Loss of heterozygosity in BRCA1 and BRCA2 markers and high‐grade malignancy in breast cancer

Loss of heterozygosity (LOH) in loci of the 17q21 and 13q1213 regions can collaborate in the inactivation of BRCA1, BRCA2, and possibly other genes implicated in the pathogenesis of breast carcinomas. We investigate allelic losses in microsatellites of the BRCA1 and BRCA2 regions, and their correlations with seven pathologic parameters in 140 breast carcinomas. Those cases showing LOH in the region of the RB gene, 13q14, were excluded from the study. The LOH analysis was performed by amplifying DNA by PCR, using four markers of the 17q21 region (D17S856, D17S855, D17S1323, and D17S1327) and four markers of the 13q1213 region (D13S290, D13S260, D13S310, and D13S267). LOH in the BRCA1 region was found in 47% of tumors, correlating significantly with estrogen receptor content (p = 0.025), progesterone receptors (p = 0.004), higher grade (p = 0.0008), peritumoral vessel invasion (p = 0.001), and lymph node metastases (p = 0.002). When we excluded the cases with LOH in the BRCA2 region and those not informative for it, the significance disappeared. In the BRCA2 region, a rate of LOH of 51% was found; it correlated significantly with estrogen receptor content (p = 0.002), progesterone receptors (p =0.03), peritumoral vessel invasion (p = 0.005), higher grade (p =0.002), and lymph node metastases (p = 0.001). When cases with BRCA1 losses and those not informative were excluded, again the significance disappeared. Concomitant losses in the BRCA1 and BRCA2 regions were found in 32% of cases, correlating significantly with lymph node metastases (p = 0.0002), estrogen receptor content (p = 0.003), progesterone receptors (p = 0.001), histologic grade (p =0.01), and peritumoral vessel invasion (p = 0.0004). These results suggest that concomitant losses in both regions could have a functional effect, influencing the presence of a poor tumor pathophenotype in breast carcinomas.     

Are BRCA1- and BRCA2-related breast cancers associated with increased mortality?

There has been contradictory evidence as to whether BRCA1 associated breast cancers have a poorer prognosis than non-BRCA1 cancers. In this issue of Breast Cancer Research Robson and colleagues provide further evidence for poorer survival in BRCA1 carriers and show that it could be attributed to failure to treat small node-negative grade 3 breast cancers with chemotherapy. There still remains little evidence for a survival difference for BRCA2 related breast cancers. Although the high contralateral breast cancer risk is confirmed by this study there is no real evidence for an increase in ipsilateral recurrence or new primary breast cancers in mutation carriers up to the 10-year point.     

BRCA1和BRCA2的始祖突变

BRCA1和BRCA2的突变与乳腺癌和卵巢癌的发生密切相关。BRCA1和BRCA2的始祖突变多种多样,而且在不同民族、不同地域的人口中突变类型和频率不尽相同。在特定的人口中,始祖突变由于存在始祖效应,其发生率较高。与昂贵的全基因扫描相比,始祖突变检测更加方便、经济和易于普及,能为相关癌症的预防和治疗提供信息。     

Baseline and post prophylactic tubal–ovarian surgery CA125 levels in BRCA1 and BRCA2 mutation carriers

