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1.
A population-based series of 649 unselected incident cases of ovarian cancer diagnosed in Ontario, Canada, during 1995-96 was screened for germline mutations in BRCA1 and BRCA2. We specifically tested for 11 of the most commonly reported mutations in the two genes. Then, cases were assessed with the protein-truncation test (PTT) for exon 11 of BRCA1, with denaturing gradient gel electrophoresis for the remainder of BRCA1, and with PTT for exons 10 and 11 of BRCA2. No mutations were found in all 134 women with tumors of borderline histology. Among the 515 women with invasive cancers, we identified 60 mutations, 39 in BRCA1 and 21 in BRCA2. The total mutation frequency among women with invasive cancers, 11.7% (95% confidence interval [95%CI] 9.2%-14.8%), is higher than previous estimates. Hereditary ovarian cancers diagnosed at age <50 years were mostly (83%) due to BRCA1, whereas the majority (60%) of those diagnosed at age >60 years were due to BRCA2. Mutations were found in 19% of women reporting first-degree relatives with breast or ovarian cancer and in 6.5% of women with no affected first-degree relatives. Risks of ovarian, breast, and stomach cancers and leukemias/lymphomas were increased nine-, five-, six- and threefold, respectively, among first-degree relatives of cases carrying BRCA1 mutations, compared with relatives of noncarriers, and risk of colorectal cancer was increased threefold for relatives of cases carrying BRCA2 mutations. For carriers of BRCA1 mutations, the estimated penetrance by age 80 years was 36% for ovarian cancer and 68% for breast cancer. In breast-cancer risk for first-degree relatives, there was a strong trend according to mutation location along the coding sequence of BRCA1, with little evidence of increased risk for mutations in the 5' fifth, but 8.8-fold increased risk for mutations in the 3' fifth (95%CI 3.6-22.0), corresponding to a carrier penetrance of essentially 100%. Ovarian, colorectal, stomach, pancreatic, and prostate cancer occurred among first-degree relatives of carriers of BRCA2 mutations only when mutations were in the ovarian cancer-cluster region (OCCR) of exon 11, whereas an excess of breast cancer was seen when mutations were outside the OCCR. For cancers of all sites combined, the estimated penetrance of BRCA2 mutations was greater for males than for females, 53% versus 38%. Past studies may have underestimated the contribution of BRCA2 to ovarian cancer, because mutations in this gene cause predominantly late-onset cancer, and previous work has focused more on early-onset disease. If confirmed in future studies, the trend in breast-cancer penetrance, according to mutation location along the BRCA1 coding sequence, may have significant impact on treatment decisions for carriers of BRCA1-mutations. As well, BRCA2 mutations may prove to be a greater cause of cancer in male carriers than previously has been thought.  相似文献   

2.
Ovarian cancer is a component of the autosomal-dominant hereditary breast-ovarian cancer syndrome and may be due to a mutation in either the BRCA1 or BRCA2 genes. Two mutations in BRCA1 (185delAG and 5382insC) and one mutation in BRCA2 (6174delT) are common in the Ashkenazi Jewish population. One of these three mutations is present in approximately 2% of the Jewish population. Each mutation is associated with an increased risk of ovarian cancer, and it is expected that a significant proportion of Jewish women with ovarian cancer will carry one of these mutations. To estimate the proportion of ovarian cancers attributable to founding mutations in BRCA1 and BRCA2 in the Jewish population and the familial cancer risks associated with each, we interviewed 213 Jewish women with ovarian cancer at 11 medical centers in North America and Israel and offered these women genetic testing for the three founder mutations. To establish the presence of nonfounder mutations in this population, we also completed the protein-truncation test on exon 11 of BRCA1 and exons 10 and 11 of BRCA2. We obtained a detailed family history on all women we studied who had cancer and on a control population of 386 Ashkenazi Jewish women without ovarian or breast cancer. A founder mutation was present in 41.3% of the women we studied. The cumulative incidence of ovarian cancer to age 75 years was found to be 6.3% for female first-degree relatives of the patients with ovarian cancer, compared with 2.0% for the female relatives of healthy controls (relative risk 3.2; 95% CI 1.5-6.8; P=.002). The relative risk to age 75 years for breast cancer among the female first-degree relatives was 2.0 (95% CI 1.4-3.0; P=.0001). Only one nonfounder mutation was identified (in this instance, in a woman of mixed ancestry), and the three founding mutations accounted for most of the observed excess risk of ovarian and breast cancer in relatives.  相似文献   

