散发性乳腺癌BRCA1和BRCA2基因突变分析

目的探讨散发性乳腺癌患者BRCA1及BRCA2基因突变与健康人的差异。方法应用聚合酶链反应-单链构象多态性（PCR-SSCP）分析方法,对83例散发性乳腺癌患者（乳腺癌组）与86例健康人（健康对照组）的血液标本,针对BRCA1和BRCA2基因,选择4个突变发生率较高的外显子[BRCA1中的第5、11（11A、11B）、18外显子,BRCA2中的第11外显子]共5对引物进行突变检测,并应用限制性片段长度多态性（RFLP）方法对具有单核苷酸多态的碱基位点作单核苷酸多态性定性分析。成组设计的定性资料比较采用χ^2检验。结果部分散发性乳腺癌患者和健康人BRCA1基因第5外显子的cDNA 273和287（C→G和A→T）,第11外显子的2430、2532、2630、2685、3191、3232和3667、3876（T→C、T→C、T→G、T→C→G、A→G、A→G和C→A）以及第18外显子的5206和5214（T→A和C→T）碱基位点处存在单个碱基的变化,散发性乳腺癌患者的BRCA1基因突变率高于健康人（14．5％比2．3％,P〈0．05）;应用RFLP方法证实cDNA 2430、2630（T→C、T→G）碱基位点的变化为单核苷酸多态（SNP）;散发性乳腺癌患者与健康人2430（T→C）碱基位点等位基因频数分布不相同,但差异无统计学意义（P〉0．05）。结论散发性乳腺癌患者BRCA1基因突变较常见,而BRCA2的突变十分罕见。     

38例散发乳腺癌患者BRCA1基因突变检测

肿瘤易感基因BRCA1(breast and ovarian canoer suscepti-bility gene,BRCA1)与乳腺癌,卵巢癌发生有密切联系,它的失活可导致细胞的恶性转化和肿瘤的发生.BRCA1基因突变者患癌的风险远高于普通群体,对于有家族史的高危人群中筛查BRCA1基因,对于乳腺癌卵巢癌患者风险评估,发病检测,早期诊断及今后的基因治疗等都有很重要的临床意义.     

家族性乳腺癌BRCA1／BRCA2基因突变的研究

目的：研究家族性乳腺癌患者BRCAl／BRCA2基因的突变位点及携带情况。方法：应用聚合酶链反应一单链构象多态性分析（singlestrand confor—marion polymorphism analysis of polymerase chain reaetion products,PCR—SSCP）和基因测序技术,对12个家族性乳腺癌家系的13例患者进行BRCA基因检测。结果：实验发现1个突变位点（4193insA）和2个核苷酸多态性位点（4165T〉A,5416C〉A）。结论：河北地区家族性乳腺癌的BRCAl基因突变率为7．7％,低于国外和国内其它地区;BRCA基因突变携带者家系中成员具有较高的发病风险。     

华东地区乳腺癌散发病例BRCA1、BRCA2基因突变

目的：探讨华东地区乳腺癌散发病例BRCA1及BRCA2基因突变情况。方法：应用PCR-SSCP-Sequencing方法,对复旦大学附属肿瘤医院79例随机乳腺癌患者的癌组织及癌旁正常乳腺组织的标本进行BRCA1和BRCA2部分基因的突变检测,共6个外显子（BRCA1中的第2、11、22外显子,BRCA2中的第9,14,22外显子）23对引物。结果：发现在BRCA1和cDNA 2430碱基处存在一个T→C的单个碱基的变化,应用RFLP方法在人群中证实为一单核苷酸多态。此SNP的分布在病例及对照中等位基因频率存在差异,但并未达到显著性水平。结论：提示华东地区人群的乳腺癌群体中的BRCA1及BRCA2的突变十分罕见。     

乳腺癌组织BRCA1,BRCA1基因区域杂合性缺失的研究

目的 研究乳腺癌组织ＢＲＣＡ１、ＢＲＣＡ２基因区域的杂合性缺失（ＬＯＨ）情况。方法 采用聚合酶链式反应（ＰＣＲ）和聚丙烯酰胺凝胶电泳,对３０例散发性乳腺癌和２例姐妹乳腺癌进行ＬＯＨ的检测,同时还采用Ｇ显带法对姐妹乳腺癌患者的外周血淋巴细胞染色体畸变情况进行分析。结果 在散发性乳腺癌中,ＢＲＣＡ１、ＢＲＣＡ２基因区域的杂合性缺失率分别为６．１２％和５．７７％;姐妹二人乳腺癌组织在ＢＲＣＡ２基因区域的     

