p53基因在甲状腺癌中的突变研究

目的:为探讨p53基因突变与甲状腺癌的发生、发展及预后的关系.方法:应用PCR单链构象多态性(SSCP)分析技术,对p53基因第7,8外显子突变进行了检测和分析.结果:在37例甲状腺癌中有11例在第7.8外显子发生突变,突变率为29.9%.p53基因突变在复发的患者中显著高于未复发的患者;p53基因突变与转移、组织学类型和分化状况无显著差异.结论:p53基因的突变可能与甲状腺癌患者预后有关.     

DHPLC检测林州市高龄组和低龄组居民食管癌p53基因外显子突变谱的比较研究

目的：研究我国食管癌高发区林州市居民高龄食管癌患者与低龄食管癌患者中抑癌基因p53全部编码外显子基因突变谱的情况，比较两组患者中p53基因突变的差异。方法：留取林州市〉70岁和〈40岁、低年龄组食管癌患者食管癌新鲜标本51例，提取DNA，PCR扩增p53第2～11外显子。DHPLC进行突变的筛查。突变样本进行DNA纯化测序分析。结果：51例患者中，p53至少有1个外显子基因突变的36例，突变率为70．6％。高年龄组突变率为63．3％（19／30），低年龄组突变率为80．9％（17／21），两者比较无统计学意义（P〉0．05）。p53有2个外显子基因突变的10例，突变率为17．6％。高年龄组突变率为26．7％（8／30），低年龄组突变率为9．5％，两者比较无统计学意义，P〉0．05。结论：p53基因突变是林州市居民食管癌发生过程中的一个发生频率很高的事件。林州市居民的p53外显子突变谱中，共有15种突变类型，共计59个突变位点，其中最多的突变类型是插入碱基C。在p53基因第2～8外显子与内含子交界的非编码区有大量的基因突变。     

DHPLC检测林州市高龄组和低龄组居民食管癌p53基因外显子突变谱的比较研究

目的:研究我国食管癌高发区林州市居民高龄食管癌患者与低龄食管癌患者中抑癌基因p53全部编码外显子基因突变谱的情况,比较两组患者中p53基因突变的差异。方法:留取林州市>70岁和<40岁、低年龄组食管癌患者食管癌新鲜标本51例,提取DNA,PCR扩增p53第2～11外显子。DHPLC进行突变的筛查。突变样本进行DNA纯化测序分析。结果:51例患者中,p53至少有1个外显子基因突变的36例,突变率为70.6%。高年龄组突变率为63.3%(19/30),低年龄组突变率为80.9%(17/21),两者比较无统计学意义(P>0.05)。p53有2个外显子基因突变的10例,突变率为17.6%。高年龄组突变率为26.7%(8/30),低年龄组突变率为9.5%,两者比较无统计学意义,P>0.05。结论:p53基因突变是林州市居民食管癌发生过程中的一个发生频率很高的事件。林州市居民的p53外显子突变谱中,共有15种突变类型,共计59个突变位点,其中最多的突变类型是插入碱基C。在p53基因第2～8外显子与内含子交界的非编码区有大量的基因突变。     

乳腺癌患者外周血DNA p53基因突变的检测及其与预后关系的研究

目的 探讨乳腺癌患者外周血中DNAp53基因突变与预后的关系。方法 对126例乳腺癌患者和92例正常对照者血浆DNA含量进行检测。外周血浆中DNA由Qiagen纯化柱纯化,组织标本DNA抽提方法参照非有机化方法。应用PCR—SSCP方法检测DNA中p53基因5,6,7,8外显子点突变。结果 健康妇女外周血中DNA的平均值为21ng/ml,而乳腺癌患者为211ng/ml(P＜0．01)。126例乳腺癌患者中有46例(35.6％)原发瘤中检出p53突变,其中30例(65．2％)患者外周血DNA中检出p53基因突变。乳腺癌患者外周血中DNA p53基因突变与临床分期、肿瘤大小、淋巴结转移情况和雌激素受体状况密切相关(P＜0．05)。肿瘤原发灶与外周血中均检出DNA p53基因突变者预后较差,22例发生复发或转移的患者中,有13例(59．0％)外周血中检出DNA p53基因突变。结论 乳腺癌患者外周血中DNA p53基因的突变,可作为一种预后指标和提示肿瘤早期复发和远处转移的预后因子。     