3.
The population of Pakistan has been reported to have the highest rate of breast cancer of any Asian population (excluding Jews in Israel) and one of the highest rates of ovarian cancer worldwide. To explore the contribution that genetic factors make to these high rates, we have conducted a case-control study of 341 case subjects with breast cancer, 120 case subjects with ovarian cancer, and 200 female control subjects from two major cities of Pakistan (Karachi and Lahore). The prevalence of BRCA1 or BRCA2 mutations among case subjects with breast cancer was 6.7% (95% confidence interval [CI] 4.1%-9.4%), and that among case subjects with ovarian cancer was 15.8% (95% CI 9.2%-22.4%). Mutations of the BRCA1 gene accounted for 84% of the mutations among case subjects with ovarian cancer and 65% of mutations among case subjects with breast cancer. The majority of detected mutations are unique to Pakistan. Five BRCA1 mutations (2080insA, 3889delAG, 4184del4, 4284delAG, and IVS14-1A-->G) and one BRCA2 mutation (3337C-->T) were found in multiple case subjects and represent candidate founder mutations. The penetrance of deleterious mutations in BRCA1 and BRCA2 is comparable to that of Western populations. The cumulative risk of cancer to age 85 years in female first-degree relatives of BRCA1-mutation-positive case subjects was 48% and was 37% for first-degree relatives of the BRCA2-mutation-positive case subjects. A higher proportion of case subjects with breast cancer than of control subjects were the progeny of first-cousin marriages (odds ratio [OR] 2.1; 95% CI 1.4-3.3; P=.001). The effects of consanguinity were significant for case subjects with early-onset breast cancer (age <40 years) (OR=2.7; 95% CI 1.5-4.9; P=.0008) and case subjects with ovarian cancer (OR=2.4; 95% CI 1.4-4.2; P=.002). These results suggest that recessively inherited genes may contribute to breast and ovarian cancer risk in Pakistan.  相似文献   

4.
Studies of families with breast cancer have indicated that male carriers of BRCA2 mutations are at increased risk of prostate cancer, particularly at an early age. To evaluate the contribution of BRCA2 mutations to early-onset prostate cancer, we screened the complete coding sequence of BRCA2 for germline mutations, in 263 men with diagnoses of prostate cancer who were 相似文献   

5.
Cancer occurrence in 164 families with breast/ovarian cancer and germline BRCA2 mutations was studied to evaluate the evidence for genotype-phenotype correlations. Mutations in a central portion of the gene (the "ovarian cancer cluster region" [OCCR]) were associated with a significantly higher ratio of cases of ovarian:breast cancer in female carriers than were mutations 5' or 3' of this region (P<.0001), extending previous observations. The optimal definition of the OCCR, as judged on the basis of deviance statistics, was bounded by nucleotides 3059-4075 and 6503-6629. The relative and absolute risks of breast and ovarian cancer associated with OCCR and non-OCCR mutations were estimated by a conditional likelihood approach, conditioning on the set of mutations observed in the families. OCCR mutations were associated both with a highly significantly lower risk of breast cancer (relative risk [RR] 0.63; 95% confidence interval (95% CI) 0.46-0.84; P=.0012) and with a significantly higher risk of ovarian cancer (RR = 1.88; 95% CI = 1.08-3.33; P=.026). No other differences in breast or ovarian cancer risk, by mutation position, were apparent. There was some evidence for a lower risk of prostate cancer in carriers of an OCCR mutation (RR = 0.52; 95% CI = 0.24-1.00; P=.05), but there was no evidence of a difference in breast cancer risk in males. By age 80 years, the cumulative risk of breast cancer in male carriers of a BRCA2 mutation was estimated as 6.92% (95% CI = 1.20%-38.57%). Possible mechanisms for the variation in cancer risk are suggested by the coincidence of the OCCR with the RAD51-binding domain.  相似文献   

