中国汉族人群中BRCA1和BRCA2基因突变携带者患乳腺癌风险的研究

背景与目的：BRCA1和BRCA2基因突变携带者终生患乳腺癌和卵巢癌的风险显著增高。通过遗传咨询,突变携带者可采取适当的措施来降低相应肿瘤的发生风险。目前,相关的报道几乎均为白种人,尚缺乏中国人群的资料。该研究旨在探索中国汉族人群中BRCA1和BRCA2基因突变携带者患乳腺癌的风险。方法：回顾20个经基因检测证实携带BRCA1或BRCA2致病性基因突变的汉族乳腺癌高风险家系。利用Kaplan-Meier生存分析法对女性BRCA1/2基因突变携带者单侧乳腺癌及对侧乳腺癌的累积发病风险进行估算。结果：BRCA1和BRCA2基因突变携带者70岁时单侧乳腺癌的累积发病风险(外显率)分别为67.2%(sx 0.100)和76.8%(sx 0.079)。与BRCA1不同的是,BRCA2基因突变携带者70岁后乳腺癌累积发病率继续增加,到80岁时达93.1%。BRCA1/2基因突变携带者对侧乳腺癌10年和20年的累积发病率分别为19.4%(sx 0.089)和50.3%(sx 0.155)。结论：中国汉族人群中BRCA1和BRCA2基因突变携带者具有很高的乳腺癌发病风险。因而对中国高风险人群进行BRCA1/2基因突变检测具有重要临床意义。     

中国汉族BRCA1/2突变的乳腺癌家系中其他肿瘤发病风险分析

目的 研究携带BRCA1/2突变的中国汉族家族性乳腺癌家系中非乳腺癌和卵巢癌的其他肿瘤发病风险.方法 采用聚合酶链反应(PCR)-直接测序法检测465个汉族家族性乳腺癌家系中先证者的BRCA1/2基因胚系突变,比较突变组与非突变组有非乳腺癌和卵巢癌的其他肿瘤家族史的比例.结果 在465例汉族家族性乳腺癌先证者中,BRCA1/2突变者47例(10.1％),非突变者418例(89.9％).在BRCA1/2突变组和非突变组中,两者总的非乳腺癌和卵巢癌的其他肿瘤家族史比例差异无统计学意义(突变组与非突变组,27.7％∶29.9％,x2=0.10,P=0.75);但两组的瘤谱分布有差别,在突变组的家族中最常见肿瘤为胃癌、胰腺癌和前列腺癌;而在非突变组家族中最常见的为肺癌、胃癌和食管癌.进一步分析发现胃癌、胰腺癌和前列腺癌3种肿瘤家族史总的比例在突变组中显著高于非突变组(突变组与非突变组,17％∶7.7％,Fisher精确概率法P=0.048).突变组家族中发生胃癌、胰腺癌和前列腺癌的风险为非突变组家族的2.47倍(95％ CI为1.07 ～ 5.74).结论 在中国汉族家族性乳腺癌患者中,相比较于非BRCA1/2突变家系,BRCA1/2突变患者的家系有相对较高的风险发生胃癌、胰腺癌和前列腺癌.     

中国BRCA1和BRCA2基因胚系突变乳腺癌的临床病理特征比较

  目的   比较中国人群中BRCA1和BRCA2基因两种突变状态的乳腺癌患者临床病理特征的差异。   方法   收集2003年10月至2015年5月北京大学肿瘤医院收治的8 627例连续的、未经家族史和年龄选择的原发性乳腺癌患者资料,经过基因测序共有521例患者携带BRCA1/2基因致病性胚系突变,其中BRCA1突变患者203例,BRCA2突变患者318例。对这些突变患者的临床病理参数进行回顾性分析。   结果   乳腺癌患者中BRCA2基因突变频率（3.7%）高于BRCA1（2.4%）。BRCA1突变者乳腺癌发病年龄比BRCA2突变者早（中位发病年龄:43.0岁 vs. 47.0岁,P<0.01）。BRCA1突变乳腺癌患者组织学分级Ⅲ级比例显著高于BRCA2突变患者（36.2% vs. 18.4%,P<0.01）,三阴性乳腺癌（ER-/PR-/HER2-）比例也显著高于BRCA2突变者（59.2% vs. 15.4%,P<0.01）。BRCA2突变患者的腋窝淋巴结阳性比例高于BRCA1突变患者（41.8% vs. 29.6%,P<0.01）。   结论   中国BRCA1和BRCA2胚系突变乳腺癌的临床病理特征存在一定差异,提示BRCA1和BRCA2胚系突变对乳腺癌生物学行为的影响可能不同,为BRCA1和BRCA2胚系突变乳腺癌更加精准的临床管理提供依据。       

