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1.
Am J Hum Genet ; 107(5): 837-848, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33022221

RESUMO

Previous research has shown that polygenic risk scores (PRSs) can be used to stratify women according to their risk of developing primary invasive breast cancer. This study aimed to evaluate the association between a recently validated PRS of 313 germline variants (PRS313) and contralateral breast cancer (CBC) risk. We included 56,068 women of European ancestry diagnosed with first invasive breast cancer from 1990 onward with follow-up from the Breast Cancer Association Consortium. Metachronous CBC risk (N = 1,027) according to the distribution of PRS313 was quantified using Cox regression analyses. We assessed PRS313 interaction with age at first diagnosis, family history, morphology, ER status, PR status, and HER2 status, and (neo)adjuvant therapy. In studies of Asian women, with limited follow-up, CBC risk associated with PRS313 was assessed using logistic regression for 340 women with CBC compared with 12,133 women with unilateral breast cancer. Higher PRS313 was associated with increased CBC risk: hazard ratio per standard deviation (SD) = 1.25 (95%CI = 1.18-1.33) for Europeans, and an OR per SD = 1.15 (95%CI = 1.02-1.29) for Asians. The absolute lifetime risks of CBC, accounting for death as competing risk, were 12.4% for European women at the 10th percentile and 20.5% at the 90th percentile of PRS313. We found no evidence of confounding by or interaction with individual characteristics, characteristics of the primary tumor, or treatment. The C-index for the PRS313 alone was 0.563 (95%CI = 0.547-0.586). In conclusion, PRS313 is an independent factor associated with CBC risk and can be incorporated into CBC risk prediction models to help improve stratification and optimize surveillance and treatment strategies.

3.
Nat Commun ; 11(1): 3833, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737321

RESUMO

Polygenic risk scores (PRS) have been shown to predict breast cancer risk in European women, but their utility in Asian women is unclear. Here we evaluate the best performing PRSs for European-ancestry women using data from 17,262 breast cancer cases and 17,695 controls of Asian ancestry from 13 case-control studies, and 10,255 Chinese women from a prospective cohort (413 incident breast cancers). Compared to women in the middle quintile of the risk distribution, women in the highest 1% of PRS distribution have a ~2.7-fold risk and women in the lowest 1% of PRS distribution has ~0.4-fold risk of developing breast cancer. There is no evidence of heterogeneity in PRS performance in Chinese, Malay and Indian women. A PRS developed for European-ancestry women is also predictive of breast cancer risk in Asian women and can help in developing risk-stratified screening programmes in Asia.


Assuntos
Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Herança Multifatorial , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Ásia/epidemiologia , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/etnologia , Estudos de Casos e Controles , Europa (Continente)/epidemiologia , Feminino , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Pessoa de Meia-Idade , Razão de Chances , Prognóstico , Risco
4.
Nat Commun ; 11(1): 1217, 2020 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-32139696

RESUMO

Known risk variants explain only a small proportion of breast cancer heritability, particularly in Asian women. To search for additional genetic susceptibility loci for breast cancer, here we perform a meta-analysis of data from genome-wide association studies (GWAS) conducted in Asians (24,206 cases and 24,775 controls) and European descendants (122,977 cases and 105,974 controls). We identified 31 potential novel loci with the lead variant showing an association with breast cancer risk at P < 5 × 10-8. The associations for 10 of these loci were replicated in an independent sample of 16,787 cases and 16,680 controls of Asian women (P < 0.05). In addition, we replicated the associations for 78 of the 166 known risk variants at P < 0.05 in Asians. These findings improve our understanding of breast cancer genetics and etiology and extend previous findings from studies of European descendants to Asian women.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Neoplasias da Mama/genética , Grupo com Ancestrais do Continente Europeu/genética , Loci Gênicos , Predisposição Genética para Doença , Feminino , Humanos , Herança Multifatorial/genética , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Receptores Estrogênicos/metabolismo , Fatores de Risco
5.
J Mol Diagn ; 22(4): 544-554, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32068069

