家族性乳腺癌患者及家系成员乳腺癌易感基因携带情况调查

目的 乳腺癌易感基因1(breast cancer susceptibility gene 1,BRCA1)和BRCA2基因已经证实与家族性乳腺癌密切相关.本研究旨在分析中国汉族家族性乳腺癌患者及家系成员BRCA1和BRCA2突变特征及携带情况.方法 收集2013 12-02-2015-06-08军事医学科学院附属医院确诊的中国汉族家族性乳腺癌患者55例及家系成员48名,共计103例样本.柚取外周静脉血提取DNA,应用聚合酶链反应(polymerase chain reaction,PCR) DNA直接测序方法检测BRCA1和BRCA2基因全编码外显子序列.结果 55例家族性乳腺癌患者中发现5个BRCA基因致病性突变位点,1个突变位点乳腺癌信息库中见报道(BRCA1:4730insG),4个为新发现突变位点(BRCA1:1937insC,4538insAG;BRCA2:1382delA,2820delA).家族性乳腺癌患者BRCA1/2突变率为9.09％(BRCA1,5.45％;BRCA2,3.64％),其中三阴性乳腺癌患者突变率为22.22％(x2 =1.99,P=0.20),早发性乳腺癌患者(≤35岁)突变率为20.00％,x2=0.79,P=0.39.48例家系成员检测到3个新发现突变位点(BRCA1:1370insA,3459insA;BRCA2:6502insT),总突变率为6.25％.结论 中国汉族家族性乳腺癌患者BRCA基因突变率显著低于国外,应重点关注有家族史的三阴性乳腺癌患者和早发性乳腺癌患者;家系成员中发现BRCA基因致病性突变,家系成员突变率和发病风险有待进一步研究,应引起重视.     

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BRCA1/ BRCA2基因的突变位点及携带情况.方法:应用聚合酶链反应-单链构象多态性分析(single strand confor- mation polymorphism analysis of polymerase chain reaction 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BRCA1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.     

MUTYH c.892-2A>G剪切位点突变在家族性乳腺癌中的意义

背景与目的：MUTYH基因变异与结直肠癌患癌风险升高有关,但其突变与乳腺癌发生的相关性尚不明确,该研究探讨MUTYH c.892-2A>G剪切位点突变在中国家族性乳腺癌中的意义。方法：采用二代测序(next generation sequencing,NGS)方法检测95个家族性乳腺癌患者及亲属MUTYH基因突变情况,并与BRCA1、BRCA2基因突变情况进行比较。结果：95个家系224名受试者中有4个家系共7名受试者检出MUTYHc.892-2A>G突变,突变率为3.1%,其中只有1例先证者检出MUTYH c.892-2A>G突变。95个家系中也只有1例先证者检出携带BRCA1突变;5个家系中共9名受试者检出携带BRCA2突变,突变率为4.0%。MUTYH c.892-2A>G突变人数分别与BRCA2、BRCA1突变人数相比较,不存在基因共突变现象。结论：MUTYH c.892-2A>G突变虽然在有乳腺癌家族史的高危正常人群中突变率较高,但很可能是低外显的乳腺癌发生相关的致病位点。     

