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1.
PLoS One ; 14(8): e0221413, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31442252

RESUMO

BACKGROUND: Fusion genes result from genomic structural changes, which can lead to alterations in gene expression that supports tumor development. The aim of the study was to use fusion genes as a tool to identify new breast cancer (BC) genes with a role in BC progression. METHODS: Fusion genes from breast tumors and BC cell lines were collected from publications. RNA-Seq data from tumors and cell lines were retrieved from databanks and analyzed for fusions with SOAPfuse or the analysis was purchased. Fusion genes identified in both tumors (n = 1724) and cell lines (n = 45) were confirmed by qRT-PCR and sequencing. Their individual genes were ranked by selection criteria that included correlation of their mRNA level with copy number. The expression of the top ranked gene was measured by qRT-PCR in normal tissue and in breast tumors from an exploratory cohort (n = 141) and a validation cohort (n = 277). Expression levels were correlated with clinical and pathological factors as well as the patients' survival. The results were followed up in BC cohorts from TCGA (n = 818) and METABRIC (n = 2509). RESULTS: Vacuole membrane protein 1 (VMP1) was the most promising candidate based on specific selection criteria. Its expression was higher in breast tumor tissue than normal tissue (p = 1x10-4), and its expression was significantly higher in HER2 positive than HER2 negative breast tumors in all four cohorts analyzed. High expression of VMP1 associated with breast cancer specific survival (BCSS) in cohort 1 (hazard ratio (HR) = 2.31, CI 1.27-4.18) and METABRIC (HR = 1.26, CI 1.02-1.57), and also after adjusting for HER2 expression in cohort 1 (HR = 2.03, CI 1.10-3.72). BCSS was not significant in cohort 2 or TCGA cohort, which may be due to differences in treatment regimens. CONCLUSIONS: The results suggest that high VMP1 expression is a potential marker of poor prognosis in HER2 positive BC. Further studies are needed to elucidate how VMP1 could affect pathways supportive of tumorigenesis.

2.
Nat Commun ; 10(1): 1741, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30988301

RESUMO

Genome-wide association studies (GWAS) have identified more than 170 breast cancer susceptibility loci. Here we hypothesize that some risk-associated variants might act in non-breast tissues, specifically adipose tissue and immune cells from blood and spleen. Using expression quantitative trait loci (eQTL) reported in these tissues, we identify 26 previously unreported, likely target genes of overall breast cancer risk variants, and 17 for estrogen receptor (ER)-negative breast cancer, several with a known immune function. We determine the directional effect of gene expression on disease risk measured based on single and multiple eQTL. In addition, using a gene-based test of association that considers eQTL from multiple tissues, we identify seven (and four) regions with variants associated with overall (and ER-negative) breast cancer risk, which were not reported in previous GWAS. Further investigation of the function of the implicated genes in breast and immune cells may provide insights into the etiology of breast cancer.


Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença , Feminino , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Humanos , Locos de Características Quantitativas
3.
Hum Mutat ; 39(5): 593-620, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29446198

RESUMO

The prevalence and spectrum of germline mutations in BRCA1 and BRCA2 have been reported in single populations, with the majority of reports focused on White in Europe and North America. The Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) has assembled data on 18,435 families with BRCA1 mutations and 11,351 families with BRCA2 mutations ascertained from 69 centers in 49 countries on six continents. This study comprehensively describes the characteristics of the 1,650 unique BRCA1 and 1,731 unique BRCA2 deleterious (disease-associated) mutations identified in the CIMBA database. We observed substantial variation in mutation type and frequency by geographical region and race/ethnicity. In addition to known founder mutations, mutations of relatively high frequency were identified in specific racial/ethnic or geographic groups that may reflect founder mutations and which could be used in targeted (panel) first pass genotyping for specific populations. Knowledge of the population-specific mutational spectrum in BRCA1 and BRCA2 could inform efficient strategies for genetic testing and may justify a more broad-based oncogenetic testing in some populations.

4.
Breast Cancer Res Treat ; 161(1): 117-134, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27796716

RESUMO

PURPOSE: Cis-acting regulatory SNPs resulting in differential allelic expression (DAE) may, in part, explain the underlying phenotypic variation associated with many complex diseases. To investigate whether common variants associated with DAE were involved in breast cancer susceptibility among BRCA1 and BRCA2 mutation carriers, a list of 175 genes was developed based of their involvement in cancer-related pathways. METHODS: Using data from a genome-wide map of SNPs associated with allelic expression, we assessed the association of ~320 SNPs located in the vicinity of these genes with breast and ovarian cancer risks in 15,252 BRCA1 and 8211 BRCA2 mutation carriers ascertained from 54 studies participating in the Consortium of Investigators of Modifiers of BRCA1/2. RESULTS: We identified a region on 11q22.3 that is significantly associated with breast cancer risk in BRCA1 mutation carriers (most significant SNP rs228595 p = 7 × 10-6). This association was absent in BRCA2 carriers (p = 0.57). The 11q22.3 region notably encompasses genes such as ACAT1, NPAT, and ATM. Expression quantitative trait loci associations were observed in both normal breast and tumors across this region, namely for ACAT1, ATM, and other genes. In silico analysis revealed some overlap between top risk-associated SNPs and relevant biological features in mammary cell data, which suggests potential functional significance. CONCLUSION: We identified 11q22.3 as a new modifier locus in BRCA1 carriers. Replication in larger studies using estrogen receptor (ER)-negative or triple-negative (i.e., ER-, progesterone receptor-, and HER2-negative) cases could therefore be helpful to confirm the association of this locus with breast cancer risk.