RESUMO

Differences in the mutation spectrum across ethnicities suggest the importance of identifying genes in addition to common high penetrant genes to estimate the associated breast cancer risk in China. A total of 1338 high-risk breast cancer patients who tested negative for germline BRCA1, BRCA2, TP53, and PTEN mutations between 2007 and 2017 were selected from the Hong Kong Hereditary Breast Cancer Family Registry. Patient samples were subjected to next-generation DNA sequencing using a multigene panel (Color Genomics). All detected pathogenic variants were validated by bidirectional DNA sequencing. The sequencing data were coanalyzed by a bioinformatics pipeline developed in-house. Sixty-one pathogenic variants (4.6%) were identified in this cohort in 11 cancer predisposition genes. Most carriers (77.1%) had early onset of breast cancer (age <45 years), 32.8% had family members with breast cancer, and 11.5% had triple-negative breast cancer. The most common mutated genes were PALB2 (1.4%), RAD51D (0.8%), and ATM (0.8%). A total of 612 variants of unknown significance were identified in 494 patients, and 87.4% of the variants of unknown significance were missense mutations. Pathogenic variants in cancer predisposition genes beyond BRCA1, BRCA2, TP53, and PTEN were detected in an additional 4.6% of patients using the multigene panel. PALB2 (1.4%) and RAD51D (0.8%) were the most commonly mutated genes in patients who tested mutation negative by a four-gene panel.

6.
Cancer Res ; 80(3): 624-638, 2020 02 01.
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. We evaluated whether PSVs in BRCA1/2 were associated with risk of overall prostate cancer or high grade (Gleason 8+) prostate cancer using an international sample of 65 BRCA1 and 171 BRCA2 male PSV carriers with prostate cancer, and 3,388 BRCA1 and 2,880 BRCA2 male PSV carriers without prostate cancer. PSVs in the 3' region of BRCA2 (c.7914+) were significantly associated with elevated risk of prostate cancer compared with reference bin c.1001-c.7913 [HR = 1.78; 95% confidence interval (CI), 1.25-2.52; P = 0.001], as well as elevated risk of Gleason 8+ prostate cancer (HR = 3.11; 95% CI, 1.63-5.95; P = 0.001). c.756-c.1000 was also associated with elevated prostate cancer risk (HR = 2.83; 95% CI, 1.71-4.68; P = 0.00004) and elevated risk of Gleason 8+ prostate cancer (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 prostate cancer. SIGNIFICANCE: Aggressive prostate cancer risk in BRCA2 mutation carriers may vary according to the specific BRCA2 mutation inherited by the at-risk individual.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Predisposição Genética para Doença , Genômica/métodos , Mutação , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Associação Genética , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Fatores de Risco , Adulto Jovem
7.
Sci Rep ; 9(1): 12524, 2019 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-31467304

RESUMO

Fanconi anemia (FA) is a genetically heterogeneous disorder with 22 disease-causing genes reported to date. In some FA genes, monoallelic mutations have been found to be associated with breast cancer risk, while the risk associations of others remain unknown. The gene for FA type C, FANCC, has been proposed as a breast cancer susceptibility gene based on epidemiological and sequencing studies. We used the Oncoarray project to genotype two truncating FANCC variants (p.R185X and p.R548X) in 64,760 breast cancer cases and 49,793 controls of European descent. FANCC mutations were observed in 25 cases (14 with p.R185X, 11 with p.R548X) and 26 controls (18 with p.R185X, 8 with p.R548X). There was no evidence of an association with the risk of breast cancer, neither overall (odds ratio 0.77, 95%CI 0.44-1.33, p = 0.4) nor by histology, hormone receptor status, age or family history. We conclude that the breast cancer risk association of these two FANCC variants, if any, is much smaller than for BRCA1, BRCA2 or PALB2 mutations. If this applies to all truncating variants in FANCC it would suggest there are differences between FA genes in their roles on breast cancer risk and demonstrates the merit of large consortia for clarifying risk associations of rare variants.


