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1.
Cancer Res ; 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31723001

RESUMO

Pathogenic sequence variants (PSV) in BRCA1 or BRCA2 (BRCA1/2) are associated with increased risk and severity of prostate cancer (PCa). We evaluated whether PSVs in BRCA1/2 were associated with risk of overall PCa or high grade (Gleason 8+) PCa using an international sample of 65 BRCA1 and 171 BRCA2 male PSV carriers with PCa, and 3,388 BRCA1 and 2,880 BRCA2 male PSV carriers without PCa. PSVs in the 3' region of BRCA2 (c.7914+) were significantly associated with elevated risk of PCa compared with reference bin c.1001-c.7913 (HR=1.78, 95%CI: 1.25-2.52, p=0.001), as well as elevated risk of Gleason 8+ PCa (HR=3.11, 95%CI: 1.63-5.95, p=0.001). c.756-c.1000 was also associated with elevated PCa risk (HR=2.83, 95%CI: 1.71-4.68, p=0.00004) and elevated risk of Gleason 8+ PCa (HR=4.95, 95%CI: 2.12-11.54, p=0.0002). No genotype-phenotype associations were detected for PSVs in BRCA1. These results demonstrate that specific BRCA2 PSVs may be associated with elevated risk of developing aggressive PCa.

2.
Hum Mutat ; 40(9): 1557-1578, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31131967

RESUMO

The multifactorial likelihood analysis method has demonstrated utility for quantitative assessment of variant pathogenicity for multiple cancer syndrome genes. Independent data types currently incorporated in the model for assessing BRCA1 and BRCA2 variants include clinically calibrated prior probability of pathogenicity based on variant location and bioinformatic prediction of variant effect, co-segregation, family cancer history profile, co-occurrence with a pathogenic variant in the same gene, breast tumor pathology, and case-control information. Research and clinical data for multifactorial likelihood analysis were collated for 1,395 BRCA1/2 predominantly intronic and missense variants, enabling classification based on posterior probability of pathogenicity for 734 variants: 447 variants were classified as (likely) benign, and 94 as (likely) pathogenic; and 248 classifications were new or considerably altered relative to ClinVar submissions. Classifications were compared with information not yet included in the likelihood model, and evidence strengths aligned to those recommended for ACMG/AMP classification codes. Altered mRNA splicing or function relative to known nonpathogenic variant controls were moderately to strongly predictive of variant pathogenicity. Variant absence in population datasets provided supporting evidence for variant pathogenicity. These findings have direct relevance for BRCA1 and BRCA2 variant evaluation, and justify the need for gene-specific calibration of evidence types used for variant classification.

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.
Nat Genet ; 49(12): 1767-1778, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29058716

RESUMO

Most common breast cancer susceptibility variants have been identified through genome-wide association studies (GWAS) of predominantly estrogen receptor (ER)-positive disease. We conducted a GWAS using 21,468 ER-negative cases and 100,594 controls combined with 18,908 BRCA1 mutation carriers (9,414 with breast cancer), all of European origin. We identified independent associations at P < 5 × 10-8 with ten variants at nine new loci. At P < 0.05, we replicated associations with 10 of 11 variants previously reported in ER-negative disease or BRCA1 mutation carrier GWAS and observed consistent associations with ER-negative disease for 105 susceptibility variants identified by other studies. These 125 variants explain approximately 16% of the familial risk of this breast cancer subtype. There was high genetic correlation (0.72) between risk of ER-negative breast cancer and breast cancer risk for BRCA1 mutation carriers. These findings may lead to improved risk prediction and inform further fine-mapping and functional work to better understand the biological basis of ER-negative breast cancer.


Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Mutação , Polimorfismo de Nucleotídeo Único , Neoplasias da Mama/etnologia , Neoplasias da Mama/metabolismo , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Predisposição Genética para Doença/etnologia , Estudo de Associação Genômica Ampla/métodos , Heterozigoto , Humanos , Receptores Estrogênicos/metabolismo , Fatores de Risco
5.
Cancer ; 123(2): 210-218, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27648926

RESUMO

BACKGROUND: Male breast cancer (MBC) is a rare disease whose etiology appears to be largely associated with genetic factors. BRCA1 and BRCA2 mutations account for about 10% of all MBC cases. Thus, a fraction of MBC cases are expected to be due to genetic factors not yet identified. To further explain the genetic susceptibility for MBC, whole-exome sequencing (WES) and targeted gene sequencing were applied to high-risk, BRCA1/2 mutation-negative MBC cases. METHODS: Germ-line DNA of 1 male and 2 female BRCA1/2 mutation-negative breast cancer (BC) cases from a pedigree showing a first-degree family history of MBC was analyzed with WES. Targeted gene sequencing for the validation of WES results was performed for 48 high-risk, BRCA1/2 mutation-negative MBC cases from an Italian multicenter study of MBC. A case-control series of 433 BRCA1/2 mutation-negative MBC and female breast cancer (FBC) cases and 849 male and female controls was included in the study. RESULTS: WES in the family identified the partner and localizer of BRCA2 (PALB2) c.419delA truncating mutation carried by the proband, her father, and her paternal uncle (all affected with BC) and the N-acetyltransferase 1 (NAT1) c.97C>T nonsense mutation carried by the proband's maternal aunt. Targeted PALB2 sequencing detected the c.1984A>T nonsense mutation in 1 of the 48 BRCA1/2 mutation-negative MBC cases. NAT1 c.97C>T was not found in the case-control series. CONCLUSIONS: These results add strength to the evidence showing that PALB2 is involved in BC risk for both sexes and indicate that consideration should be given to clinical testing of PALB2 for BRCA1/2 mutation-negative families with multiple MBC and FBC cases. Cancer 2017;123:210-218. © 2016 American Cancer Society.


Assuntos
Neoplasias da Mama Masculina/genética , Exoma/genética , Predisposição Genética para Doença/genética , Proteínas Nucleares/genética , Proteínas Supressoras de Tumor/genética , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Estudos de Casos e Controles , Análise Mutacional de DNA/métodos , Proteína do Grupo de Complementação N da Anemia de Fanconi , Feminino , Humanos , Itália , Masculino , Mutação/genética , Linhagem
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.
Nat Commun ; 7: 11375, 2016 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-27117709

RESUMO

Common variants in 94 loci have been associated with breast cancer including 15 loci with genome-wide significant associations (P<5 × 10(-8)) with oestrogen receptor (ER)-negative breast cancer and BRCA1-associated breast cancer risk. In this study, to identify new ER-negative susceptibility loci, we performed a meta-analysis of 11 genome-wide association studies (GWAS) consisting of 4,939 ER-negative cases and 14,352 controls, combined with 7,333 ER-negative cases and 42,468 controls and 15,252 BRCA1 mutation carriers genotyped on the iCOGS array. We identify four previously unidentified loci including two loci at 13q22 near KLF5, a 2p23.2 locus near WDR43 and a 2q33 locus near PPIL3 that display genome-wide significant associations with ER-negative breast cancer. In addition, 19 known breast cancer risk loci have genome-wide significant associations and 40 had moderate associations (P<0.05) with ER-negative disease. Using functional and eQTL studies we implicate TRMT61B and WDR43 at 2p23.2 and PPIL3 at 2q33 in ER-negative breast cancer aetiology. All ER-negative loci combined account for ∼11% of familial relative risk for ER-negative disease and may contribute to improved ER-negative and BRCA1 breast cancer risk prediction.