PARP抑制剂治疗BRCA1/2突变转移性乳腺癌的研究进展

近些年PARP抑制剂成为治疗乳腺癌临床研究新热点,大量研究证实其在BRCA1/2突变转移性乳腺癌患者中获益。本文就PARP抑制剂的作用机制和几种PARP抑制剂治疗BRCA1/2突变转移性乳腺癌患者的研究进展进行综述。     

中国BRCA1/2突变阳性和突变阴性乳腺癌病理学特征的比较性研究

背景与目的：BRCA1和BRCA2是两个最主要的遗传性乳腺癌相关基因,本研究旨在发现中国BRCA1/2突变阳性乳腺癌的病理学特征。方法：本研究入组了2012—2016年间287例接受过BRCA1/2基因突变检测的乳腺癌,对其中BRCA1/2突变阳性和突变阴性患者的组织病理学和免疫组织化学检测结果进行了比较性研究。结果：在287例乳腺癌中,66例为BRCA1突变阳性,47例为BRCA2突变阳性,174例为BRCA1/2突变阴性。BRCA1突变的乳腺癌表现为更高的组织学分级（P＜0.001）,更高比例的三阴性乳腺癌（72.7%,P＜0.001）。BRCA1突变阳性和BRCA2突变阳性的乳腺癌中人表皮生长因子受体2（human epidermal growth factor receptor 2,HER2）的阳性表达率较BRCA1/2突变阴性的乳腺癌更低（P＜0.001）。BRCA1突变阳性乳腺癌基底标志物细胞角蛋白5/6（cytokeratin 5/6,CK5/6）和表皮生长因子受体（epidermal growth factor receptor,EGFR）的阳性率为50%,明显高于其他两组（P＜0.001）,雄激素受体（androgen receptor,AR）的阳性率也更低（P＜0.05）。结论：中国BRCA1突变阳性乳腺癌更多为三阴性乳腺癌,具有CK5/6和EGFR的阳性率更高等特点,并且BRCA1和BRCA2突变阳性乳腺癌中HER2受体阳性率也更低。     

乳腺癌BRCA1/2基因大片段重排的研究进展北大核心CSCD

乳腺癌是女性最常见的恶性肿瘤,BRCA1与BRCA2是乳腺癌最重要的易感基因,携带BRCA1/2胚系突变的女性,其乳腺癌的终身患病风险显著增高。BRCA1/2致病性突变多为单个或数个碱基改变引起的移码突变和无义突变,但常规的Sanger测序筛查方法尚不足以发现BRCA1/2其他胚系缺陷类型,如大片段重排。随着基因检测方法的进步,多种BRCA1/2基因重排被发现,在遗传性乳腺癌家族接受常规BRCA1/2基因测序未发现突变的情况下,应认真考虑检测大片段重排,以免漏诊。     

BRCA突变乳腺癌的临床研究进展

BRCA1和BRCA2是遗传性乳腺癌的主要相关基因。随着PARP抑制剂的临床应用,BRCA突变也成为了乳腺癌的治疗靶点。在BRCA突变乳腺癌患者中,talazoparib、veliparib、奥拉帕利、尼拉帕利等PARP抑制剂已被广泛应用在新辅助治疗、辅助治疗和晚期治疗各个阶段,治疗模式有PARP抑制剂单药、联合化疗、联合免疫治疗等多种方式。本文就BRCA突变乳腺癌的临床研究进展进行综述。      

胚系BRCA基因突变乳腺癌的临床诊治进展

BRCA基因是最常见的乳腺癌易感基因,胚系BRCA突变患者罹患乳腺癌的风险显著增加.随着对BRCA基因的深入研究以及聚ADP-核糖聚合酶(poly ADP-ribose polymerase,PARP)抑制剂的出现,BRCA突变已成为乳腺癌治疗的新靶点.在BRCA突变乳腺癌的治疗中,PARP抑制剂和铂类为两大主要药物选...     

