| 1. |
- Antoniou, A, et al.
(författare)
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Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case series unselected for family history: A combined analysis of 22 studies
- 2003
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 72:5, s. 1117-1130
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Archey, WB, et al.
(författare)
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Increased CpG methylation of the estrogen receptor gene in BRCA1-linked estrogen receptor-negative breast cancers
- 2002
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Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 1476-5594 .- 0950-9232. ; 21:46, s. 7034-7041
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Tidskriftsartikel (refereegranskat)abstract
- A distinctive feature of BRCA1-linked breast cancers is that they typically do not express estrogen receptor-alpha (ERalpha). Previous investigation suggests that methylation of CpGs within the ERa promoter mediates repression of gene expression in some ERalpha-negative breast cancers. To determine if methylation of CpGs within the ERalpha promoter is associated with BRCA1-linked breast cancers, we evaluated methylation in exon 1 of the ERalpha gene in 40 ERalpha-negative breast cancers, 20 of which were non BRCA1-linked and 20 BRCA1-linked. CpG methylation was evaluated by either methylation-sensitive restriction digest (HpaII), methylation-sensitive PCR (MSP), or direct sequencing of bisulfite-treated genomic DNA. Results from HpaII digests and MSP documented a high degree of methylation, the MSP data showing slightly higher methylation in the BRCA1-linked group. CpGs analysed by direct sequencing showed an overall average methylation of 25% among non BRCA1-linked cancers and 40% among BRCA1-linked cancers (P=0.0031). The most notable difference was found at five particular CpGs, each of which exhibited a greater than twofold increase in methylation in the BRCA1-linked group compared to the non BRCA1-linked group (P < 0.03 for each CpG). Methylation of certain critical CpGs may represent an important factor in transcriptional repression of the ERa gene in BRCA1-linked breast cancers.
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| 3. |
- Arver, Brita, et al.
(författare)
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First BRCA1 and BRCA2 gene testing implemented in the health care system of Stockholm
- 2001
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Ingår i: Genetic Testing. - : Mary Ann Liebert Inc. - 1557-7473 .- 1090-6576. ; 5:1, s. 41282-41282
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to optimize the criteria for the BRCA1 and BRCA2 gene testing and to improve oncogenetic counseling in the Stockholm region. Screening for inherited breast cancer genes is laborious and a majority of tested samples turn out to be negative. The frequencies of mutations in the BRCA1 and BRCA2 genes differ across populations. Between 1997 and 2000, 160 families with breast and/or ovarian cancer were counseled and screened for mutations in the two genes. Twenty-five BRCA1 and two BRCA2 disease-causing mutations were found. Various factors associated with the probability of finding a BRCA1 mutation in the families were estimated. Age of onset in different generations and other malignancies were also studied. Families from our region in which both breast and ovarian cancer occur were likely to carry a BRCA1 mutation (34%). In breast-only cancer families, mutations were found only in those with very early onset. All breast-only cancer families with a mutation had at least one case of onset before 36 years of age and a young median age of onset (< 43 years). Other malignancies than breast and ovarian cancers did not segregate in the BRCA1 families and surveillance for other malignancies is not needed, in general. Decreasing age of onset with successive generations was common and must be taken into account when surveillance options are considered.
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| 4. |
- Bergthorsson, J.T., et al.