Assuntos
Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla/métodos , Receptores Estrogênicos/genética , Proteína BRCA1/genética , Cromossomos Humanos Par 2/genética , Ciclofilinas/genética , Feminino , Genótipo , Heterozigoto , Humanos , Mutação , Polimorfismo de Nucleotídeo Único , Fatores de Risco , tRNA Metiltransferases
8.
Hum Mol Genet ; 24(18): 5345-55, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26130695

RESUMO

Numerous genetic factors that influence breast cancer risk are known. However, approximately two-thirds of the overall familial risk remain unexplained. To determine whether some of the missing heritability is due to rare variants conferring high to moderate risk, we tested for an association between the c.5791C>T nonsense mutation (p.Arg1931*; rs144567652) in exon 22 of FANCM gene and breast cancer. An analysis of genotyping data from 8635 familial breast cancer cases and 6625 controls from different countries yielded an association between the c.5791C>T mutation and breast cancer risk [odds ratio (OR) = 3.93 (95% confidence interval (CI) = 1.28-12.11; P = 0.017)]. Moreover, we performed two meta-analyses of studies from countries with carriers in both cases and controls and of all available data. These analyses showed breast cancer associations with OR = 3.67 (95% CI = 1.04-12.87; P = 0.043) and OR = 3.33 (95% CI = 1.09-13.62; P = 0.032), respectively. Based on information theory-based prediction, we established that the mutation caused an out-of-frame deletion of exon 22, due to the creation of a binding site for the pre-mRNA processing protein hnRNP A1. Furthermore, genetic complementation analyses showed that the mutation influenced the DNA repair activity of the FANCM protein. In summary, we provide evidence for the first time showing that the common p.Arg1931* loss-of-function variant in FANCM is a risk factor for familial breast cancer.


Assuntos
Processamento Alternativo , Códon sem Sentido , DNA Helicases/genética , Reparo do DNA , Éxons , Adulto , Idade de Início , Alelos , Sítios de Ligação , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Estudos de Casos e Controles , DNA Helicases/metabolismo , Análise Mutacional de DNA , Feminino , Expressão Gênica , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Ribonucleoproteína Nuclear Heterogênea A1 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Humanos , Metanálise como Assunto , Pessoa de Meia-Idade , Motivos de Nucleotídeos , Matrizes de Pontuação de Posição Específica , Ligação Proteica , Fatores de Risco , Adulto Jovem
9.
Hum Mutat ; 35(7): 828-40, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24659262

RESUMO

CDKN2A codes for two oncosuppressors by alternative splicing of two first exons: p16INK4a and p14ARF. Germline mutations are found in about 40% of melanoma-prone families, and most of them are missense mutations mainly affecting p16INK4a. A growing number of p16INK4a variants of uncertain significance (VUS) are being identified but, unless their pathogenic role can be demonstrated, they cannot be used for identification of carriers at risk. Predicting the effect of these VUS by either a "standard" in silico approach, or functional tests alone, is rather difficult. Here, we report a protocol for the assessment of any p16INK4a VUS, which combines experimental and computational tools in an integrated approach. We analyzed p16INK4a VUS from melanoma patients as well as variants derived through permutation of conserved p16INK4a amino acids. Variants were expressed in a p16INK4a-null cell line (U2-OS) and tested for their ability to block proliferation. In parallel, these VUS underwent in silico prediction analysis and molecular dynamics simulations. Evaluation of in silico and functional data disclosed a high agreement for 15/16 missense mutations, suggesting that this approach could represent a pilot study for the definition of a protocol applicable to VUS in general, involved in other diseases, as well.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Variação Genética , Melanoma/genética , Motivos de Aminoácidos , Substituição de Aminoácidos , Linhagem Celular Tumoral , Proliferação de Células , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Humanos , Melanoma/diagnóstico , Modelos Moleculares , Mutação de Sentido Incorreto , Conformação Proteica , Neoplasias Cutâneas
10.
Breast Cancer Res Treat ; 132(3): 1009-23, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21769658

