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1.
Nat Rev Gastroenterol Hepatol ; 17(2): 111-130, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31900466

RESUMO

Colorectal cancer (CRC), a leading cause of cancer-related death worldwide, evolves as a result of the stepwise accumulation of a series of genetic and epigenetic alterations in the normal colonic epithelium, leading to the development of colorectal adenomas and invasive adenocarcinomas. Although genetic alterations have a major role in a subset of CRCs, the pathophysiological contribution of epigenetic aberrations in this malignancy has attracted considerable attention. Data from the past couple of decades has unequivocally illustrated that epigenetic marks are important molecular hallmarks of cancer, as they occur very early in disease pathogenesis, involve virtually all key cancer-associated pathways and, most importantly, can be exploited as clinically relevant disease biomarkers for diagnosis, prognostication and prediction of treatment response. In this Review, we summarize the current knowledge on the best-studied epigenetic modifications in CRC, including DNA methylation and histone modifications, as well as the role of non-coding RNAs as epigenetic regulators. We focus on the emerging potential for the bench-to-bedside translation of some of these epigenetic alterations into clinical practice and discuss the burgeoning evidence supporting the potential of emerging epigenetic therapies in CRC as we usher in the era of precision medicine.

2.
Elife ; 92020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31939734

RESUMO

Somatic copy number alterations (CNAs) are a hallmark of cancer, but their role in tumorigenesis and clinical relevance remain largely unclear. Here, we developed CNApp, a web-based tool that allows a comprehensive exploration of CNAs by using purity-corrected segmented data from multiple genomic platforms. CNApp generates genome-wide profiles, computes CNA scores for broad, focal and global CNA burdens, and uses machine learning-based predictions to classify samples. We applied CNApp to the TCGA pan-cancer dataset of 10,635 genomes showing that CNAs classify cancer types according to their tissue-of-origin, and that each cancer type shows specific ranges of broad and focal CNA scores. Moreover, CNApp reproduces recurrent CNAs in hepatocellular carcinoma and predicts colon cancer molecular subtypes and microsatellite instability based on broad CNA scores and discrete genomic imbalances. In summary, CNApp facilitates CNA-driven research by providing a unique framework to identify relevant clinical implications. CNApp is hosted at https://tools.idibaps.org/CNApp/.

3.
PLoS One ; 13(9): e0203051, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30188916

RESUMO

OBJECTIVE: The aim of this study was to validate a molecular classification of colorectal cancer (CRC) based on microsatellite instability (MSI), CpG island methylator phenotype (CIMP) status, BRAF, and KRAS and investigate each subtype's response to chemotherapy. DESIGN: This retrospective observational study included a population-based cohort of 878 CRC patients. We classified tumours into five different subtypes based on BRAF and KRAS mutation, CIMP status, and MSI. Patients with advanced stage II (T4N0M0) and stage III tumours received 5-fluoruracil (5-FU)-based chemotherapy or no adjuvant treatment based on clinical criteria. The main outcome was disease-free survival (DFS). RESULTS: Patients with the combination of microsatellite stable (MSS) tumours, BRAF mutation and CIMP positive exhibited the worst prognosis in univariate (log rank P<0.0001) and multivariate analyses (hazard ratio 1.75, 95% CI 1.05-2.93, P = 0.03) after adjusting for age, sex, chemotherapy, and TNM stage. Treatment with 5-FU-based regimens improved prognosis in patients with the combination of MSS tumours, KRAS mutation and CIMP negative (log rank P = 0.003) as well as in patients with MSS tumours plus BRAF and KRAS wild-type and CIMP negative (log-rank P<0.001). After adjusting for age, sex, and TNM stage in the multivariate analysis, only patients with the latter molecular combination had independently improved prognosis after adjuvant chemotherapy (hazard ratio 2.06, 95% CI 1.24-3.44, P = 0.005). CONCLUSION: We confirmed the prognostic value of stratifying CRC according to molecular subtypes using MSI, CIMP status, and somatic KRAS and BRAF mutation. Patients with traditional chromosomally unstable tumours obtained the best benefit from adjuvant 5-FU-based chemotherapy.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Neoplasias Colorretais/classificação , Neoplasias Colorretais/tratamento farmacológico , Fluoruracila/uso terapêutico , Adulto , Idoso , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Ilhas de CpG , Metilação de DNA , Feminino , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Mutação , Estadiamento de Neoplasias , Prognóstico , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Estudos Retrospectivos
4.
BMC Bioinformatics ; 19(1): 224, 2018 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-29898651