Assuntos
Neoplasias da Mama/genética , Proteína do Grupo de Complementação C da Anemia de Fanconi/genética , Deleção de Sequência , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/metabolismo , Estudos de Casos e Controles , Anemia de Fanconi/genética , Proteína do Grupo de Complementação C da Anemia de Fanconi/metabolismo , Feminino , Predisposição Genética para Doença , Variação Genética , Humanos
8.
Clin Epigenetics ; 11(1): 67, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053176

RESUMO

BACKGROUND: Genetic aberrations in DNA repair genes are linked to cancer, but less is reported about epigenetic regulation of DNA repair and functional consequences. We investigated the intragenic methylation loss at the three prime repair exonuclease 2 (TREX2) locus in laryngeal (n = 256) and colorectal cancer cases (n = 95) and in pan-cancer data from The Cancer Genome Atlas (TCGA). RESULTS: Significant methylation loss at an intragenic site of TREX2 was a frequent trait in both patient cohorts (p = 0.016 and < 0.001, respectively) and in 15 out of 22 TCGA studies. Methylation loss correlated with immunohistochemically staining for TREX2 (p < 0.0001) in laryngeal tumors and improved overall survival of laryngeal cancer patients (p = 0.045). Chromatin immunoprecipitation, demethylation experiments, and reporter gene assays revealed that the region of methylation loss can function as a CCAAT/enhancer binding protein alpha (CEBPA)-responsive enhancer element regulating TREX2 expression. CONCLUSIONS: The data highlight a regulatory role of TREX2 DNA methylation for gene expression which might affect incidence and survival of laryngeal cancer. Altered TREX2 protein levels in tumors may affect drug-induced DNA damage repair and provide new tailored therapies.


Assuntos
Metilação de DNA , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/metabolismo , Neoplasias Laríngeas/mortalidade , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Regulação para Cima , Idoso , Linhagem Celular Tumoral , Reparo do DNA , Epigênese Genética , Exodesoxirribonucleases/química , Feminino , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Humanos , Neoplasias Laríngeas/genética , Neoplasias Laríngeas/metabolismo , Masculino , Pessoa de Meia-Idade , Fosfoproteínas/química , Domínios Proteicos , Análise de Sobrevida
9.
Am J Hematol ; 94(6): 650-657, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30900772

RESUMO

The present study aimed to define a subtype of complex/monosomal karyotype (CK/MK) acute myeloid leukemia (AML) by its distinct clinical features, p53 signaling and responses to p53 targeting agents. Ninety-eight young adults (range: 21-60 years; median: 49 years) with CK/MK AML were studied. They received standard induction, consolidation and allogeneic hematopoietic stem cell transplantation from siblings or matched unrelated donors if available. Chromosomal abnormalities most commonly affected chromosome 5 (30%), 7 (22%) and 17 (21%). Next generation sequencing of a 54-myeloid gene panel were available in 76 patients. Tumor protein 53 (TP53) mutations were most common (49%) and associated with the presence of -5/5q- (P < .001) and -17/17p- (P < .001), but not -7/7q- (P = .370). This "typical" CK/MK AML subtype was associated with significantly lower presenting white cell counts, higher number of karyotypic abnormalities, and inferior leukemia-free and overall survivals, compared with CK/MK AML without the typical features. Blood or bone marrow samples from typical CK/MK AML patients showed defective p53 signaling upon induction by etoposide. In vitro drug sensitivity analysis showed that they were sensitive to APR-246 that targeted mutant p53, but resistant to MDM2 antagonist MI-77301. Novel therapeutic strategies targeting TP53 mutations in CK/MK AML should be developed and tested in clinical trials.


Assuntos
Cariótipo Anormal , Antineoplásicos/administração & dosagem , Cromossomos Humanos , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda , Monossomia , Proteína Supressora de Tumor p53 , Adolescente , Adulto , Cromossomos Humanos/genética , Cromossomos Humanos/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
10.
Oncotarget ; 9(38): 25025-25033, 2018 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-29861850