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。     

河北省家族性和散发性乳腺癌易感基因1/2突变的研究

目的探讨河北省家族性和散发性乳腺癌患者乳腺癌易感基因(BRCA)1/2的突变位点及携带情况。方法采用聚合酶链反应-单链构象多态性分析和基因测序技术对18例家族性乳腺癌患者、50例散发性乳腺癌患者、23例乳腺良性疾病患者及20例健康对照组血样标本的基因组DNA进行BRCA1/2基因突变的检测。定性资料采用χ2检验和Fisher's确切概率法进行分析,定量资料采用t检验进行分析。结果 68例乳腺癌患者基因突变率为7.35%(5/68),均发生在BRCA1基因(162ATTTTT;4142GTTGTG;4196CAACAT;4196delA,4142GTTGTG;5379GAAAAA),无BRCA2基因突变,BRCA1基因的突变率高于BRCA2基因(χ2=4.829,P=0.028);其中,18例家族性乳腺癌基因突变3例,50例散发性乳腺癌突变2例,二者间差异无统计学意义(χ2=3.117,P=0.111)。乳腺良性疾病患者未见BRCA1/2基因突变。健康对照组未见BRCA1基因突变,但有1例BRCA2基因突变[TTTCAGA-TGTCAA(6291insG,6294delG)]。家族性乳腺癌患者、散发性乳腺癌患者、乳腺良性疾病患者和健康对照组的BRCA1基因突变率差异有统计学意义(χ2=8.248,P=0.041)。在1例家族性乳腺癌标本中发现1个核苷酸多态性位点,位于BRCA1第20外显子下游第35个碱基处GA(IVS20+35GA)。结论本研究丰富了中国人群BRCA1/2基因的突变谱,并为将来乳腺癌的普查和临床基因检测提供了筛查模式。     

苏州地区乳腺癌患者BRCA1和BRCA2基因突变的分析

目的 探讨中国苏州地区乳腺癌患者乳腺癌易感基因1(BRCA1)和乳腺癌易感基因2(BRCA2)基因的突变位点及携带情况，并对携带致病突变基因患者的家系成员进行基因筛查和风险管理。方法 收集2018年7月至2021年10月确诊的85例乳腺癌患者，其中早发性乳腺癌40例，家族性乳腺癌36例，三阴性乳腺癌35例。采用高通量测序技术，对患者外周血中BRCA1和BRCA2基因的外显子及其部分内含子序列进行检测，将检测到的致病突变与ClinVar数据库进行对照，确定是否为新发现的致病突变。通过对家系先证者进行遗传咨询和肿瘤易感基因检测，进一步对携带致病基因患者的健康家系成员进行BRCA基因突变筛查。结果 85例乳腺癌患者中BRCA1和BRCA2的总致病突变率为21.2%(18/85),其中BRCA1致病突变率为11.8%(10/85), BRCA2致病突变率为9.4%(8/85)。在18例致病性突变患者中发现3个新发位点，分别为BRCA1基因c.1559dupA,BRCA2基因c.8939-8941delinsT和BRCA2基因c.3677-3678insATGAAAT。进一步对携带BRCA1/B...     

丽水市家族性乳腺癌患者BRCA1基因突变分析

摘 要：［目的］ 研究丽水市家族性乳腺癌患者BRCA1基因突变及意义。［方法］ 选取丽水市家族性乳腺癌患者32例,其中5例为双侧乳腺癌,抽取入组患者的外周静脉血,抽提全血基因组DNA,应用 PCR 技术对BRCA1的22个外显子基因序列扩增后直接测序。［结果］ 32例家族性乳腺癌患者中共发现7例BRCA1基因突变,其中2例双侧乳腺癌患者检测出BRCA1基因突变,BRCA1基因突变率为21.86％,8个在BIC数据库中均有报道的突变位点。在第3、11、13号外显子发生3例4个位点同义突变,在第11、16号外显子发生6例4个位点错义突变。突变位点多数位于第11号外显子上,其中有2个同义突变、3个错义突变即2731C>T、3232A>G、3667A>G。［结论］ BRCA1基因突变在丽水市家族性乳腺癌患者中有其自身特点,研究将为丽水市乳腺癌患者的一级和二级预防提供参考依据。     

