Contralateral breast cancer risk in BRCA1 and BRCA2 mutation carriers in a large cohort of unselected Chinese breast cancer patients

To estimate the cumulative risk of contralateral breast cancer (CBC) in BRCA1/2 carriers in a large cohort of unselected Chinese breast cancer patients. Our study comprised 9,401 unselected Chinese breast cancer patients and BRCA1/2 germline mutations were determined in all patients. After a median follow-up of 5.7 years, 181 patients developed CBC in this cohort. Compared to noncarriers, BRCA1 and BRCA2 carriers had a 4.52-fold (95% CI, 2.63–7.76) and 5.54-fold (95% CI, 3.51–8.74) increased risk of CBC, respectively. The 10-year cumulative risk of CBC was 15.5% (95% CI, 9.9–24.2) for BRCA1 carriers, 17.5% (95% CI, 10.9–28.0) for BRCA2 carriers and 3.2% (95% CI, 2.5–4.1) for noncarriers. Younger age at first breast cancer diagnosis was significantly associated with an increased 10-year risk of CBC for BRCA1 carriers (≤40 years vs. >40 years: 21.5% vs. 11.9%, unadjusted hazard ratio [HR] = 2.51, 95% CI, 1.03–6.15, p = 0.044), but not for BRCA2 carriers and noncarriers. The 10-year cumulative CBC risk was significantly higher in both BRCA1 and BRCA2 carriers who had a family history of breast cancer than in those who did not (BRCA1: 27.5% vs. 9.4%, adjusted HR = 2.64, 95% CI, 1.01–6.97, p = 0.049; BRCA2: 27.1% vs. 12.8%, adjusted HR = 2.29, 95% CI, 1.04–5.06, p = 0.040). In conclusion, the risk of CBC was a substantial high in BRCA1/2 carriers in unselected Chinese breast cancer patients, and CBC risk is much more remarkable in both BRCA1 and BRCA2 carriers who had a family history of breast cancer. Younger age at first breast cancer diagnosis also enhanced CBC risk in BRCA1 carriers.     

Predictors of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers

Purpose:

The objective of this study was to estimate the risk of contralateral breast cancer in BRCA1 and BRCA2 carriers; and measure the extent to which host, family history, and cancer treatment-related factors modify the risk.

Patients and methods:

Patients were 810 women, with stage I or II breast cancer, for whom a BRCA1 or BRCA2 mutation had been identified in the family. Patients were followed from the initial diagnosis of cancer until contralateral mastectomy, contralateral breast cancer, death, or last follow-up.

Results:

Overall, 149 subjects (18.4%) developed a contralateral breast cancer. The 15-year actuarial risk of contralateral breast cancer was 36.1% for women with a BRCA1 mutation and was 28.5% for women with a BRCA2 mutation. Women younger than 50 years of age at the time of breast cancer diagnosis were significantly more likely to develop a contralateral breast cancer at 15 years, compared with those older than 50 years (37.6 vs 16.8% P=0.003). Women aged <50 years with two or more first-degree relatives with early-onset breast cancer were at high risk of contralateral breast cancer, compared with women with fewer, or no first-degree relatives with breast cancer (50 vs 36% P=0.005). The risk of contralateral breast cancer was reduced with oophorectomy (RR 0.47; 95% CI 0.30–0.76; P=0.002).

Conclusion:

The risk of contralateral breast cancer risk in BRCA mutation carriers declines with the age of diagnosis and increases with the number of first-degree relatives affected with breast cancer. Oophorectomy reduces the risk of contralateral breast cancer in young women with a BRCA mutation.     

The efficacy of taxane chemotherapy for metastatic breast cancer in BRCA1 and BRCA2 mutation carriers

BACKGROUND:

We assessed the efficacy of taxane chemotherapy in BRCA1‐ and BRCA2‐associated patients compared with sporadic metastatic breast cancer patients.

METHODS:

Response rates (RRs) to and progression‐free survival (PFS) after taxane chemotherapy of 35 BRCA1‐associated and 13 BRCA2‐associated metastatic breast cancer patients were compared with those outcomes in 95 matched (1:2) sporadic patients. Matching was performed for age at and year of diagnosis of primary breast cancer, year of metastatic disease, and line of therapy (first vs second or third).