甲状腺癌p53基因甲基化的研究

目的 探讨甲状腺癌 p53基因甲基化状态.方法 用限制性内切酶HpaⅠ和MspⅠ酶切甲状腺癌及癌旁组织DNA,通过聚合酶链反应(PCR)扩增p53基因第5外显子,经琼脂糖凝胶电泳后,分析其电泳图谱.结果12例甲状腺癌中9例p53基因第5外显子出现高甲基化状态,而5例癌旁组织为低甲基化状态.结论p53基因高甲基化状态与甲状腺癌发生以及p53基因点突变有关.     

肝细胞癌p53和Rb基因改变的分析

目的 研究肝细胞癌p53和Rb基因的突变特点和规律。探讨2种抗癌基因在肝癌发生过程中的作用及其与细胞学和预后的关系。方法 应用PCR－SSCP和PCR－RFLP法检测65例肝癌p53基因第5－8外显子和Rb基因17和21外显子的突变率。结果 肝癌p53基因突变率为50．8％,以缺失为主;Rb基因的突变率为38．5％;p53和Rb基因同时突变率为12．3％。结论 肝细胞癌中既有p53基因突变也存在Rb基因突变,两者在肝癌的发生中均有重要作用。p53和Rb基因同时突变与肝癌组织学分级密切相关。     

大肠癌p53抑癌基因突变与临床病理特点的关系

目的：探讨p53基因突变与大肠癌临床病理特点的关系。方法：应用ＰＣＲ－ＳＳＣＰ技术检测１３５例大肠癌患者p53基因等５、６、７、８外显子的突变。结果：１５３例大肠癌患者p53基因的突变率为５４.07%,p53基因突变与大肠癌的病理分级、临床分期、淋巴结转移及年龄均有关。结论p53基因与大肠癌的发生、发展及转归均有明显的关系。检测p53基因突变既可作为大肠癌的诊断方法。也可作为大肠癌预后的判定指标。     

大肠癌 p53 抑癌基因突变与临床病理特点的关系

目的 :探讨p53基因突变与大肠癌临床病理特点的关系。方法 :应用PCR SSCP技术检测 135例大肠癌患者p53基因第 5、6、7、8外显子的突变。结果 :153例大肠癌患者p53基因的突变率为54 0 7% ,p53基因突变与大肠癌的病理分级、临床分期、淋巴结转移及年龄均有关。结论 :p53基因与大肠癌的发生、发展及转归均有明显的关系。检测p53基因突变既可作为大肠癌的诊断方法 ,也可作为大肠癌预后的判定指标。     

肺腺癌p53基因突变与临床病理特征关系的研究

目的探讨p53基因在肺腺癌中突变的频率、位置和在肺腺癌发生发展中的作用及与其临床病理特征的关系。方法聚合酶链式反应一单链构象多态性（PCR－SSCP）检测31例肺腺癌的P53基因第5～8外显子突变。结果14例（45％）出现P53基因5～8外显子突变，其中7、8外显子突变占73％。P53基因突变男性显著高于女性（P—0．003），在肿瘤≤3cm的病例p53基因突变率显著低于肿瘤＞3cm的病例（P=0．005）。p53基因突变与吸烟史、年龄、组织学类型、分化程度、淋巴结状况、国际病理TNM分期及瘤栓无显著性差异（P＞0．05）。结论肺腺癌中P53突变率为45％，主要分布在第7、8外显子，P53基因突变参与肺腺癌癌变的始动和腺癌的进展。     