中国家族性和早发性乳腺癌BRCA1基因突变的研究

目的　研究中国家族性和早发性乳腺癌患者的BRCA1基因突变情况。方法　选取 4 1例家族性和早发性乳腺癌患者的外周血单个核细胞DNA ,应用PCR SSCP和DNA序列测定方法 ,对BRCA1基因全序列进行突变检测和分析。结果　 4 1例乳腺癌患者中 ,3例发生BRCA1疾病相关性突变 ,其中年龄 <35岁的患者 2例 ,具有乳腺癌家族史的患者 1例。结论　中国早发性乳腺癌患者的BRCA1突变发生率与西方国家相近 ,而家族性乳腺癌患者的突变发生率明显低于西方国家。     

乳腺癌与BRCA

ＢＲＣＡ１和ＢＲＣＡ２基因的发现为乳腺癌的早期诊断和治疗及提高生存率和生存质量带来了希望。其在乳腺癌中有较高的突变率和特异性。本文综述乳腺癌的基因筛查及与ＢＲＣＡ之间的关系。     

186例乳腺癌患者BRCA1基因突变检测

目的 分析186例散发乳腺癌患者肿瘤易感基因BRCA1（breast and orarian cancer susceptibility gene,BRCA1)突变情况及突变位置。方法 应用PCR－SSCP（single-stranded canformational polymorphs,SSCP)和直接测序方法定位,检测乳腺癌部分患者部分BRCA1基因外显子和内含子与外显子之间接拼区突变及突变位置。结果 186例患者中,有13例发生BRCA1基因突变,突变例数占总例数的7．0％,其中8例突变位置在内含子与外显子的拼接区,5例突变位置在外显子上。结论 筛查BRCA1基因突变对于乳腺癌患病风险评估、发病检测、早期诊断及基因治疗具有重要的临床意义。     

散发性乳腺癌中BRCA1基因突变的探讨

肿瘤易感基因BRCA1是近年来乳腺癌的研究热点之一。据文献报道,欧美人群中家族性乳腺癌的BRCA1突变率较高,达45%左右^[1],而且突变率与家族中具有乳腺癌和卵巢癌病史的人数呈正相关;遗传性乳腺癌-卵巢癌综合征中BRCA1基因突变检出率更高,可达90%^[2],而其与散发性乳腺癌的关系不能确定,其确切功能和作用机制尚不清楚。本文采用PCR-SSCP(聚合酶链反应-单链构象多态性)结合银染的方法,检测了50例散发的乳腺癌患者BRCA1基因的突变情况。     

散发性乳腺癌患者血浆BRCA1基因启动子异常甲基化的检测

目的:探讨散发性乳腺癌组织及外周血浆中BRCA1基因启动子异常甲基化状况及其在散发性乳腺癌诊断中的价值。方法:用甲基化特异PCR方法对散发性乳腺癌患者癌组织、癌旁组织及相应血浆进行BRCA1异常甲基化检测。结果:93例散发性乳腺癌组织中,BRCA1基因启动子异常甲基化率为29%(27/93),相应血浆中BRCA1的甲基化检出率为24.7%(23/93),而癌旁组织、正常对照血浆未检出甲基化,只检出未甲基化的BRCA1。血浆中甲基化改变与肿瘤组织甲基化状况显著相关(P<0.05);BRCA1异常甲基化与髓样癌和粘液腺癌的组织分型显著相关(P<0.05),也与肿瘤淋巴结转移显著相关(P<0.005);但与散发性乳腺癌患者年龄(绝经与否)及肿瘤分级无显著的相关性(P>0.05)。结论:血浆BRCA1基因异常甲基化改变的检测在散发性乳腺癌的特异诊断、组织分型和淋巴结恶性转移等方面有一定的应用价值。     

231例乳腺癌患者乳腺癌易感基因 BRCA1 的突变检测及分析

目的：研究中国妇女BRCA1基因突变与遗传性、家族性和早发性乳腺癌的关系。方法：选取231例乳腺癌患者石蜡标本,显微切割提取癌组织,酚抽提法提取DNA,紫外分光光度仪测定DNA纯度及含量,PCR扩增exon2、exon11和exon20片段直接测序,与基因库序列比对分析其突变情况。结果：231例乳腺癌中发现突变33例,突变率为14．28％,统计分析发现,≤35岁年龄组与36－45岁组比较,P值为0．724,无统计学差异。46－55岁年龄组与＞55岁组比较,P 值为0．868,亦无统计学差异。将上述两组合并后统计发现,≤45岁年龄组患者突变率高于＞45岁组患者,P值为0．002,有显著统计学差异。结论：BRCA1突变与乳腺癌尤其是早发性乳腺癌密切相关。     