50例乳腺癌患者BBCA1基因exon11突变研究

[目的]检测50例乳腺癌患者BRCA1基因exon11突变情况及突变位置,探讨BRCA1突变与乳腺癌的关系。[方法]采取50例乳腺癌全血标本为实验组,28例非癌乳腺全血标本为对照组。应用PCR和DNA直接测序法检测所有标本BRCA1基因exon11的突变情况。[结果]28例非癌乳腺组织BRCA1基因exon11未检出突变,50例乳腺癌中有6例发生基因突变。占总例数的12．0％。6例中2例发生多个位点突变,19号标本5个突变位点：2685T→C,2201C→T。2731C→T,3232A→G,3667A→G;30号标本2个突变位点：2685T→C;204T→A。8个位点为错义突变：2532T→C,2685T→C2例,2731C→T,3232A→G,3667A→G2例,2041T→A。3个位点为同义突变：2630T→G2例,2201C→T。发现两个新位点2201位和2731位。[结论]BRCA1基因exon11突变与乳腺癌的发生关系密切,对其进行检测可能对乳腺癌的患病风险评估及早期诊断具有重要意义。     

中国湖南家族性和早发性乳腺癌BRCA1和BRCA2基因突变分析

背景与目的:BRCA1和BRCA2基因是已经证实的乳腺癌遗传易感基因,与家族性及早发性乳腺癌密切相关.本研究旨在分析中国湖南省家族性和早发性乳腺癌中BRCA1和BRCA2基因的突变位点及携带情况.方法:以来自湖南地区的50例家族性和早发性乳腺癌(发病年龄≤35岁)为研究对象,其中26例(52%)有乳腺痛家族史.由静脉血提取基因组DNA,对BRCA1和BRCA2基因的全部编码序列进行扩增.突变分析由变性高效液相色谱分析(DHPLC)进行预筛,之后进行DNA测序证实.结果:在50例乳腺癌患者中发现有5种致病性突变,其中2种为新发现突变--BRCA2基因无义突变2372C>G和移码突变2808delACAA.BRCA1基因中发现一种已报道的无义突变220C>T;其他两种为已报道的BRCA2移码突变位点1796delTTTAT和6275delTT.我们还发现4个未知功能的突变位点(UV)及11个基因多态性位点.湖南家族性乳腺癌中BRCA1突变率4%低于BRCA2突变率16%. 结论:在中国湖南人群中,BRCA2基因的突变对于遗传性乳腺癌的发生可能具有较重要意义:新发现的2个突变位点可能是中国人群中的特有突变;湖南地区BRCA1在家族性乳腺癌中突变率明显低于国内外报道,而BRCA2突变发生率与西方国家相近,但明显高于国内其他地区,这可能是中国湖南人群中的特有特征.     

乳腺癌BRCA1 基因突变的筛查研究

 目的 研究BRCA1基因在散发性乳腺癌中的突变情况，探讨BRCA1基因突变与乳腺癌的关系。方法 应用PCR-SSCP（single-strand conformation polymorphism analysis）分析和DNA直接测序法，检测65例散发性乳腺癌BRCAI第2，3，5，8，10，12，13，14，15，16，17，18，19，20和21外显子基因突变情况。结果 65例中共检测出4例突变，其中1例为5外显子的错义突变（287A〉T），1例为12外显子的错义突变（4285G〉A），1例为17外显子的错义突变（5115T〉C），1例为18外显子的错义突变（5206T〉A）。乳腺癌BRCA1的基因突变率为6．2％（4／65）。结论 BRCA1基因突变与散发性乳腺癌有密切关系。     

Absence of genomic BRCA1 and BRCA2 rearrangements in Ashkenazi breast and ovarian cancer families

A substantial proportion of Ashkenazi Jewish (AJ) breast and ovarian cancer families carry one of three founder mutations in BRCA1 (185delAG, 5382InsC) and BRCA2 (6174delT). Non-founder mutations are identified in another 2–4% of such families. The extent to which major genomic rearrangements in BRCA contribute to breast and ovarian cancer in the Ashkenazim is not well understood. We identified AJ individuals with breast and/or ovarian cancer undergoing hereditary breast/ovarian cancer risk assessment since 2006 without evidence of a deleterious mutation on BRCA gene sequencing who were screened for major gene rearrangements in BRCA1 and BRCA2. For each proband, the pre-test probability of identifying a deleterious BRCA mutation was estimated using the Myriad II model. We identified 108 affected individuals who underwent large rearrangement testing (80 breast cancer, 19 ovarian cancer, nine both breast and ovarian cancer). The mean estimated AJ specific pre-test probability of a deleterious mutation in BRCA1 and BRCA2 was 24.7% (range: 4.4–88.9%). No genomic rearrangements were identified in either the entire group or in the 26 subjects with pre-test mutation prevalence estimates exceeding 30%. Major gene rearrangements involving the BRCA1 and BRCA2 genes appear to contribute little to the burden of inherited predisposition to breast and ovarian cancer in the Ashkenazim.     