胃癌组织p53基因突变点检测意义

目的 进一步明确胃黏膜癌变进程中基因变异的规律。方法 用PCR单链构象多态性（SSCP）方法对18例胃癌组织以及正常胃黏膜中p53基因突变情况进行分析。结果 p53基因突变10例（10／18）占55．6％,其中第5外显子突变4例,第7外显子突变3例,第6外显子突变2例,第8例显子突变1例。结论 p53基因结构和产物的变化可以作为肿瘤相关标志,对评估胃癌病人的预后和指导临床治疗有一定的作用。     

Mutations and allelic loss of p53 in primary tumor DNA from potentially cured patients with colorectal carcinoma.

PURPOSE: To compare p53 alterations in survivors and nonsurvivors after surgery for colorectal cancer. PATIENTS AND METHODS: Twenty-nine potentially cured patients with colorectal carcinoma, without recurrent disease for more than 6 years after their primary surgery, were selected to match a group of 41 colorectal cancer patients with early metastatic spread to the liver. All patients were screened for mutations in the p53 gene, exons 5 to 9, by denaturing gradient gel electrophoresis and subsequent sequencing. RESULTS: The frequency of p53 mutations was significantly different in cured patients (60%) compared with patients with early relapse (41%, P <.05). A significant difference was found in the distribution of mutations, indicating that potentially cured patients had a different proportion of mutations in conserved regions of p53 (P =.02). This difference was explained by a significantly different frequency of mutations in exon 8 (40% v 15%, P =.03), which is part of the conserved region V. All mutations in region V were codon 273 mutations in cured patients, whereas three of four mutations were located in codon 273 in patients with metastatic disease. Allelic loss of p53 (loss of heterozygosity [LOH]) was demonstrated in 26% of the cured patients and in 39% of patients with metastatic disease (P =.36). The combination of mutation and LOH of p53 was the same (17%) in both groups. CONCLUSION: A large number of p53 mutations in colorectal cancer do not promote disease progression. Some mutations, particularly within conserved regions, may even counteract negative functional effects of other p53 structural alterations. A complete loss of p53 function was not related to survival or progression after curative operation of colorectal carcinoma.     

大肠癌原发灶和肝转移灶p53变异及蛋白表达

目的 了解Ｐ５３及其蛋白在大肠癌发生、转移过程中的动态变化。方法Ｐ５３基因外显子５－９以ＤＧＧＥ及自动ＤＮＡ序列分析来检测,Ｐ５３蛋白表达以免疫组化方法检测。结果 ３４例中２１例呈Ｐ５３变异,占６１．８％,其中５例仅在肝转移灶发现Ｐ５３变异,其余均为原发灶、转移灶生的变异。另有２例原发灶即有Ｐ５３变异者,在转移灶出现了新增加的变异。在３７处变异中,２７和为错义突变占７３．０％;６处为无义突变占１６     

p53 Gene Mutations Associated with Anaplastic Transformation of Human Thyroid Carcinomas

Anaplastic carcinoma of the thyroid gland, which is one of the most aggressive, malignant tumors in humans, is considered to originate from preexisting differentiated thyroid cancer. To define the genetic alterations associated with such progression, we examined nine cases of anaplastic thyroid carcinoma for mutation in exons 4–9 of the p53 tumor suppressor gene. Preliminary screening for mutation by RNase protection analysis demonstrated that two out of nine anaplastic carcinomas contained sequence alterations in the p53 gene. Subsequent DNA sequencing identified the mutated nucleotides in these two cases; one was a nonsense mutation at codon 165, and the other was a single-base deletion at codon 176 resulting in the creation of a stop codon downstream due to frameshift. The fact that no mutations were detected in coexisting foci of papillary carcinomas from the same patients shows that these mutations of the p53 gene occurred after development of papillary carcinomas. These results suggest that p53 gene mutation triggers the progression from differentiated into anaplastic carcinoma in the human thyroid gland.     

p53 gene mutations associated with anaplastic transformation of human thyroid carcinomas.