(författare)
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BRCA1 and BRCA2 mutation status and cancer family history of Danish women affected with multifocal or bilateral breast cancer at a young age
- 2001
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 38:6, s. 361-368
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Tidskriftsartikel (refereegranskat)abstract
- Introduction - A small fraction of breast cancer is the result of germline mutations in the BRCA1 and BRCA2 cancer susceptibility genes. Mutation carriers frequently have a positive family history of breast and ovarian cancer, are often diagnosed at a young age, and may have a higher incidence of double or multiple primary breast tumours than breast cancer patients in general. Objectives - To estimate the prevalence and spectrum of BRCA1 and BRCA2 mutations in young Danish patients affected with bilateral or multifocal breast cancer and to determine the relationship of mutation status to family history of cancer. Subjects - From the files of the Danish Breast Cancer Cooperative Group (DBCG), we selected 119 breast cancer patients diagnosed before the age of 46 years with either bilateral (n=59) or multifocal (n=61) disease. Methods - DNA from the subjects was screened for BRCA1 and BRCA2 mutations using single strand conformation analysis (SSCA) and the protein truncation test (PTT). Observed and expected cancer incidence in first degree relatives of the patients was estimated using data from the Danish Cancer Registry. Results - Twenty four mutation carriers were identified (20%), of whom 13 had a BRCA1 mutation and 11 carried a BRCA2 mutation. Two mutations in BRCA1 were found repeatedly in the material and accounted for seven of the 24 (29%) mutation carriers. The mutation frequency was about equal in patients with bilateral (22%) and multifocal breast cancer (18%). The incidence of breast and ovarian cancer was greatly increased in first degree relatives of BRCA1 and BRCA2 mutation carriers, but to a much lesser degree in relatives of non-carriers. An increased risk of cancer was also noted in brothers of non-carriers. Conclusions - A relatively broad spectrum of germline mutations was observed in BRCA1 and BRCA2 and most of the mutations are present in other populations. Our results indicate that a diagnosis of bilateral and multifocal breast cancer is predictive of BRCA1 and BRCA2 mutation status, particularly when combined with information on the patients' age at diagnosis and family history of breast/ovarian cancer.
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| 5. |
- Borg, Åke
(författare)
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Hereditary prostate cancer: a new piece of the puzzle.
- 2001
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 7:2, s. 153-155
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Tidskriftsartikel (refereegranskat)abstract
- An eagerly awaited prostate cancer susceptibility gene has been announced. But does the candidate live up to expectations?
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| 6. |
- Borg, Åke, et al.
(författare)
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High frequency of multiple melanomas and breast and pancreas carcinomas in CDKN2A mutation-positive melanoma families
- 2000
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Ingår i: Journal of the National Cancer Institute. - 0027-8874. ; 92:15, s. 6-1260
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: : Inherited mutations in the CDKN2A tumor suppressor gene, which encodes the p16(INK4a) protein, and in the cyclin-dependent kinase 4 (CDK4) gene confer susceptibility to cutaneous malignant melanoma. We analyzed families with two or more cases of melanoma for germline mutations in CDKN2A and CDK4 to elucidate the contribution of these gene defects to familial malignant melanoma and to the occurrence of other cancer types.METHODS: : The entire CDKN2A coding region and exon 2 of the CDK4 gene of an affected member of each of 52 families from southern Sweden with at least two cases of melanoma in first- or second-degree relatives were screened for mutations by use of polymerase chain reaction-single-strand conformation polymorphism analysis. Statistical tests were two-sided.RESULTS: : CDKN2A mutations were found in 10 (19%) of the 52 families. Nine families carried an identical alteration consisting of the insertion of arginine at position 113 of p16(INK4a), and one carried a missense mutation, in which the valine at position 115 was replaced with a glycine. The 113insArg mutant p16(INK4a) was unable to bind cdk4 and cdk6 in an in vitro binding assay. Six of the 113insArg families had at least one member with multiple primary melanomas; the 113insArg families also had a high frequency of other malignancies-in particular, breast cancer (a total of eight cases compared with the expected 2.1; P =.0014) and pancreatic cancer (a total of six cases compared with the expected 0.16; P<.0001). Families with breast cancer also had a propensity for multiple melanomas in females, suggesting that a sex-dependent factor may modify the phenotypic expression of CDKN2A alterations.CONCLUSIONS: : Our findings confirm that the majority of CDKN2A-associated melanoma families in Sweden are due to a single founder mutation. They also show that families with the CDKN2A 113insArg mutation have an increased risk not only of multiple melanomas and pancreatic carcinoma but also of breast cancer.
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| 7. |
- Borg, Åke
(författare)
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Molecular and pathological characterization of inherited breast cancer.