6.
Germline mutations in the BRCA1 or BRCA2 genes predispose their carriers to breast or/and ovary cancers during their lifetime. The most frequent mutations: 5382insC, 185delAG, C61G and 4153delA in BRCA1, and 6174delT and 9631delC in BRCA2 were studied in a group of 148 probands admitted for genetic counseling, using allele-specific amplification (ASA) PCR test. Fifteen carriers of three different mutations: 5382insC, 185delAG and C61G in BRCA1 were found. Two families carried the 185delAG mutation and additional two C61G in BRCA1. Nobody carried the mutation 4153delA in BRCA1 nor 6174delT or 9631delC in BRCA2. Most of the carriers of a germline mutation were observed among the patients who developed bilateral breast cancer (17%). The lowest frequency of the germline mutations was found in the healthy persons who had two or more relatives affected with breast or ovarian cancer.  相似文献   

7.
Germline mutations in BRCA1 and BRCA2 confer high risks of breast and ovarian cancer, but the average magnitude of these risks is uncertain and may depend on the context. Estimates based on multiple-case families may be enriched for mutations of higher risk and/or other familial risk factors, whereas risk estimates from studies based on cases unselected for family history have been imprecise. We pooled pedigree data from 22 studies involving 8,139 index case patients unselected for family history with female (86%) or male (2%) breast cancer or epithelial ovarian cancer (12%), 500 of whom had been found to carry a germline mutation in BRCA1 or BRCA2. Breast and ovarian cancer incidence rates for mutation carriers were estimated using a modified segregation analysis, based on the occurrence of these cancers in the relatives of mutation-carrying index case patients. The average cumulative risks in BRCA1-mutation carriers by age 70 years were 65% (95% confidence interval 44%-78%) for breast cancer and 39% (18%-54%) for ovarian cancer. The corresponding estimates for BRCA2 were 45% (31%-56%) and 11% (2.4%-19%). Relative risks of breast cancer declined significantly with age for BRCA1-mutation carriers (P trend.0012) but not for BRCA2-mutation carriers. Risks in carriers were higher when based on index breast cancer cases diagnosed at <35 years of age. We found some evidence for a reduction in risk in women from earlier birth cohorts and for variation in risk by mutation position for both genes. The pattern of cancer risks was similar to those found in multiple-case families, but their absolute magnitudes were lower, particularly for BRCA2. The variation in risk by age at diagnosis of index case is consistent with the effects of other genes modifying cancer risk in carriers.  相似文献   

8.
BRCA2 gene mutations in Slovenian male breast cancer patients   总被引:1,自引:0,他引:1  
Male breast cancer (MBC) is a rare disease, comprising less than 1% of breast cancer patients in Slovenia. Some inherited cases are due to the mutations of BRCA1 or BRCA2 genes. There is no information available about the frequency of BRCA gene mutations in Slovenian MBC population. The purpose of this study was to characterize BRCA germline mutations in Slovenian MBC patients. Forty-one patients who were diagnosed with breast cancer at the Institute of Oncology Ljubljana between 1970 and 2006 were proposed to take part in this study. Of them, 27 agreed to follow a genetic counseling session and 25 patients agreed to provide a blood sample for genetic testing. The BRCA1 and BRCA2 genes from the MBC patients were screened for four highly recurrent mutations in the Slovenian population. When an additional breast cancer case or an ovarian cancer was present in the family, a more extended analysis was performed. No BRCA1 mutations were found. A BRCA2 gene mutation was identified in four MBC patients. Three of them carried the Slovenian founder mutation IVS16-2A>G. All four mutations were confined to the patients with a family history of breast cancer. Among the MBC patients with a family history of breast cancer in the first- or second-degree relatives, the frequency of BRCA2 gene mutation was 50%. The median age of the patients with a BRCA2 gene mutation was 60 years, not significantly different from those without a mutation. The BRCA2 mutations were diagnosed in 16% of our MBC patients.  相似文献   