RESUMO

Mutations in BRCA1 and BRCA2 predispose carriers to early onset breast and ovarian cancer. A common problem in clinical genetic testing is interpretation of variants with unknown clinical significance. The Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium was initiated to evaluate and implement strategies to characterize the clinical significance of BRCA1 and BRCA2 variants. As an initial project of the ENIGMA Splicing Working Group, we report splicing and multifactorial likelihood analysis of 25 BRCA1 and BRCA2 variants from seven different laboratories. Splicing analysis was performed by reverse transcriptase PCR or mini gene assay, and sequencing to identify aberrant transcripts. The findings were compared to bioinformatic predictions using four programs. The posterior probability of pathogenicity was estimated using multifactorial likelihood analysis, including co-occurrence with a deleterious mutation, segregation and/or report of family history. Abnormal splicing patterns expected to lead to a non-functional protein were observed for 7 variants (BRCA1 c.441+2T>A, c.4184_4185+2del, c.4357+1G>A, c.4987-2A>G, c.5074G>C, BRCA2 c.316+5G>A, and c.8754+3G>C). Combined interpretation of splicing and multifactorial analysis classified an initiation codon variant (BRCA2 c.3G>A) as likely pathogenic, uncertain clinical significance for 7 variants, and indicated low clinical significance or unlikely pathogenicity for another 10 variants. Bioinformatic tools predicted disruption of consensus donor or acceptor sites with high sensitivity, but cryptic site usage was predicted with low specificity, supporting the value of RNA-based assays. The findings also provide further evidence that clinical RNA-based assays should be extended from analysis of invariant dinucleotides to routinely include all variants located within the donor and acceptor consensus splicing sites. Importantly, this study demonstrates the added value of collaboration between laboratories, and across disciplines, to collate and interpret information from clinical testing laboratories to consolidate patient management.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Adulto , Idoso , Sequência de Bases , Simulação por Computador , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Testes Genéticos , Humanos , Funções Verossimilhança , Pessoa de Meia-Idade , Modelos Genéticos , Dados de Sequência Molecular , Análise Multivariada , Mutação , Isoformas de Proteínas/genética , Sítios de Splice de RNA , Análise de Sequência de RNA
12.
Mutat Res ; 671(1-2): 26-32, 2009 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-19712690

RESUMO

The CDKN2A locus encodes for two distinct tumor suppressor proteins, p16(INK4A) and p14(ARF), involved in cell cycle regulation. CDKN2A germline mutations have been associated with familial predisposition to melanoma and other tumor types. Besides bona-fide pathogenic mutations, many sequence variants have been identified, but their effect is not well known. We detected the p.Gly23Asp missense mutation in one of the two tested melanoma patients of a family with three melanoma cases. Even though the mutated amino acid is located in a conserved domain that specifically binds to and blocks the function of CDK4/6, its lack of segregation with disease suggested a series of functional assays to discriminate between a pathogenic variant and a neutral polymorphism. The effect of this mutation has been investigated exploiting four p16(INK4A) properties: its ability (i) to bind CDK4, (ii) to inhibit pRb phosphorylation, (iii) to evenly localize in the cell, and (iv) to cause cell cycle arrest. The mutant protein properties were evaluated transfecting three different cell lines (U2-OS and NM-39, both p16-null, and SaOS 2, p53 and pRb-null) with plasmids expressing either p16(wt), p16(23Asp), or the p16(32Pro) pathogenic variant. We found that p16(23Asp) was less efficient than p16(wt) in CDK4 binding, in inhibiting pRb phosphorylation, in inducing G1 cell cycle arrest; moreover, its pattern of distribution throughout the cell was suggestive of protein aggregation, thus assessing a pathogenic role for p16(23Asp) in familial melanoma.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/fisiologia , Genes p16 , Melanoma/genética , Mutação de Sentido Incorreto , Ciclo Celular , Humanos , Fosforilação , Polimorfismo Genético , Proteínas Salivares Ricas em Prolina/metabolismo
13.
Mod Pathol ; 22(1): 58-65, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18820669

