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1.
Trends Cancer ; 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33139182

RESUMO

Since its discovery, partner and localizer of breast cancer 2 (BRCA2) (PALB2) has emerged as a major tumor suppressor gene linked to breast cancer (BC), pancreatic cancer (PC), and ovarian cancer (OC) susceptibility. Its protein product plays a pivotal role in the maintenance of genome integrity. Here we discuss the first functional evaluation of a large set of PALB2 missense variants of uncertain significance (VUSs). Assessment of 136 VUSs interrogating a range of PALB2 biological functions resulted in the identification of 15 variants with consistent loss of function across different assays. All loss-of-function variants are located at the PALB2 coiled coil (CC) or at the WD40 domain, highlighting the importance of modular domains mechanistically involved in the DNA damage response (DDR) and pinpointing their roles in tumor suppression.

2.
NPJ Breast Cancer ; 6: 44, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32964118

RESUMO

Germline genetic variation has been suggested to influence the survival of breast cancer patients independently of tumor pathology. We have studied survival associations of genetic variants in two etiologically unique groups of breast cancer patients, the carriers of germline pathogenic variants in BRCA1 or BRCA2 genes. We found that rs57025206 was significantly associated with the overall survival, predicting higher mortality of BRCA1 carrier patients with estrogen receptor-negative breast cancer, with a hazard ratio 4.37 (95% confidence interval 3.03-6.30, P = 3.1 × 10-9). Multivariable analysis adjusted for tumor characteristics suggested that rs57025206 was an independent survival marker. In addition, our exploratory analyses suggest that the associations between genetic variants and breast cancer patient survival may depend on tumor biological subgroup and clinical patient characteristics.

3.
J Natl Cancer Inst ; 2020 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-32853342

RESUMO

BACKGROUND: We assessed the clinical utility of a first-degree breast cancer family history (FH) and polygenic risk score (PRS) to inform screening decisions among women aged 30-50 years. METHOD: Two established breast cancer models evaluated digital mammography screening strategies in the 1985 US birth cohort by risk groups defined by family history and polygenic risk score (PRS) based on 313-single nucleotide polymorphism. Strategies varied in initiation age (30, 35, 40, 45, 50) and interval (annual, hybrid, biennial [B], triennial). The benefits, breast cancer deaths averted, life years gained (LYG) and harms, false-positive (FP) mammograms, overdiagnoses, were compared those seen with three established screening guidelines. RESULTS: Women with a breast cancer FH who initiate biennial screening at age 40 years (vs. 50) had a 36% (model range: 29%-40%) increase in LYG and 20% (model range: 16%-24%) more breast cancer deaths averted, but 21% (model range: 17%-23%) more overdiagnoses and 63% (model range: 62%-64%) more false positives. Screening tailored to PRS vs. biennial 50-74 screening had smaller positive effects on LYG (20%) and breast cancer deaths averted (11%) but also smaller increases in overdiagnoses (10%) and false positives (26%). Combined use of FH and PRS vs. B50-74 had the greatest increase in LYG (29%) and breast cancer deaths averted (18%). CONCLUSION: Our results suggest that breast cancer family history and polygenic risk could guide screening decisions before age 50 years among women at increased risk for breast cancer, but should consider expected increases in overdiagnoses and false positives.

5.
Nat Commun ; 11(1): 3353, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620889

RESUMO

Genome-wide association studies (GWAS) have led to the identification of hundreds of susceptibility loci across cancers, but the impact of further studies remains uncertain. Here we analyse summary-level data from GWAS of European ancestry across fourteen cancer sites to estimate the number of common susceptibility variants (polygenicity) and underlying effect-size distribution. All cancers show a high degree of polygenicity, involving at a minimum of thousands of loci. We project that sample sizes required to explain 80% of GWAS heritability vary from 60,000 cases for testicular to over 1,000,000 cases for lung cancer. The maximum relative risk achievable for subjects at the 99th risk percentile of underlying polygenic risk scores (PRS), compared to average risk, ranges from 12 for testicular to 2.5 for ovarian cancer. We show that PRS have potential for risk stratification for cancers of breast, colon and prostate, but less so for others because of modest heritability and lower incidence.