RESUMO

BACKGROUND: Mutational signatures have been proved as a valuable pattern in somatic genomics, mainly regarding cancer, with a potential application as a biomarker in clinical practice. Up to now, several bioinformatic packages to address this topic have been developed in different languages/platforms. MutationalPatterns has arisen as the most efficient tool for the comparison with the signatures currently reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) database. However, the analysis of mutational signatures is nowadays restricted to a small community of bioinformatic experts. RESULTS: In this work we present Mutational Signatures in Cancer (MuSiCa), a new web tool based on MutationalPatterns and built using the Shiny framework in R language. By means of a simple interface suited to non-specialized researchers, it provides a comprehensive analysis of the somatic mutational status of the supplied cancer samples. It permits characterizing the profile and burden of mutations, as well as quantifying COSMIC-reported mutational signatures. It also allows classifying samples according to the above signature contributions. CONCLUSIONS: MuSiCa is a helpful web application to characterize mutational signatures in cancer samples. It is accessible online at http://bioinfo.ciberehd.org/GPtoCRC/en/tools.html and source code is freely available at https://github.com/marcos-diazg/musica .


Assuntos
Biologia Computacional/métodos , Bases de Dados Genéticas , Genes Neoplásicos , Mutação , Neoplasias/genética , Transcriptoma , Navegador , Variação Genética , Genoma Humano , Humanos , Neoplasias/diagnóstico , Software
5.
Clin Cancer Res ; 24(12): 2820-2827, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29535127

RESUMO

Purpose: A recent study reported that 5-fluorouracil (5-FU)-based chemotherapy is less effective in treating patients with advanced colorectal cancer demonstrating hypermethylation of the TFAP2E gene. The aim of our study was to confirm and validate these findings in large, uniformly treated, well-characterized patient cohorts.Experimental Design: Two cohorts of 783 patients with colorectal cancer: 532 from a population-based, multicenter cohort (EPICOLON I) and 251 patients from a clinic-based trial were used to study the effectiveness of TFAP2E methylation and expression as a predictor of response of colorectal cancer patients to 5-FU-based chemotherapy. DNA methylation status of the TFAP2E gene in patients with colorectal cancer was assessed by quantitative bisulfite pyrosequencing analysis. IHC analysis of the TFAP2E protein expression was also performed.Results: Correlation between TFAP2E methylation status and IHC staining was performed in 607 colorectal cancer samples. Among 357 hypermethylated tumors, only 141 (39.6%) exhibited loss of protein expression. Survival was not affected by TFAP2E hypermethylation in stage IV patients [HR, 1.21; 95% confidence interval (CI), 0.79-1.87; log-rank P = 0.6]. In stage II-III cases, disease-free survival was not influenced by TFAP2E hypermethylation status in 5-FU-treated (HR, 0.91; 95% CI, 0.52-1.59; log-rank P = 0.9) as well as in nontreated patients (HR, 0.88; 95% CI, 0.5-1.54; log-rank P = 0.7).Conclusions:TFAP2E hypermethylation does not correlate with loss of its protein expression. Our large, systematic, and comprehensive study indicates that TFAP2E methylation and expression may not play a major role in predicting response to 5-FU-based chemotherapy in patients with colorectal cancer. Clin Cancer Res; 24(12); 2820-7. ©2018 AACR.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Metilação de DNA , Regulação Neoplásica da Expressão Gênica , Fator de Transcrição AP-2/genética , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Biomarcadores , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Ilhas de CpG , Fluoruracila/administração & dosagem , Seguimentos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Estadiamento de Neoplasias , Prognóstico , Modelos de Riscos Proporcionais
6.
PLoS One ; 12(9): e0184937, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28953955

