1. |
- Palmio, Johanna, et al.
(author)
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Hereditary myopathy with early respiratory failure: occurrence in various populations
- 2014
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In: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 85:3, s. 345-353
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Journal article (peer-reviewed)abstract
- Objective Several families with characteristic features of hereditary myopathy with early respiratory failure (HMERF) have remained without genetic cause. This international study was initiated to clarify epidemiology and the genetic underlying cause in these families, and to characterise the phenotype in our large cohort. Methods DNA samples of all currently known families with HMERF without molecular genetic cause were obtained from 12 families in seven different countries. Clinical, histopathological and muscle imaging data were collected and five biopsy samples made available for further immunohistochemical studies. Genotyping, exome sequencing and Sanger sequencing were used to identify and confirm sequence variations. Results All patients with clinical diagnosis of HMERF were genetically solved by five different titin mutations identified. One mutation has been reported while four are novel, all located exclusively in the FN3 119 domain (A150) of A-band titin. One of the new mutations showed semirecessive inheritance pattern with subclinical myopathy in the heterozygous parents. Typical clinical features were respiratory failure at mid-adulthood in an ambulant patient with very variable degree of muscle weakness. Cytoplasmic bodies were retrospectively observed in all muscle biopsy samples and these were reactive for myofibrillar proteins but not for titin. Conclusions We report an extensive collection of families with HMERF with five different mutations in exon 343 of TTN, which establishes this exon as the primary target for molecular diagnosis of HMERF. Our relatively large number of new families and mutations directly implies that HMERF is not extremely rare, not restricted to Northern Europe and should be considered in undetermined myogenic respiratory failure.
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2. |
- Bartkova, Jirina, et al.
(author)
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Aberrations of the MRE11-RAD50-NBS1 DNA damage sensor complex in human breast cancer : MRE11 as a candidate familial cancer-predisposing gene
- 2008
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In: Molecular Oncology. - : Wiley. - 1574-7891. ; 2:4, s. 296-316
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Journal article (peer-reviewed)abstract
- The MRE11, RAD50, and NBS1 genes encode proteins of the MRE11-RAD50-NBS1 (MRN) complex critical for proper maintenance of genomic integrity and tumour suppression; however, the extent and impact of their cancer-predisposing defects, and potential clinical value remain to be determined. Here, we report that among a large series of approximately 1000 breast carcinomas, around 3%, 7% and 10% tumours showed aberrantly reduced protein expression for RAD50, MRE11 and NBS1, respectively. Such defects were more frequent among the ER/PR/ERBB2 triple-negative and higher-grade tumours, among familial (especially BRCA1/BRCA2-associated) rather than sporadic cases, and the NBS1 defects correlated with shorter patients' survival. The BRCA1-associated and ER/PR/ERBB2 triple-negative tumours also showed high incidence of constitutively active DNA damage signalling (gamma H2AX) and p53 aberrations. Sequencing the RAD50, MRE11 and NBS1 genes of 8 patients from non-BRCA1/2 breast cancer families whose tumours showed concomitant reduction/loss of all three MRN-complex proteins revealed two germline mutations in MRE11: a missense mutation R202G and a truncating mutation R633STOP (R633X). Gene transfer and protein analysis of cell culture models with mutant MRE11 implicated various destabilization patterns among the MRN complex proteins including NBS1, the abundance of which was restored by re-expression of wild-type MRE11. We propose that germline mutations qualify MRE11 as a novel candidate breast cancer susceptibility gene in a subset of non-BRCA1/2 families. Our data have implications for the concept of the DNA damage response as an intrinsic anti-cancer barrier, various components of which become inactivated during cancer progression and also represent the bulk of breast cancer susceptibility genes discovered to date.
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3. |
- Couch, Fergus J., et al.