- 2001
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Ingår i: Seminars in Cancer Biology. - : Elsevier BV. - 1096-3650 .- 1044-579X. ; 11:5, s. 375-385
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Tidskriftsartikel (refereegranskat)abstract
- The two major breast cancer susceptibility genes, BRCA1 and BRCA2, account for the majority of familial breast–ovarian cancer, but only a modest proportion of breast cancer families without ovarian or male breast cancer. Search for additional breast cancer genes with traditional linkage analysis has so far been unsuccessful, probably due to genetic heterogeneity. Pooling of families of different ethnical, cultural, and geographical origin proved to be a useful approach when identifying BRCA1 and BRCA2, but for genes mutated only in specific populations it is important not to introduce locus heterogeneity by pooling. Genetic heterogeneity can possibly be circumvented by using objective means, such as tumour histopathology or gene expression profiling, for subclassification of families prior to linkage analysis. Also, additional breast cancer genes can be identified by further characterization of the function of BRCA1 and BRCA2 and their interacting proteins.
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| 8. |
- Borg, Åke, et al.
(författare)
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Predicting the future of breast cancer.
- 2003
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 9:1, s. 16-18
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Tidskriftsartikel (refereegranskat)
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| 9. |
- Esteller, Manel, et al.
(författare)
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DNA methylation patterns in hereditary human cancers mimic sporadic tumorigenesis
- 2001
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 10:26, s. 3001-3007
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Tidskriftsartikel (refereegranskat)abstract
- Cancer cells have aberrant patterns of DNA methylation including hypermethylation of gene promoter CpG islands and global demethylation of the genome. Genes that cause familial cancer, as well as other genes, can be silenced by promoter hypermethylation in sporadic tumors, but the methylation of these genes in tumors from kindreds with inherited cancer syndromes has not been well characterized. Here, we examine CpG island methylation of 10 genes (hMLH1, BRCA1, APC, LKB1, CDH1, p16(INK4a), p14(ARF), MGMT, GSTP1 and RARbeta2) and 5-methylcytosine DNA content, in inherited (n = 342) and non-inherited (n = 215) breast and colorectal cancers. Our results show that singly retained alleles of germline mutated genes are never hypermethylated in inherited tumors. However, this epigenetic change is a frequent second "hit", associated with the wild-type copy of these genes in inherited tumors where both alleles are retained. Global hypomethylation was similar between sporadic and hereditary cases, but distinct differences existed in patterns of methylation at non-familial genes. This study demonstrates that hereditary cancers "mimic" the DNA methylation patterns present in the sporadic tumors.
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| 10. |
- Gentile, Massimiliano, et al.
(författare)
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Deletion mapping of chromosome segment 11q24-q25, exhibiting extensive allelic loss in early onset breast cancer
- 2001
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Ingår i: International Journal of Cancer. - 0020-7136 .- 1097-0215. ; 92:2, s. 208-213
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Tidskriftsartikel (refereegranskat)abstract
- Frequent allelic deletions at chromosome 11q24-q25 have been described in both early and late onset breast cancers, suggesting the existence of a gene locus implicated in the initiation and/or progression of the disease. In the present study we fine mapped this region further by loss of heterozygosity (LOH) analysis in a population of early onset breast cancer cases (n = 102, 22 to 36 years old). Loss of chromosomal material was assessed for possible association with patient survival as well as Nottingham histologic grade (NHG). Additionally, we investigated the involvement of the 11q24-q25 locus in a group of familial breast cancer cases with no detectable BRCA1 or BRCA2 gene alterations (n = 32, ages 28 to 40 years). Among the consecutive patients, extensive LOH was observed for all markers at 11q24-q25, with frequencies ranging from 42% to 54%. Deletion at the D11S4125 marker was found to be associated with reduced survival (p = 0.026), whereas the adjacent D11S387 marker correlated with higher histologic grade (p = 0.042). In the familial cases, the most telomeric markers showed substantially lower proportions of LOH, ranging from 10% to 21%. Comparison of the two patient groups demonstrated that this difference in LOH frequency was statistically significant for the D11S4098, D11S968, D11S387 and D11S4125 markers (p = 0.020, p = 0.029, p = 0.0070 and p = 0.0030, respectively). We conclude that 11q25 may harbor a gene implicated in early onset breast cancer. Our data suggest that the most probable position for this locus is defined by the markers D11S387 and D11S4125 and furthermore that it may play a less significant role in familial breast cancer cases not linked to either of the BRCA genes.
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