RESUMO

BACKGROUND & AIMS: High-risk features of colonic polyps are based on size, number, and pathologic characteristics. Surveillance colonoscopy is often recommended according to these findings. This study aimed to determine whether the molecular characteristics of polyps might provide information about the risk of metachronous advanced neoplasia. METHODOLOGY: We retrospectively included 308 patients with colonic polyps. A total of 995 polyps were collected and tested for somatic BRAF and KRAS mutations. Patients were classified into 3 subgroups, based on the polyp mutational profile at baseline, as follows: non-mutated polyps (Wild-type), at least one BRAF-mutated polyp, or at least one KRAS-mutated polyp. At surveillance, advanced adenomas were defined as adenomas ≥ 10 mm and/or with high grade dysplasia or a villous component. In contrast, advanced serrated polyps were defined as serrated polyps ≥ 10 mm in any location, located proximal to the splenic flexure with any size or with dysplasia. RESULTS: At baseline, 289 patients could be classified as wild-type (62.3%), BRAF mutated (14.9%), or KRAS mutated (22.8%). In the univariate analysis, KRAS mutations were associated with the development of metachronous advanced polyps (OR: 2.36, 95% CI: 1.22-4.58; P = 0.011), and specifically, advanced adenomas (OR: 2.42, 95% CI: 1.13-5.21; P = 0.023). The multivariate analysis, adjusted for age and sex, also showed associations with the development of metachronous advanced polyps (OR: 2.27, 95% CI: 1.15-4.46) and advanced adenomas (OR: 2.23, 95% CI: 1.02-4.85). CONCLUSIONS: Our results suggested that somatic KRAS mutations in polyps represent a potential molecular marker for the risk of developing advanced neoplasia.


Assuntos
Pólipos do Colo/genética , Neoplasias Colorretais/genética , Predisposição Genética para Doença/genética , Mutação , Segunda Neoplasia Primária/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Pólipos do Colo/complicações , Pólipos do Colo/diagnóstico , Neoplasias Colorretais/complicações , Neoplasias Colorretais/patologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Segunda Neoplasia Primária/complicações , Segunda Neoplasia Primária/patologia , Estudos Retrospectivos
7.
Gastroenterology ; 153(1): 106-112.e2, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28400194

RESUMO

BACKGROUND & AIMS: We investigated whether patients with multiple serrated polyps, but not meeting the World Health Organization criteria for serrated polyposis syndrome, and their relatives have similar risks for colorectal cancer (CRC) as those diagnosed with serrated polyposis. METHODS: We collected data from patients with more than 10 colonic polyps, recruited in 2008-2009 from 24 hospitals in Spain for a study of causes of multiple colonic polyps. We analyzed data from 53 patients who met the criteria for serrated polyposis and 145 patients who did not meet these criteria, but who had more than 10 polyps throughout the colon, of which more than 50% were serrated. We calculated age- and sex-adjusted standardized incidence ratios (SIRs) for CRC in both groups, as well as in their first-degree relatives. RESULTS: The prevalence of CRC was similar between patients with confirmed serrated polyposis and multiple serrated polyps (odds ratio, 1.35; 95% confidence interval [CI], 0.64-2.82; P = .40). The SIR for CRC in patients with serrated polyposis (0.51; 95% CI, 0.01-2.82) did not differ significantly from the SIR for CRC in patients with multiple serrated polyps (0.74; 95% CI, 0.20-1.90; P = .70). The SIR for CRC also did not differ significantly between first-degree relatives of these groups (serrated polyposis: 3.28, 95% CI, 2.16-4.77; multiple serrated polyps: 2.79, 95% CI, 2.10-3.63; P = .50). Kaplan-Meier analysis showed no differences in the incidence of CRC between groups during the follow-up period (log-rank, 0.6). CONCLUSIONS: The risk of CRC in patients with multiple serrated polyps who do not meet the criteria for serrated polyposis, and in their first-degree relatives, is similar to that of patients diagnosed with serrated polyposis.