Screening of 185DelAG, 1014DelGT and 3889DelAG BRCA1 Mutations in Breast Cancer Patients from North-East India

Around 1.35 million people of worldwide suffer from breast cancer each year, whereas in India, 1 in every 17women develops the disease. Mutations of the Breast Cancer 1 (BRCA1) gene account for the majority of breast/ovarian cancer families. The purpose of study was to provide a prevalence of BRCA1 germline mutations in theNorth-East Indian population. In relation to the personal and family history with the breast cancer, we foundmutations in 6.25% and 12.5% respectively. Three mutations, 185DelAG, 1014DelGT and 3889DelAG, wereobserved in our North-East Indian patients in exons 2 and 11, resulting in truncation of the BRCA1 protein byforming stop codons individually at amino acid positions 39, 303 and 1265. Our results point to a necessity foran extensive mutation screening study of high risk breast cancer cases in our North-East Indian population,which will provide better decisive medical and surgical preventive options.     

Nonsense Mutation at Codon 63 of the BRCA1 Gene in Japanese Breast Cancer Patients

The involvement of abnormalities of the BRCA1 gene in breast cancers in Japanese patients without any family history of this cancer was investigated by polymerase chain reaction-based single-strand conformation polymorphism analysis of the DNA sequences corresponding to the zinc finger domain (exons 2, 3 and 5) and the binding domain with Rad51 (exon 11) of the BRCA1 protein. An identical nonsense mutation at codon 63 (TTA to TAA) was found in 2 of 56 (3.5%) breast cancers from independent patients. The nucleotide change was also detected in the DNAs from non-cancerous tissues of both patients and therefore was a germline mutation. One of the patients was a member of a pedigree involving 3 ovarian cancer and 1 gastric cancer patients, while the other patient had no family history of malignancy. The same germline mutation at codon 63 was reported in four other independent Japanese pedigrees with frequent breast cancer, but not in such families in other countries. These observations suggest that the mutation commonly originated from a single Japanese ancestor. No other mutation of the BRCA1 gene was observed in the samples analyzed in this study. A low incidence of germline mutation and the absence of somatic mutation suggest that the aberration of the BRCA1 gene is involved only in a subset of Japanese breast cancers.     

Linkage Analysis of BRCA1 in Japanese Breast Cancer Families

We examined the involvement of BRCA1, which plays a major role in Western breast cancer families, in Japanese breast cancer families. Eleven families, in which at least three individuals within third degree relatives were affected by breast cancer, were collected. Five of them were early-onset breast cancer families, in which the average age at diagnosis was less than 45 years, and the other six were late-onset families. Ovarian cancer was observed in one patient in the early-onset families. Using seven polymorphic markers on chromosome 17q21, D17S250, ERBB2, THRA1, D17S579, D17S588, GIP and NME1, linkage to BRCA1 was analyzed. Linkage was not detected in any single family. Assuming homogeneity in an inherited component that confines the susceptibility to breast cancer in all families, we summed the LOD scores of all families. The cumulative LOD score obtained was –1.86 for D17S588 at θ = 0.001, indicating no linkage with BRCA1. Since the proportion of families linked to BRCA1 is larger in Western early-onset breast cancer families than in late-onset ones, we also summed the LOD scores of five early-onset families. However, again a negative LOD score was obtained. These results suggest that BRCA1 is not a major breast cancer susceptibility gene in Japanese familial breast cancer.     

Prevalence of BRCA1 and BRCA2 Germline Mutations in Patients of African Descent with Early-Onset and Familial Colombian Breast Cancer