RESULTS:

Among BRCA1‐associated patients, the RR was worse (objective response [OR], 23% vs 38%; progressive disease [PD], 60% vs 19%; P < 0.001); and the median PFS shorter (2.2 vs 4.9 months; P = 0.04) compared with sporadic patients. In the subgroup of hormone receptor (HRec)‐negative patients, BRCA1‐associated patients (n = 20) had a worse RR (OR, 20% vs 42%, respectively; PD, 70% vs 26%, respectively; P = 0.03) and a shorter PFS (1.8 vs 3.8 months; P = 0.004) compared with sporadic patients (n = 19). These outcomes in HRec‐positive patients were similar in BRCA1‐associated (n = 11) and sporadic (n = 61) patients (OR, 36% vs 38%; PD, 28% vs 20%; median PFS, both 5.7 months). In BRCA2‐associated patients, who were mainly HRec‐positive, the OR was higher than in sporadic patients (89% vs 38%, respectively; P = 0.02), whereas the median PFS was not significantly different (7.1 vs 5.7 months, respectively).

CONCLUSIONS:

BRCA1‐associated, HRec‐negative metastatic breast cancer patients were less sensitive to taxane chemotherapy than sporadic HRec‐negative patients. HRec‐positive BRCA1‐ and BRCA2‐associated patients had a sensitivity to taxane chemotherapy similar to that of sporadic patients. Cancer 2012;. © 2011 American Cancer Society.     

Coffee consumption and breast cancer risk among BRCA1 and BRCA2 mutation carriers

Although there are several plausible biologic mechanisms whereby coffee consumption might influence the risk of breast cancer, epidemiologic evidence is limited. We assessed the association between coffee consumption and breast cancer risk among high-risk women who carry BRCA mutations. We performed a matched case-control analysis on 1,690 women with a BRCA1 or BRCA2 mutation from 40 centers in 4 countries. Average lifetime coffee consumption was estimated via a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for potential confounders, the ORs for breast cancer in BRCA carriers who habitually drank 0, 1-3, 4-5 and 6 or more cups of coffee were 1.00, 0.90 (95% CI 0.72-1.12), 0.75 (95% CI 0.47-1.19) and 0.31 (95% CI 0.13-0.71; p-trend = 0.02). The effect was limited to the consumption of caffeinated coffee. These results suggest that among women with BRCA gene mutation, coffee consumption is unlikely to be harmful and that high levels of consumption may in fact be related to reduced breast cancer risk.     

Diabetes and breast cancer among women with BRCA1 and BRCA2 mutations

BACKGROUND:

Hyperinsulinemia and the metabolic syndrome are both risk factors for breast cancer. It is not clear if diabetes is associated with the risk of breast cancer in women with a BRCA1 or BRCA2 mutation.

METHODS:

The authors reviewed the medical histories of 6052 women with a BRCA1 or BRCA2 mutation, half of whom had been diagnosed with breast cancer. They estimated the odds ratio for breast cancer, given a self‐report of diabetes. They then estimated the hazard ratio for a new diagnosis of diabetes associated with a history of breast cancer.

RESULTS:

There was no excess of diabetes in the period before the diagnosis of breast cancer, compared with controls with no diagnosis of breast cancer. The risk of diabetes was doubled among BRCA carriers in the 15‐year period after the diagnosis of breast cancer (relative risk, 2.0; 95% confidence interval [CI], 1.4‐2.8; P = .0001), compared with carriers without cancer. The risk was particularly high for women with a body mass index (BMI) >25.0 kg/m² (odds ratio, 5.8; 95% CI, 4.0‐8.6; P = .0001).

CONCLUSIONS:

After a diagnosis of breast cancer, women with a BRCA1 or BRCA2 mutation face a 2‐fold increase in the risk of diabetes, which is exacerbated by a high BMI. Cancer 2011. © 2010 American Cancer Society.     