Assuntos
Adenoma/diagnóstico , Pólipos do Colo/genética , Pólipos do Colo/patologia , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/epidemiologia , Vigilância da População , Adenoma/patologia , Adulto , Idoso , Pólipos do Colo/diagnóstico , Colonoscopia , Neoplasias Colorretais/patologia , DNA Glicosilases/genética , Análise Mutacional de DNA , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Prevalência , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Fatores de Risco , Síndrome , Carga Tumoral
8.
PLoS One ; 12(3): e0174305, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28355283

RESUMO

There is an unambiguous association of Streptococcus gallolyticus infection with colorectal cancer, although there is limited information about epidemiology or interaction between molecular and environmental factors. We performed an original quantitative analysis of S. gallolyticus in unselected colorectal cancer patients (n = 190) and their association with clinical, pathological tumor molecular profiles (microsatellite instability, hypermethylator phenotype and chromosomal instability pathways), and other biological factors in colorectal tumor and normal tissues (cytomegalovirus and Epstein-Barr virus infection). We developed a new quantitative method to assess bacterial load. Analytical validation was reached with a very high sensitivity and specificity. Our results showed a 3.2% prevalence of S. gallolyticus infection in our unselected cohort of colorectal cancer cases (6/190). The average S. gallolyticus copy number was 7,018 (range 44-34,585). No previous reports relating to S. gallolyticus infection have been published for unselected cohorts of patients. Finally, and despite a low prevalence of S. gallolyticus in this study, we were able to define a specific association with tumor tissue (p = 0.03) and with coinfection with Epstein-Barr virus (p = 0.042; OR: 9.49; 95% IC: 1.1-82.9). The prevalence data provided will be very useful in the design of future studies, and will make it possible to estimate the sample size needed to assess precise objectives. In conclusion, our results show a low prevalence of S. gallolyticus infection in unselected colorectal cancer patients and an association of positive S. gallolyticus infection with tumor tissue and Epstein-Barr virus coinfection. Further studies will be needed to definitively assess the prevalence of S. gallolyticus in colorectal cancer and the associated clinicopathological and molecular profiles.


Assuntos
Neoplasias Colorretais/microbiologia , Infecções Estreptocócicas/complicações , Streptococcus gallolyticus/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Colo/microbiologia , Colo/patologia , Neoplasias Colorretais/genética , Feminino , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Infecções Estreptocócicas/genética
9.
J Gene Med ; 19(4)2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28306219

RESUMO

BACKGROUND: We identified a new and a recurrent POLD1 mutation associated with predisposition to colorectal cancer (CRC). We characterized the molecular and clinical nature of the potential POLD1 founder mutation in families from Valencia (Spain). METHODS: Clinical and molecular data were collected from four independent families known to have a POLD1 Leu474Pro mutation. To establish its founder effect, haplotype construction was performed using 14 flanking POLD1 polymorphic markers. We calculated penetrance estimates and clinical expressivity, globally and stratified by age and sex. RESULTS: We included 32 individuals from the four families: 20 carriers and 12 noncarriers. A common haplotype was identified in these families in a region comprising 2,995 Mb, confirming L474P as the first founder POLD1 mutation identified. Thirteen tumors diagnosed in 10 POLD1 carriers: eight CRC, three endometrial and two other tumors were considered. The median age of cancer onset for POLD1 mutation carriers was 48 years. The observed penetrance was 50% and the cumulative risk at age of 50 years was 30%. CONCLUSIONS: The findings of the present study contribute to a better understanding of CRC genetics in the Spanish population. The clinical phenotype for this mutation is similar to that in Lynch syndrome. Future studies using next generation sequencing with large gene panels for any hereditary cancer condition will offer the possibility of detecting POLE/POLD1 mutations in unsuspected clinical situations, demonstrating a more real and unbiased picture of the associated phenotype.