Assuntos
Alelos , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/etiologia , Genes BRCA1 , Genes BRCA2 , Heterozigoto , Mutação , Biomarcadores Tumorais , Cromossomos Humanos Par 11 , Feminino , Expressão Gênica , Predisposição Genética para Doença , Variação Genética , Humanos , Locos de Características Quantitativas , Risco
5.
Br J Cancer ; 115(7): 776-83, 2016 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-27537391

RESUMO

BACKGROUND: The impact of an inherited BRCA2 mutation on the prognosis of women with breast cancer has not been well documented. We studied the effects of oestrogen receptor (ER) status, other prognostic factors and treatments on survival in a large cohort of BRCA2 mutation carriers. METHODS: We identified 285 breast cancer patients with a 999del5 BRCA2 mutation and matched them with 570 non-carrier patients. Clinical information was abstracted from patient charts and pathology records and supplemented by evaluation of tumour grade and ER status using archived tissue specimens. Univariate and multivariate hazard ratios (HR) were estimated for breast cancer-specific survival using Cox regression. The effects of various therapies were studied in patients treated from 1980 to 2012. RESULTS: Among mutation carriers, positive ER status was associated with higher risk of death than negative ER status (HR=1.94; 95% CI=1.22-3.07, P=0.005). The reverse association was seen for non-carriers (HR=0.71; 95% CI: 0.51-0.97; P=0.03). CONCLUSIONS: Among BRCA2 carriers, ER-positive status is an adverse prognostic factor. BRCA2 carrier status should be known at the time when treatment decisions are made.


Assuntos
Neoplasias da Mama/genética , Estrogênios , Genes BRCA2 , Mutação , Neoplasias Hormônio-Dependentes/genética , Síndromes Neoplásicas Hereditárias/genética , Receptores Estrogênicos/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/química , Neoplasias da Mama/mortalidade , Neoplasias da Mama/terapia , Feminino , Humanos , Islândia/epidemiologia , Masculino , Pessoa de Meia-Idade , Neoplasias Hormônio-Dependentes/química , Neoplasias Hormônio-Dependentes/mortalidade , Neoplasias Hormônio-Dependentes/terapia , Segunda Neoplasia Primária/epidemiologia , Segunda Neoplasia Primária/genética , Síndromes Neoplásicas Hereditárias/mortalidade , Síndromes Neoplásicas Hereditárias/terapia , Prognóstico , Modelos de Riscos Proporcionais , Resultado do Tratamento , Adulto Jovem
6.
Breast Cancer Res ; 18(1): 64, 2016 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-27459855

RESUMO

BACKGROUND: Multiple recent genome-wide association studies (GWAS) have identified a single nucleotide polymorphism (SNP), rs10771399, at 12p11 that is associated with breast cancer risk. METHOD: We performed a fine-scale mapping study of a 700 kb region including 441 genotyped and more than 1300 imputed genetic variants in 48,155 cases and 43,612 controls of European descent, 6269 cases and 6624 controls of East Asian descent and 1116 cases and 932 controls of African descent in the Breast Cancer Association Consortium (BCAC; http://bcac.ccge.medschl.cam.ac.uk/ ), and in 15,252 BRCA1 mutation carriers in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). Stepwise regression analyses were performed to identify independent association signals. Data from the Encyclopedia of DNA Elements project (ENCODE) and the Cancer Genome Atlas (TCGA) were used for functional annotation. RESULTS: Analysis of data from European descendants found evidence for four independent association signals at 12p11, represented by rs7297051 (odds ratio (OR) = 1.09, 95 % confidence interval (CI) = 1.06-1.12; P = 3 × 10(-9)), rs805510 (OR = 1.08, 95 % CI = 1.04-1.12, P = 2 × 10(-5)), and rs1871152 (OR = 1.04, 95 % CI = 1.02-1.06; P = 2 × 10(-4)) identified in the general populations, and rs113824616 (P = 7 × 10(-5)) identified in the meta-analysis of BCAC ER-negative cases and BRCA1 mutation carriers. SNPs rs7297051, rs805510 and rs113824616 were also associated with breast cancer risk at P < 0.05 in East Asians, but none of the associations were statistically significant in African descendants. Multiple candidate functional variants are located in putative enhancer sequences. Chromatin interaction data suggested that PTHLH was the likely target gene of these enhancers. Of the six variants with the strongest evidence of potential functionality, rs11049453 was statistically significantly associated with the expression of PTHLH and its nearby gene CCDC91 at P < 0.05. CONCLUSION: This study identified four independent association signals at 12p11 and revealed potentially functional variants, providing additional insights into the underlying biological mechanism(s) for the association observed between variants at 12p11 and breast cancer risk.


Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Mapeamento Cromossômico , Cromossomos Humanos Par 12 , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Alelos , Proteína BRCA1/genética , Estudos de Casos e Controles , Biologia Computacional/métodos , Bases de Dados Genéticas , Elementos Facilitadores Genéticos , Epigênese Genética , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Genótipo , Haplótipos , Heterozigoto , Humanos , Mutação , Razão de Chances , Polimorfismo de Nucleotídeo Único , Vigilância da População , Regiões Promotoras Genéticas , Locos de Características Quantitativas , Risco
7.
Cancer Med ; 2(4): 437-46, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24156016

RESUMO

Amplification of 8p12-p11 is relatively common in breast cancer and several genes within the region have been suggested to affect breast tumor progression. The aim of the study was to map the amplified 8p12-p11 region in a large set of breast tumors in an effort to identify the genetic driver and to explore its impact on tumor progression and prognosis. Copy number alterations (CNAs) were mapped in 359 tumors, and gene expression data from 577 tumors (359 tumors included) were correlated with CNA, clinical-pathological factors, and protein expression (39 tumors). 8p12-p11 was amplified in 11.4% of tumors. The smallest region of amplification harbored one full-length gene, ZNF703. ZNF703 mRNA expression was significantly higher in estrogen receptor (ER)-positive than ER-negative tumors (P = 2 × 10(-16)), a reflection of high expression in luminal tumors. Forty-eight percent of tumors with ZNF703 amplification were luminal B tumors in which the best correlation between DNA copy number and mRNA was seen (P = 1.2 × 10(-7)) as well as correlation between mRNA and protein expression (P = 0.02). High ZNF703 mRNA correlated with poor survival in patients with ER-positive luminal B tumors (log rank P = 0.04). Furthermore, high ZNF703 mRNA expression correlated with poor outcome in patients with ZNF703 copy number neutral, ER-positive, luminal B tumors (log rank P = 0.004). The results support ZNF703 as the driver gene of the 8p12 amplification and suggest that independent of amplification, high expression of the gene affects prognosis in luminal B tumors.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Proteínas de Transporte/genética , Amplificação de Genes , Expressão Gênica , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/mortalidade , Proteínas de Transporte/metabolismo , Mapeamento Cromossômico , Cromossomos Humanos Par 8 , Feminino , Perfilação da Expressão Gênica , Humanos , Pessoa de Meia-Idade , Gradação de Tumores , Prognóstico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
8.
PLoS Genet ; 9(3): e1003173, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23544012

RESUMO

Common genetic variants contribute to the observed variation in breast cancer risk for BRCA2 mutation carriers; those known to date have all been found through population-based genome-wide association studies (GWAS). To comprehensively identify breast cancer risk modifying loci for BRCA2 mutation carriers, we conducted a deep replication of an ongoing GWAS discovery study. Using the ranked P-values of the breast cancer associations with the imputed genotype of 1.4 M SNPs, 19,029 SNPs were selected and designed for inclusion on a custom Illumina array that included a total of 211,155 SNPs as part of a multi-consortial project. DNA samples from 3,881 breast cancer affected and 4,330 unaffected BRCA2 mutation carriers from 47 studies belonging to the Consortium of Investigators of Modifiers of BRCA1/2 were genotyped and available for analysis. We replicated previously reported breast cancer susceptibility alleles in these BRCA2 mutation carriers and for several regions (including FGFR2, MAP3K1, CDKN2A/B, and PTHLH) identified SNPs that have stronger evidence of association than those previously published. We also identified a novel susceptibility allele at 6p24 that was inversely associated with risk in BRCA2 mutation carriers (rs9348512; per allele HR = 0.85, 95% CI 0.80-0.90, P = 3.9 × 10(-8)). This SNP was not associated with breast cancer risk either in the general population or in BRCA1 mutation carriers. The locus lies within a region containing TFAP2A, which encodes a transcriptional activation protein that interacts with several tumor suppressor genes. This report identifies the first breast cancer risk locus specific to a BRCA2 mutation background. This comprehensive update of novel and previously reported breast cancer susceptibility loci contributes to the establishment of a panel of SNPs that modify breast cancer risk in BRCA2 mutation carriers. This panel may have clinical utility for women with BRCA2 mutations weighing options for medical prevention of breast cancer.


Assuntos
Proteína BRCA2/genética , Neoplasias da Mama/genética , Cromossomos Humanos Par 6/genética , Estudo de Associação Genômica Ampla , Adulto , Idoso , Alelos , Proteína BRCA1/genética , Neoplasias da Mama/patologia , Feminino , Predisposição Genética para Doença , Genótipo , Heterozigoto , Humanos , Pessoa de Meia-Idade , Mutação , Polimorfismo de Nucleotídeo Único , Fatores de Risco
9.
BMC Cancer ; 12: 621, 2012 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-23270421