Assuntos
Predisposição Genética para Doença , Modelos Genéticos , Herança Multifatorial , Neoplasias/epidemiologia , Animais , Feminino , Estudo de Associação Genômica Ampla , Humanos , Incidência , Masculino , Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Medição de Risco/métodos , Fatores de Risco
6.
Nat Rev Clin Oncol ; 17(11): 687-705, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32555420

RESUMO

The European Collaborative on Personalized Early Detection and Prevention of Breast Cancer (ENVISION) brings together several international research consortia working on different aspects of the personalized early detection and prevention of breast cancer. In a consensus conference held in 2019, the members of this network identified research areas requiring development to enable evidence-based personalized interventions that might improve the benefits and reduce the harms of existing breast cancer screening and prevention programmes. The priority areas identified were: 1) breast cancer subtype-specific risk assessment tools applicable to women of all ancestries; 2) intermediate surrogate markers of response to preventive measures; 3) novel non-surgical preventive measures to reduce the incidence of breast cancer of poor prognosis; and 4) hybrid effectiveness-implementation research combined with modelling studies to evaluate the long-term population outcomes of risk-based early detection strategies. The implementation of such programmes would require health-care systems to be open to learning and adapting, the engagement of a diverse range of stakeholders and tailoring to societal norms and values, while also addressing the ethical and legal issues. In this Consensus Statement, we discuss the current state of breast cancer risk prediction, risk-stratified prevention and early detection strategies, and their implementation. Throughout, we highlight priorities for advancing each of these areas.

8.
Breast Cancer Res ; 22(1): 8, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31948486

RESUMO

BACKGROUND: The effect of risk-reducing salpingo-oophorectomy (RRSO) on breast cancer risk for BRCA1 and BRCA2 mutation carriers is uncertain. Retrospective analyses have suggested a protective effect but may be substantially biased. Prospective studies have had limited power, particularly for BRCA2 mutation carriers. Further, previous studies have not considered the effect of RRSO in the context of natural menopause. METHODS: A multi-centre prospective cohort of 2272 BRCA1 and 1605 BRCA2 mutation carriers was followed for a mean of 5.4 and 4.9 years, respectively; 426 women developed incident breast cancer. RRSO was modelled as a time-dependent covariate in Cox regression, and its effect assessed in premenopausal and postmenopausal women. RESULTS: There was no association between RRSO and breast cancer for BRCA1 (HR = 1.23; 95% CI 0.94-1.61) or BRCA2 (HR = 0.88; 95% CI 0.62-1.24) mutation carriers. For BRCA2 mutation carriers, HRs were 0.68 (95% CI 0.40-1.15) and 1.07 (95% CI 0.69-1.64) for RRSO carried out before or after age 45 years, respectively. The HR for BRCA2 mutation carriers decreased with increasing time since RRSO (HR = 0.51; 95% CI 0.26-0.99 for 5 years or longer after RRSO). Estimates for premenopausal women were similar. CONCLUSION: We found no evidence that RRSO reduces breast cancer risk for BRCA1 mutation carriers. A potentially beneficial effect for BRCA2 mutation carriers was observed, particularly after 5 years following RRSO. These results may inform counselling and management of carriers with respect to RRSO.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/epidemiologia , Mutação , Salpingo-Ooforectomia/métodos , Adulto , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Estudos de Coortes , Feminino , Humanos , Incidência , Agências Internacionais , Menopausa , Pessoa de Meia-Idade , Estudos Prospectivos , Comportamento de Redução do Risco
9.
Cancer Epidemiol Biomarkers Prev ; 29(2): 368-378, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31792088