RESUMO

Despite recent advances in surgical and multidisciplinary treatment, prognosis for patients with esophageal adenocarcinoma remains poor, and the low prognostic significance of pTNM staging suggests that additional parameters are needed. To identify genomic abnormalities characteristic of esophageal adenocarcinoma, a panel of 33 samples obtained at surgery from previously untreated patients were analyzed by muliplex ligation-dependent probe amplification technique. We detected frequent gains of 6p, 8q, 13q, 17q, 20q, and losses of 4q, 5q, 15q, and 18q. When DNA copy number changes were correlated to clinicopathological features of patients no association was found between the number of chromosomal aberrations and gender, age, tumor grade or pTNM staging. However, interestingly, a significant correlation between patient survival and total number of chromosomal aberrations was found when esophageal adenocarcinoma cases were stratified according to the median of survival (20 months) (P=0.002) or the median of aberrations (12 aberrations) (P=0.014). Evaluation of the distribution of gains and losses at the level of single chromosomes indicated that gains on chromosomes 5, 6, 8, 11, 20 and losses on chromosomes 1, 3, 5, 11, and 18 were significantly different in the two survival groups. Furthermore, when single gene imbalances were analyzed in further details, we found that besides alterations that involve genes shared by both survival groups, a few genes (KIAA0170, EMS1, ABCC4, F3, and MIF) were altered only in samples from patients with poor survival. Thus, we established a good correlation between the total number of chromosomal alterations and survival, suggesting that the estimation of total imbalances might represent an additional indicator of disease outcome. In addition, the finding of alterations specific for the more aggressive esophageal adenocarcinoma subset might represent promising biomarkers to increase the accuracy of clinical outcome prediction.


Assuntos
Adenocarcinoma/genética , Adenocarcinoma/patologia , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Dosagem de Genes , Adenocarcinoma/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , DNA de Neoplasias/genética , Neoplasias Esofágicas/mortalidade , Feminino , Humanos , Hibridização in Situ Fluorescente , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Reação em Cadeia da Polimerase , Prognóstico
14.
J Clin Oncol ; 26(1): 26-31, 2008 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18165637

RESUMO

PURPOSE: A growing number of sequence changes of unknown clinical significance are being identified in the BRCA1 gene. However, these variants cannot be used for identification and surveillance of at-risk individuals unless their pathogenic role can be demonstrated. The frequency of these variants makes research on this subject a relevant topic in the field of predisposition to breast and ovarian cancers. Herein, we investigate the pathogenicity of the BRCA1 p.Val1688del (c.5181_5183delGTT) variant, which recurs in our population. PATIENTS AND METHODS: Recent studies have drawn attention to different strategies that, if considered singly, do not usually provide sufficient power to firmly state for or against causality, thus forcing to a re-evaluation of the literature on each specific variant. To increase the power of our study, we used a recently described strategy that integrates data from multiple independent evidences. By this approach, we analyzed data from the comprehensive study of 12 breast/ovarian cancer families carrying p.Val1688del. RESULTS: We succeeded in integrating five independent evidences of disease causality including segregation, tumor pathology, and evolutionary and epidemiologic data. Under this model, we obtained a final score of 349,000:1 in favor of disease causality. This result largely matches established cutoffs, and thus is readily translatable into a clear clinical message. CONCLUSION: We show that p.Val1688del is a pathogenic mutation deriving from a common founder. Notably, this study alone increases by 15% the number of BRCA1-positive families in our patients' cohort, thus substantially contributing to explain many of the families wherein prediction of a BRCA1 mutation contrasted with the absence of a molecular recognizable defect.


Assuntos
Neoplasias da Mama/genética , Genes BRCA1 , Mutação , Neoplasias Ovarianas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Análise Mutacional de DNA , DNA de Neoplasias/sangue , DNA de Neoplasias/genética , Éxons , Feminino , Amplificação de Genes , Humanos , Itália/epidemiologia , Perda de Heterozigosidade , Pessoa de Meia-Idade , Neoplasias Ovarianas/epidemiologia , Linhagem , Reação em Cadeia da Polimerase , Fatores de Risco
15.
Eur J Cancer ; 42(10): 1475-83, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16759848