BRCA1/2突变乳腺癌临床诊治新进展—机遇和挑战

BRCA1/2胚系突乳腺癌具有特殊的发病机制及临床病理特征,其临床决策有别于散发性乳腺癌。随着基因测序技术的发展,越来越多的BRCA1/2突变乳腺癌被检测出。BRCA1/2突变乳腺癌的相关临床管理越来越得到重视。本文总结近年来的相关文献,对BRCA1/2突变乳腺癌患者的基因检测和手术、化疗、靶向治疗等诊疗进展进行综述,以期为BRCA1/2突变患者的临床决策提供帮助。      

BRCA1、BRCA2基因突变与乳腺癌风险预测及治疗

BRCA1/2基因突变与肿瘤的发生关系密切，其机制主要为BRCA1/2蛋白在细胞分裂过程中对染色体结构和基因序列的完整性起到监护作用，从而预防肿瘤的发生。但BRCA1/2基因突变在乳腺癌中的作用机制始终存在争议。探讨BRCA1/2基因的结构与功能、常见突变类型和位点及它们在乳腺癌临床风险预测中的作用，可为临床靶向治疗提供指导。     

Will Chinese ovarian cancer patients benefit from knowing the BRCA2 mutation status?

In Western countries,the mutation status of the BRCA1 and BRCA2 genes is commonly determined for genetic counseling among members of families with a history of breast or ovarian cancer,especially for w...     

Oral contraceptives and risk of ovarian and breast cancers in BRCA mutation carriers: a meta-analysis

Prophylactic salpingo-oophorectomy is currently the only effective strategy available for decreasing ovarian cancer risk in BRCA1/2 mutation carriers. Significantly decreased risk of ovarian cancer associated with the use of combined oral contraceptives (COCs) was shown in the general population, which could be an alternative approach for those who do not accept risk-reducing surgery. Cohort, case-control and case-case studies published in English up to December 2009 reporting the association of ovarian or breast cancer risk with the use of COCs and presenting BRCA status were selected for meta-analysis. Meta-analysis of three case-control studies showed a significant risk reduction of ovarian cancer in BRCA1/2 mutation carriers who were associated with any past COC use (odds ratio [OR]: 0.57; 95% CI: 0.47-0.70; p < 0.001) and significant trend by duration of COC use (OR: 0.95; 95% CI: 0.93-0.97; p < 0.001). No significant increase in breast cancer risk associated with COC use has been found in case-control studies in BRCA1 (OR: 1.08; p = 0.250), in BRCA2 (OR: 1.03; p = 0.788) mutation carriers or in case-case studies in BRCA1/2 carriers (OR: 0.80; p = 0.147). Significantly increased risk of breast cancer was only shown on a subset of cohort studies in BRCA1 mutation carriers (OR: 1.48; 95% CI: 1.14-1.92). In conclusion, meta-analysis confirmed significantly decreased ovarian cancer risk in BRCA1/2 mutation carriers associated with the use of COCs comparable to the relative extent shown in the general population. Data on the risk of breast cancer associated with COC use in BRCA mutation carriers are heterogeneous and results are inconsistent. COCs can be considered as an alternative strategy in the chemoprevention of ovarian cancer in BRCA1 mutation carriers who do not accept prophylactic salpingo-oophorectomy above the age of 30 years.     

A single nucleotide polymorphism in the 5' untranslated region of RAD51 and risk of cancer among BRCA1/2 mutation carriers.

