIH446生长和迁移的抑制作用。方法:设计并人工合成4条Kras siRNA（针对野生型Kras基因的Kras siRNA1~ Kras siRNA3;针对突变型Kras 基因的Kras siRNA4）,并分别转入A549和NCIH446细胞。RTPCR和Western blotting检测不同Kras siRNA对Kras mRNA和蛋白表达的影响,MTT法检测不同Kras siRNA对A549和NCIH446细胞增殖的抑制作用,Transwell实验和Hoechst 33258染色检测Kras siRNA对细胞迁移和凋亡的影响。结果:靶向突变型Kras的Kras siRNA4能特异性抑制A549细胞中Kras的表达,但对Nras和Hras的表达没有影响。Kras siRNA4抑制A549细胞的增殖,但不影响含野生型Kras基因的NCIH446细胞的增殖。Kras siRNA4还能诱导A549细胞凋亡、抑制A549细胞迁移。结论: 针对突变型Kras基因的siRNA可特异性抑制Kras突变型肺癌细胞的增殖和迁移,并诱导该细胞凋亡,Kras siRNA可望用于Kras突变型肿瘤特别是肺癌的个体化治疗。     

胰腺癌的基因诊断及基因治疗的研究现状

1 癌基因的研究 1993年人们开始认识到K—ras基因突变是发生在胰腺癌的早期阶段,德国学者还报告了两例经粪便检出K—ras基因突变,并经手术切除证实为极小的胰腺癌病例。 1996年Tada报告了138例非胰腺疾病死亡剖检例胰导管上皮粘液细胞增生灶K—ras基因第     

K—ras基因在胰腺癌早期诊断中的研究进展

目前胰腺癌的手术切除率和 5年生存率仍然很低 ,关键在于早期诊断十分困难。近年来分子生物学研究发现 ,胰腺癌 K- ras基因第 1 2密码子点突变率很高 ,与胰腺癌发生早期关系密切 ,有望弥补目前临床诊断方法的不足 ,成为胰腺癌早期诊断的基因标志物。本文就近年来 K- ras基因在胰腺癌早期诊断中的研究进展作一综述。1　临床标本的 K- ras基因突变检测及意义1 .1　手术切除标本的 K- ras基因突变　 1 988年Almoguera等 [1]首次报道采用 Rnase A错配切割法检测手术切除标本中 K- ras基因突变 ,结果 2 2例胰腺癌中 2 1例检出突变 ,突变率为 …     

纤维支气管镜脱落细胞H—ras基因突变对肺癌的诊断

为探讨纤维文气管镜直视下毛刷脱落细胞中H－ras基因突变在肺癌中的诊断价值。采用在纤维支气管镜直视下毛刷脱落细胞中应用PCR－RFLP方法（polymerasechainreactionrestrictionfragmentlengthpolymorphisms）检测H－ras基因点突变。对14例肺部疾病患者进行了检测。结果显示有7例首先在纤维文气管镜刷检的脱落细胞中发现H－ras基因点突变。而同时的细胞学检查为阴性，追踪观察1～8个月，病理诊断为肺癌。提示该方法是对可疑肺癌患者动态观察协助确诊的新手段。     

人类癌症并不经常发生P21蛋白第12氨基酸的突变

最近的研究指出人膀胱癌细胞株细胞致癌基因C-Ha-ras 发生了点突变,C-Ha-ras 基因产物是P21,突变将P21第12氨基酸从甘氨酸转变为缬氨酸,突变后的P21的膀胱癌细胞株DNA 转化N1H3T3 细胞的能力有关.其他有关ras 基因的P21经突变后似     

3-氯-4-二氯甲基-5-羟基-2(5氢)-呋喃酮诱导人胚胎肝细胞ras基因突变

背景与目的:研究饮水氯化消毒副产物3-氯-4-二氯甲基-5-羟基-2(5氢)-呋喃酮(3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone,MX)对体外培养的人胚胎肝细胞(L-02细胞)ras基因突变的诱导。材料与方法:MX染毒剂量为300μmol/L,以二甲基亚砜(DMSO)做溶剂对照,将L-02细胞连续染毒培养12d后,收获细胞提取基因组DNA,应用PCR-克隆测序法检测ras基因(K-ras、H-ras、N-ras)12、13、61密码子是否存在突变。结果:MX染毒组H-ras基因57密码子的GAT置换成GGT,未检测到K-ras、N-ras及H-ras12、13、61密码子突变,DMSO溶剂对照组相应的ras基因目的片段均未检测到突变。结论:MX可能诱导L-02细胞ras基因突变。     