Assuntos
DNA Polimerase III/genética , Grupo com Ancestrais do Continente Europeu/genética , Efeito Fundador , Genética Populacional , Mutação de Sentido Incorreto , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/genética , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Haplótipos , Heterozigoto , Humanos , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Penetrância , Fenótipo , Polimorfismo de Nucleotídeo Único , Vigilância da População , Espanha , Adulto Jovem
10.
World J Gastroenterol ; 22(13): 3516-30, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-27053844

RESUMO

Molecular advances support the existence of an alternative pathway of colorectal carcinogenesis that is based on the hypermethylation of specific DNA regions that silences tumor suppressor genes. This alternative pathway has been called the serrated pathway due to the serrated appearance of tumors in histological analysis. New classifications for colorectal cancer (CRC) were proposed recently based on genetic profiles that show four types of molecular alterations: BRAF gene mutations, KRAS gene mutations, microsatellite instability, and hypermethylation of CpG islands. This review summarizes what is known about the serrated pathway of CRC, including CRC molecular and clinical features, prognosis, and response to chemotherapy.


Assuntos
Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/genética , Neoplasias Colorretais , Técnicas de Diagnóstico Molecular , Neoplasias Colorretais/classificação , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Ilhas de CpG , Metilação de DNA , Predisposição Genética para Doença , Humanos , Instabilidade de Microssatélites , Mutação , Estadiamento de Neoplasias , Fenótipo , Valor Preditivo dos Testes , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Resultado do Tratamento
11.
Hum Mol Genet ; 25(12): 2600-2611, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-26936820

RESUMO

DNA methylation (DNAm) has been linked to changes in chromatin structure, gene expression and disease. The DNAm level can be affected by genetic variation; although, how this differs by CpG dinucleotide density and genic location of the DNAm site is not well understood. Moreover, the effect of disease causing variants on the DNAm level in a tissue relevant to disease has yet to be fully elucidated. To this end, we investigated the phenotypic profiles, genetic effects and regional genomic heritability for 196080 DNAm sites in healthy colorectum tissue from 132 unrelated Colombian individuals. DNAm sites in regions of low-CpG density were more variable, on average more methylated and were more likely to be significantly heritable when compared with DNAm sites in regions of high-CpG density. DNAm sites located in intergenic regions had a higher mean DNAm level and were more likely to be heritable when compared with DNAm sites in the transcription start site (TSS) of a gene expressed in colon tissue. Within CpG-dense regions, the propensity of the DNAm level to be heritable was lower in the TSS of genes expressed in colon tissue than in the TSS of genes not expressed in colon tissue. In addition, regional genetic variation was associated with variation in local DNAm level no more frequently for DNAm sites within colorectal cancer risk regions than it was for DNAm sites outside such regions. Overall, DNAm sites located in different genomic contexts exhibited distinguishable profiles and may have a different biological function.