9.
Germ-line BRCA1 and BRCA2 mutations account for most of familial breast-ovarian cancer. In Ashkenazi Jews, there is a high population frequency (approximately 2%) of three founder mutations: BRCA1 185delAG, BRCA1 5382insC, and BRCA2 6174delT. This study examined the frequency of these mutations in a series of Ashkenazi women with ovarian cancer unselected for family history, compared with the frequency of these mutations in families ascertained on the basis of family history of at least two affected women. Penetrance was compared, both according to the method of family ascertainment (i.e., on the basis of an unselected ovarian cancer proband vs. on the basis of family history) and for the BRCA1 founder mutations compared with the BRCA2 6174delT mutation. There was a high frequency (10/22; [45%]) of germ-line mutations in Ashkenazi women with ovarian cancer, even in those with minimal or no family history (7/18 [39%]). In high-risk Ashkenazi families, a founder mutation was found in 59% (25/42). Families with any case of ovarian cancer were significantly more likely to segregate a founder mutation than were families with site-specific breast cancer. Penetrance was higher in families ascertained on the basis of family history than in families ascertained on the basis of an unselected proband, but this difference was not significant. Penetrance of BRCA1 185delAG and BRCA1 5382insC was significantly higher than penetrance of BRCA2 6174delT (hazard ratio 2.1 [95% CI 1.2-3.8]; two-tailed P = .01). Thus, the high rate of germ-line BRCA1/BRCA2 mutations in Ashkenazi women and families with ovarian cancer is coupled with penetrance that is lower than previously estimated. This has been shown specifically for the BRCA2 6174delT mutation, but, because of ascertainment bias, it also may be true for BRCA1 mutations.  相似文献   

10.
Breast cancer is the most common malignancy among women. Chilean studies reveal that this cancer presents the third highest mortality rate. A family history of breast cancer is one of the major risk factors for the development of this disease. BRCA1 and BRCA2 are the two main hereditary breast cancer susceptibility genes, and mutations in these genes are related to inherited breast cancer. In specific populations only some mutations have been found to be associated with susceptibility. The purpose of this study was to establish the frequency of 5382insC (BRCA1) and 6174delT (BRCA2) germline mutations in 382 healthy Chilean women with at least two relatives affected with breast cancer and in probands and their relatives from 8 high risk families for breast cancer, using mismatch PCR assay. The results obtained showed that 5382insC and 6174delT mutations were not found in either of the groups studied. The ethnic origin of the contemporary Chilean population and the data reported in the literature suggest that these mutations may be absent or have a very low frequency in this population.. This genetic study is part of a breast cancer screening program that also includes annual mammography and clinical breast examination over a five-year period. Strategies to reduce morbidity and mortality associated with breast cancer lie in early detection in women with genetic risk.  相似文献   

11.
Mutation analysis of BRCA1 and BRCA2 in a male breast cancer population.   总被引:12,自引:6,他引:6  
A population-based series of 54 male breast cancer cases from Southern California were analyzed for germ-line mutations in the inherited breast/ovarian cancer genes, BRCA1 and BRCA2. Nine (17%) of the patients had a family history of breast and/or ovarian cancer in at least one first-degree relative. A further seven (13%) of the patients reported breast/ovarian cancer in at least one second-degree relative and in no first-degree relatives. No germ-line BRCA1 mutations were found. Two male breast cancer patients (4% of the total) were found to carry novel truncating mutations in the BRCA2 gene. Only one of the two male breast cancer patients carrying a BRCA2 mutation had a family history of cancer, with one case of ovarian cancer in a first-degree relative. The remaining eight cases (89%) of male breast cancer with a family history of breast/ovarian cancer in first-degree relatives remain unaccounted for by mutations in either the BRCA1 gene or the BRCA2 gene.  相似文献   

12.
Women with mutations in the breast cancer genes BRCA1 or BRCA2 have an increased lifetime risk of developing breast, ovarian and other BRCA-associated cancers. However, the number of detected germline mutations in families with hereditary breast and ovarian cancer (HBOC) syndrome is lower than expected based upon genetic linkage data. Undetected deleterious mutations in the BRCA genes in some high-risk families are due to the presence of intragenic rearrangements such as deletions, duplications or insertions that span whole exons. This article reviews the molecular aspects of BRCA1 and BRCA2 rearrangements and their frequency among different populations. An overview of the techniques used to screen for large rearrangements in BRCA1 and BRCA2 is also presented. The detection of rearrangements in BRCA genes, especially BRCA1, offers a promising outlook for mutation screening in clinical practice, particularly in HBOC families that test negative for a germline mutation assessed by traditional methods.  相似文献   