The aim of this study was to determine whether BRCA1 and BRCA2 mutation carriers have different baseline CA125 levels compared with non-carriers, and whether a significant difference in pre- and post-operative CA125 levels exists in BRCA mutation carriers undergoing risk-reducing bilateral salpingo-oophorectomy (RRBSO). The study also considered whether CA125 measurements should continue in unaffected BRCA mutation carriers after RRBSO. 383 Eligible women were identified through retrospective review of the BRCA Carrier Clinic at The Royal Marsden NHS Foundation Trust, London, UK. These women all had CA125 levels measured as they were either a carrier or at risk of a BRCA1 or BRCA2 mutation. Of these, 76 went on to have a negative predictive test for their familial mutation and so are classed as ‘non-carriers’. 133 BRCA1 and 87 BRCA2 carriers had RRBSO, with a further 26 BRCA1 carriers, 28 BRCA2 carriers and one non-carrier developing ovarian cancer. The remaining 21 BRCA1 and 28 BRCA2 carriers did not have RRBSO or develop ovarian cancer in the time of study follow-up. CA125 levels were measured as surveillance or as part of pre-RRBSO care. CA125 measurement post-RRBSO was continued in 48 BRCA1 and 40 BRCA2 carriers. In 154 BRCA1 mutation carriers, the median baseline (i.e. before RRBSO and with no clinical signs of ovarian cancer) CA125 level was 9.0 U/ml (range 2–78) and was 10.0 U/ml (range 1–43) in 115 BRCA2 mutation carriers. When compared with the 75 non-carriers (median baseline CA125 10.0 U/ml; range 2–52), there was no significant difference between the BRCA1, BRCA2 and non-carrier groups. There was a significant reduction in CA125 from pre- to post-RRBSO in 48 BRCA1 carriers (p = 0.04) but no significant difference in 40 BRCA2 mutation carriers (p = 0.5). Out of a total of 220 mutation carriers who underwent RRBSO, two had an incidental ovarian cancer found on histopathology and another developed primary peritoneal cancer during the follow-up period. Our study is the first to compare initial serum CA125 levels in BRCA1 and BRCA2 mutation carriers with those of non-carriers. Our study found no significant difference between the three groups. A drop in CA125 levels after RRBSO in BRCA1 carriers supports the finding of earlier studies, but differed in that the fall was not seen in BRCA2 carriers. The finding of only one case of post-operative peritoneal cancer in 220 carriers undergoing RRBSO supports the discontinuation of post-RRBSO serum CA125 monitoring in BRCA mutation carriers.     

Are the hereditary forms of BRCA1 and BRCA2 breast cancer sensitive to estrogens?

There is emerging evidence from clinical and experimental data that familial breast cancers, including BRCA1 and BRCA2 related forms, could be in fact estrogen-sensitive. Interactions between BRCA1 gene expression and estrogens have been reported. On one hand, BRCA1 expression could be induced by estradiol in experimental models. On the other hand, recent studies indicate that BRCA 1 interacts with and regulates the activity of estrogen receptor ERalpha. Endogenous or exogenous estrogens, such as oral contraceptive, may also increase the risk of breast cancer in BRCA1 mutation carriers in clinical studies. Conversely, prophylactic oophorectomy and anti-estrogens may decrease the risk of familial breast cancer. Prospective studies are thus required to estimate the potential benefits of estrogen suppression therapies for prevention or adjuvant treatment of familial breast cancer. Oral contraception and hormonal replacement therapy after menopause should be used with caution in BRCA1 or BRCA2 mutation carriers.     

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。     

A gene-environment interaction between occupation and BRCA1/BRCA2 mutations in male breast cancer?

The association of male breast cancer (MBC) with a positive breast cancer (BC) family history and with BRCA1/2 germ-line mutations points to a genetic component; a relationship with occupation has also been reported. Recently, we identified pathogenetic BRCA1/2 mutations in a population-based series of Italian MBC patients: here in, we investigated interactions between a carrier status for BRCA1/2 mutations and occupation using a case-case design and estimating case-only odds ratios (CORs). Truck-driving was the most frequent occupation (3/4 BRCA-related cases and 2/19 unrelated cases). An interaction between carrier status and working as a truck-driver emerged, when we classified MBC cases as "ever/never-held" this job title (COR 25.5; 95% Confidence Limits (CL): 1.1-1,412.5) or according to truck-driving as the "longest-held" work (COR 54.0; 95% CL: 1.6-2,997.5). The possible modifying effect on MBC risk in subjects carrying BRCA1/2 germ-line mutations of an occupation characterised by exposure to chemicals such as polycyclic aromatic hydrocarbons (PAH) that are capable of inducing DNA damage, may provide clues to the role of environmental exposures in modifying BC risk in mutation carriers in both genders.     

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BRCA1、BRCA2基因突变及其临床应用

乳腺癌的发生与遗传因素密切相关.研究表明,乳腺癌易感基因(BRCA)1、2在乳腺癌的发生、发展过程中具有重要作用,针对BRCA基因突变的研究对乳腺癌的预防、诊断及治疗具有重要意义.     