大肠肿瘤与基因复合突变

随着分子生物学实验技术和理论的发展,特别是癌基因、抑癌基因研究的深入,基因变异与肿瘤发生发展的关系已日益受到重视。本文试将大肠肿瘤中某些基因变异的作用及其相互关系加以综述,并作初步探讨。一、原癌基因突变大肠肿瘤中,已被确认的一个重要的体细胞改变是ras基因突变。约50％的大肠癌以及相同百分比的、大于1cm的腺瘤,存在ras基因突变,相反,小于1cm的大肠腺瘤,突变发生率低于10％。ras基因突变多见于c—ki—ras基因,多位于基因的第十二位编码区。该位点由于原有的Gly被置     

甲状腺癌组织中H-ras基因突变及蛋白表达的预后价值

对５４例甲状腺癌标本分别用ＰＣＲ－ＲＦＬＰ法检测Ｈ－ｒａｓ基因第１２位密码子的突变及免疫组化法检测ｐ２１ｒａｓ蛋白，并用时序检验分析ｒａｓ基因突变和ｐ２１ｒａｓ蛋白表达与甲状腺癌的关系。结果发现，甲状腺癌中１８例（３３．３％）有ｒａｓ基因突变和４９例（９０．７％）有ｐ２１ｒａｓ蛋白过度表达。临床分期晚、分化程度低的甲状腺癌突变率较高，具有Ｈ－ｒａｓ原癌基因突变和ｐ２１ｒａｓ蛋白阳性的病例有较高的复发率和死亡率。表明ｒａｓ基因突变及其蛋白过度表达在甲状腺癌的发生和发展过程中发挥作用，是预后不良的标志     

原发性非小细胞肺癌中K－ras基因突变的研究

目的探讨非小细胞肺癌（Non－smallcelllungcancer,NSCLC）组织中K－ras第12密码子点突变与NSCLC发生和发展的相关性。方法采用针对K－ras基因第12密码子特异点突变方式的引物进行PCR及银染法,分析175例新鲜NSCLC手术切除标本、43例癌旁组织及5例良性肺部疾患组织中K－ras基因第12密码子中CGT、GTT和GAT三种不同点突变方式。结果175例NSCLC组织中出现K－ras12密码子GGT→CGT突变率为34．86％（61／175）,GGT→GTT突变率40．57％（71／175）及GGT→GAT突变率37．71％（66／175）,总突变率为62．3％（109／175）。其中,同时出现CGT／GTT二个点突变为10．1％(11／109),CGT／GAT9．2％(10／109),GTT／GAT12．8％(14／109),而CGT／GTT／GAT均出现突变占23．9％(26／109)。其中Ⅰ期、Ⅱ期、Ⅲ期突变率分别为64．3％、56．8％及64．0％,另外腺癌突变率为63．8％、鳞癌为60．5％及腺鳞癌为64．5％,因此K－ras点突变与肺癌的分期及病理类型均无相关性（P＞0．05）。然而,37例腺癌突变组中出现GTT／GAT突变率为17．2％(10／58)明显高于鳞癌的3．5％(3／86),二者具有明显差异（P＜0．01）。43例癌旁组织与5例良性肺部疾患组织均未发现K－ras点突变。结论K－ras12密码子点突变及多点突变普遍存在于NSCLC中,其中肺腺癌出现GTT／GAT二个点突变明显高于鳞癌,结果提示K－ras基因点突变是肺癌发生和发展的一个重要因素。     

肝细胞癌p53基因突变初步研究

本文应用快速银染多了矣酶链反应单链构像多态（ＰＣＲ－ＳＳＣＰ）方法检测了３０例肝细胞癌（ＨＣＣ）组织中ｐ５３基因变异情况。结果１３例癌组织中有异常电带，其中２闰于第５外显子，各有３例位于第６和第７外显子，位于第８显子有５例，ｐ５３基因变异的病例乙型肝炎表面抗原均阳性，实验结果表明：本技术能有效检测出基因突变；肝细胞癌中ｐ53基因突变率较高且有多个位点；肝细胞癌ｐ５３基因突变可能与乙型肝炎病毒感染有关     

K-ras and p53 mutations are an independent unfavourable prognostic indicator in patients with non-small-cell lung cancer.