Nuclear morphometric features in benign breast tissue and risk of subsequent breast cancer

Germ-line mutations in BRCA1 and BRCA2 are responsible for about 30–60% of the hereditary breast and ovarian cancer (HBOC). A large number of point mutations have been described in both genes. However, large deletions and duplications that disrupt one or more exons are overlooked by point mutation detection approaches. Over the past years several rearrangements have been identified in BRCA1, while few studies have been designed to screen this type of mutations in BRCA2. Our aim was to estimate the prevalence of large genomic rearrangements in the BRCA2 gene in Spanish breast/ovarian cancer families. The multiplex ligation-dependent probe amplification (MLPA) was employed to search gross deletions or duplications of BRCA2 in 335 Spanish moderate to high-risk breast/ovarian cancer families previously screened negative for point mutations by conventional methods. Four different and novel large genomic alterations were consistently identified by MLPA in five families, respectively: deletions of exon 2, exons 10–12 and exons 15–16 and duplication of exon 20 (in two families). RT-PCR experiments confirmed the deletion of exons 15–16. All patients harbouring a genomic rearrangement were members of high-risk families, with three or more breast/ovarian cancer cases or the presence of breast cancer in males. We provide evidence that the BRCA2 rearrangements seem to account for a relatively small proportion of familial breast cancer cases in Spanish population. The screening for these alterations as part of the comprehensive genetic testing can be recommended, especially in multiple case breast/ovarian families and families with male breast cancer cases.     

BRCA1 and BRCA2 germline mutations in 85 Iranian breast cancer patients

Breast cancer is the most common cancer in Iranian women (Mousavi et al in Asian Pac J Cancer Prev 9(2):275–278, 2008). Genetic predisposition accounts for 15% of all breast cancers and germline mutations in breast cancer susceptibility genes, BRCA1 and BRCA2 are responsible for a substantial proportion of high-risk breast and breast/ovarian cancer families (Collaborative Group on Hormonal Factors in Breast Cancer in Lancet 350:1047–1059, 1997; Lee et al in Int Nurs Rev 55:355–359, 2008; Hulka and Stark in Lancet 346:883–887, 1995; Kelsey in Epidemiol Rev 15:256–263, 1993; Tischer et al in J Biol Chem 266:11947–11954, 1991; Newman et al in: Proc Natl Acad Sci USA 85:3044–3048, 1988). Therefore, the aim of this study was to investigate mutations of BRCA1/2 in high risk Iranian families. We screened 85 patients who met our minimal criteria. The entire coding sequences and each intron/exon boundaries of BRCA1/2 genes were screened by direct sequencing. In the present study, we could detect the novel following mutations: p.Glu1735 p.Gly1140Ser, p.Ile26Val, p.Leu1418X, p.Glu23Gln, p.Leu3X, p.Asn1403His, p.Lys581X, p.Pro938Arg, p.Thr77Arg, p.Arg7Cys, p.Ser177Thr, IVS7+83(TT), IVS8−70(-CATT), IVS2+9(-GC), IVS1−20(-GA), IVS1−8(-AG), IVS2+24(AG), IVS5−8 (A–G), IVS2(35–39)TTcctatGAT in BRCA1 and p.Glu1391Gly, 1994_1995 (Ins A), IVS6-70−T>G in BRCA2. In agreement with findings in other populations, we found that family history is a good predictor of being a mutation carrier. Five pathogenic BRCA1 mutations and one pathogenic BRCA2 mutation were detected in 85 index cases.     

