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1.
Am J Hum Genet ; 108(1): 163-175, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33357406

RESUMO

The lack of functional evidence for the majority of missense variants limits their clinical interpretability and poses a key barrier to the broad utility of carrier screening. In Lynch syndrome (LS), one of the most highly prevalent cancer syndromes, nearly 90% of clinically observed missense variants are deemed "variants of uncertain significance" (VUS). To systematically resolve their functional status, we performed a massively parallel screen in human cells to identify loss-of-function missense variants in the key DNA mismatch repair factor MSH2. The resulting functional effect map is substantially complete, covering 94% of the 17,746 possible variants, and is highly concordant (96%) with existing functional data and expert clinicians' interpretations. The large majority (89%) of missense variants were functionally neutral, perhaps unexpectedly in light of its evolutionary conservation. These data provide ready-to-use functional evidence to resolve the ∼1,300 extant missense VUSs in MSH2 and may facilitate the prospective classification of newly discovered variants in the clinic.


Assuntos
Predisposição Genética para Doença/genética , Proteína 2 Homóloga a MutS/genética , Mutação de Sentido Incorreto/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA/genética , Células HEK293 , Humanos
3.
PLoS One ; 15(7): e0235613, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32634176

RESUMO

Germline variants inactivating the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 cause Lynch syndrome that implies an increased cancer risk, where colon and endometrial cancer are the most frequent. Identification of these pathogenic variants is important to identify endometrial cancer patients with inherited increased risk of new cancers, in order to offer them lifesaving surveillance. However, several other genes are also part of the MMR pathway. It is therefore relevant to search for variants in additional genes that may be associated with cancer risk by including all known genes involved in the MMR pathway. Next-generation sequencing was used to screen 22 genes involved in the MMR pathway in constitutional DNA extracted from full blood from 199 unselected endometrial cancer patients. Bioinformatic pipelines were developed for identification and functional annotation of variants, using several different software tools and custom programs. This facilitated identification of 22 exonic, 4 UTR and 9 intronic variants that could be classified according to pathogenicity. This study has identified several germline variants in genes of the MMR pathway that potentially may be associated with an increased risk for cancer, in particular endometrial cancer, and therefore are relevant for further investigation. We have also developed bioinformatics strategies to analyse targeted sequencing data, including low quality data and genomic regions outside of the protein coding exons of the relevant genes.


Assuntos
Reparo de Erro de Pareamento de DNA , Neoplasias do Endométrio/patologia , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Variações do Número de Cópias de DNA , DNA de Neoplasias/sangue , DNA de Neoplasias/química , DNA de Neoplasias/metabolismo , Neoplasias do Endométrio/genética , Éxons , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Íntrons , Fatores de Risco , Regiões não Traduzidas/genética
4.
Gan To Kagaku Ryoho ; 47(7): 1113-1115, 2020 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-32668864

RESUMO

Here, we report about a woman in her 30s who had peritoneal dissemination and multiple colon cancer with high-frequency microsatellite instability(MSI-H). Her father, paternal grandfather, and maternal grandmother had a history of colorectal cancer treatment. Thus, Lynch syndrome was suspected. We performed R0 resection for peritoneal dissemination and subsequent peritoneal dissemination. A 435-gene panel testing using a next-generation sequencer identified MSH2 and other mutations in the tumor. Hence, we speculated that she could have a germline mutation of MSH2, which causes Lynch syndrome. In the future, if she wishes to receive genetic counseling and undergo germline testing for variants to confirm the diagnosis of Lynch syndrome, we will perform them after receiving informed consent.