RESUMO

BACKGROUND: Tobacco smoking and alcohol consumption have been intensively studied in the general population to assess their effects on the risk of breast cancer, but very few studies have examined these effects in BRCA1 and BRCA2 mutation carriers. Given the high breast cancer risk for mutation carriers and the importance of BRCA1 and BRCA2 in DNA repair, better evidence on the associations of these lifestyle factors with breast cancer risk is essential. METHODS: Using a large international pooled cohort of BRCA1 and BRCA2 mutation carriers, we conducted retrospective (5,707 BRCA1 mutation carriers and 3,525 BRCA2 mutation carriers) and prospective (2,276 BRCA1 mutation carriers and 1,610 BRCA2 mutation carriers) analyses of alcohol and tobacco consumption using Cox proportional hazards models. RESULTS: For both BRCA1 and BRCA2 mutation carriers, none of the smoking-related variables was associated with breast cancer risk, except smoking for more than 5 years before a first full-term pregnancy (FFTP) when compared with parous women who never smoked. For BRCA1 mutation carriers, the HR from retrospective analysis (HRR) was 1.19 [95% confidence interval (CI), 1.02-1.39] and the HR from prospective analysis (HRP) was 1.36 (95% CI, 0.99-1.87). For BRCA2 mutation carriers, smoking for more than 5 years before an FFTP showed an association of a similar magnitude, but the confidence limits were wider (HRR = 1.25; 95% CI, 1.01-1.55 and HRP = 1.30; 95% CI, 0.83-2.01). For both carrier groups, alcohol consumption was not associated with breast cancer risk. CONCLUSIONS: The finding that smoking during the prereproductive years increases breast cancer risk for mutation carriers warrants further investigation. IMPACT: This is the largest prospective study of BRCA mutation carriers to assess these important risk factors.

10.
Genet Med ; 22(3): 622-632, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31636395

RESUMO

PURPOSE: Inherited pathogenic variants in PALB2 are associated with increased risk of breast and pancreatic cancer. However, the functional and clinical relevance of many missense variants of uncertain significance (VUS) identified through clinical genetic testing is unclear. The ability of patient-derived germline missense VUS to disrupt PALB2 function was assessed to identify variants with potential clinical relevance. METHODS: The influence of 84 VUS on PALB2 function was evaluated using a cellular homology directed DNA repair (HDR) assay and VUS impacting activity were further characterized using secondary functional assays. RESULTS: Four (~5%) variants (p.L24S,c.71T>C; p.L35P,c.104T>C; pI944N,c.2831T>A; and p.L1070P,c.3209T>C) disrupted PALB2-mediated HDR activity. These variants conferred sensitivity to cisplatin and a poly(ADP-ribose) polymerase (PARP) inhibitor and reduced RAD51 foci formation in response to DNA damage. The p.L24S and p.L35P variants disrupted BRCA1-PALB2 protein complexes, p.I944N was associated with protein instability, and both p.I944N and p.L1070P mislocalized PALB2 to the cytoplasm. CONCLUSION: These findings show that the HDR assay is an effective method for screening the influence of inherited variants on PALB2 function, that four missense variants impact PALB2 function and may influence cancer risk and response to therapy, and suggest that few inherited PALB2 missense variants disrupt PALB2 function in DNA repair.

11.
Int J Cancer ; 146(8): 2130-2138, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-31265136

RESUMO

A small number of circulating proteins have been reported to be associated with breast cancer risk, with inconsistent results. Herein, we attempted to identify novel protein biomarkers for breast cancer via the integration of genomics and proteomics data. In the Breast Cancer Association Consortium (BCAC), with 122,977 cases and 105,974 controls of European descendants, we evaluated the associations of the genetically predicted concentrations of >1,400 circulating proteins with breast cancer risk. We used data from a large-scale protein quantitative trait loci (pQTL) analysis as our study instrument. Summary statistics for these pQTL variants related to breast cancer risk were obtained from the BCAC and used to estimate odds ratios (OR) for each protein using the inverse-variance weighted method. We identified 56 proteins significantly associated with breast cancer risk by instrumental analysis (false discovery rate <0.05). Of these, the concentrations of 32 were influenced by variants close to a breast cancer susceptibility locus (ABO, 9q34.2). Many of these proteins, such as insulin receptor, insulin-like growth factor receptor 1 and other membrane receptors (OR: 0.82-1.18, p values: 6.96 × 10-4 -3.28 × 10-8 ), are linked to insulin resistance and estrogen receptor signaling pathways. Proteins identified at other loci include those involved in biological processes such as alcohol and lipid metabolism, proteolysis, apoptosis, immune regulation and cell motility and proliferation. Consistent associations were observed for 22 proteins in the UK Biobank data (p < 0.05). The study identifies potential novel biomarkers for breast cancer, but further investigation is needed to replicate our findings.