(author)
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AURKA F31I polymorphism and breast cancer risk in BRCA1 and BRCA2 mutation carriers: A consortium of investigators of modifiers of BRCA1/2 study
- 2007
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In: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 16:7, s. 1416-1421
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Journal article (peer-reviewed)abstract
- The AURKA oncogene is associated with abnormal chromosome segregation and aneuploidy and predisposition to cancer. Amplification of AURKA has been detected at higher frequency in tumors from BRCA1 and BRCA2 mutation carriers than in sporadic breast tumors, suggesting that overexpression of AURKA and inactivation of BRCA1 and BRCA2 cooperate during tumor development and progression. The F31I polymorphism in AURKA has been associated with breast cancer risk in the homozygous state in prior studies. We evaluated whether the AURKA F31I polymorphism modifies breast cancer risk in BRCA1 and BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2. Consortium of Investigators of Modifiers of BRCA1/2 was established to provide sufficient statistical power through increased numbers of mutation carriers to identify polymorphisms that act as modifiers of cancer risk and can refine breast cancer risk estimates in BRCA1 and BRCA2 mutation carriers. A total of 4,935 BRCA1 and 2,241 BRCA2 mutation carriers and 11 individuals carrying both BRCA1 and BRCA2 mutations was genotyped for F31I. Overall, homozygosity for the 311 allele was not significantly associated with breast cancer risk in BRCA1 and BRCA2 carriers combined [hazard ratio (HR), 0.91; 95% confidence interval (95% CI), 0.77-1.061. Similarly, no significant association was seen in BRCA1 (HR, 0.90; 95% Cl, 0.75-1.08) or BRCA2 carriers (HR, 0.93; 95% CI, 0.67-1.29) or when assessing the modifying effects of either bilateral prophylactic oophorectomy or menopausal status of BRCA1 and BRCA2 carriers. In summary, the F31I polymorphism in AURKA is not associated with a modified risk of breast cancer in BRCA1 and BRCA2 carriers.
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4. |
- Fagerholm, Rainer, et al.
(author)
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NAD(P)H:quinone oxidoreductase 1 NQO1*2 genotype (P187S) is a strong prognostic and predictive factor in breast cancer
- 2008
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 40:7, s. 844-53
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Journal article (peer-reviewed)abstract
- NQO1 guards against oxidative stress and carcinogenesis and stabilizes p53. We find that a homozygous common missense variant (NQO1(*)2, rs1800566(T), NM_000903.2:c.558C>T) that disables NQO1 strongly predicts poor survival among two independent series of women with breast cancer (P = 0.002, N = 1,005; P = 0.005, N = 1,162), an effect particularly evident after anthracycline-based adjuvant chemotherapy with epirubicin (P = 7.52 x 10(-6)) and in p53-aberrant tumors (P = 6.15 x 10(-5)). Survival after metastasis was reduced among NQO1(*)2 homozygotes, further implicating NQO1 deficiency in cancer progression and treatment resistance. Consistently, response to epirubicin was impaired in NQO1(*)2-homozygous breast carcinoma cells in vitro, reflecting both p53-linked and p53-independent roles of NQO1. We propose a model of defective anthracycline response in NQO1-deficient breast tumors, along with increased genomic instability promoted by elevated reactive oxygen species (ROS), and suggest that the NQO1 genotype is a prognostic and predictive marker for breast cancer.
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5. |
- Götz, Alexandra, et al.