RESUMO

BACKGROUND: The minor allele of SNP rs3803662 has been shown to correlate with increased breast cancer risk and with lower expression of TOX3. The SNP is closely located to TOX3 residing within an uncharacterised gene LOC643714. The aim of the study was to examine the association of the risk allele with expression of TOX3 and LOC643714, and of mRNA levels and genotype with clinical and pathological characteristics. METHODS: The SNP was genotyped in DNA isolated from blood and normal tissue from 160 breast cancer patients and mRNA levels were measured by microarrays and quantitative real-time (qRT)-PCR in breast tumours. Association with clinical and pathological characteristics was analysed by parametric tests. RESULTS: An association of the risk allele of rs3803662 with lower TOX3 expression was confirmed in oestrogen receptor (ER) positive tumours. It was more often observed in lobular tumours (p = 0.04), and carriers of the risk allele who had been diagnosed with luminal A tumours had shorter overall survival (OS) than carriers of the non-risk allele (p = 0.01). Positive correlation between the mRNA levels of TOX3 and LOC643714 was observed (r = 0.44 and p < 0.001). Association analysis with tumour pathology showed that low TOX3 and LOC643714 expression correlated with high Ki67 levels (p = 0.026 and p = 0.002) and the basal subtype (p < 0.001 and p < 0.001), whereas high expression correlated with ER (p = 0.004 and p < 0.001) and progesterone receptor (PgR) (p = 0.005 and p < 0.001) expression. Furthermore, high TOX3 and LOC643714 correlated with positive lymph nodes (p < 0.001 and p = 0.01). Patients with ER positive tumours and high levels of TOX3 mRNA had shorter overall- and distant metastasis free-survival (p = 0.017 and p = 0.021), an effect mostly attributable to patients with luminal B tumours. CONCLUSIONS: The results suggest that the effect of the risk allele of rs3803662 is strongest in luminal A tumours and that the expression levels of TOX3 and/or LOC643714 affect the progression of breast cancer. The effect may vary depending on the subtype and developmental stage of the tumour.


Assuntos
Neoplasias da Mama/genética , Polimorfismo de Nucleotídeo Único , Receptores de Progesterona/genética , Alelos , Análise de Variância , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Feminino , Estudos de Associação Genética , Genótipo , Humanos , RNA Mensageiro/metabolismo , Receptores de Progesterona/metabolismo , Análise de Sobrevida
10.
Breast Cancer Res Treat ; 136(1): 295-302, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23011509

RESUMO

Several common germline variants identified through genome-wide association studies of breast cancer risk in the general population have recently been shown to be associated with breast cancer risk for BRCA1 and/or BRCA2 mutation carriers. When combined, these variants can identify marked differences in the absolute risk of developing breast cancer for mutation carriers, suggesting that additional modifier loci may further enhance individual risk assessment for BRCA1 and BRCA2 mutation carriers. Recently, a common variant on 6p22 (rs9393597) was found to be associated with increased breast cancer risk for BRCA2 mutation carriers [hazard ratio (HR) = 1.55, 95 % confidence interval (CI) 1.25-1.92, p = 6.0 × 10(-5)]. This observation was based on data from GWAS studies in which, despite statistical correction for multiple comparisons, the possibility of false discovery remains a concern. Here, we report on an analysis of this variant in an additional 6,165 BRCA1 and 3,900 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). In this replication analysis, rs9393597 was not associated with breast cancer risk for BRCA2 mutation carriers (HR = 1.09, 95 % CI 0.96-1.24, p = 0.18). No association with ovarian cancer risk for BRCA1 or BRCA2 mutation carriers or with breast cancer risk for BRCA1 mutation carriers was observed. This follow-up study suggests that, contrary to our initial report, this variant is not associated with breast cancer risk among individuals with germline BRCA2 mutations.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama , Mutação em Linhagem Germinativa , Adulto , Idoso , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Cromossomos Humanos Par 6/genética , Feminino , Seguimentos , Estudos de Associação Genética , Predisposição Genética para Doença , Heterozigoto , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Fatores de Risco
11.
Cancer Res ; 72(16): 4028-36, 2012 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-22706203

RESUMO

Breast tumors from BRCA1 germ line mutation carriers typically exhibit features of the basal-like molecular subtype. However, the specific genes recurrently mutated as a consequence of BRCA1 dysfunction have not been fully elucidated. In this study, we used gene expression profiling to molecularly subtype 577 breast tumors, including 73 breast tumors from BRCA1/2 mutation carriers. Focusing on the RB1 locus, we analyzed 33 BRCA1-mutated, 36 BRCA2-mutated, and 48 non-BRCA1/2-mutated breast tumors using a custom-designed high-density oligomicroarray covering the RB1 gene. We found a strong association between the basal-like subtype and BRCA1-mutated breast tumors and the luminal B subtype and BRCA2-mutated breast tumors. RB1 was identified as a major target for genomic disruption in tumors arising in BRCA1 mutation carriers and in sporadic tumors with BRCA1 promoter methylation but rarely in other breast cancers. Homozygous deletions, intragenic breaks, or microdeletions were found in 33% of BRCA1-mutant tumors, 36% of BRCA1 promoter-methylated basal-like tumors, 13% of non-BRCA1-deficient basal-like tumors, and 3% of BRCA2-mutated tumors. In conclusion, RB1 was frequently inactivated by gross gene disruption in BRCA1 hereditary breast cancer and BRCA1-methylated sporadic basal-like breast cancer but rarely in BRCA2 hereditary breast cancer and non-BRCA1-deficient sporadic breast cancers. Together, our findings show the existence of genetic heterogeneity within the basal-like breast cancer subtype that is based upon BRCA1 status.