RESUMO

Germline mutations in BRCA1 and BRCA2 (BRCA1/2) are associated with increased risk of breast and ovarian cancer. The penetrance of breast and ovarian cancer in BRCA1/2 mutation carriers has been well characterized in Caucasian but not in Asian. Two studies have investigated the breast cancer risk in Asian women with BRCA1/2 mutations, and no published estimates are available for ovarian cancer. Therefore, we estimated the age-specific cumulative risk of BRCA1/2-associated breast and ovarian cancer in Chinese women. From Jan 2007 to Nov 2015, the Hong Kong Hereditary Breast Cancer Family Registry identified 1635 families with hereditary breast-ovarian cancer. Among probands in these families, 66 had BRCA1 mutations, 84 had BRCA2 mutations, and 1,485 tested negative for BRCA1/2 mutations. Using the female first-degree relatives of these probands, we estimated the risk of breast and ovarian cancer using a modified marginal likelihood approach. Estimates of breast cancer penetrance by age 70 were 53.7% (95% CI 34.5-71.6%) for BRCA1 mutation carriers and 48.3% (95% CI 31.8-68.5%) for BRCA2. The estimated risk of ovarian cancer by age 70 was 21.5% and 7.3% for Chinese women carrying BRCA1 or BRCA2 mutation respectively. A meta-analysis of available studies in Asian women revealed pooled estimates of breast cancer risk by age 70 of 44.8% (95% CI 33-57.2%) and 40.7% (95% CI 31.3-50.9%) for BRCA1 and BRCA2 mutation carriers respectively. These data suggest that BRCA1/2-associated breast cancer risk for Chinese women is similar to that for Caucasian women, although BRCA1/2-associated ovarian cancer risks are lower for Chinese women.

11.
Oncotarget ; 9(8): 7832-7843, 2018 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-29487695

RESUMO

BRCA1/2 mutations are significant risk factors for hereditary breast and ovarian cancer (HBOC), its mutation frequency in HBOC of Chinese ethnicity is around 9%, in which nearly half are recurrent mutations. In Hong Kong and China, genetic testing and counseling are not as common as in the West. To reduce the barrier of testing, a multiplex SNaPshot genotyping panel that targeted 25 Chinese BRCA1/2 mutation hotspots was developed, and its feasibility was evaluated in a local cohort of 441 breast and 155 ovarian cancer patients. For those who tested negative, they were then subjected to full-gene testing with next-generation sequencing (NGS). BRCA mutation prevalence in this cohort was 8.05% and the yield of the recurrent panel was 3.52%, identifying over 40% of the mutation carriers. Moreover, from 79 Chinese breast cancer cases recruited overseas, 2 recurrent mutations and one novel BRCA2 mutation were detected by the panel and NGS respectively. The developed genotyping panel showed to be an easy-to-perform and more affordable testing tool that can provide important contributions to improve the healthcare of Chinese women with cancer as well as family members that harbor high risk mutations for HBOC.

12.
J Mol Diagn ; 18(4): 580-94, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27157322

RESUMO

Mutation in BRCA1/BRCA2 genes accounts for 20% of familial breast cancers, 5% to 10% of which may be due to other less penetrant genes which are still incompletely studied. Herein, a four-gene panel was used to examine the prevalence of BRCA1, BRCA2, TP53, and PTEN in hereditary breast and ovarian cancers in Southern Chinese population. In this cohort, 948 high-risk breast and/or ovarian patients were recruited for genetic screening by next-generation sequencing (NGS). The performance of our NGS pipeline was evaluated with 80 Sanger-validated known mutations and eight negative cases. With appropriate bioinformatics analysis pipeline, the detection sensitivity of NGS is comparable with Sanger sequencing. The prevalence of BRCA1/BRCA2 germline mutations was 9.4% in our Chinese cohort, of which 48.8% of the mutations arose from hotspot mutations. With the use of a tailor-made algorithm, HomopolymerQZ, more mutations were detected compared with single mutation detection algorithm. The frequencies of PTEN and TP53 were 0.21% and 0.53%, respectively, in the Southern Chinese patients with breast and/or ovarian cancers. High-throughput NGS approach allows the incorporation of control cohort that provides an ethnicity-specific data for polymorphic variants. Our data suggest that hotspot mutations screening such as SNaPshot could be an effective preliminary screening alternative adopted in a standard clinical laboratory without NGS setup.


Assuntos
Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Síndrome Hereditária de Câncer de Mama e Ovário/diagnóstico , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Sequenciamento de Nucleotídeos em Larga Escala , Adulto , Algoritmos , Alelos , Feminino , Frequência do Gene , Genes BRCA1 , Genes BRCA2 , Genes p53 , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Pessoa de Meia-Idade , PTEN Fosfo-Hidrolase/genética , Reprodutibilidade dos Testes , Fluxo de Trabalho
13.
Breast Cancer Res Treat ; 157(2): 211-215, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27125668