BackgroundPathogenic germline mutations in the BRCA1 and BRCA2 (BRCA1/2) genes contribute to hereditary breast/ovarian cancer (OC) in White/mestizo Colombian women. As there is virtually no genetic data on breast cancer (BC) in Colombians of African descent, we conducted a comprehensive BRCA1/2 mutational analysis of 60 Afro-Colombian families affected by breast/OC.Materials and MethodsMutation screening of the complete BRCA1/2 genes for small-scale mutations and large genomic alterations was performed in these families using next-generation sequencing and multiplex ligation-dependent probe amplification analysis.ResultsFour pathogenic germline mutations, including one novel mutation, were identified, comprising 3 in BRCA1 and one in BRCA2. The prevalence of BRCA1/2 mutations, including one BRCA1 founder mutation (c.5123C>A) previously identified in this sample set, was 3.9% (2/51) in female BC-affected families and 33.3% (3/9) in those affected by both breast and OC. Haplotype analysis of 2 BRCA2_c.2701delC carriers (one Afro-Colombian and one previously identified White/mestizo Colombian patient with BC) suggested that the mutation arose in a common ancestor.ConclusionOur data showed that 2/5 (40%) mutations (including the one previously identified in this sample set) are shared by White/mestizo Colombian and Afro-Colombian populations. This suggests that these 2 populations are closely related. Nevertheless, variations in the BRCA1/2 mutational spectrum among Afro-Colombian subgroups from different regions of the country were observed, suggesting that specific genetic risk assessment strategies need to be developed.     

Distribution of BRCA1 and BRCA2 Mutations in Asian Patients with Breast Cancer

Breast cancer is the most prevalent cancer in Asian females, and the incidence of breast cancer has been increasing in Asia. Because Asian patients develop breast cancer at a younger age than their Caucasian counterparts, the contributions of BRCA1 and BRCA2 (BRCA1/2) mutations in Asians are expected to be different than in Caucasians. The prevalence of BRCA1/2 mutations in the Asian population varies among countries and studies. Most Asian studies have reported more frequent mutations in BRCA2 than in BRCA1, with the exception of studies from India and Pakistan. In addition, the contribution of large genomic rearrangements of BRCA1/2 genes is relatively small in Asian populations in comparison to other ethnic populations. Various statistical models for the prediction of BRCA1/2 mutations have underestimated the risk of having these genetic mutations in Asians, especially in predicting BRCA2 gene mutation. Until recently, BRCA1/2 mutation analyses in Asia were mostly conducted by independent single institutions with different patient selection criteria and using various genotyping methods. However, a couple of Asian groups have initiated nationwide studies collecting BRCA1/2 mutational data. These national collaborative studies will help a comprehensive understanding of the prevalence of BRCA1/2 mutations in the Asian population.     

BRCA1 and BRCA2 Common Mutations in Iranian Breast Cancer Patients: a Meta Analysis

Background: To date several common mutations in BRCA1 and BRCA2 associated with breast cancer havebeen reported in different populations. However, the common BRCA1 and BRCA2 mutations among breastcancer patients in Iran have not been described in detail. Materials and Methods: To comprehensively assessthe frequency and distribution of the most common BRCA1 and BRCA2 mutations in Iranian breast cancerpatients, we conducted this meta-analysis on 13 relevant published studies indentified in a literature searchon PubMed and SID. Results: A total of 11 BRCA1 and BRCA2 distinct common mutations were identified,reported twice or more in the articles, of which 10 (c.2311T>C, c.3113A>G, c.4308T>C, c.4837A>G, c.2612C>T,c.3119G>A, c.3548A>G, c.5213G>A c.IVS16-92A/G, and c.IVS16-68A/G) mutations were in BRCA1, and 1(c.4770A>G) was in BRCA2. The mutations were in exon 11, exon 13, intron 16, and exon 20 of BRCA1 andexon 11 of BRCA2. All have been previously reported in different populations. Conclusions: These meta analysisresults should be helpful in understanding the possibility of any first true founder mutation of BRCA1/BRCA2in the Iranian population. In addition, they will be of significance for diagnostic testing, genetic counseling andfor epidemiological studies.     

乳腺癌BRCA1基因突变及其蛋白表达研究

目的 :探讨散发性乳腺癌的BRCA1基因突变及其蛋白表达与临床病理因素的关系。方法 :收集乳腺癌患者外周血 10 2份、新鲜肿瘤组织 30份 ,分别采用PCR SSCP、DHPLC和基因测序对BRCA1基因第 2、8- 1、8- 2和 2 0外显子进行突变检测 ;对 10 4例肿瘤组织切片进行免疫组化染色标记BRCA1蛋白表达 ,分析免疫组化结果与临床资料的关系。结果 :分别在外显子 8- 1和 8- 2的 2 882 1和 2 8978位点上发现 3例碱基缺失和置换现象。BRCA1蛋白在乳腺癌组织中表达下降 ,且与患者生存状态有关。结论 :在中国散发性乳腺癌患者中BRCA1基因外显子 2、8和 2 0的突变率较低 (2 3% ) ,可以认为在普通中国人群中乳腺癌的发生与该部分碱基序列突变的关系不大 ,但BRCA1蛋白低表达乳腺癌患者复发的危险性增大