BRCA1相关A蛋白复合物基因单核苷酸多态性与三阴性乳腺癌易感性研究

背景与目的：BRCA1突变与三阴性乳腺癌发病相关目前已得到学者公认。该研究旨在分析BRCA1相关A蛋白复合物相关基因的单核苷酸多态性(single nucleotide polymorphisms,SNP)与三阴性乳腺癌发病风险的关系,寻找和确定与汉族人群三阴性乳腺癌遗传易感性相关的基因型和单体型。方法：2008年-2011年间414例在复旦大学附属肿瘤医院接受原发性乳腺癌手术的三阴性乳腺癌患者和354例健康妇女进入本病例对照研究。通过对Abraxas、BRE、Rap80、NBA1和BRCC36基因组DNA的37个SNP位点的检测,分析它们与三阴性乳腺癌的相关性。研究者随后检测了652例其他类型乳腺癌和890例健康女性的DNA以证实发现的SNP是否为三阴性特有的遗传相关位点。结果：该研究在第一步研究中发现,NBA1启动子区rs7250266位点突变的G等位基因在三阴性乳腺癌患者中的频率显著低于在正常女性中的频率(0.14 vs 0.19,P<0.01)。对rs7250266位点基因分型显示：与携带CC基因型个体比较,携带GC型个体的三阴性乳腺癌的发病风险显著降低(GC∶OR=0.70,95%CI：0.51~0.97;GG∶OR=0.48,95%CI：0.21~1.07,P=0.03)。单体型分析也证实NBA1基因的不同单体型间三阴性乳腺癌发病风险不同。第二步的研究结果显示,rs7250266位点突变在非三阴性的乳腺癌与正常人群中差异无统计学意义(0.19 vs 0.18,P=0.85)。结论：NBA1基因的rs7250266位点的单核苷酸多态性与汉族女性的三阴性乳腺癌发病风险相关,其突变型等位基因携带者罹患三阴性乳腺癌的风险低于野生型等位基因携带者。     

Smoking and the risk of breast cancer among carriers of BRCA mutations

The effect of cigarette smoking on the risk of breast cancer is controversial, although most studies show little or no effect. It has been suggested that smoking may reduce the risk of developing hereditary breast cancer. We completed a case-control study on 1,097 women with breast cancer who were BRCA1 or BRCA2 mutation carriers and 1,097 age-matched controls with a mutation in the same gene but without breast cancer. There were no statistically significant differences between the cases and controls in terms of the number of current and ex-smokers (41.2% and 40.4%, respectively) or the age at smoking commencement (18.2 years and 18.5 years, respectively). There were no statistically significant differences between cases and controls regarding beginning smoking within 5 years of menarche (OR = 1.03; 95% CI 0.83 to l.28) or before the first pregnancy (OR = 1.09; 95% CI = 0.90 to 1.33). In conclusion, contrary to our previous report, smoking does not appear to be a risk factor for breast cancer among carriers of BRCA mutations.     

The risk of breast cancer in women with a BRCA1 mutation from North America and Poland

Women with a BRCA1 mutation face a high lifetime risk of breast cancer. It is unknown to what extent environmental factors modify the inherent genetic risk. If women from different countries, but with similar mutations, experience different levels of cancer risk, nongenetic risk modifiers are likely to be present. Study subjects were a cohort of 1477 women with a BRCA1 mutation, from Canada (n = 358), the United States (n = 256) and Poland (n = 863). The women were followed for a mean of 4.3 years and 130 incident cases of breast cancer were recorded. Annual cancer incidence rates were calculated, and based on these, penetrance curves were constructed for women from North America and Poland. In a Cox proportional hazards model, residence in Poland, versus North America, was associated with an adjusted hazard ratio of 0.54 (95% CI 0.34-0.86; p = 0.01). The risk of breast cancer to age 70 was estimated to be 49% for women from Poland and 72% for women from North America. Among women with BRCA1 mutations, the risk of breast cancer in women who reside in Poland is less than that of women who reside in North America. The reasons for the difference are unknown, but this observation suggests that environmental factors or genetic modifiers are important in determining risk.     

