| 1. |
- Kainu, T, et al.
(författare)
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Somatic deletions in hereditary breast cancers implicate 13q21 as a putative novel breast cancer susceptibility locus
- 2000
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 97:17, s. 9603-9608
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Tidskriftsartikel (refereegranskat)abstract
- A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, theta = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
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| 2. |
- Hautaniemi, S, et al.
(författare)
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A strategy for identifying putative causes of gene expression variation in human cancers
- 2004
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Ingår i: Journal of the Franklin Institute. - : Elsevier BV. - 0016-0032. ; 341:1-2, s. 77-88
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Tidskriftsartikel (refereegranskat)abstract
- The majority of microarray studies focus on analysis of gene expression differences between various specimens or conditions. However, the causes of this variability from one cancer to another, from one sample to another and from one gene to another often remain unknown. In this study, we present a systematic procedure for finding genes whose expression levels are altered due to an intrinsic or extrinsic explanatory phenomenon. The procedure consists of three stages: preprocessing, data integration and statistical analysis. We tested and verified the utility of this approach in a case study, where expression and copy number levels of 13,824 genes were determined in 14 breast cancer cell lines. The procedure resulted in identification of 92 genes whose expression levels could be explained by the variability of gene copy number. This set includes several genes that are known to be both overexpressed and amplified in breast cancer. Thus, these genes may represent an important set of primary, genetically altered genes that drive cancer progression. (C) 2003 The Franklin Institute.
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| 3. |
- Rozenblum, E, et al.
(författare)
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A genomic map of a 6-Mb region at 13q21-q22 implicated in cancer development: identification and characterization of candidate genes
- 2002
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Ingår i: Human Genetics. - : Springer Science and Business Media LLC. - 1432-1203 .- 0340-6717. ; 110:2, s. 111-121
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Tidskriftsartikel (refereegranskat)abstract
- Chromosomal region 13q21-q22 harbors a putative breast cancer susceptibility gene and has been implicated as a common site for somatic deletions in a variety of malignant tumors. We have built a complete physical clone contig for a region between D13S1308 and AFM220YE9 based on 18 yeast artificial chromosome and 81 bacterial artificial chromosome (BAC) clones linked together by 22 genetic markers and 61 other sequence tagged sites. Combining data from 47 sequenced BACs (as of June 2001), we have assembled in silico an integrated 5.7-Mb genomic map with 90% sequence coverage. This area contains eight known genes, two hypothetical proteins, 24 additional Unigene clusters, and approximately 100 predicted genes and exons. We have determined the cDNA and genomic sequence, and tissue expression profiles for the KIAA1008 protein (homologous to the yeast mitotic control protein dis3+), KLF12 (AP-2 repressor), progesterone induced blocking factor 1, zinc finger transcription factor KLF5, and LIM domain only-7, and for the hypothetical proteins FLJ22624 and FLJ21869. Mutation screening of the five known genes in 19 breast cancer families has revealed numerous polymorphisms, but no deleterious mutations. These data provide a basis and resources for further analyses of this chromosomal region in the development of cancer.
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| 4. |
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| 5. |
- Skotheim, RI, et al.
(författare)
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Topoisomerase-II alpha is upregulated in malignant peripheral nerve sheath tumors and associated with clinical outcome
- 2003
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Ingår i: Journal of Clinical Oncology. - 1527-7755. ; 21:24, s. 4586-4591
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To identify target genes of clinical significance for patients with malignant peripheral-nerve sheath tumor (MPNST), an aggressive cancer for which no consensus therapy exists. Materials and Methods: Biopsies and clinical data from 51 patients with MPNST were included in this study. Based on our previous research implicating chromosome arm 17q amplification in MPNST, we performed gene expression analyses of 14 MPNSTs using chromosome 17-specific cDNA microarrays. Copy numbers of selected gene probes and centromere probes were then determined by interphase fluorescence in situ hybridization in 16 MPNSTs. Finally, we generated a tissue microarray containing 79 samples from 44 MPNSTs, on which in situ protein expressions of candidate genes were examined and related to clinical end points. Results: Among several deregulated genes found by cDNA microarray analyses, topoisomerase IIalpha (TOP2A) was the most overexpressed gene in MPNSTs compared with benign neurofibromas. Excess copies of the TOP2A were also seen at the DNA level in 10 of 16 cases, and high expression of the TOP2A protein was seen in 83% of the tumors on the tissue microarray. The TOP2A-expressing tumors were associated with poor cancer-specific survival and presence of metastases. Conclusion: We have identified TOP2A as a target gene in MPNST, using a focused gene expression profiling followed by a DNA copy number evaluation and clinical validation of the encoded protein using a tissue microarray. This study is the first to suggest that TOP2A expression may be a predictive factor for adverse outcome in MPNST. (C) 2003 by American Society of Clinical Oncology.
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| 6. |
- 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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| 7. |
- Hedenfalk, I, et al.