Is no news good news? Inconclusive genetic test results in BRCA1 and BRCA2 from patients and professionals' perspectives

Background

Women from families with a high risk of breast or ovarian cancer in which genetic testing for mutations in the BRCA1/2 genes is inconclusive are a vulnerable and understudied group. Furthermore, there are no studies of the professional specialists who treat them - geneticists, genetic counsellors/nurses, oncologists, gynaecologists and breast surgeons.

Methods

We conducted a small qualitative study that investigated women who had developed breast cancer under the age of 45 and who had an inconclusive BRCA1/2 genetic diagnostic test (where no mutations or unclassified variants were identified). We arranged three focus groups for affected women and their close female relatives - 13 women took part. We also interviewed 12 health professionals who were involved in the care of these women.

Results

The majority of the women had a good grasp of the meaning of their own or a family member's inconclusive result, but a few indicated some misunderstanding. Most of the women in this study underwent the test for the benefit of others in the family and none mentioned that they were having the test purely for themselves. A difficult issue for sisters of affected women was whether or not to undertake prophylactic breast surgery. The professionals were sensitive to the difficulties in explaining an inconclusive result. Some felt frustrated that technology had not as yet provided them with a better tool for prediction of risk.

Conclusions

Some of the women were left with the dilemma of what decision to make regarding medical management of their cancer risk. For the most part, the professionals believed that the women should be supported in whatever management decisions they considered best, provided these decisions were based on a complete and accurate understanding of the genetic test that had taken place in the family.     

前列腺癌与BRCA2基因

英国科学家一项新研究发现，男性体内一种“BRCAZ”基因如果因变异而产生缺陷，那么患前列腺癌的危险性有可能比常人高出4至5倍。英国“癌症研究运动”组织科学家伊斯顿博士领导的一个小组，对欧洲和美国173个家族总共近sop名成员进行调查分析后发现，“BRCAZ”基因存在变异的男性，70岁前患上前列腺癌的可能性为1／9，而普通男性的发病可能性只有1／50－‘“BRCAZ”基因于1995年由英国癌症研究所发现，并被命名为官腺癌基因”。在具有乳腺癌遗传史的家族中，l／3的乳腺癌患者与该基因变异有关。研究还表明，“BRCAZ”基因存在变异…     

Inherited predisposition to breast cancer: after the BRCA1 and BRCA2 genes,what next?

Germline mutations of the breast cancer predisposing known genes, BRCA1 and BRCA2, with an autosomal dominant transmission explain only a part of the familial aggregation of breast cancer. Mainly involved in families with cases of ovarian cancer or male breast cancer, they account for a small proportion of families where only female breast cancer cases are observed. A third predisposing gene, called BRCA3, has been sought for a long time but without success. Recently, genetic epidemiology studies have shown evidence for non-mendelian inheritance. The familial residual risk non due to BRCA1 or BRCA2 genes could be explain by a polygenic model, corresponding to the multiplicative effects of several genes, more frequent in population but conferring moderate risks of cancer. The identification of these low penetrance genes is the challenge over the next years. We present here a focusing of recent knowledge on breast cancer predisposing genes, the perspectives of research and their implications in the practice of genetic counselling.     

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...     

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.     

散发性甲状腺癌中BRCA1和BRCA2的表达情况

目的 探讨乳腺癌易感基因1(breast cancer susceptibility gene 1,BRCA1)和乳腺癌易感基因2(breast canc-er susceptibility gene 2,BRCA2)在散发性甲状腺癌中的表达和意义.方法 应用免疫组化法,检测散发性甲状腺癌中BRCA1和BRCA2的表达...     

BRCA1和BRCA2基因与乳腺癌相关的研究进展

BRCA1和BRCA2基因是与乳腺癌尤其是遗传性乳腺癌发生发展密切相关的抑癌基因.研究表明,部分乳腺癌患者存在BRCA1和BRCA2基凶突变,而且出现这两个基因突变的乳腺癌表现出不同的病理学特点.通过检测乳腺癌患者BRCA1和BRCA2基因的突变情况,将有助于对乳腺癌患者预后的早期评估.     

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。