Collaboration of breast cancer clinic and genetic counseling division for BRCA1 and BRCA2 mutation family in Japan

BACKGROUND: BRCA1 and BRCA2 mutations cause high breast cancer incidence rates as high as 80% Although prophylactic therapy is still controversial, several prophylactic therapies have been proposed and tried for BRCA1 and BRCA2 mutation carriers. Prophylactic surgery, chemo-prevention and precise screening have been proposed as prophylactic therapy. All BRCA1 and BRCA2 mutation carriers need knowledge about their disease and the countermeasures that are used to protect against onset of disease. Counseling plays an important role in this regard for people with genetic diseases. Therefore, collaboration between breast cancer clinics and genetic counseling services is the most important issue in clinical practice. Our group consists of three national universities and a general hospital. In this article we describe our trial to construct a clinical system against hereditary breast cancer as an interim report for the Japanese Ministry of Health, Labour and Welfare. PATIENTS AND METHODS: Twenty familial breast cancer patients were registered in this study. The whole sequence of BRCA1 and BRCA2 were analyzed. If pathological mutations were detected, their first degree families were introduced to the counseling division at each institute when candidates visited counseling divisions. RESULTS AND DISCUSSION: Four cases of a deleterious mutation in BRCA1 or BRCA2 were detected among 20 cases. Their first degree relatives are now under consideration for visiting counseling divisions. The clinical system described in this study should play a role to protect BRCA1 or BRCA2 mutation carriers in Japan.     

BRCA1 expression modulates chemosensitivity of BRCA1-defective HCC1937 human breast cancer cells

Germline mutations of the tumour suppressor gene BRCA1 are involved in the predisposition and development of breast cancer and account for 20-45% of all hereditary cases. There is an increasing evidence that these tumours are characterised by a specific phenotype and pattern of gene expression. We have hypothesised that differences in chemosensitivity might parallel molecular heterogeneity of hereditary and sporadic breast tumours. To this end, we have investigated the chemosensitivity of the BRCA1-defective HCC1937 breast cancer cell line, and the BRCA1-competent MCF-7 (hormone-sensitive) and MDA-MB231 (hormone-insensitive) breast cancer cell lines using the MTT assay. The 50% inhibitory concentration (IC(50)) for the individual compounds were derived by interpolate plot analysis of the logarithmic scalar concentration curve after a 48 h exposure. HCC1937 cells were significantly (P<0.005) more sensitive to cisplatin (CDDP) (IC(50) : 30-40 microM) compared with MCF-7 (IC(50) : 60-70 microM) and MDA-MB231 (IC(50) : 90-100 microM) cells. On the other hand, BRCA1-defective breast cancer cells were significantly less sensitive to doxorubicin (Dox) (IC(50) : 45-50 microM) compared with MCF-7 (IC(50) : 1-5 microM) and MDA-MB231 (IC(50) : 5-10 microM) (P<0.02), as well as to paclitaxel (Tax) (IC(50) : >2 microM for HCC1937, 0.1-0.2 microM for MCF-7 and 0.01-0.02 microM for MDA-MB231) (P<0.001). Full-length BRCA1 cDNA transfection of BRCA1-defective HCC1937 cells led to the reconstituted expression of BRCA1 protein in HCC1937/(WT)BRCA1-derived cell clone, but did not reduce tumour cell growth in soft agar. BRCA1 reconstitution reverted the hypersensitivity to CDDP (P<0.02), and restored the sensitivity to Dox (P<0.05) and Tax (P<0.001), compared with parental HCC1937 cells. Taken together, our findings suggest a specific chemosensitivity profile of BRCA1-defective cells in vitro, which is dependent on BRCA1 protein expression, and suggest prospective preclinical and clinical investigation for the development of tailored therapeutical approaches in this setting.     

MicroRNA expression signatures for the prediction of BRCA1/2 mutation‐associated hereditary breast cancer in paraffin‐embedded formalin‐fixed breast tumors