13.
BRCA1/BRCA2 germline mutations are associated with an increased breast/ovarian cancer risk. Offspring gender ratios may be skewed against male births in BRCA1 mutation carriers. In addition, the lack of viable homozygous BRCA1/BRCA2-mutation carriers implies that recurrent miscarriages may be associated with homozygous fetuses. Jewish Israeli high-risk women who were tested for being carriers of the predominant BRCA1/BRCA2 mutations in Jewish high-risk families were analyzed for the sex of offspring and the rate of spontaneous miscarriages. Overall, 817 women participated: 393 BRCA1/BRCA2-mutation carriers (229 with breast/ovarian cancer) and 424 high-risk noncarriers (208 with breast/ovarian cancer). No differences between the male-to-female offspring ratios of all study groups were noted. Among mutation carriers, the offspring male-to-female ratio was 0.97 (444 : 460), and among mutation carriers with cancer it was 0.92 (262 : 284). Similarly, no offspring gender skewing was noted among high-risk noncarriers, regardless of health status. The rates of three or more spontaneous miscarriages among participants with at least one live birth were 4.37% (15/343) among mutation carriers and 3% (12/401) among high-risk women (P = not significant). In conclusion, the offspring gender ratio is similar in high-risk Jewish families and in the general population. The issue of the rate of recurrent miscarriages in high-risk Jewish women is unresolved.  相似文献   

14.
15.
To define the prevalence and relative contributions of BRCA1 and BRCA2 mutations among African American families with breast cancer, we analyzed 28 DNA samples from patients identified through two oncology clinics. The entire coding regions of BRCA1 and BRCA2 were screened by protein truncation test, heteroduplex analysis, or single-stranded conformation polymorphism followed by DNA sequencing of variant bands. Deleterious protein-truncating BRCA1 and BRCA2 mutations were identified in five patients or 18% of the entire cohort. Only 8% (1 of 13) of women with a family history of breast cancer, but no ovarian cancer, had mutations. The mutation rates were higher for women from families with a history of breast cancer and at least one ovarian cancer (three of six, 50%). One woman with a family history of undocumented cancers was also found to carry a deleterious mutation in BRCA2. The spectrum of mutations was unique in that one novel BRCA1 mutation (1625del5) and three novel BRCA2 mutations (1536del4, 6696delTC, and 7795delCT) were identified. No recurrent mutations were identified in this cohort, although one BRCA2 (2816insA) mutation had been previously reported. In addition, two BRCA1 and four BRCA2 missense mutations of unknown significance were identified, one of which was novel. Taken together with our previous report on recurrent mutations seen in unrelated families, we conclude that African Americans have a unique mutation spectrum in BRCA1 and BRCA2 genes, but recurrent mutations are likely to be more widely dispersed and therefore not readily identifiable in this population.  相似文献   

16.
To establish the contribution of germline BRCA1 and BRCA2 mutations to familial ovarian cancer, we have analyzed both genes in DNA samples obtained from an affected individual in each of 112 families containing at least two cases of epithelial ovarian cancer. Germline mutations were found in 43% of the families; BRCA1 mutations were approximately four times more common than BRCA2 mutations. The extent of family history of ovarian and breast cancers was strongly predictive of BRCA1-mutation status. Segregation analysis suggests that a combination of chance clustering of sporadic cases and insensitivity of mutation detection may account for the remaining families; however, the contribution of other genes cannot be excluded. We discuss the implications for genetic testing and clinical management of familial ovarian cancer arising from the data presented in these studies.  相似文献   