RESUMO

The BRCA1 gene is responsible for a high number of hereditary breast and ovarian cancers that cluster in families with a strong genetic predisposition. Despite intense investigation, the accumulating findings on BRCA1 biological functions have not yet been translated into specific therapeutic approaches, also due to the lack of suitable experimental models. The purpose of this study was to establish and characterize cell cultures and xenografts from patients with BRCA1 -/- ovarian cancers. We derived two ovarian cancer cell lines, termed PD-OVCA1 and PD-OVCA2, both from patients previously treated with chemotherapy, that propagate in SCID mice as well as in vitro for a limited number of passages. Both cell lines expressed cytokeratins and the CA125 tumour marker. A detailed molecular characterization highlighted both constitutive and somatic genetic events that abrogate BRCA1 gene function. Both cell lines were shown to lose the wild type BRCA1 allele; intriguingly, these deletions were apparently accompanied by gain of one or more copies of the mutant alleles. Finally, a genomic profile of major chromosomal aberrations was obtained by the Multiplex Ligation-dependent Probe Amplification (MLPA) technique, which disclosed chromosomal imbalances targeting specific genes in each cell line. The PD-OVCA1 and PD-OVCA2 ovarian cancer cell lines will provide a valuable tool for new experimental models for the study of BRCA1-associated tumour biology.


Assuntos
Genes BRCA1 , Neoplasias Ovarianas/patologia , Células Tumorais Cultivadas/patologia , Idoso , Animais , Antígeno Ca-125/metabolismo , Técnicas de Cultura de Células/métodos , Feminino , Genoma , Genótipo , Humanos , Camundongos , Neoplasias Ovarianas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante Heterólogo/métodos , Células Tumorais Cultivadas/metabolismo
16.
Genes Chromosomes Cancer ; 45(9): 791-7, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16715518

RESUMO

The presence of genomic rearrangements of the BRCA1 gene in breast and/or ovarian cancer families has been intensively investigated in patients from various countries over the last years. A number of different rearrangements have been reported by several studies that clearly document the involvement of this mutation type in genetic predisposition to breast and ovarian cancer. Population-specific studies are now needed to evaluate the prevalence of genomic rearrangements before deciding whether to include ad hoc screening procedures into standard diagnostic mutation detection approaches. Indeed, the vast majority of the studies have been performed on small, highly selected, sample sets because of the limitations imposed by the laborious technical approaches. Moreover, prevalence figures are likely to differ across different countries according to the ethnic origin of each specific population. Here we analyze a large cohort of 653 Italian probands, negative for BRCA1 and BRCA2 point mutations, gathered from four National Institutions. We report the identification of BRCA1 genomic rearrangements in 12 independent families. Noteworthy, half of the probands carry mutations that recur in more than one Italian family. Considering the whole spectrum of Italian BRCA1 gene rearrangements identified thus far in consecutive patients, we estimate that alterations of this type account for 19% (95% CI: 0.11 < 0.19 < 0.28) of the BRCA1 mutation positive families. We conclude that the search for major genomic rearrangements is essential for an accurate and comprehensive BRCA1 mutation detection strategy in Italy.


Assuntos
Neoplasias da Mama/genética , Rearranjo Gênico/genética , Genes BRCA1 , Genes BRCA2 , Neoplasias Ovarianas/genética , Mutação Puntual , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Bases , Neoplasias da Mama/epidemiologia , Feminino , Genoma Humano , Humanos , Itália/epidemiologia , Pessoa de Meia-Idade , Dados de Sequência Molecular , Neoplasias Ovarianas/epidemiologia , Prevalência
17.
J Natl Cancer Inst ; 98(4): 285-8, 2006 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-16478747