Screening for germline mutations in breast cancer‐associated genes BRCA1 and BRCA2 is indicated for patients with breast cancer from high‐risk breast cancer families and influences both treatment options and clinical management. However, only 25% of selected patients test positive for BRCA1/2 mutation, indicating that additional diagnostic biomarkers are necessary. We analyzed 124 formalin‐fixed paraffin‐embedded (FFPE) tumor samples from patients with hereditary (104) and sporadic (20) invasive breast cancer, divided into two series (A and B). Microarray expression profiling of 829 human miRNAs was performed on 76 samples (Series A), and bioinformatics tool Prophet was used to develop and test a microarray classifier. Samples were stratified into a training set (n = 38) for microarray classifier generation and a test set (n = 38) for signature validation. A 35‐miRNA microarray classifier was generated for the prediction of BRCA1/2 mutation status with a reported 95% (95% CI = 0.88–1.0) and 92% (95% CI: 0.84–1.0) accuracy in the training and the test set, respectively. Differential expression of 12 miRNAs between BRCA1/2 mutation carriers versus noncarriers was validated by qPCR in an independent tumor series B (n = 48). Logistic regression model based on the expression of six miRNAs (miR‐142‐3p, miR‐505*, miR‐1248, miR‐181a‐2*, miR‐25* and miR‐340*) discriminated between tumors from BRCA1/2 mutation carriers and noncarriers with 92% (95% CI: 0.84–0.99) accuracy. In conclusion, we identified miRNA expression signatures predictive of BRCA1/2 mutation status in routinely available FFPE breast tumor samples, which may be useful to complement current patient selection criteria for gene testing by identifying individuals with high likelihood of being BRCA1/2 mutation carriers.     

Opposing effects of BRCA1 mRNA expression on patient survival in breast and colorectal cancer and variations among African American,Asian, and younger patients

Breast cancer (BC) and colorectal cancer (CRC) are common and show poor survival in advanced stages. Using The Cancer Genome Atlas (TCGA) computational tool cBioPortal, we evaluated overall patient survival in BRCA1 mRNA-low versus -high cohorts (<−1.29 versus >1.05 SD from mean BRCA1 expression, respectively). Analysis included 1082 BC patients with mRNA data (PanCancer Atlas), 382 CRCs (Firehose Legacy) and 592 CRCs (PanCancer Atlas). As previously reported, BRCA1 mRNA-low tumor expression positively correlated with BC patient survival but was negatively associated in CRC. We observed a correlation between BRCA1 mRNA-high and age <45 years at CRC diagnosis using a Fisher’s exact test [Firehose Legacy database (p-value = 0.0091); CRC PanCancer Atlas (p-value = 0.0778)]. We correlated BRCA1 mRNA-low expression and basal BC (p-value = 0.0016) and BRCA1 mRNA-low tumors and frequency of African American patients (p-value = 0.0448) with BC. Other trends included higher frequency of advanced lymph node stage and mucinous adenocarcinoma among BRCA1 mRNA-low CRC and higher frequency of males in BRCA1 mRNA-high BC and CRC. African Americans more frequently had BRCA1 mRNA-low BC and BRCA1 mRNA-high CRC and the opposite was observed among Asians. Using a gene co-expression tool (cBioPortal), we observed TOP2A and ATAD5 levels correlate (Spearman’s correlation>0.6) with BRCA1 in BC and CRC, whereas LMNB2 correlates with BRCA1 in CRC, suggesting tissue-specific BRCA1 interactions. Our results indicate potential for BRCA1 mRNA expression levels as a prognostic biomarker in BC and CRC, suggest tissue-specificity in BRCA1 molecular interactions, and point to BRCA1 mRNA-high levels as a characteristic of CRC tumors in younger versus older individuals.     

Tamoxifen and contralateral breast cancer in BRCA1 and BRCA2 carriers: an update

Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80%, and following the first diagnosis the 10-year risk of contralateral breast cancer is approximately 30%. It has been shown that both tamoxifen and oophorectomy prevent contralateral breast cancer, but it is not clear whether there is a benefit in giving tamoxifen to women who have previously undergone an oophorectomy. Furthermore, the relative degree of protection in BRCA1 and BRCA2 carriers has not been well evaluated. We studied 285 women with bilateral breast cancer and a BRCA1 or BRCA2 mutation, and 751 control women with unilateral breast cancer and a BRCA1 or BRCA2 mutation in a matched case-control study. Control women were of similar age and had a similar age of diagnosis of breast cancer and had been followed for as long as the case for a second primary breast cancer. The history of tamoxifen use for treating the first breast cancer was compared between bilateral and unilateral cases. The multivariate odds ratio for contralateral breast cancer associated with tamoxifen use was 0.50 for carriers of BRCA1 mutations (95% CI, 0.30-0.85) and was 0.42 for carriers of BRCA2 mutations (95% CI, 0.17-1.02). The protective effect of tamoxifen was not seen among women who had undergone an oophorectomy (OR = 0.83; 95%CI, 0.24-2.89) but this subgroup was small. In contrast, a strong protective effect of tamoxifen was apparent among women who were premenopausal or who had undergone natural menopause (OR = 0.44; 95% CI, 0.27-0.65).     