Assuntos
Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Neoplasias da Mama/sangue , Neoplasias da Mama/genética , Proteínas de Neoplasias/sangue , Proteínas de Neoplasias/genética , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Humanos , Locos de Características Quantitativas
12.
J Natl Cancer Inst ; 112(3): 295-304, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31143935

RESUMO

BACKGROUND: DNA methylation plays a critical role in breast cancer development. Previous studies have identified DNA methylation marks in white blood cells as promising biomarkers for breast cancer. However, these studies were limited by low statistical power and potential biases. Using a new methodology, we investigated DNA methylation marks for their associations with breast cancer risk. METHODS: Statistical models were built to predict levels of DNA methylation marks using genetic data and DNA methylation data from HumanMethylation450 BeadChip from the Framingham Heart Study (n = 1595). The prediction models were validated using data from the Women's Health Initiative (n = 883). We applied these models to genomewide association study (GWAS) data of 122 977 breast cancer patients and 105 974 controls to evaluate if the genetically predicted DNA methylation levels at CpG sites (CpGs) are associated with breast cancer risk. All statistical tests were two-sided. RESULTS: Of the 62 938 CpG sites CpGs investigated, statistically significant associations with breast cancer risk were observed for 450 CpGs at a Bonferroni-corrected threshold of P less than 7.94 × 10-7, including 45 CpGs residing in 18 genomic regions, that have not previously been associated with breast cancer risk. Of the remaining 405 CpGs located within 500 kilobase flaking regions of 70 GWAS-identified breast cancer risk variants, the associations for 11 CpGs were independent of GWAS-identified variants. Integrative analyses of genetic, DNA methylation, and gene expression data found that 38 CpGs may affect breast cancer risk through regulating expression of 21 genes. CONCLUSION: Our new methodology can identify novel DNA methylation biomarkers for breast cancer risk and can be applied to other diseases.

13.
Int J Epidemiol ; 49(4): 1117-1131, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31872213

RESUMO

BACKGROUND: Conventional epidemiologic studies have evaluated associations between circulating lipid levels and breast cancer risk, but results have been inconsistent. As Mendelian randomization analyses may provide evidence for causal inference, we sought to evaluate potentially unbiased associations between breast cancer risk and four genetically predicted lipid traits. METHODS: Previous genome-wide association studies (GWAS) have identified 164 discrete variants associated with high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), triglycerides and total cholesterol. We used 162 of these unique variants to construct weighted genetic scores (wGSs) for a total of 101 424 breast cancer cases and 80 253 controls of European ancestry from the Breast Cancer Association Consortium (BCAC). Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between per standard deviation increase in genetically predicted lipid traits and breast cancer risk. Additional Mendelian randomization analysis approaches and sensitivity analyses were conducted to assess pleiotropy and instrument validity. RESULTS: Corresponding to approximately 15 mg/dL, one standard deviation increase in genetically predicted HDL-C was associated with a 12% increased breast cancer risk (OR: 1.12, 95% CI: 1.08-1.16). Findings were consistent after adjustment for breast cancer risk factors and were robust in several sensitivity analyses. Associations with genetically predicted triglycerides and total cholesterol were inconsistent, and no association for genetically predicted LDL-C was observed. CONCLUSIONS: This study provides strong evidence that circulating HDL-C may be associated with an increased risk of breast cancer, whereas LDL-C may not be related to breast cancer risk.

14.
Nat Commun ; 10(1): 5296, 2019 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-31757951

RESUMO

Heterozygous carriers of germ-line loss-of-function variants in the DNA repair gene PALB2 are at a highly increased lifetime risk for developing breast cancer. While truncating variants in PALB2 are known to increase cancer risk, the interpretation of missense variants of uncertain significance (VUS) is in its infancy. Here we describe the development of a relatively fast and easy cDNA-based system for the semi high-throughput functional analysis of 48 VUS in human PALB2. By assessing the ability of PALB2 VUS to rescue the DNA repair and checkpoint defects in Palb2 knockout mouse embryonic stem (mES) cells, we identify various VUS in PALB2 that impair its function. Three VUS in the coiled-coil domain of PALB2 abrogate the interaction with BRCA1, whereas several VUS in the WD40 domain dramatically reduce protein stability. Thus, our functional assays identify damaging VUS in PALB2 that may increase cancer risk.