RESUMO

Recently, RECQL was reported as a new breast cancer susceptibility gene. RECQL belongs to the RECQ DNA helicase family which unwinds double strand DNA and involved in the DNA replication stress response, telomere maintenance and DNA repair. RECQL deficient mice cells are prone to spontaneous chromosomal instability and aneuploidy, suggesting a tumor-suppressive role of RECQL in cancer. In this study, RECQL gene mutation screening was performed on 1110 breast cancer patients who were negative for BRCA1, BRCA2, TP53 and PTEN gene mutations and recruited from March 2007 to June 2015 in the Hong Kong Hereditary and High Risk Breast Cancer Program. Four different RECQL pathogenic mutations were identified in six of the 1110 (0.54 %) tested breast cancer patients. The identified mutations include one frame-shift deletion (c.974_977delAAGA), two splicing site mutations (c.394+1G>A, c.867+1G>T) and one nonsense mutation (c.796C>T, p.Gln266Ter). Two of the mutations (c.867+1G>T and p.Gln266Ter) were seen in more than one patients. This study provides the basis for existing of pathogenic RECQL mutations in Southern Chinese breast cancer patients. The significance of rare variants in RECQL gene in the estimation of breast cancer risk warranted further investigation in larger cohort of patients and in other ethnic groups.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Neoplasias da Mama/genética , Mutação , RecQ Helicases/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Feminino , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Linhagem , Análise de Sequência de DNA/métodos , Adulto Jovem
14.
Hum Mol Genet ; 23(8): 2043-54, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24282031

RESUMO

Colorectal cancer (CRC) presents as a very heterogeneous disease which cannot sufficiently be characterized with the currently known genetic and epigenetic markers. To identify new markers for CRC we scrutinized the methylation status of 231 DNA repair-related genes by methyl-CpG immunoprecipitation followed by global methylation profiling on a CpG island microarray, as altered expression of these genes could drive genomic and chromosomal instability observed in these tumors. We show for the first time hypermethylation of MMP9, DNMT3A and LIG4 in CRC which was confirmed in two CRC patient groups with different ethnicity. DNA ligase IV (LIG4) showed strong differential promoter methylation (up to 60%) which coincided with downregulation of mRNA in 51% of cases. This functional association of LIG4 methylation and gene expression was supported by LIG4 re-expression in 5-aza-2'-deoxycytidine-treated colon cancer cell lines, and reduced ligase IV amounts and end-joining activity in extracts of tumors with hypermethylation. Methylation of LIG4 was not associated with other genetic and epigenetic markers of CRC in our study. As LIG4 is located on chromosome 13 which is frequently amplified in CRC, two loci were tested for gene amplification in a subset of 47 cases. Comparison of amplification, methylation and expression data revealed that, in 30% of samples, the LIG4 gene was amplified and methylated, but expression was not changed. In conclusion, hypermethylation of the LIG4 promoter is a new mechanism to control ligase IV expression. It may represent a new epigenetic marker for CRC independent of known markers.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Colorretais/genética , DNA Ligases/genética , Metilação de DNA , Amplificação de Genes , Regulação Neoplásica da Expressão Gênica , Regiões Promotoras Genéticas/genética , Western Blotting , Ciclo Celular , Proliferação de Células , Colo/metabolismo , Ilhas de CpG/genética , DNA (Citosina-5-)-Metiltransferases/genética , DNA Ligase Dependente de ATP , DNA Ligases/metabolismo , Feminino , Inativação Gênica , Humanos , Masculino , Metaloproteinase 9 da Matriz/genética , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas
15.
Hum Mutat ; 32(4): 407-14, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21309036

RESUMO

Recently, we identified 3' end deletions in the EPCAM gene as a novel cause of Lynch syndrome. These truncating EPCAM deletions cause allele-specific epigenetic silencing of the neighboring DNA mismatch repair gene MSH2 in tissues expressing EPCAM. Here we screened a cohort of unexplained Lynch-like families for the presence of EPCAM deletions. We identified 27 novel independent MSH2-deficient families from multiple geographical origins with varying deletions all encompassing the 3' end of EPCAM, but leaving the MSH2 gene intact. Within The Netherlands and Germany, EPCAM deletions appeared to represent at least 2.8% and 1.1% of the confirmed Lynch syndrome families, respectively. MSH2 promoter methylation was observed in epithelial tissues of all deletion carriers tested, thus confirming silencing of MSH2 as the causative defect. In a total of 45 families, 19 different deletions were found, all including the last two exons and the transcription termination signal of EPCAM. All deletions appeared to originate from Alu-repeat mediated recombination events. In 17 cases regions of microhomology around the breakpoints were found, suggesting nonallelic homologous recombination as the most likely mechanism. We conclude that 3' end EPCAM deletions are a recurrent cause of Lynch syndrome, which should be implemented in routine Lynch syndrome diagnostics.