Anaplastic carcinoma of the thyroid gland, which is one of the most aggressive, malignant tumors in humans, is considered to originate from preexisting differentiated thyroid cancer. To define the genetic alterations associated with such progression, we examined nine cases of anaplastic thyroid carcinoma for mutation in exons 4-9 of the p53 tumor suppressor gene. Preliminary screening for mutation by RNase protection analysis demonstrated that two out of nine anaplastic carcinomas contained sequence alterations in the p53 gene. Subsequent DNA sequencing identified the mutated nucleotides in these two cases; one was a nonsense mutation at codon 165, and the other was a single-base deletion at codon 176 resulting in the creation of a stop codon downstream due to frameshift. The fact that no mutations were detected in coexisting foci of papillary carcinomas from the same patients shows that these mutations of the p53 gene occurred after development of papillary carcinomas. These results suggest that p53 gene mutation triggers the progression from differentiated into anaplastic carcinoma in the human thyroid gland.     

High frequency of G/C transversion on p53 gene alterations in breast cancers from Taiwan

p53 gene mutation is a very frequent event in many human cancers and is associated with a poor clinical outcome in breast cancer patients. Analysis of p53 gene mutations can also provide clues to the etiology of tumor formation. The present study was conducted to investigate the p53 mutations in patients with breast cancer from Taiwan. Tumor samples from 119 patients undergoing mastectomy for breast cancer were evaluated. The mutational status of the p53 gene (exons 5-8) was screened by polymerase chain reaction-single strand conformation polymorphism analysis followed by direct sequencing. Of all 119 cases of breast carcinoma, 26 mutations of the p53 gene were found in 22 cases (18.5%). Among these mutations, 78% (20/26) were point mutations with the majority of those being missense mutations (75%, 15 of 20 mutations) and the other 22% (6/26) were frameshift mutations. No significant correlation between p53 mutations and clinicopathological features was found, including HER2 status. Moreover, our results disclosed distinct mutation spectra in excess transversions to transitions (15/21, 71.4% vs. 6/21, 28.6%) with GC to CG dominant (6/15, 40%). Mutation hot spots we identified at codons 167, 185, 186, 210, 265 and 295 have rarely been documented in the literature. These findings showed that p53 gene mutation might contribute to the pathogenesis of breast carcinoma. Furthermore, the different mutation spectrum with high transversions in G:C to C:G may imply that the exogenous mutagens outweigh the endogenous processes in breast cancer in patients in Taiwan.     

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.     

p53 Mutations and protein overexpression in primary colorectal cancer and its liver metastasis

Although there have already been many studiesreported about p53 statIJs on primary colorectal cancerand / or hepatic metastases,t'. 2] we have not found anyrepoft that compares p53 status between primary andmetastatic lesions in each patient on an individual level.34 patieflts with colorectal cancer and liver metastaseswere chosen for this study. P53 status in Primary and livermetastatic tllmor lesions of every individual wereinvestigated, in order to understand that p53 gene statusduring tumo…     

Role of p53 mutations in endocrine tumorigenesis: mutation detection by polymerase chain reaction-single strand conformation polymorphism.

To elucidate the molecular basis for endocrine tumorigenesis, p53 mutations in human endocrine tumors were analyzed by using polymerase chain reaction-single strand conformation polymorphism. Exons 5 through 10 of the p53 gene were studied in genomic DNAs from 134 primary endocrine tumors and 6 human endocrine cancer-derived cell lines. Mutations were detected and identified in 4 endocrine tumors, including one parathyroid adenoma and three thyroid carcinoma cell lines. The sites of these mutations were in exons 5 (codon 151 and 152) and 7 (codon 248 and 255). In all of three tumor cell lines, but not in a parathyroid adenoma, the normal allele encoding the p53 gene was lost. However, p53 mutations were not found in any other endocrine tumors or cell lines. Based upon these results, we concluded that the p53 gene may play a role in the tumorigenesis of a limited number of parathyroid adenoma and thyroid cancers, and that the p53 mutation with an allelic loss of the p53 gene is an important factor in malignant tumorigenesis of the thyroid gland.     