Assuntos
Proteína BRCA1/deficiência , Neoplasias da Mama/genética , Genes do Retinoblastoma , Neoplasia de Células Basais/genética , Proteína BRCA1/genética , Proteína BRCA1/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Hibridização Genômica Comparativa , Feminino , Dosagem de Genes , Rearranjo Gênico , Genes BRCA1 , Mutação em Linhagem Germinativa , Humanos , Hibridização in Situ Fluorescente , Neoplasia de Células Basais/metabolismo , Neoplasia de Células Basais/patologia , Proteína do Retinoblastoma/biossíntese , Proteína do Retinoblastoma/genética , Transcriptoma
12.
Breast Cancer Res Treat ; 132(3): 1119-26, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22212556

RESUMO

Klotho (KL) is a putative tumor suppressor gene in breast and pancreatic cancers located at chromosome 13q12. A functional sequence variant of Klotho (KL-VS) was previously reported to modify breast cancer risk in Jewish BRCA1 mutation carriers. The effect of this variant on breast and ovarian cancer risks in non-Jewish BRCA1/BRCA2 mutation carriers has not been reported. The KL-VS variant was genotyped in women of European ancestry carrying a BRCA mutation: 5,741 BRCA1 mutation carriers (2,997 with breast cancer, 705 with ovarian cancer, and 2,039 cancer free women) and 3,339 BRCA2 mutation carriers (1,846 with breast cancer, 207 with ovarian cancer, and 1,286 cancer free women) from 16 centers. Genotyping was accomplished using TaqMan(®) allelic discrimination or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Data were analyzed within a retrospective cohort approach, stratified by country of origin and Ashkenazi Jewish origin. The per-allele hazard ratio (HR) for breast cancer was 1.02 (95% CI 0.93-1.12, P = 0.66) for BRCA1 mutation carriers and 0.92 (95% CI 0.82-1.04, P = 0.17) for BRCA2 mutation carriers. Results remained unaltered when analysis excluded prevalent breast cancer cases. Similarly, the per-allele HR for ovarian cancer was 1.01 (95% CI 0.84-1.20, P = 0.95) for BRCA1 mutation carriers and 0.9 (95% CI 0.66-1.22, P = 0.45) for BRCA2 mutation carriers. The risk did not change when carriers of the 6174delT mutation were excluded. There was a lack of association of the KL-VS Klotho variant with either breast or ovarian cancer risk in BRCA1 and BRCA2 mutation carriers.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Glucuronidase/genética , Heterozigoto , Neoplasias Ovarianas/genética , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Modelos de Riscos Proporcionais
13.
Breast Cancer Res Treat ; 133(2): 583-94, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22002566

RESUMO

Amplification of chromosomal region 11q13, containing the cell cycle regulatory gene CCND1, is frequently found in breast cancer and other malignancies. It is associated with the favourable oestrogen receptor (ER)-positive breast tumour phenotype, but also with poor prognosis and treatment failure. 11q13 spans almost 14 Mb and contains more than 200 genes and is affected by various patterns of copy number gains, suggesting complex mechanisms and selective pressure during tumour progression. In this study, we used 32 k tiling BAC array CGH to analyse 94 CCND1-amplified breast tumours from sporadic, hereditary, and familial breast cancers to fine map chromosome 11q13. A set containing 281 CCND1-non-amplified breast tumours was used for comparisons. We used gene expression data to further validate the functional effect of gene amplification. We identified six core regions covering 11q13.1-q14.1 that were amplified in different combinations. The major core contained CCND1, whereas two cores were found proximal of CCND1 and three distal. The majority of the CCND1-amplified tumours were ER-positive and classified as luminal B. Furthermore, we found that CCND1 amplification is associated with a more aggressive phenotype within histological grade 2 tumours and luminal A subtype tumours. Amplification was equally prevalent in familial and sporadic tumours, but strikingly rare in BRCA1- and BRCA2-mutated tumours. We conclude that 11q13 includes many potential target genes in addition to CCND1.


Assuntos
Neoplasias da Mama/genética , Cromossomos Humanos Par 11 , Ciclina D1/genética , Amplificação de Genes , Neoplasias da Mama/mortalidade , Mapeamento Cromossômico , Análise por Conglomerados , Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA , Família , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Proteínas Repressoras/genética , Análise de Sobrevida
14.
PLoS Genet ; 6(10): e1001183, 2010 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-21060860