We examined 159 consecutive cases of non-small-cell lung cancer (NSCLC) for a mutation at codon 12 of the K-ras gene and for a mutation of the p53 gene occurring in exons 5-8. Eleven (6.9%) had mutations of the K-ras (ras+) and 57 (35.8%) had mutations of the p53 (p53+). There were 95 cases (59.7%) with ras- p53-, seven cases (4.4%) with ras+/p53-, 53 cases (33.3%) with ras-/p53+ and four cases (2.5%) with ras+/p53+. The ras+ group had a worse prognosis than the ras group in all cases and in 107 early-stage cases (stage I-II, P<0.05). The p53+ group had a worse prognosis in 107 early-stage cases (P<0.01), but there was no statistically significant difference when 52 advanced-stage cases (stage III-IV) or all patients were considered. Both ras and p53 mutations were unfavourable prognostic factors in 94 cases with adenocarcinoma, but there was no statistical significance in 57 cases with squamous cell carcinoma. According to Cox''s model, the pathological stage, ras mutation and p53 mutation were found to be independent prognostic factors. Our results suggest that ras and p53 mutations were independent unfavourable prognostic markers especially in the early stage of NSCLC or in adenocarcinoma.     

The Harvey ras 1 gene is activated in papillomavirus-associated carcinomas of the upper alimentary canal in cattle

The possible activation of ras sequences in papillomavirus-associated carcinomas of the upper alimentary canal of cattle was investigated by restriction enzyme and hybridization analysis, and by DNA-mediated transformation of NIH3T3 cells. In three cancers, a squamous cell carcinoma of the palate, a squamous cell carcinoma of the rumen, and a transitional cell carcinoma of the urinary bladder, repetitive DNA sequences present in the Ha-ras 1 locus showed anomalous restriction patterns, indicating rearrangements and, in the case of the palate cancer, amplification. Genomic DNA from several cancers was capable of inducing focus formation in the NIH3T3 transformation test. DNA from primary, secondary and tertiary transformants was analysed by hybridization to bovine ras probes and by nucleotide sequencing of polymerase chain reaction products. Bovine Ha-ras 1 sequences were found in all transformants, but no nucleotide differences were detected in exon 1 or exon 2 between normal, cancer and transformed cells. It is concluded that the Ha-ras 1 gene is activated in alimentary canal carcinomas, although the activating mutation has not yet been mapped. The possible relationship between papillomavirus infection and activation of the ras gene is considered.     

Clinical implications of K-ras mutations in malignant epithelial tumors of the endometrium.

Tumorigenesis in humans and experimental animals appears to involve the activation of ras protooncogenes for a number of organ systems and seems to be important to the development of the metastatic phenotype in several model systems. Clinically, the presence of activated ras protooncogenes has been reported to be a negative prognostic factor in the myelodysplastic syndrome and in adenocarcinoma of the lung. In the present study we examined 49 cases of endometrial carcinoma for mutations in the first exon of K-ras using the polymerase chain reaction and direct sequencing. Mutations in codon 12 or 13 of K-ras were detected in 6 of 49 cases (12.2%). These six cases consisted of five endometrioid endometrial carcinomas, each of which had a mutation in codon 12, and one case of clear cell carcinoma, which had a mutation in codon 13. In our study the presence of mutations in K-ras appeared to be an unfavorable prognostic factor. Three of six patients with the mutation died during follow-up, while only 7% of the 43 patients without K-ras mutations expired during this same period. In multivariate analysis using the Cox proportional hazard model, K-ras activation appeared to be an independent risk factor when compared with clinical stage, depth of myometrial invasion, and patient age. Thus, our findings support the hypothesis that K-ras protooncogene activation plays an important role in determining the aggressiveness of endometrial carcinoma.     

Frequent association of p53 gene mutation in invasive bladder cancer.