17.
INTRODUCTION: Hereditary breast cancer has been partly attributed to germline mutations in the BRCA1 gene that are deleterious for BRCA1 protein activity. This paper analyzes the incidence and characteristics of detectable BRCA1 mutations and polymorphisms in a hospital-based consecutive series of breast cancer patients from southern Italy to investigate the incidence and the association of these molecular alterations with breast cancer biology and family history. METHODS: One hundred cases with familial characteristics were selected from a consecutive series of 511 patients with a first diagnosis of breast cancer. DNA from peripheral blood was screened for whole BRCA1 gene mutations utilizing dHPLC as a pre-screening analysis and automatic DNA sequencing for the identification of specific alterations. RESULTS: In the overall series of 511 patients, 100 had a family history of breast cancer and were investigated for BRCA1 mutations. Two types of BRCA1 mutations were identified, 5382insC in six cases and 4566delA in one case. The 5382insC mutation was present in two out of six cases with ovarian cancer while 4566delA in one case of male cancer. The most frequent missense polymorphisms were E1038G, P871L, K1183R in exon 11, S1613G, M1652I in exon 16 and D1778G in exon 22. Confirming what found in previous studies, patients in whom pathological BRCA1 mutations were detected had early-onset breast cancer (p=0.05), positive nodal status (p=0.05), lower ER (p=0.02) and PgR (p=0.01) content. Interestingly, the K1183R polymorphism and, less strongly, S1613G polymorphism were associated to mutational risk (K1183R: OR 0.1 p=0.03; S1613G: OR 2.7 p=0.08). CONCLUSION: Mutations in the BRCA1 gene are frequent also in our consecutive series of patients from southern Italy. An association between two detected single nucleotide polymorphisms (SNPs) and BRCA1 mutational risk was ascertained. Finally, we confirm the fact that peculiar clinical-pathological features seem to characterize patients with a family history of breast cancer and BRCA1 alterations.  相似文献   

18.
The genetic etiology of hereditary breast cancer has not been fully elucidated. Although germline mutations of high-penetrance genes such as BRCA1/2 are implicated in development of hereditary breast cancers, at least half of all breast cancer families are not linked to these genes. To identify a comprehensive spectrum of genetic factors for hereditary breast cancer in a Chinese population, we performed an analysis of germline mutations in 2,165 coding exons of 152 genes associated with hereditary cancer using next-generation sequencing (NGS) in 99 breast cancer patients from families of cancer patients regardless of cancer types. Forty-two deleterious germline mutations were identified in 21 genes of 34 patients, including 18 (18.2%) BRCA1 or BRCA2 mutations, 3 (3%) TP53 mutations, 5 (5.1%) DNA mismatch repair gene mutations, 1 (1%) CDH1 mutation, 6 (6.1%) Fanconi anemia pathway gene mutations, and 9 (9.1%) mutations in other genes. Of seven patients who carried mutations in more than one gene, 4 were BRCA1/2 mutation carriers, and their average onset age was much younger than patients with only BRCA1/2 mutations. Almost all identified high-penetrance gene mutations in those families fulfill the typical phenotypes of hereditary cancer syndromes listed in the National Comprehensive Cancer Network (NCCN) guidelines, except two TP53 and three mismatch repair gene mutations. Furthermore, functional studies of MSH3 germline mutations confirmed the association between MSH3 mutation and tumorigenesis, and segregation analysis suggested antagonism between BRCA1 and MSH3. We also identified a lot of low-penetrance gene mutations. Although the clinical significance of those newly identified low-penetrance gene mutations has not been fully appreciated yet, these new findings do provide valuable epidemiological information for the future studies. Together, these findings highlight the importance of genetic testing based on NCCN guidelines and a multi-gene analysis using NGS may be a supplement to traditional genetic counseling.  相似文献   

19.
20.
Recently, BRCA1 germline mutations were found in a high proportion (14-34%) of patients with triple-negative breast cancer (TNBC). BRCA2 was either not analyzed or showed much lower mutation frequencies. Therefore, we screened a group of TNBC patients (n = 30) of white European descent for mutations in BRCA2 as well as in BRCA1. Cases were unselected for age of disease-onset (median age at breast cancer diagnosis was 58 years, ranging from 37 to 74 years), family history of cancer and BRCA1 and BRCA2 mutation status. Half of the patients (15/30) showed a family history of breast and/or ovarian cancer. A high frequency of deleterious germline mutations was observed in BRCA2 (5/30; 16.7%), and only one case showed a BRCA1 mutation (3.3%). Although the study group was small, these results point to BRCA2 mutations being important in TNBC.  相似文献   

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