(author)
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Exome sequencing identifies mitochondrial alanyl-tRNA synthetase mutations in infantile mitochondrial cardiomyopathy
- 2011
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In: American Journal of Human Genetics. - : Cell Press. - 0002-9297 .- 1537-6605. ; 88:5, s. 635-642
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Journal article (peer-reviewed)abstract
- Infantile cardiomyopathies are devastating fatal disorders of the neonatal period or the first year of life. Mitochondrial dysfunction is a common cause of this group of diseases, but the underlying gene defects have been characterized in only a minority of cases, because tissue specificity of the manifestation hampers functional cloning and the heterogeneity of causative factors hinders collection of informative family materials. We sequenced the exome of a patient who died at the age of 10 months of hypertrophic mitochondrial cardiomyopathy with combined cardiac respiratory chain complex I and IV deficiency. Rigorous data analysis allowed us to identify a homozygous missense mutation in AARS2, which we showed to encode the mitochondrial alanyl-tRNA synthetase (mtAlaRS). Two siblings from another family, both of whom died perinatally of hypertrophic cardiomyopathy, had the same mutation, compound heterozygous with another missense mutation. Protein structure modeling of mtAlaRS suggested that one of the mutations affected a unique tRNA recognition site in the editing domain, leading to incorrect tRNA aminoacylation, whereas the second mutation severely disturbed the catalytic function, preventing tRNA aminoacylation. We show here that mutations in AARS2 cause perinatal or infantile cardiomyopathy with near-total combined mitochondrial respiratory chain deficiency in the heart. Our results indicate that exome sequencing is a powerful tool for identifying mutations in single patients and allows recognition of the genetic background in single-gene disorders of variable clinical manifestation and tissue-specific disease. Furthermore, we show that mitochondrial disorders extend to prenatal life and are an important cause of early infantile cardiac failure.
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6. |
- Heikkinen, Tuomas, et al.
(author)
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Variants on the promoter region of PTEN affect breast cancer progression and patient survival
- 2011
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In: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 13:6, s. R130-
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Journal article (peer-reviewed)abstract
- INTRODUTION:The PTEN gene, a regulator of the phosphatidylinositol-3-kinase (PI3K)/Akt oncogenic pathway, is mutated in various cancers and its expression has been associated with tumor progression in a dose-dependent fashion. We investigated the effect of germline variation in the promoter region of the PTEN gene on clinical characteristics and survival in breast cancer.METHODS:We screened the promoter region of the PTEN gene for germline variation in 330 familial breast cancer cases and further determined the genotypes of three detected PTEN promoter polymorphisms -903GA, -975GC, and -1026CA in a total of 2,412 breast cancer patients to evaluate the effects of the variants on tumor characteristics and disease outcome. We compared the gene expression profiles in breast cancers of 10 variant carriers and 10 matched non-carriers and performed further survival analyses based on the differentially expressed genes.RESULTS: All three promoter variants associated with worse prognosis. The Cox's regression hazard ratio for 10-year breast cancer specific survival in multivariate analysis was 2.01 (95% CI 1.17 to 3.46) P = 0.0119, and for 5-year breast cancer death or distant metastasis free survival 1.79 (95% CI 1.03 to 3.11) P = 0.0381 for the variant carriers, indicating PTEN promoter variants as an independent prognostic factor. The breast tumors from the promoter variant carriers exhibited a similar gene expression signature of 160 differentially expressed genes compared to matched non-carrier tumors. The signature further stratified patients into two groups with different recurrence free survival in independent breast cancer gene expression data sets.CONCLUSIONS:Inherited variation in the PTEN promoter region affects the tumor progression and gene expression profile in breast cancer. Further studies are warranted to establish PTEN promoter variants as clinical markers for prognosis in breast cancer.
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7. |
- Jiang, Hai, et al.
(author)
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The combined status of ATM and p53 link tumor development with therapeutic response
- 2009
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In: Genes & Development. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 23:16, s. 1895-1909
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Journal article (peer-reviewed)abstract
- While the contribution of specific tumor suppressor networks to cancer development has been the subject of considerable recent study, it remains unclear how alterations in these networks are integrated to influence the response of tumors to anti-cancer treatments. Here, we show that mechanisms commonly used by tumors to bypass early neoplastic checkpoints ultimately determine chemotherapeutic response and generate tumor-specific vulnerabilities that can be exploited with targeted therapies. Specifically, evaluation of the combined status of ATM and p53, two commonly mutated tumor suppressor genes, can help to predict the clinical response to genotoxic chemotherapies. We show that in p53-deficient settings, suppression of ATM dramatically sensitizes tumors to DNA-damaging chemotherapy, whereas, conversely, in the presence of functional p53, suppression of ATM or its downstream target Chk2 actually protects tumors from being killed by genotoxic agents. Furthermore, ATM-deficient cancer cells display strong nononcogene addiction to DNA-PKcs for survival after DNA damage, such that suppression of DNA-PKcs in vivo resensitizes inherently chemoresistant ATM-deficient tumors to genotoxic chemotherapy. Thus, the specific set of alterations induced during tumor development plays a dominant role in determining both the tumor response to conventional chemotherapy and specific susceptibilities to targeted therapies in a given malignancy.