Structural alterations of the p53 gene were investigated to elucidate the molecular biological difference between superficial and invasive bladder cancer by polymerase chain reaction single-strand conformation polymorphism analysis. In 25 bladder cancers obtained from 23 patients, p53 gene mutations were investigated in exon regions 4 to 11. Twenty-four were transitional cell carcinomas, and the remaining one was a squamous cell carcinoma. Only one of 13 superficial bladder cancers, including pTis, pTa, and pT1, was found to have p53 gene mutation. However, of 12 invasive bladder cancers with pT2, pT3, and pT4, six primary carcinomas, including a squamous cell carcinoma and one metastatic carcinoma, were found to have p53 gene mutations. The number of cancers examined in Grades 1, 2, and 3 was three, seven, and 15, respectively. p53 gene mutation was not found in any of the ten cancers with Grades 1 and 2, while eight of 15 bladder cancers with Grade 3 were found to have p53 gene mutation. The results indicated that the incidence of p53 gene mutations appeared to be much higher in invasive-type and high-grade bladder cancers than in superficial and low-grade ones. Our results are compatible with the recently published results by Sidransky et al. [Science (Washington DC), 252: 706-709, 1991] showing that p53 gene mutations were frequently found in invasive bladder cancers by sequence analysis on polymerase chain reaction amplified products corresponding to exons 5 to 9. Our results are also compatible with previously reported results by Olumi et al. (Cancer Res., 50: 7081-7083, 1990) showing that the loss of chromosome 17p, revealed by analysis with restriction fragment length polymorphism, was frequent in high-grade bladder cancers. In this study, p53 gene mutations were often found in exon 4 as well as in other exons. Therefore, this region should also be examined for screening of mutations of this gene in bladder cancer. There appeared to be no consistent mutation sites in exons 4 to 11 of the p53 gene and no specific patterns of the mutation in bladder cancer.     

子宫内膜癌组织中抑癌基因PTEN突变和表达的探讨

目的：研究抑癌基因PTEN在子宫内膜癌组织中的突变频率、分布和表达，探讨其在子宫内膜癌发病中的意义。方法：提取40例新鲜子宫内膜癌及癌周组织的基因组DNA，应用聚合酶键式反应—单链构象多态性分析(PCR—SSCP)方法，研究PTEN基因9个外显子的突变情况，并对突变样本进行测序分析。采用免疫组织化学法进行PTEN蛋白表达研究，并与组织学类型、临床分期、病理分级、淋巴结转移和雌孕激素受体状态的相关性进行分析。结果：40例子宫内膜癌中共检测到突变为18例，占45、0％。18例结果显示，8例为错义突变，10例分别为无意义突变、插入和缺失，形成截短蛋白。异常突变点中44、0％为外显子5，28.0％为外显子8，17．0％为外显子3，外显子1和6各有1例。免疫组化结果显示PTEN主要分布于细胞浆中：23／40例(57．5％)子宫内膜癌中PTEN表达完全缺失，10／40例(25．0％)表达部分缺失。PTEN在子宫内膜癌的表达与组织学类型和临床分期有关，与病理分级、肌层侵润及淋巴结转移无明显相关性。PTEN表达缺失率在雌孕激素受体阳性的癌组织中明显高于雌孕激素受体阴性的癌组织。结论：PTEN可能和子宫内膜癌的发生有关。     

Demonstration of ras and p53 Gene Mutations in Carcinomas in the Forestomach and Intestine and Soft Tissue Sarcomas Induced by N-Methyl-N-nitrosourea in the Rat

The presence of ras family and p53 gene mutations in rat forestomach, intestine and liver tumors and soft tissue sarcomas induced by N methyl- N -nitrosourea (MNU) was examined using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by direct sequencing analysis. In the forestomach squamous cell carcinomas (SCC), Ha- ros and p53 mutations were detected in 2 (40%) and 4 (80%) of 5 cases, respectively. The figures for Ki- ras and p53 gene mutations in adenocarcinomas of the large and small intestines were 3 (18.8%) and 5 (31.3%) of 16 cases. Soft tissue sarcomas in different sites were found to have mutations of Ki- ras in 7 (23.3%)and of p53 in 9 (30%) of 30 cases. One forestomach SCC and 2 soft tissue sarcomas had double p53 mutations in different exons. Single cases of forestomach SCC and intestinal adenocarcinoma had mutations in both Ki- ras and p53 genes. No mutations were found in counterpart benign tumors or hepatocellular adenomas. The p53 mutation spectrum revealed preferential clustering within exon 8 for the forestomach SCCs, and exons 5 and 8 for the intestinal adenocarcinomas, whereas the distribution was evenly spread through exons 5 to 8 in soft tissue sarcomas. All the detected ras or p53 mutations were G:C to A:T transitions. These results indicate firstly that specific Ki- ras , Ha- ras and p53 gene mutations in MNU-induced lesions are related to particular alkylation sites (G:C to A:T transitions) and secondly, although not essential, Ki- ras , Ha- ras or p53 gene mutations may be involved in the progression stage of forestomach, intestine and soft tissue neoplasms induced by MNU.