RAD51 colocalizes with both BRCA1 and BRCA2, and genetic variants in RAD51 would be candidate BRCA1/2 modifiers. We searched for RAD51 polymorphisms by sequencing 20 individuals. We compared the polymorphism allele frequencies between female BRCA1/2 mutation carriers with and without breast or ovarian cancer and between population-based ovarian cancer cases with BRCA1/2 mutations to cases and controls without mutations. We discovered two single nucleotide polymorphisms (SNPs) at positions 135 g-->c and 172 g-->t of the 5' untranslated region. In an initial group of BRCA1/2 mutation carriers, 14 (21%) of 67 breast cancer cases carried a "c" allele at RAD51:135 g-->c, whereas 8 (7%) of 119 women without breast cancer carried this allele. In a second set of 466 mutation carriers from three centers, the association of RAD51:135 g-->c with breast cancer risk was not confirmed. Analyses restricted to the 216 BRCA2 mutation carriers, however, showed a statistically significant association of the 135 "c" allele with the risk of breast cancer (adjusted odds ratio, 3.2; 95% confidence limit, 1.4-40). BRCA1/2 mutation carriers with ovarian cancer were only about one half as likely to carry the RAD51:135 g-->c SNP. Analysis of the RAD51:135 g-->c SNP in 738 subjects from an Israeli ovarian cancer case-control study was consistent with a lower risk of ovarian cancer among BRCA1/2 mutation carriers with the "c" allele. We have identified a RAD51 5' untranslated region SNP that may be associated with an increased risk of breast cancer and a lower risk of ovarian cancer among BRCA2 mutation carriers. The biochemical basis of this risk modifier is currently unknown.     

BRCA1, BRCA2 and TP53 mutations in very early-onset breast cancer with associated risks to relatives

Pathological mutations in BRCA1, BRCA2 and TP53 are associated with an increased risk of breast cancer. This study evaluated mutation frequency of these genes in early-onset breast cancer patients, and correlated this with family history and determined relative risks to family members. Patients with breast adenocarcinoma diagnosed 30 years were ascertained between 1980 and 1997. Family history was established and mutation screening of BRCA1, BRCA2 and TP53 genes was performed. Estimates of penetrance and relative risk were undertaken. DNA was obtained from 100/139 women. 17/36 familial cases had a BRCA1, BRCA2 or TP53 mutation. Of 64 non-familial cases, one BRCA2, two BRCA1 and two TP53 mutations were detected. Penetrance estimates (by age 70) for breast cancer were 84% for BRCA1 mutations and 91% for BRCA2 mutations and for ovarian cancer, 60% and 26%, respectively. Relative risks associated with mutations were consistent with previous studies. BRCA1 and BRCA2 mutations in patients with breast cancer 30 years are predicted strongly by family history. The majority of families with ovarian cancer were due to mutations in BRCA1/2 whereas these mutations only accounted for 30-50% of the excess breast cancers.     

Use of Exogenous Hormones and Risks of Breast and Ovarian Cancers in BRCA1/2 Mutation Carriers; Methodological and Clinical Considerations

Risks of breast and ovarian cancer among BRCA1/2 mutation carriers are high, even for the young. Recommendations for use of exogenous hormones designed for BRCA1/2 mutation carriers may therefore be appropriate. Here we review studies on the associations between oral contraceptives (OC) and hormone-replacement therapy (HRT) use and the risks of breast or ovarian cancer among BRCA1/2 carriers. Almost all studies had a retrospective design. OC use reduced the risk of ovarian cancer, but high uptake of bilateral prophylactic oophorectomy (BPO) renders this protective association hardly relevant for most BRCA1/2 mutation carriers. As long as a positive association between OC use and breast cancer risk cannot be ruled out, it may be necessary to consider alternative methods of contraception. Evidence on HRT is scarce. Assuming similar associations for BRCA1/2 carriers as for the general population it may be advisable to use HRT for a short period only.     

The BOADICEA model of genetic susceptibility to breast and ovarian cancer

Several genes conferring susceptibility to breast and ovarian cancer, notably BRCA1 and BRCA2, have been identified. The majority of the familial aggregation of breast cancer is, however, not explained by these genes. We have previously derived, using segregation analysis, a susceptibility model (BOADICEA, Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) in which susceptibility to these genes is explained by mutations in BRCA1 and BRCA2 together with a polygenic component reflecting the joint multiplicative effect of multiple genes of small effect on breast cancer risk. Here, we consider the predictions made by this model. The overall familial risks of breast cancer predicted by this model are close to those observed in epidemiological studies. The predicted prevalences of BRCA1 and BRCA2 mutations among unselected cases of breast and ovarian cancer are also consistent with observations from population-based studies. These predictions are closer to the observed values than those obtained using the Claus model and BRCAPRO. The predicted mutation probabilities and cancer risks in individuals with a family history (FH) can differ markedly from those predicted by other models. We conclude that this model provides a rational basis for risk assessment in individuals with a FH of breast or ovarian cancer.     