Mechanisms of relapse in acute leukaemia: involvement of p53 mutated subclones in disease progression in acute lymphoblastic leukaemia

Mutations of the p53 tumour suppressor gene are infrequent at presentation of both acute myeloblastic leukaemia (AML) and acute lymphoblastic leukaemia (ALL), being found in between 5-10% of AML and 2-3% of ALL. Here we have studied the frequency of detection of p53 mutations at relapse of both AML and B-precursor ALL. In those patients with detectable mutations at relapse we investigated whether the mutation was detectable at presentation and was thus an early initiating event or whether it had arisen as a late event associated with relapse. Bone marrow samples from 55 adults and children with relapsed AML (n = 41) or ALL (n = 14) were analysed for p53 gene alterations by direct sequencing of exons 5-9. For samples where a p53 mutation was found at relapse, analysis of presentation samples was carried out by direct sequencing of the exon involved, or by allele-specific polymerase chain reaction (PCR) if the mutation could not be detected using direct sequencing. A p53 mutated gene was found at relapse in seven out of 55 cases. The frequency was higher in relapsed ALL (four out of 14 cases; 28.6%) compared to AML (three out of 41 cases; 7.3%). In five out of the seven cases presentation samples were available to study for the presence of the mutation. In two out of two AML patients the p53 mutation was detectable in the presentation sample by direct sequencing. In three ALL patients analysis of presentation material by direct sequencing showed a small mutant peak in one case, the other two being negative despite the sample analysed containing > 90% blast cells. However in both of these patients, the presence of p53 mutation was confirmed in the presentation sample using allele-specific PCR. In one of these patients the emergence of a subclone at relapse was confirmed by clonality analysis using IgH fingerprinting. Our results confirm that in ALL p53 mutations are present in a proportion of patients at relapse. Furthermore cells carrying the mutation are detectable at presentation in a minor clone suggesting that p53 mutations in ALL may be a mechanism contributing to disease relapse.     

p53基因突变和STK15基因过表达与喉癌发生的关系

目的　探讨p5 3基因突变和STK15基因表达与喉癌发生发展的关系。方法　自 5 5例术前未经化疗和放疗的喉鳞状细胞癌患者的新鲜手术标本中 ,分别取配对癌组织和癌旁正常组织进行以下检测 :(1)提取DNA ,采用聚合酶链反应 单链构象多态性 (PCR SSCP)银染结合DNA直接测序 ,检测喉鳞癌组织中p5 3基因第 7外显子 (p5 3E7)和第 8外显子 (p5 3E8)的突变情况 ;(2 )提取总RNA ,反转录合成cDNA ,以 β actin为内对照进行PCR扩增 ,分析STK15基因表达的水平。结果　 5 5例喉癌组织中 ,17例 (30 .9% )发生p5 3E7突变 ,未发现p5 3E8突变 ;癌组织STK15基因表达与 β actin表达平均密度比值 (ADV)为 1.2 2± 0 .4 9。癌旁正常组织发生p5 3E7突变 1例 (1.8% ) ,p5 3E8突变 1例 (1.8% ) ;癌旁正常组织ADV为 0 .99± 0 .5 4。喉癌组织p5 3E7突变率显著高于癌旁正常组织 (χ2 =8.6 6 ,P <0 .0 1)。癌组织STK15基因表达高于癌旁正常组织 (t=4 .5 39,P <0 .0 1)。 17例p5 3基因突变的患者中 ,14例 (82 .4 % )癌组织STK15基因表达高于癌旁正常组织 ;38例癌组织STK15基因表达高于癌旁正常组织的患者中 ,14例 (36 .8% )存在p5 3E7突变。 2 5 .5 %的喉癌患者同时发生p5 3E7突变与STK15基因表达增高。结论　同时发生p5 3基因突变和STK