RESUMO

The considerable uncertainty regarding cancer risks associated with inherited mutations of BRCA2 is due to unknown factors. To investigate whether common genetic variants modify penetrance for BRCA2 mutation carriers, we undertook a two-staged genome-wide association study in BRCA2 mutation carriers. In stage 1 using the Affymetrix 6.0 platform, 592,163 filtered SNPs genotyped were available on 899 young (<40 years) affected and 804 unaffected carriers of European ancestry. Associations were evaluated using a survival-based score test adjusted for familial correlations and stratified by country of the study and BRCA2*6174delT mutation status. The genomic inflation factor (λ) was 1.011. The stage 1 association analysis revealed multiple variants associated with breast cancer risk: 3 SNPs had p-values<10(-5) and 39 SNPs had p-values<10(-4). These variants included several previously associated with sporadic breast cancer risk and two novel loci on chromosome 20 (rs311499) and chromosome 10 (rs16917302). The chromosome 10 locus was in ZNF365, which contains another variant that has recently been associated with breast cancer in an independent study of unselected cases. In stage 2, the top 85 loci from stage 1 were genotyped in 1,264 cases and 1,222 controls. Hazard ratios (HR) and 95% confidence intervals (CI) for stage 1 and 2 were combined and estimated using a retrospective likelihood approach, stratified by country of residence and the most common mutation, BRCA2*6174delT. The combined per allele HR of the minor allele for the novel loci rs16917302 was 0.75 (95% CI 0.66-0.86, ) and for rs311499 was 0.72 (95% CI 0.61-0.85, ). FGFR2 rs2981575 had the strongest association with breast cancer risk (per allele HR = 1.28, 95% CI 1.18-1.39, ). These results indicate that SNPs that modify BRCA2 penetrance identified by an agnostic approach thus far are limited to variants that also modify risk of sporadic BRCA2 wild-type breast cancer.


Assuntos
Proteína BRCA2/genética , Neoplasias da Mama/genética , Estudo de Associação Genômica Ampla/métodos , Polimorfismo de Nucleotídeo Único , Adulto , Cromossomos Humanos Par 10 , Cromossomos Humanos Par 20 , Proteínas de Ligação a DNA/genética , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Frequência do Gene , Predisposição Genética para Doença/genética , Haplótipos , Heterozigoto , Humanos , Desequilíbrio de Ligação , Pessoa de Meia-Idade , Mutação , Penetrância , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Fatores de Risco , Fatores de Transcrição/genética
15.
Breast Cancer Res ; 12(4): R50, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20637093

RESUMO

INTRODUCTION: A significant proportion of high-risk breast cancer families are not explained by mutations in known genes. Recent genome-wide searches (GWS) have not revealed any single major locus reminiscent of BRCA1 and BRCA2, indicating that still unidentified genes may explain relatively few families each or interact in a way obscure to linkage analyses. This has drawn attention to possible benefits of studying populations where genetic heterogeneity might be reduced. We thus performed a GWS for linkage on nine Icelandic multiple-case non-BRCA1/2 families of desirable size for mapping highly penetrant loci. To follow up suggestive loci, an additional 13 families from other Nordic countries were genotyped for selected markers. METHODS: GWS was performed using 811 microsatellite markers providing about five centiMorgan (cM) resolution. Multipoint logarithm of odds (LOD) scores were calculated using parametric and nonparametric methods. For selected markers and cases, tumour tissue was compared to normal tissue to look for allelic loss indicative of a tumour suppressor gene. RESULTS: The three highest signals were located at chromosomes 6q, 2p and 14q. One family contributed suggestive LOD scores (LOD 2.63 to 3.03, dominant model) at all these regions, without consistent evidence of a tumour suppressor gene. Haplotypes in nine affected family members mapped the loci to 2p23.2 to p21, 6q14.2 to q23.2 and 14q21.3 to q24.3. No evidence of a highly penetrant locus was found among the remaining families. The heterogeneity LOD (HLOD) at the 6q, 2p and 14q loci in all families was 3.27, 1.66 and 1.24, respectively. The subset of 13 Nordic families showed supportive HLODs at chromosome 6q (ranging from 0.34 to 1.37 by country subset). The 2p and 14q loci overlap with regions indicated by large families in previous GWS studies of breast cancer. CONCLUSIONS: Chromosomes 2p, 6q and 14q are candidate sites for genes contributing together to high breast cancer risk. A polygenic model is supported, suggesting the joint effect of genes in contributing to breast cancer risk to be rather common in non-BRCA1/2 families. For genetic counselling it would seem important to resolve the mode of genetic interaction.


Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Genoma Humano/genética , Estudo de Associação Genômica Ampla/métodos , Proteína BRCA1/genética , Proteína BRCA2/genética , Mapeamento Cromossômico , Cromossomos Humanos Par 14/genética , Cromossomos Humanos Par 2/genética , Cromossomos Humanos Par 6/genética , Saúde da Família , Feminino , Haplótipos , Humanos , Islândia , Escore Lod , Masculino , Modelos Genéticos , Herança Multifatorial , Linhagem
16.
Breast Cancer Res ; 12(3): R42, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20576095