Germline mutations in BRCA1 and BRCA2 in breast-ovarian families from a breast cancer risk evaluation clinic.

PURPOSE: Data from the Breast Cancer Linkage Consortium suggest that the proportion of familial breast and ovarian cancers linked to BRCA1 or BRCA2 may be as high as 98% depending on the characteristics of the families, suggesting that mutations in BRCA1 or BRCA2 may entirely account for hereditary breast and ovarian cancer families. We sought to determine what proportion of families with both breast and ovarian cancers seen in a breast cancer risk evaluation clinic are accounted for by coding region germline mutations in BRCA1 and BRCA2 as compared to a linkage study group. We also evaluated what clinical parameters were predictive of mutation status. PATIENTS AND METHODS: Affected women from 100 families with at least one case of breast cancer and at least one case of ovarian cancer in the same lineage were screened for germline mutations in the entire coding regions of BRCA1 and BRCA2 by conformation-sensitive gel electrophoresis, a polymerase chain reaction-based heteroduplex analysis, or direct sequencing. RESULTS: Unequivocal deleterious mutations were found in 55% (55 of 100) of the families studied. Mutations in BRCA1 and BRCA2 accounted for 80% and 20% of the mutations overall, respectively. Using multivariate analysis, the strongest predictors of detecting a mutation in BRCA1 or BRCA2 in this study group were the presence of a single family member with both breast and ovarian cancer (P <.0009; odds ratio [OR], 5.68; 95% confidence interval [CI], 2.04 to 15.76) and a young average age at breast cancer diagnosis in the family (P <.0016; OR, 1.69; 95% CI, 1.23 to 2.38). CONCLUSION: These results suggest that at least half of breast/ovarian families evaluated in a high-risk cancer evaluation clinic may have germline mutations in BRCA1 or BRCA2. Whether the remaining families have mutations in noncoding regions in BRCA1, mutations in other, as-yet-unidentified, low-penetrance susceptibility genes, or represent chance clustering remains to be determined.     

Somatic mutations in the BRCA1 gene in Chinese women with sporadic breast cancer

Recent studies suggested that breast cancer patients who carry a BRCA1 germline mutation benefit from poly (ADP-ribose) polymerase (PARP) inhibitors; therefore, it would be of great interest to detect BRCA1 somatic mutations in sporadic breast cancers. In this study, we detected BRCA1 somatic mutations in tumor cDNA from 144 Chinese women with sporadic breast cancer by using polymerase chain reaction (PCR)-direct sequencing assay. In total, eight BRCA1 alterations (three nonsense mutations and five missense mutations) were identified in this cohort of 144 sporadic breast cancers. We further confirmed that 5 out of 144(3.5%) sporadic breast cancer cases carried a BRCA1 somatic mutation, including two novel nonsense mutations (c.191_212del22 and c.2963C>G) resulting in a truncated protein and three missense mutations (c.114G>T, c.925A>C, and c.824G>A). The two cases with BRCA1 somatic truncating mutations also contained a TP53 somatic mutation in the tumors. Our study suggested that a small subset of sporadic breast cancers do harbor BRCA1 somatic mutations; these patients who carry a BRCA1 somatic mutation may be potential candidates for treatment with PARP inhibitors.     