(författare)
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Gene-expression profiles in hereditary breast cancer
- 2001
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Ingår i: New England Journal of Medicine. - 0028-4793. ; 344:8, s. 48-539
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Many cases of hereditary breast cancer are due to mutations in either the BRCA1 or the BRCA2 gene. The histopathological changes in these cancers are often characteristic of the mutant gene. We hypothesized that the genes expressed by these two types of tumors are also distinctive, perhaps allowing us to identify cases of hereditary breast cancer on the basis of gene-expression profiles.METHODS: RNA from samples of primary tumor from seven carriers of the BRCA1 mutation, seven carriers of the BRCA2 mutation, and seven patients with sporadic cases of breast cancer was compared with a microarray of 6512 complementary DNA clones of 5361 genes. Statistical analyses were used to identify a set of genes that could distinguish the BRCA1 genotype from the BRCA2 genotype.RESULTS: Permutation analysis of multivariate classification functions established that the gene-expression profiles of tumors with BRCA1 mutations, tumors with BRCA2 mutations, and sporadic tumors differed significantly from each other. An analysis of variance between the levels of gene expression and the genotype of the samples identified 176 genes that were differentially expressed in tumors with BRCA1 mutations and tumors with BRCA2 mutations. Given the known properties of some of the genes in this panel, our findings indicate that there are functional differences between breast tumors with BRCA1 mutations and those with BRCA2 mutations.CONCLUSIONS: Significantly different groups of genes are expressed by breast cancers with BRCA1 mutations and breast cancers with BRCA2 mutations. Our results suggest that a heritable mutation influences the gene-expression profile of the cancer.
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| 8. |
- Kallioniemi, I., et al.
(författare)
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Characterization of random rough surfaces from scattered intensities by neural networks
- 2001
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Ingår i: Journal of Modern Optics. - 0950-0340 .- 1362-3044. ; 48:9, s. 1447-1453
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Tidskriftsartikel (refereegranskat)abstract
- Optical scatterometry, a non-invasive characterization method, is used to infer the statistical properties of random rough surfaces. The Gaussian model with rms-roughness sigma and correlation length Lambda is considered in this paper but the employed technique is applicable to any representation of random rough surfaces. Surfaces with wide ranges of Lambda and sigma, up to 5 wavelengths (lambda), are characterized with neural networks. Two models are used: self-organizing map (SOM) for rough classification and multi-layer perceptron (MLP) for quantitative estimation with nonlinear regression. Models infer Lambda and sigma from scattering, thus involving the inverse problem. The intensities are calculated with the exact electromagnetic theory, which enables a wide range of parameters. The most widely known neural network model in practise is SOM, which we use to organize samples into discrete classes with resolution Delta Lambda = Delta sigma = 0.5 lambda. The more advanced MLP model is trained for optimal behaviour by providing it with known parts of input (scattering) and output (surface parameters). We show that a small amount of data is sufficient for an excellent accuracy on the order of 0.3 lambda and 0.15 lambda for estimating Lambda and sigma, respectively.
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| 9. |
- Mahlamaki, EH, et al.
(författare)
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Frequent amplification of 8q24, 11q, 17q, and 20q-specific genes in pancreatic cancer
- 2002
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 35:4, s. 353-358
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Tidskriftsartikel (refereegranskat)abstract
- Genetic changes involved in the development and progression of pancreatic cancer are still partly unknown, despite the progress in recent years. In this study, comparative genomic hybridization analysis in 31 pancreatic cancer cell lines showed that chromosome arms 8q, 11q, 17q, and 20q are frequently gained in this tumor type. Copy number analysis of selected genes from these chromosome arms by fluorescence in situ hybridization showed amplification of the MYC oncogene in 54% of the cell lines, whereas CCNDI was amplified in 28%. In the 17q arm, the ERB82 oncogene was amplified in 20% of the cell lines, TBX2 in 50%, and BIRC5 in 58%, indicating increased involvement toward the q telonnere of chromosome 17. In the 20q arm, the amplification frequencies varied from 32% to 83%, with the CTSZ gene at 20q 13 being most frequently affected. These results illustrate that amplification of genes from the 8q, 11q, 17q, and 20q chromosome arms is common in pancreatic cancer.
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| 10. |
- Syrjakoski, K, et al.
(författare)
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BRCA2 mutations in 154 Finnish male breast cancer patients
- 2004
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Ingår i: Neoplasia. - : Elsevier BV. - 1522-8002 .- 1476-5586. ; 6:5, s. 541-545
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Tidskriftsartikel (refereegranskat)abstract
- The etiology and pathogenesis of male breast cancer (MBC) are poorly known. This is due to the fact that the disease is rare, and large-scale genetic epidemiologic studies have been difficult to carry out. Here, we studied the frequency of eight recurrent Finnish BRCA2 founder mutations in a large cohort of 154 MBC patients (65% diagnosed in Finland from 1967 to 1996). Founder mutations were detected in 10 patients (6.5%), eight of whom carried the 9346(-2) A>G mutation. Two novel mutations (4075 delGT and 5808 del5) were discovered in a screening of the entire BRCA2 coding region in 34 samples. However, these mutations were not found in the rest of the 120 patients studied. Patients with positive family history of breast and/or ovarian cancer were often BRCA2 mutation carriers (44%), whereas those with no family history showed a low frequency of involvement (3.6%; P < .0001). Finally, we found only one Finnish MBC patient with 999 del5, the most common founder mutation in Finnish female breast cancer (FBC) patients, and one that explains most of the hereditary FBC and MBC cases in Iceland. The variation in BRCA2 mutation spectrum between Finnish MBC patients and FBC patients in Finland and breast cancer patients in Iceland suggests that modifying genetic and environmental factors may significantly influence the penetrance of MBC and FBC in individuals carrying germline BRCA2 mutations in some populations.
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