RESUMO

INTRODUCTION: Breast cancer is a profoundly heterogeneous disease with respect to biologic and clinical behavior. Gene-expression profiling has been used to dissect this complexity and to stratify tumors into intrinsic gene-expression subtypes, associated with distinct biology, patient outcome, and genomic alterations. Additionally, breast tumors occurring in individuals with germline BRCA1 or BRCA2 mutations typically fall into distinct subtypes. METHODS: We applied global DNA copy number and gene-expression profiling in 359 breast tumors. All tumors were classified according to intrinsic gene-expression subtypes and included cases from genetically predisposed women. The Genomic Identification of Significant Targets in Cancer (GISTIC) algorithm was used to identify significant DNA copy-number aberrations and genomic subgroups of breast cancer. RESULTS: We identified 31 genomic regions that were highly amplified in > 1% of the 359 breast tumors. Several amplicons were found to co-occur, the 8p12 and 11q13.3 regions being the most frequent combination besides amplicons on the same chromosomal arm. Unsupervised hierarchical clustering with 133 significant GISTIC regions revealed six genomic subtypes, termed 17q12, basal-complex, luminal-simple, luminal-complex, amplifier, and mixed subtypes. Four of them had striking similarity to intrinsic gene-expression subtypes and showed associations to conventional tumor biomarkers and clinical outcome. However, luminal A-classified tumors were distributed in two main genomic subtypes, luminal-simple and luminal-complex, the former group having a better prognosis, whereas the latter group included also luminal B and the majority of BRCA2-mutated tumors. The basal-complex subtype displayed extensive genomic homogeneity and harbored the majority of BRCA1-mutated tumors. The 17q12 subtype comprised mostly HER2-amplified and HER2-enriched subtype tumors and had the worst prognosis. The amplifier and mixed subtypes contained tumors from all gene-expression subtypes, the former being enriched for 8p12-amplified cases, whereas the mixed subtype included many tumors with predominantly DNA copy-number losses and poor prognosis. CONCLUSIONS: Global DNA copy-number analysis integrated with gene-expression data can be used to dissect the complexity of breast cancer. This revealed six genomic subtypes with different clinical behavior and a striking concordance to the intrinsic subtypes. These genomic subtypes may prove useful for understanding the mechanisms of tumor development and for prognostic and treatment prediction purposes.


Assuntos
Neoplasias da Mama/classificação , Neoplasias da Mama/genética , Hibridização Genômica Comparativa , Perfilação da Expressão Gênica , Neoplasia de Células Basais/classificação , Neoplasia de Células Basais/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteína BRCA1/genética , Proteína BRCA2/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Feminino , Seguimentos , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Mutação/genética , Neoplasia de Células Basais/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , Taxa de Sobrevida
17.
Breast Cancer Res ; 12(3): R25, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20459607

RESUMO

INTRODUCTION: HER2 gene amplification and protein overexpression (HER2+) define a clinically challenging subgroup of breast cancer with variable prognosis and response to therapy. Although gene expression profiling has identified an ERBB2 molecular subtype of breast cancer, it is clear that HER2+ tumors reside in all molecular subtypes and represent a genomically and biologically heterogeneous group, needed to be further characterized in large sample sets. METHODS: Genome-wide DNA copy number profiling, using bacterial artificial chromosome (BAC) array comparative genomic hybridization (aCGH), and global gene expression profiling were performed on 200 and 87 HER2+ tumors, respectively. Genomic Identification of Significant Targets in Cancer (GISTIC) was used to identify significant copy number alterations (CNAs) in HER2+ tumors, which were related to a set of 554 non-HER2 amplified (HER2-) breast tumors. High-resolution oligonucleotide aCGH was used to delineate the 17q12-q21 region in high detail. RESULTS: The HER2-amplicon was narrowed to an 85.92 kbp region including the TCAP, PNMT, PERLD1, HER2, C17orf37 and GRB7 genes, and higher HER2 copy numbers indicated worse prognosis. In 31% of HER2+ tumors the amplicon extended to TOP2A, defining a subgroup of HER2+ breast cancer associated with estrogen receptor-positive status and with a trend of better survival than HER2+ breast cancers with deleted (18%) or neutral TOP2A (51%). HER2+ tumors were clearly distinguished from HER2- tumors by the presence of recurrent high-level amplifications and firestorm patterns on chromosome 17q. While there was no significant difference between HER2+ and HER2- tumors regarding the incidence of other recurrent high-level amplifications, differences in the co-amplification pattern were observed, as shown by the almost mutually exclusive occurrence of 8p12, 11q13 and 20q13 amplification in HER2+ tumors. GISTIC analysis identified 117 significant CNAs across all autosomes. Supervised analyses revealed: (1) significant CNAs separating HER2+ tumors stratified by clinical variables, and (2) CNAs separating HER2+ from HER2- tumors. CONCLUSIONS: We have performed a comprehensive survey of CNAs in HER2+ breast tumors, pinpointing significant genomic alterations including both known and potentially novel therapeutic targets. Our analysis sheds further light on the genomically complex and heterogeneous nature of HER2+ tumors in relation to other subgroups of breast cancer.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Amplificação de Genes , Dosagem de Genes , Perfilação da Expressão Gênica , Genoma Humano , Receptor ErbB-2/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Cromossomos Artificiais Bacterianos , Cromossomos Humanos Par 17/genética , Feminino , Humanos , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , Taxa de Sobrevida
18.
J Clin Oncol ; 28(11): 1813-20, 2010 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-20231686