miRNA expression patterns in normal breast tissue and invasive breast cancers of BRCA1 and BRCA2 germ-line mutation carriers

miRNA deregulation has been found to promote carcinogenesis. Little is known about miRNA deregulation in hereditary breast tumors as no miRNA expression profiling studies have been performed in normal breast tissue of BRCA1 and BRCA2 mutation carriers. miRNA profiles of 17 BRCA1- and 9 BRCA2-associated breast carcinomas were analyzed using microarrays. Normal breast tissues from BRCA1 and BRCA2 mutation carriers (both n = 5) and non-mutation carriers (n = 10) were also included. Candidate miRNAs were validated by qRT-PCR. Breast carcinomas showed extensive miRNA alteration compared to normal breast tissues in BRCA1 and BRCA2 mutation carriers. Moreover, normal breast tissue from BRCA1 mutation carriers already showed miRNA alterations compared to non-mutation carriers. Chromosomal distribution analysis showed several hotspots containing down- or up-regulated miRNAs. Pathway analysis yielded many similarities between the BRCA1 and BRCA2 axes with miRNAs involved in cell cycle regulation, proliferation and apoptosis. Lesser known pathways were also affected, including cellular movement and protein trafficking. This study provides a comprehensive insight into the potential role of miRNA deregulation in BRCA1/2-associated breast carcinogenesis. The observed extensive miRNA deregulation is likely the result of genome-wide effects of chromosomal instability caused by impaired BRCA1 or BRCA2 function. This study''s results also suggest the existence of common pathways driving breast carcinogenesis in both BRCA1 and BRCA2 germ-line mutation carriers.     

A role for BRCA1 in sporadic breast cancer

To test the hypothesis that altered expression of BRCA1 protein may play an important role in sporadic breast cancer development, 50 randomly selected primary breast cancers (frozen sections, 5 years' median follow-up) were immunolabelled with two monoclonal BRCA1 antibodies (MS110 and MS13). MS110 labelling was exclusively nuclear showing no relation to outcome or tumour pathology. Western blotting demonstrated crossreactivity, suggesting antibody nonspecificity. MS13 labelling was predominantly cytoplasmic. Intense labelling predicted decreased overall survival (P=0.012), disease-free survival (P=0.029), oestrogen receptor negativity (P=0.0004) and c-erbB-2 overexpression (P=0.006). Western blotting detected a 110 kDa molecule consistent with BRCA1 delta11b splice variant. BRCA1 protein is postulated to function as a tumour suppressor. We demonstrate cytoplasmic localisation in sporadic breast cancer suggesting excess delta11b splice variant production, reduced production of full-length BRCA1 and thus postulate reduced tumour suppressor activity. BRCA1 protein appears to have a significant role in both sporadic and hereditary breast cancers.     

The association between smoking and cancer incidence in BRCA1 and BRCA2 mutation carriers

Tobacco smoke is an established carcinogen, but the association between tobacco smoking and cancer risk in BRCA mutation carriers is not clear. The aim of this study was to evaluate prospectively the association between tobacco smoking and cancer incidence in a cohort of BRCA1 and BRCA2 mutation carriers. The study population consisted of unaffected BRCA mutation carriers. Information on lifestyle including smoking histories, reproductive factors, and past medical histories was obtained through questionnaires. Incident cancers were updated biennially via follow‐up questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using time‐dependent Cox regression models. There were 700 incident cancers diagnosed over 26,711 person‐years of follow‐up. The most frequent cancers seen in BRCA mutation carriers were breast (n = 428; 61%) and ovarian (n = 109; 15%) cancer. Compared to nonsmokers, (ever) smoking was associated with a modest increased risk of all cancers combined (HR = 1.17; 95%CI 1.01–1.37). Women in the highest group of total pack‐years (4.3–9.8) had an increased risk of developing any cancer (HR = 1.27; 95%CI 1.04–1.56), breast cancer (HR = 1.33, 95%CI 1.02–1.75), and ovarian cancer (HR = 1.68; 95%CI 1.06–2.67) compared to never smokers. The associations between tobacco smoking and cancer did not differ by BRCA mutation type or by age at diagnosis. This prospective study suggests that tobacco smoking is associated with a modest increase in the risks of breast and ovarian cancer among women with BRCA1 or BRCA2 mutation.     