Assuntos
Neoplasias da Mama/genética , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Técnicas Genéticas , Células-Tronco Embrionárias Murinas/metabolismo , Proteínas Mutantes/metabolismo , Mutação de Sentido Incorreto , Animais , DNA Complementar , Proteína do Grupo de Complementação N da Anemia de Fanconi/metabolismo , Citometria de Fluxo , Predisposição Genética para Doença , Instabilidade Genômica , Humanos , Camundongos , Camundongos Knockout
15.
EBioMedicine ; 48: 203-211, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31629678

RESUMO

BACKGROUND: We previously conducted a systematic field synopsis of 1059 breast cancer candidate gene studies and investigated 279 genetic variants, 51 of which showed associations. The major limitation of this work was the small sample size, even pooling data from all 1059 studies. Thereafter, genome-wide association studies (GWAS) have accumulated data for hundreds of thousands of subjects. It's necessary to re-evaluate these variants in large GWAS datasets. METHODS: Of these 279 variants, data were obtained for 228 from GWAS conducted within the Asian Breast Cancer Consortium (24,206 cases and 24,775 controls) and the Breast Cancer Association Consortium (122,977 cases and 105,974 controls of European ancestry). Meta-analyses were conducted to combine the results from these two datasets. FINDINGS: Of those 228 variants, an association was observed for 12 variants in 10 genes at a Bonferroni-corrected threshold of P < 2·19 × 10-4. The associations for four variants reached P < 5 × 10-8 and have been reported by previous GWAS, including rs6435074 and rs6723097 (CASP8), rs17879961 (CHEK2) and rs2853669 (TERT). The remaining eight variants were rs676387 (HSD17B1), rs762551 (CYP1A2), rs1045485 (CASP8), rs9340799 (ESR1), rs7931342 (CHR11), rs1050450 (GPX1), rs13010627 (CASP10) and rs9344 (CCND1). Further investigating these 10 genes identified associations for two additional variants at P < 5 × 10-8, including rs4793090 (near HSD17B1), and rs9210 (near CYP1A2), which have not been identified by previous GWAS. INTERPRETATION: Though most candidate gene variants were not associated with breast cancer risk, we found 14 variants showing an association. Our findings warrant further functional investigation of these variants. FUND: National Institutes of Health.


Assuntos
Grupo com Ancestrais do Continente Asiático , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Grupo com Ancestrais do Continente Europeu , Predisposição Genética para Doença , Variação Genética , Alelos , Grupo com Ancestrais do Continente Asiático/genética , Caspase 8 , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Genótipo , Humanos , Razão de Chances , Polimorfismo de Nucleotídeo Único , Vigilância da População , Risco
16.
Nucleic Acids Res ; 47(20): 10662-10677, 2019 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-31586400

RESUMO

While biallelic mutations in the PALB2 tumor suppressor cause Fanconi anemia subtype FA-N, monoallelic mutations predispose to breast and familial pancreatic cancer. Although hundreds of missense variants in PALB2 have been identified in patients to date, only a few have clear functional and clinical relevance. Herein, we investigate the effects of 44 PALB2 variants of uncertain significance found in breast cancer patients and provide detailed analysis by systematic functional assays. Our comprehensive functional analysis reveals two hotspots for potentially deleterious variations within PALB2, one at each terminus. PALB2 N-terminus variants p.P8L [c.23C>T], p.Y28C [c.83A>G], and p.R37H [c.110G>A] compromised PALB2-mediated homologous recombination. At the C-terminus, PALB2 variants p.L947F [c.2841G>T], p.L947S [c.2840T>C], and most strikingly p.T1030I [c.3089C>T] and p.W1140G [c.3418T>C], stood out with pronounced PARP inhibitor sensitivity and cytoplasmic accumulation in addition to marked defects in recruitment to DNA damage sites, interaction with BRCA2 and homologous recombination. Altogether, our findings show that a combination of functional assays is necessary to assess the impact of germline missense variants on PALB2 function, in order to guide proper classification of their deleteriousness.