RESUMO

PURPOSE Human epidermal growth factor receptor 2 (HER2) gene amplification or protein overexpression (HER2 positivity) defines a clinically challenging subgroup of patients with breast cancer (BC) with variable prognosis and response to therapy. We aimed to investigate the heterogeneous biologic appearance and clinical behavior of HER2-positive tumors using molecular profiling. PATIENTS AND METHODS Hierarchical clustering of gene expression data from 58 HER2-amplified tumors of various stage, histologic grade, and estrogen receptor (ER) status was used to construct a HER2-derived prognostic predictor that was further evaluated in several large independent BC data sets. RESULTS Unsupervised analysis identified three subtypes of HER2-positive tumors with mixed stage, histologic grade, and ER status. One subtype had a significantly worse clinical outcome. A prognostic predictor was created based on differentially expressed genes between the subtype with worse outcome and the other subtypes. The predictor was able to define patient groups with better and worse outcome in HER2-positive BC across multiple independent BC data sets and identify a sizable HER2-positive group with long disease-free survival and low mortality. Significant correlation to prognosis was also observed in basal-like, ER-negative, lymph node-positive, and high-grade tumors, irrespective of HER2 status. The predictor included genes associated with immune response, tumor invasion, and metastasis. CONCLUSION The HER2-derived prognostic predictor provides further insight into the heterogeneous biology of HER2-positive tumors and may become useful for improved selection of patients who need additional treatment with new drugs targeting the HER2 pathway.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/diagnóstico , Carcinoma Basocelular/diagnóstico , Perfilação da Expressão Gênica , Linfonodos/patologia , Receptor ErbB-2/metabolismo , Receptores Estrogênicos/metabolismo , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/terapia , Carcinoma Basocelular/genética , Carcinoma Basocelular/terapia , Feminino , Amplificação de Genes , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , Receptor ErbB-2/genética , Taxa de Sobrevida
19.
J Negat Results Biomed ; 7: 5, 2008 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-18637200

RESUMO

Several mutations in the PALB2 gene (partner and localizer of BRCA2) have been associated with an increased risk of breast cancer, including a founder mutation, 1592delT, reported in Finnish breast cancer families. Although most often the risk is moderate, it doesn't exclude families with high-risk mutations to exist and such observations have been reported. To see if high-risk PALB2-mutations may be present in the geographically confined population of Iceland, linkage analysis was done on 111 individuals, thereof 61 breast cancer cases, from 9 high-risk non-BRCA1/BRCA2 breast cancer families, targeting the PALB2 region. Also, screening for the 1592delT founder mutation in the 9 high-risk families and in 638 unselected breast cancer cases was performed. The results indicate no linkage in any of the high-risk families and screening for the 1592delT mutation was negative in all samples. PALB2 appears not to be a significant factor in high-risk breast cancer families in Iceland and the 1592delT mutation is not seen to be associated with breast cancer in Iceland.


Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença , Proteínas Nucleares/genética , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteína do Grupo de Complementação N da Anemia de Fanconi , Feminino , Humanos , Islândia , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
20.
Int J Cancer ; 119(5): 1052-60, 2006 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-16570289

RESUMO

Comparative genomic hybridization (CGH) analysis has shown that chromosome 5q deletions are the most frequent aberration in breast tumors from BRCA1 mutation carriers. To map the location of putative 5q tumor suppressor gene(s), 26 microsatellite markers covering chromosome 5 were used in loss of heterozygosity (LOH) analysis of breast tumors from BRCA1 (n = 42) and BRCA2 mutation carriers (n = 67), as well as in sporadic cases (n = 65). High-density array CGH was also used to map chromosome 5 imbalance in 10 BRCA1 tumors. A high LOH frequency was found in BRCA1 tumors (range 19-82%), as compared to BRCA2 and sporadic tumors (ranges 11-44% and 7-43%, respectively). In all, 11 distinct chromosome 5 regions with LOH were observed, the most frequent being 5q35.3 (82%), 5q14.2 (71%) and 5q33.1 (69%) in BRCA1 tumors; 5q35.3 (44%), 5q31.3 (43%) and 5q13.3 (43%) in BRCA2 tumors and 5q31.3 (43%) in sporadic tumors. Array CGH analysis confirmed the very high frequency of 5q deletions, including candidate tumor suppressor genes such as XRCC4, RAD50, RASA1, APC and PPP2R2B. In addition, 2 distinct homozygous deletions were identified, spanning regions of 0.7-1.5 Mbp on 5q12.1 and 5q12.3-q13.1, respectively. These regions include only a few genes, most notably BRCC3/DEPDC1B (pleckstrin/G protein interacting and RhoGAP domains) and PIK3R1 (PI3 kinase P85 regulatory subunit). Significant association (p < or = 0.05) was found between LOH at certain 5q regions and factors of poor prognosis, including negative estrogen and progesterone receptor status, high grade, large tumor size and high portion of cells in S-phase. In conclusion, our results confirm a very high prevalence of chromosome 5q alterations in BRCA1 tumors, pinpointing new regions and genes that should be further investigated.


Assuntos
Neoplasias da Mama/genética , Mapeamento Cromossômico , Cromossomos Humanos Par 5 , Genes BRCA1 , Genes BRCA2 , Mutação em Linhagem Germinativa , Perda de Heterozigosidade , Adulto , Idoso , Desequilíbrio Alélico , Neoplasias da Mama/patologia , Feminino , Deleção de Genes , Heterozigoto , Humanos , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase
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