RESUMO

A single-nucleotide polymorphism (SNP) in the promoter of the MDM2 gene, SNP309 (a T-->G change), was recently implicated in the early onset of cancer in individuals with Li-Fraumeni syndrome and of sporadic soft-tissue sarcoma. SNP309 induces an increase in the level of Mdm2 protein, which causes attenuation of the p53 pathway. To investigate the effect of this polymorphism in colorectal cancer pathogenesis, we genotyped 153 colorectal cancer patients who were randomly selected from among 330 consecutive patients stratified according to p53 mutation status and age at diagnosis, for alleles of MDM2-SNP309. Among the 77 patients with p53 wild-type tumors, the median age at colorectal cancer diagnosis was 71.5 years for patients with the T/T genotype and 61.0 years for patients with SNP309 (T/G or G/G genotype) (estimated difference between medians [Hodges-Lehmann method] = 8.0 years, 95% confidence interval = 1.0 to 16.0 years; P = .03 [two-sided Wilcoxon rank sum test]). Our data indicate that MDM2-SNP309 is a modifier of the age at colorectal cancer onset for patients whose tumors have a wild-type p53 gene.


Assuntos
Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Genes p53 , Mutação , Polimorfismo de Nucleotídeo Único , Proteínas Proto-Oncogênicas c-mdm2/genética , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Genótipo , Glicina , Humanos , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Treonina
19.
Breast Cancer Res Treat ; 81(1): 71-9, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-14531499

RESUMO

Mutations in BRCA1 and BRCA2 show different expressivity with respect to cancer risk, and allelic heterogeneity may be present in both genes. We collected 179 pedigrees with identified germline mutation (104 BRCA1 and 75 BRCA2), ascertained in six collaborating centers of the Italian Consortium for Hereditary Breast and Ovarian Cancer. Significant heterogeneity was detected for several variables, and a logistic regression model including age of diagnosis in the proband, presence of ovarian cancer in the family, presence of prostate or pancreatic cancer in the family, and presence of male breast cancer in the family proved to be effective in predicting the presence of a mutation in a gene rather than the other. Excess of familial aggregation of both breast and ovarian cancer was observed in both genes. Proportion of ovarian cancer was increased in the 5' portion of BRCA1, and presence of prostate or pancreatic cancer in a family was correlated with presence of ovarian cancer in BRCA2.


Assuntos
Neoplasias da Mama/genética , Genes BRCA1 , Genes BRCA2 , Mutação em Linhagem Germinativa , Linhagem , Feminino , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Genótipo , Humanos , Itália , Masculino , Fenótipo , Análise de Regressão , Fatores de Risco
20.
Hum Mol Genet ; 12(9): 1055-61, 2003 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-12700174

RESUMO

The recent identification of major genomic rearrangements in breast and breast/ovarian cancer families has widened the mutational spectrum of the BRCA1 gene, thus increasing the number of informative patients who can benefit from molecular screening. Numerous types of alterations have been identified in different populations with variable frequencies, probably due to both ethnic diversity and the technical approach employed. In fact, although several methods have been successfully used to detect large genomic deletions and insertions, most are laborious, time-consuming, and of variable sensitivity. In order to estimate the contribution of BRCA1 genomic rearrangements to breast/ovarian cancer predisposition in Italian families, we applied, for the first time as a diagnostic tool, the recently described multiplex ligation-dependent probe amplification (MLPA) methodology. Among the 37 hereditary breast/ovarian cancer (HBOC) families selected, all had a high prior probability of BRCA1 mutation, and 15 were previously shown to carry a mutation in either the BRCA2 (five families) or BRCA1 gene (10 families, including one genomic rearrangement). The application of BRCA1-MLPA to the remaining 22 uninformative families allowed the identification of five additional genomic rearrangements. Moreover, we observed that loss of constitutive heterozygosity of polymorphic markers in linkage disequilibrium is predictive of such BRCA1 alterations. By means of this approach, we demonstrate that BRCA1 genomic deletions account for more than one-third (6/15) of the pathogenic BRCA1 mutations in our series. We therefore propose to systematically include MLPA in the BRCA1 mutational analysis of breast/ovarian cancer families.


Assuntos
Neoplasias da Mama/genética , Genes BRCA1 , Neoplasias Ovarianas/genética , Recombinação Genética , Feminino , Humanos , Itália , Masculino
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