Assuntos
Colo/metabolismo , Metilação de DNA/genética , Epigênese Genética , Reto/metabolismo , Pólipos do Colo/genética , Pólipos do Colo/metabolismo , Ilhas de CpG/genética , Feminino , Regulação da Expressão Gênica , Genoma Humano , Genômica , Humanos , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas
12.
J Med Genet ; 52(7): 498-502, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25908759

RESUMO

BACKGROUND: The prevalence of MLH1 constitutional epimutations in the general population is unknown. We sought to analyse the prevalence of MLH1 constitutional epimutations in unselected and selected series of patients with colorectal cancer (CRC). METHODS: Patients with diagnoses of CRC (n=2123) were included in the unselected group. For comparison, a group of 847 selected patients with CRC who fulfilled the revised Bethesda guidelines (rBG) were also included. Somatic and constitutional MLH1 methylation was assayed via methylation-specific multiplex ligation-dependent probe amplification of cases lacking MLH1 expression. Germline alterations in mismatch-repair (MMR) genes were assessed via Sanger sequencing and methylation-specific multiplex ligation-dependent probe amplification. RESULTS: Loss of MLH1 expression occurred in 5.5% of the unselected series and 12.5% of the selected series (p<0.0001). No constitutional epimutations in MLH1 were detected in the unselected population (0/62); five cases from the selected series were positive for MLH1 epimutations (15.6%, 5/32; p=0.004). CONCLUSIONS: Our results suggest a negligible prevalence of MLH1 constitutional epimutations in unselected cases of CRC. Therefore, MLH1 constitutional epimutation analysis should be conducted only for patients who fulfil the rBG and who lack MLH1 expression with methylated MLH1.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/genética , Metilação de DNA/genética , Epigênese Genética/genética , Mutação/genética , Proteínas Nucleares/genética , Sequência de Bases , Reparo de Erro de Pareamento de DNA/genética , Testes Genéticos/normas , Humanos , Repetições de Microssatélites/genética , Dados de Sequência Molecular , Proteína 1 Homóloga a MutL , Prevalência , Regiões Promotoras Genéticas/genética , Análise de Sequência de DNA , Estatísticas não Paramétricas
13.
Eur J Cancer ; 50(13): 2241-50, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24953332

RESUMO

BACKGROUND AND AIMS: Individuals with tumours showing mismatch repair (MMR) deficiency not linked to germline mutations or somatic methylation of MMR genes have been recently referred as having 'Lynch-like syndrome' (LLS). The genetic basis of these LLS cases is unknown. MUTYH-associated polyposis patients show some phenotypic similarities to Lynch syndrome patients. The aim of this study was to investigate the prevalence of germline MUTYH mutations in a large series of LLS patients. METHODS: Two hundred and twenty-five probands fulfilling LLS criteria were included in this study. Screening of MUTYH recurrent mutations, whole coding sequencing and a large rearrangement analysis were undertaken. Age, sex, clinical, pathological and molecular characteristics of tumours including KRAS mutations were assessed. RESULTS: We found a prevalence of 3.1% of MAP syndrome in the whole series of LLS (7/225) and 3.9% when only cases fulfilling clinical criteria were considered (7/178). Patients with MUTYH biallelic mutations had more adenomas than monoallelic (P=0.02) and wildtype patients (P<0.0001). Six out of nine analysed tumours from six biallelic MUTYH carriers harboured KRAS-p.G12C mutation. This mutation was found to be associated with biallelic MUTYH germline mutation when compared with reported series of unselected colorectal cancer cohorts (P<0.0001). CONCLUSIONS: A proportion of unexplained LLS cases is caused by biallelic MUTYH mutations. The obtained results further justify the inclusion of MUTYH in the diagnostic strategy for Lynch syndrome-suspected patients.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , DNA Glicosilases/genética , Mutação em Linhagem Germinativa , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas p21(ras) , Proteínas ras/genética
14.
Hum Mol Genet ; 23(13): 3506-12, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24501277