Oral contraceptive use and breast or ovarian cancer risk in BRCA1/2 carriers: A meta-analysis

BackgroundWomen with BRCA1 or BRCA2 mutations are at increased risk of breast and ovarian cancer. Oral contraceptives (OC) use has been associated with a reduction in ovarian cancer risk and with a moderately increased breast cancer risk, which tends to level off in the few years after stopping. The association between oral contraceptive and BRCA1 or BRCA2 gene mutations carriers is unclear.MethodsWe performed a comprehensive literature search updated to March 2010 of studies on the associations between OC users and breast or ovarian cancer for ascertained BRCA1/2 carriers. We obtained summary risk estimated for ever OC users, for duration of use and time since stopping.ResultsA total of 2855 breast cancer cases and 1503 ovarian cancer cases, carrying an ascertained BRCA1/2 mutation, were included in our meta-analyses, based on overall 18 studies. Use of OC was associated with a significant reduced risk of ovarian cancer for BRCA1/2 carriers (summary relative risk (SRR) = 0.50; 95% confidence interval (CI), 0.33–0.75). We also observed a significant 36% risk reduction for each additional 10 years of OC use (SRR: 0.64; 95% CI, 0.53–0.78; P trend < 0.01). We found no evidence of a significant association between OC and breast cancer risk in carriers (SRR: 1.13; 95% CI, 0.88–1.45) and with duration of use. OC formulations used before 1975 were associated with a significant increased risk of breast cancer (SRR: 1.47; 95% 1.06, 2.04), but no evidence of a significant association was found with use of more recent formulations (SRR: 1.17; 95% 0.74, 1.86).ConclusionsOC users carrying an ascertained BRCA1/2 mutation have a reduced risk of ovarian cancer, proportional to the duration of use. There is no evidence that recent OC formulations increase breast cancer risk in carriers.     

Family history of cancer and cancer risks in women with BRCA1 or BRCA2 mutations

Women who carry a deleterious mutation in BRCA1 or BRCA2 have high lifetime risks of breast and ovarian cancers. However, the influence of a family history of these cancers on these risks in women with BRCA mutations is unclear. We calculated cancer incidence rates for a multinational cohort comprising 3011 women with BRCA1 or BRCA2 mutations who were followed up for a mean of 3.9 years, during which time 243 incident breast or ovarian cancers were recorded. The 10-year cumulative risks of breast cancer were 18.1% (95% confidence interval [CI] = 13.3% to 22.8%) for women with a BRCA1 mutation and 15.2% (95% CI = 9.1% to 21.2%) for women with a BRCA2 mutation. Among women with a BRCA1 mutation, the risk of breast cancer increased by 1.2-fold for each first-degree relative with breast cancer before age 50 years (hazard ratio [HR] = 1.21; 95% confidence interval [CI] = 0.94 to 1.57) and the risk of ovarian cancer increased by 1.6 fold for each first- or second-degree relative with ovarian cancer (HR = 1.61; 95% CI = 1.21 to 2.14). Among women with a BRCA2 mutation, the risk of breast cancer increased by 1.7-fold for each first-degree relative younger than 50 years with breast cancer (HR = 1.67; 95% CI = 1.04 to 2.07).     

A novel de novo BRCA1 mutation in a Chinese woman with early onset breast cancer

Germline mutations in the two breast cancer susceptibility genes, BRCA1 and BRCA2 account for a significant portion of hereditary breast/ovarian cancer. De novo mutations such as multiple exon deletion are rarely occurred in BRCA1 and BRCA2. During our mutation screening for BRCA1/2 genes to Chinese women with risk factors for hereditary breast/ovarian cancer, we identified a novel germline mutation, consisting of a deletion from exons 1 to 12 in BRCA1 gene, in a patient diagnosed with early onset triple negative breast cancer with no family history of cancer. None of her parents carried the mutation and molecular analysis showed that this novel de novo germline mutation resulted in down-regulation of BRCA1 gene expression.