Assuntos
Neoplasias da Mama/genética , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Mutação de Sentido Incorreto/genética , Linhagem Celular Tumoral , Simulação por Computador , Dano ao DNA , Feminino , Loci Gênicos , Recombinação Homóloga/genética , Humanos , Cinética , Rad51 Recombinase/metabolismo , Reprodutibilidade dos Testes
19.
Public Health Rev ; 40: 2, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30858992

RESUMO

Background: Younger women at higher-than-population-average risk for breast cancer may benefit from starting screening earlier than presently recommended by the guidelines. The Personalized Risk Stratification for Prevention and Early Detection of Breast Cancer (PERSPECTIVE) approach aims to improve the prevention of breast cancer through differential screening recommendations based on a personal risk estimate. In our study, we used deliberative stakeholder consultations to engage health professionals in an in-depth dialog to explore the feasibility of the proposed implementation strategies for this new personalized breast cancer screening approach. Methods: Deliberative stakeholder consultation is a qualitative descriptive study design used to engage health professionals in the discussion, while the mediators play a more passive role. A purposeful sample of 11 health professionals (family physicians and genetic counselors) working in Montreal was used. The deliberations were organized in two phases, including small group deliberations according to the deliberants' health profession and a mixed group deliberation combining participants from the small groups. Inductive thematic content analysis was performed on the transcripts by two coders to create the deliberative and analytic outputs. Quality of deliberations was assessed quantitatively using the de Vries method and qualitatively using participant observation. Results: One of our key findings was that health professionals lacked understanding of the two steps of the screening approach: risk stratification "screening," which is an evaluation for the level of risk and screening for disease. As part of this confusion, the main topic of concern was a justification of program implementation as a population-wide screening, based on their uncertainty that it will be beneficial for women with near-population risks. Despite the noted difficulties concerning implementation, health professionals acknowledged the substantial benefits of the proposed PERSPECTIVE program. Conclusions: Our study was the first to evaluate the perspectives of health professionals on the implementation and benefits of a new program for breast cancer risk stratification with the purpose of personalizing screening for disease. This new multi-step approach to screening requires more clarity in communication with health professionals. To implement and maintain effective screening, engagement of family physicians with other health professionals or even development of a centralized public health system may be needed.

20.
Genes (Basel) ; 10(3)2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30823486

RESUMO

Genetic variants affecting the regulation of gene expression are among the main causes of human diversity. The potential importance of regulatory polymorphisms is underscored by results from Genome Wide Association Studies, which have already implicated such polymorphisms in the susceptibility to complex diseases such as breast cancer. In this study, we re-sequenced the promoter regions of 24 genes involved in pathways related to breast cancer including sex steroid action, DNA repair, and cell cycle control in 60 unrelated Caucasian individuals. We constructed haplotypes and assessed the functional impact of promoter variants using gene reporter assays and electrophoretic mobility shift assays. We identified putative functional variants within the promoter regions of estrogen receptor 1 (ESR1), ESR2, forkhead box A1 (FOXA1), ubiquitin interaction motif containing 1 (UIMC1) and cell division cycle 7 (CDC7). The functional polymorphism on CDC7, rs13447455, influences CDC7 transcriptional activity in an allele-specific manner and alters DNA⁻protein complex formation in breast cancer cell lines. Moreover, results from the Breast Cancer Association Consortium show a marginal association between rs13447455 and breast cancer risk (p=9.3x10-5), thus warranting further investigation. Furthermore, our study has helped provide methodological solutions to some technical difficulties that were encountered with gene reporter assays, particularly regarding inter-clone variability and statistical consistency.


Assuntos
Neoplasias da Mama/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ligação a DNA/genética , Grupo com Ancestrais do Continente Europeu/genética , Chaperonas de Histonas/genética , Proteínas Nucleares/genética , Polimorfismo de Nucleotídeo Único , Proteínas Serina-Treonina Quinases/genética , Receptores de Esteroides/genética , Receptor alfa de Estrogênio/genética , Receptor beta de Estrogênio/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Células HeLa , Fator 3-alfa Nuclear de Hepatócito/genética , Humanos , Células MCF-7 , Regiões Promotoras Genéticas
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