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9. |
- Schmidt, Marjanka K, et al.
(author)
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Do MDM2 SNP309 and TP53 R72P interact in breast cancer susceptibility? A large pooled series from the breast cancer association consortium
- 2007
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In: Cancer Research. - 0008-5472 .- 1538-7445. ; 67:19, s. 9584-9590
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Journal article (peer-reviewed)abstract
- Association studies in large series of breast cancer patients can be used to identify single-nucleotide polymorphisms (SNP) contributing to breast cancer susceptibility. Previous studies have suggested associations between variants in TP53 (R72P) and MDM2 (SNP309) and cancer risk. Data from molecular studies suggest a functional interaction between these genes. We therefore investigated the effect of TP53 R72P and MDM2 SNP309 on breast cancer risk and age at onset of breast cancer in a pooled series of 5,191 cases and 3,834 controls from the Breast Cancer Association Consortium (BCAC). Breast cancer risk was not found to be associated with the combined variant alleles [odds ratio (OR), 1.00; 95% confidence interval (95% CI), 0.81–1.23]. Estimated ORs were 1.01 (95% CI, 0.93–1.09) per MDM2 SNP309 allele and 0.98 (95% CI, 0.91–1.04) for TP53 R72P. Although we did find evidence for a 4-year earlier age at onset for carriers of both variant alleles in one of the breast cancer patient series of the BCAC (the German series), we were not able to confirm this effect in the pooled analysis. Even so, carriers of both variant alleles did not have different risk estimates for bilateral or estrogen receptor–positive breast cancer. In conclusion, in this large collaborative study, we did not find an association of MDM2 SNP309 and TP53 R72P, separately or in interaction, with breast cancer. This suggests that any effect of these two variants would be very small and possibly confined to subgroups that were not assessed in our present study.
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10. |
- Tommiska, Johanna, et al.
(author)
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ATM variants and cancer risk in breast cancer patients from Southern Finland
- 2006
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In: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 6, s. 209-
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Journal article (peer-reviewed)abstract
- Background: Individuals heterozygous for germline ATM mutations have been reported to have an increased risk for breast cancer but the role for ATM genetic variants for breast cancer risk has remained unclear. Recently, a common ATM variant, ATMivs38 - 8T> C in cis with the ATMex39 5557G> A ( D1853N) variant, was suggested to associate with bilateral breast cancer among familial breast cancer patients from Northern Finland. We have here evaluated the 5557G> A and ivs38- 8T> C variants in an extensive case-control association analysis. We also aimed to investigate whether there are other ATM mutations or variants contributing to breast cancer risk in our population. Methods: Two common ATM variants, 5557G> A and ivs38- 8T> C, previously suggested to associate with bilateral breast cancer, were genotyped in an extensive set of 786 familial and 884 unselected breast cancer cases as well as 708 healthy controls. We also screened the entire coding region and exon-intron boundaries of the ATM gene in 47 familial breast cancer patients and constructed haplotypes of the patients. The identified variants were also evaluated for increased breast cancer risk among additional breast cancer cases and controls. Results: Neither of the two common variants, 5557G> A and ivs38- 8T> C, nor any haplotype containing them, was significantly associated with breast cancer risk, bilateral breast cancer or multiple primary cancers in any of the patient groups or subgoups. Three rare missense alterations and one intronic change were each found in only one patient of over 250 familial patients studied and not among controls. The fourth missense alteration studied further was found with closely similar frequencies in over 600 familial cases and controls. Conclusion: Altogether, our results suggest very minor effect, if any, of ATM genetic variants on familial breast cancer in Southern Finland. Our results do not support association of the 5557G> A or ivs38- 8T> C variant with increased breast cancer risk or with bilateral breast cancer.
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