Reproductive factors in hereditary breast cancer

Background: An early age at menarche, a short menstrual cycle length, and a high age at first full term pregnancy or nulliparity are known risk factors for breast cancer. These risk factors have previously been reported to differ between breast cancer patients with and without a family history of breast cancer and also between breast cancer patients and controls. Methods: Self-administered questionnaires were filled out by 95 women belonging to 24 families with known BRCA1 mutations, 16 women belonging to nine families with known BRCA2 mutations, and 95 women belonging to 65 families with hereditary breast cancer where no BRCA1 or BRCA2 mutations could be detected. Thirty-nine women were BRCA1 mutation carriers and 56 women were BRCA1 negative, 11 women were BRCA2 carriers and five BRCA2 negative. All women were born between 1905 and 1979. Results: Age at menarche, physiological menstrual cycle length at age 30 or at current age in younger women (when not using oral contraceptives), age at first full term pregnancy, and nulliparity did not significantly differ between BRCA1 mutation carriers and BRCA1 negative women. Too few women were BRCA2 negative to serve as a control group. BRCA2 mutation carriers were therefore compared with BRCA1 negative and BRCA2 negative women. None of the above reproductive factors did significantly differ between BRCA2 mutation carriers and from BRCA1 and BRCA2 families. Women from non-BRCA1/BRCA2 hereditary breast cancer families had a higher age at menarche, but this was no longer significant after adjustment for other factors in a multivariate model. Conclusion: Our results suggest that reproductive risk factors of breast cancer are not related to BRCA1 or BRCA2 carrier status. There was also no indication that these factors differ in carriers of unknown susceptibility genes compared with non-carriers from BRCA1 and BRCA2 families.     

<Emphasis Type="Italic">PALB2</Emphasis> analysis in <Emphasis Type="Italic">BRCA2</Emphasis>-like families

BRCA2 and PALB2 function together in the Fanconi anemia (FA)–Breast Cancer (BRCA) pathway. Mono-allelic and bi-allelic BRCA2 and PALB2 mutation carriers share many clinical characteristics. Mono-allelic germline mutations of BRCA2 and PALB2 are risk alleles of female breast cancer and have also been reported in familial pancreatic cancer, and bi-allelic mutations cause a severe form of Fanconi anemia. In view of these similarities, we investigated whether the prevalence of PALB2 mutations was increased in breast cancer families with the occurrence of BRCA2 associated tumours other than female breast cancer. PALB2 mutation analysis was performed in 110 non-BRCA1/2 cancer patients: (a) 53 ovarian cancer patients from female breast-and/or ovarian cancer families; (b) 45 breast cancer patients with a first or second degree relative with pancreatic cancer; and (c) 12 male breast cancer patients from female breast cancer families. One truncating PALB2 mutation, c.509_510delGA, resulting in p.Arg170X, was found in a male breast cancer patient. We conclude that germline mutations of PALB2 do not significantly contribute to cancer risk in non-BRCA1/2 cancer families with at least one patient with ovarian cancer, male breast cancer, and/or pancreatic cancer.     

Evaluation of the BOADICEA risk assessment model in women with a family history of breast cancer

The ability of the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) model to predict BRCA1 and BRCA2 mutations and breast cancer incidence in women with a family history of breast cancer was evaluated. Observed mutations in 263 screened families were compared to retrospective predictions. Similarly, observed breast cancers in 640 women were compared to retrospective predictions of breast cancer incidence. The ratios of observed to expected number of BRCA1- , BRCA2- and BRCA(1 or 2) mutations were 1.43 (95% CI 1.05–1.90), 0.63 (95% CI 0.34–1.08), and 1.12 (95% CI 0.86–1.44), showing a significant underestimation of BRCA1 mutations. Discrimination between carriers and non-carriers as measured by area under the receiver operating characteristic (ROC) curve was 0.83 (95% CI 0.76–0.88). The ratio of observed to expected number of invasive breast cancers was 1.41 (0.91–2.08). The corresponding area under the ROC curve for prediction of invasive breast cancer at individual level was 0.62 (95% CI 0.52–0.73). In conclusion, the BOADICEA model can predict the total prevalence of BRCA(1 or 2) mutations and the incidence of invasive breast cancers. The mutation probability as generated by BOADICEA can be used clinically as a guideline for screening, and thus decrease the proportion of negative mutation analyses. Likewise, individual breast cancer risks can be used for selecting women whose risk of breast cancer indicates follow-up. Application of local mutation frequencies of BRCA1 and BRCA2 could improve the ability to distinguish between the two genes.