乳腺癌易感基因蛋白在乳腺癌组织中的表达及其与临床病理关系

目的 :探讨乳腺癌易感基因 (BRCA1 )蛋白在乳腺癌组织中的表达以及与乳腺癌临床病理的关系 ,了解BRCA1 蛋白的表达与P53及C -erbB2 表达之间的相关性。方法 :采用LDP免疫组化法对 60例乳腺癌 ,1 0例乳腺良性疾病患者的石腊标本进行了BRCA1 蛋白 ,P53 ,C -erbB2 的联合检测 ,结合患者的年龄、家族史、病理组织学分级 ,腋淋巴结的转移情况 ,雌、孕激素受体状况等因素进行相关分析。结果 :BRCA1 蛋白的阳性表达率在恶性组为 61 .66 % (37 60 ) ,在良性组表达为 0 (0 1 0 )。BRCA1 蛋白的表达绝大部分为胞质表达。BRCA1 蛋白的表达与年龄呈负相关 (r=- 0 .2 95 ,P <0 .0 5) ,与家族史呈正相关 (r=0 .50 9,P <0 .0 1 )BRCA1 蛋白的表达在不同组织学分级中 (Ⅰ～Ⅲ )存在差异 (P <0 .0 5) ,随着组织学分级的增加BRCA1 蛋白阳性表达的程度也增高 (r=0 .41 3 ,P <0 .0 1 ) ,BRCA1 蛋白的表达在有无腋淋巴结转移的病例中存在差异 (P <0 .0 5) ,随着腋淋巴结转移数目的增加 ,BRCA1 蛋白阳性表达的程度也增高 (r=0 .365 ,P <0 .0 1 )。BRCA1 蛋白的表达与ER、PR之间以及与P53及C -erbB2表达之间本研究未见其相关性。结论 :BRCA1 蛋白的表达与年轻、有家族史 ,组织学分级高 ,腋淋巴结转移相关 ,随着进一步研究的深     

BRCA1 and BRCA2 mutations among breast cancer patients from the Philippines

Age-adjusted incidence rates of breast cancer vary more than 10-fold worldwide, with the highest rates reported in North America and Europe. The highest breast cancer incidence rates in Southeast Asia have been reported for the Manila Cancer Registry in the Philippines, with an age-standardized rate of 47.7 per 100,000 per year. The possible contribution of hereditary factors to these elevated rates has not been investigated. We conducted a case-control study of 294 unselected incident breast cancer cases and 346 female controls from Manila, Philippines. Cases and controls were selected from women below the age of 65 undergoing evaluation at the PGH in Manila because of a suspicious breast mass. Molecular analysis identified 12 BRCA2 mutations and 3 BRCA1 mutations. We estimate the prevalence of BRCA mutations among unselected breast cancer cases in the Philippines to be 5.1% (95% CI: 2.6-7.6%), with a prevalence of 4.1% (95% CI: 1.8-6.4%) for BRCA2 mutations alone. The BRCA2 4265delCT and 4859delA mutations were found in 2 and 4 unrelated cases, respectively; haplotype analysis confirmed that these, and the BRCA1 5454delC mutation, are founder mutations. BRCA2 mutations were also found in 2 of 346 controls (0.6%; 95% CI: 0.2-1.4%). Compared with non-carrier cases, the cumulative risk of breast cancer for first-degree relatives of mutation carriers was 24.3% to age 50, compared with <4% for first-degree relatives of non-carrier cases (RR = 6.6; 95% CI: 2.6-17.2; p= 7.5 x 10(-6)). Our data suggest that penetrance of BRCA mutations is not reduced in the Philippines. Germline mutations in the BRCA2 gene contribute more than mutations BRCA1 to breast cancer in the Philippines, due in large part to the presence of 2 common founder mutations.