Assuntos
Antígenos de Neoplasias/genética , Moléculas de Adesão Celular/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Variação Genética , Mutação em Linhagem Germinativa/genética , Deleção de Sequência/genética , Antígenos de Neoplasias/metabolismo , Sequência de Bases , Moléculas de Adesão Celular/metabolismo , Metilação de DNA , Molécula de Adesão da Célula Epitelial , Modelos Genéticos , Dados de Sequência Molecular , Proteína 2 Homóloga a MutS/genética , Proteína 2 Homóloga a MutS/metabolismo , Países Baixos , Regiões Promotoras Genéticas , Recidiva
16.
Lancet Oncol ; 12(1): 49-55, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21145788

RESUMO

BACKGROUND: Lynch syndrome is caused by germline mutations in MSH2, MLH1, MSH6, and PMS2 mismatch-repair genes and leads to a high risk of colorectal and endometrial cancer. We previously showed that constitutional 3' end deletions of EPCAM can cause Lynch syndrome through epigenetic silencing of MSH2 in EPCAM-expressing tissues, resulting in tissue-specific MSH2 deficiency. We aim to establish the risk of cancer associated with such EPCAM deletions. METHODS: We obtained clinical data for 194 carriers of a 3' end EPCAM deletion from 41 families known to us at the Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands and compared cancer risk with data from a previously described cohort of 473 carriers from 91 families with mutations in MLH1, MSH2, MSH6, or a combined EPCAM-MSH2 deletion. FINDINGS: 93 of the 194 EPCAM deletion carriers were diagnosed with colorectal cancer; three of the 92 women with EPCAM deletions were diagnosed with endometrial cancer. Carriers of an EPCAM deletion had a 75% (95% CI 65-85) cumulative risk of colorectal cancer before the age of 70 years (mean age at diagnosis 43 years [SD 12]), which did not differ significantly from that of carriers of combined EPCAM-MSH2 deletion (69% [95% CI 47-91], p=0·8609) or mutations in MSH2 (77% [64-90], p=0·5892) or MLH1 (79% [68-90], p=0·5492), but was higher than noted for carriers of MSH6 mutation (50% [38-62], p<0·0001). By contrast, women with EPCAM deletions had a 12% [0-27] cumulative risk of endometrial cancer, which was lower than was that noted for carriers of a combined EPCAM-MSH2 deletion (55% [20-90], p<0·0001) or of a mutation in MSH2 (51% [33-69], p=0·0006) or MSH6 (34% [20-48], p=0·0309), but did not differ significantly from that noted for MLH1 (33% [15-51], p=0·1193) mutation carriers. This risk seems to be restricted to deletions that extend close to the MSH2 gene promoter. Of 194 carriers of an EPCAM deletion, three had duodenal cancer and four had pancreatic cancer. INTERPRETATION: EPCAM deletion carriers have a high risk of colorectal cancer; only those with deletions extending close to the MSH2 promoter have an increased risk of endometrial cancer. These results underscore the effect of mosaic MSH2 deficiency, leading to variable cancer risks, and could form the basis of an optimised protocol for the recognition and targeted prevention of cancer in EPCAM deletion carriers.