RESUMO

Germline mutations in DNA polymerase ɛ (POLE) and δ (POLD1) have been recently identified in families with multiple colorectal adenomas and colorectal cancer (CRC). All reported cases carried POLE c.1270C>G (p.Leu424Val) or POLD1 c.1433G>A (p.Ser478Asn) mutations. Due to the scarcity of cases reported so far, an accurate clinical phenotype has not been defined. We aimed to assess the prevalence of these recurrent mutations in unexplained familial and early-onset CRC and polyposis, and to add additional information to define the clinical characteristics of mutated cases. A total of 858 familial/early onset CRC and polyposis patients were studied: 581 familial and early-onset CRC cases without mismatch repair (MMR) deficiency, 86 cases with MMR deficiency and 191 polyposis cases. Mutation screening was performed by KASPar genotyping assays and/or Sanger sequencing of the involved exons. POLE p.L424V was identified in a 28-year-old polyposis and CRC patient, as a de novo mutation. None of the 858 cases studied carried POLD1 p.S478N. A new mutation, POLD1 c.1421T>C (p.Leu474Pro), was identified in a mismatch repair proficient Amsterdam II family. Its pathogenicity was supported by cosegregation in the family, in silico predictions, and previously published yeast assays. POLE and POLD1 mutations explain a fraction of familial CRC and polyposis. Sequencing the proofreading domains of POLE and POLD1 should be considered in routine genetic diagnostics. Until additional evidence is gathered, POLE and POLD1 genetic testing should not be restricted to polyposis cases, and the presence of de novo mutations, considered.


Assuntos
Polipose Adenomatosa do Colo/genética , Neoplasias Colorretais/genética , DNA Polimerase III/genética , DNA Polimerase II/genética , Mutação em Linhagem Germinativa/genética , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas de Ligação a Poli-ADP-Ribose
15.
PLoS One ; 7(1): e30812, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22292045

RESUMO

In colorectal cancer (CRC), an inherited susceptibility risk affects about 35% of patients, whereas high-penetrance germline mutations account for <6% of cases. A considerable proportion of sporadic tumors could be explained by the coinheritance of multiple low-penetrance variants, some of which are common. We assessed the susceptibility to CRC conferred by genetic variants at the TGFBR1 locus. We analyzed 14 polymorphisms and the allele-specific expression (ASE) of TGFBR1 in 1025 individuals from the Spanish population. A case-control study was undertaken with 504 controls and 521 patients with sporadic CRC. Fourteen polymorphisms located at the TGFBR1 locus were genotyped with the iPLEX Gold (MassARRAY-Sequenom) technology. Descriptive analyses of the polymorphisms and haplotypes and association studies were performed with the SNPator workpackage. No relevant associations were detected between individual polymorphisms or haplotypes and the risk of CRC. The TGFBR1*9A/6A polymorphism was used for the ASE analysis. Heterozygous individuals were analyzed for ASE by fragment analysis using cDNA from normal tissue. The relative level of allelic expression was extrapolated from a standard curve. The cutoff value was calculated with Youden's index. ASE was found in 25.4% of patients and 16.4% of controls. Considering both bimodal and continuous types of distribution, no significant differences between the ASE values of patients and controls were identified. Interestingly, a combined analysis of the polymorphisms and ASE for the association with CRC occurrence revealed that ASE-positive individuals carrying one of the most common haplotypes (H2: 20.7%) showed remarkable susceptibility to CRC (RR: 5.25; 95% CI: 2.547-5.250; p<0.001) with a synergy factor of 3.7. In our study, 54.1% of sporadic CRC cases were attributable to the coinheritance of the H2 haplotype and TGFBR1 ASE. These results support the hypothesis that the allelic architecture of cancer genes, rather than individual polymorphisms, more accurately defines the CRC risk.


Assuntos
Carcinoma/genética , Neoplasias Colorretais/genética , Epistasia Genética/fisiologia , Loci Gênicos , Proteínas Serina-Treonina Quinases/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma/epidemiologia , Estudos de Casos e Controles , Neoplasias Colorretais/epidemiologia , Feminino , Loci Gênicos/genética , Loci Gênicos/fisiologia , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptores de Fatores de Crescimento Transformadores beta/fisiologia , Fatores de Risco , Adulto Jovem
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