Assuntos
Antígenos de Neoplasias/genética , Moléculas de Adesão Celular/genética , Neoplasias Colorretais/genética , Neoplasias do Endométrio/genética , Deleção de Sequência , Adolescente , Adulto , Idoso , Estudos de Coortes , Neoplasias Colorretais/etiologia , Neoplasias do Endométrio/etiologia , Molécula de Adesão da Célula Epitelial , Feminino , Deleção de Genes , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 2 Homóloga a MutS/genética , Regiões Promotoras Genéticas , Risco
17.
Cancer Res ; 63(16): 4878-81, 2003 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-12941809

RESUMO

Colorectal cancer is believed to progress through an adenoma-carcinoma sequence. However, recent evidence increasingly supports the existence of an alternative route for colorectal carcinogenesis through serrated polyps, a group that encompasses a morphological spectrum, including hyperplastic polyp (HP), admixed hyperplastic polyp/adenoma (HP/AD), and serrated adenoma (SA; the latter two manifest epithelial dysplasia). We have studied a large series of serrated polyps for BRAF and KRAS mutations. BRAF mutations were detected in 18 of 50 (36%) HPs, 2 of 10 (20%) HP/ADs, and 9 of 9 (100%) SAs. Twenty-six of 29 mutations caused amino acid substitutions at valine 599, the known hotspot. KRAS mutations were detected in 9 of 50 (18%) HPs, 6 of 10 (60%) HP/ADs, and 0 of 9 (0%) SAs. BRAF and KRAS mutations are mutually exclusive (P = 0.001). The associations of BRAF mutations with SAs (P < 0.001) and KRAS mutations with HP/ADs (P = 0.005) are statistically significant. A majority (90%) of the serrated polyps showing dysplasia had mutations in either BRAF or KRAS, significantly different from those without dysplasia (54%; P = 0.014). Our data highlight the important role of activation of the RAS-RAF-mitogen-activated protein/extracellular signal-regulated kinase kinase-extracellular signal-regulated kinase-mitogen-activated protein kinase pathway in the initiation and progression of serrated neoplasms. Acquisition of a BRAF mutation appears to be associated with the progression of HP to SA, whereas progression to HP/AD is predominantly associated with acquisition of a KRAS mutation. The high incidence of BRAF mutations in HPs and SAs is consistent with the notion that the group of colorectal cancers carrying BRAF mutations may harbor most that have progressed through the HP-SA-carcinoma pathway.


Assuntos
Adenoma/genética , Pólipos do Colo/genética , Neoplasias Colorretais/genética , Genes ras , Mutação , Proteínas Oncogênicas/genética , Feminino , Humanos , Hiperplasia , Masculino , Proteínas Proto-Oncogênicas B-raf
18.
Cancer Res ; 62(22): 6451-5, 2002 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-12438234

RESUMO

Activation of the RAS/RAF/extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase pathway by RAS mutations is commonly found in human cancers. Recently, we reported that mutation of BRAF provides an alternative route for activation of this signaling pathway and can be found in melanomas, colorectal cancers, and ovarian tumors. Here we perform an extensive characterization of BRAF mutations in a large series of colorectal tumors in various stages of neoplastic transformation. BRAF mutations were found in 11 of 215 (5.1%) colorectal adenocarcinomas, 3 of 108 (2.8%) sporadic adenomas, 1 of 63 (1.6%) adenomas from familial adenomatous polyposis (FAP) patients, and 1 of 3 (33%) hyperplastic polyps. KRAS mutations were detected in 34% of carcinomas, 31% of sporadic adenomas, 9% of FAP adenomas, and no hyperplastic polyps. Eight of 16 BRAF mutations were V599E, the previously described hotspot, and none of these was associated with a KRAS mutation in the same lesion. The remaining eight mutations involve other conserved amino acids in the kinase domain, and 62.5% have a KRAS mutation in the same tumor. Our data suggest that BRAF mutations are, to some extent, biologically similar to RAS mutations in colorectal cancer because both occur at approximately the same stage of the adenoma-carcinoma sequence, both are associated with villous morphology, and both are less common in adenomas from FAP cases. By contrast, colorectal adenocarcinomas with BRAF mutations are associated with early Dukes' tumor stages (P = 0.006) and no such relationship was observed for KRAS mutations. The presence in some colorectal neoplasms of mutations in both BRAF and KRAS suggests that modulation of the RAS-RAF-extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase signaling pathway may occur by mutation of multiple components.


Assuntos
Adenocarcinoma/genética , Neoplasias Colorretais/genética , Genes ras/genética , Mutação , Proteínas Proto-Oncogênicas c-raf/genética , Adenocarcinoma/patologia , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Animais , Pólipos do Colo/genética , Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Estadiamento de Neoplasias , Fenótipo , Proteínas Proto-Oncogênicas B-raf , Homologia de Sequência de Aminoácidos
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