Assuntos
Neoplasias do Colo , Proteína 2 Homóloga a MutS/genética , Adulto , Neoplasias do Colo/genética , Feminino , Mutação em Linhagem Germinativa , Humanos , Instabilidade de Microssatélites , Proteína 1 Homóloga a MutL
5.
Jpn J Clin Oncol ; 50(6): 635-642, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32372090

RESUMO

BACKGROUND: Regular endoscopic surveillance for Lynch syndrome is reported to reduce colorectal cancer (CRC)-related mortality. However, the appropriate surveillance intervals are still unclear. We evaluated the adequacy of annual colonoscopy and investigated the differences in tumor occurrence rates between individual patients. METHODS: In total, 25 patients with Lynch syndrome who underwent colonoscopic surveillance between 2007 and 2016 at the Iwakuni Clinical Center were included. We retrospectively investigated the surveillance frequency and the clinical features associated with tumor development. RESULTS: Colonoscopic surveillance was performed every 397 days on average. A total of 101 tumors, including 8 intramucosal carcinomas and 15 carcinomas, were observed within the study period. Annual colonoscopy detected six malignancies, including a carcinoma requiring surgery. Tumor incidence was associated with tumor existence in the initial colonoscopies (P = 0.018). Patients with a tumor occurrence rate of 0.4 tumors per year during our observation period were significantly more likely to have malignancies detected during regular surveillance than patients who had a lower occurrence rate (P < 0.001). Malignancy occurrence rate was strongly associated with tumor occurrence rate (P < 0.001, R2 = 0.44). CONCLUSIONS: Annual colonoscopic surveillance for Lynch syndrome patients was effective in reducing the risk of CRC progression, but was insufficient to completely avoid surgery. Because the tumor occurrence rate differed substantially between individuals, more intensive surveillance was required for high-risk patients.


Assuntos
Variação Biológica da População , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais/diagnóstico , Adulto , Idoso , Colonoscopia , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/etiologia , Neoplasias Colorretais/genética , Neoplasias Colorretais Hereditárias sem Polipose/complicações , Feminino , Humanos , Incidência , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Mutação , Estudos Retrospectivos
6.
PLoS Genet ; 16(5): e1008798, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32469861

RESUMO

Alterations in epigenetic silencing have been associated with ageing and tumour formation. Although substantial efforts have been made towards understanding the mechanisms of gene silencing, novel regulators in this process remain to be identified. To systematically search for components governing epigenetic silencing, we developed a genome-wide silencing screen for yeast (Saccharomyces cerevisiae) silent mating type locus HMR. Unexpectedly, the screen identified the mismatch repair (MMR) components Pms1, Mlh1, and Msh2 as being required for silencing at this locus. We further found that the identified genes were also required for proper silencing in telomeres. More intriguingly, the MMR mutants caused a redistribution of Sir2 deacetylase, from silent mating type loci and telomeres to rDNA regions. As a consequence, acetylation levels at histone positions H3K14, H3K56, and H4K16 were increased at silent mating type loci and telomeres but were decreased in rDNA regions. Moreover, knockdown of MMR components in human HEK293T cells increased subtelomeric DUX4 gene expression. Our work reveals that MMR components are required for stable inheritance of gene silencing patterns and establishes a link between the MMR machinery and the control of epigenetic silencing.


Assuntos
Proteína 1 Homóloga a MutL/genética , Proteínas MutL/genética , Proteína 2 Homóloga a MutS/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Acetilação , Reparo de Erro de Pareamento de DNA , Epigênese Genética , Inativação Gênica , Genes Fúngicos Tipo Acasalamento , Hereditariedade , Histonas/metabolismo , Saccharomyces cerevisiae/genética , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/metabolismo , Sirtuína 2/metabolismo , Telômero/genética
7.
Mol Cell ; 78(6): 1252-1263.e3, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32362315

RESUMO

Crossover recombination is critical for meiotic chromosome segregation, but how mammalian crossing over is accomplished is poorly understood. Here, we illuminate how strands exchange during meiotic recombination in male mice by analyzing patterns of heteroduplex DNA in recombinant molecules preserved by the mismatch correction deficiency of Msh2-/- mutants. Surprisingly, MSH2-dependent recombination suppression was not evident. However, a substantial fraction of crossover products retained heteroduplex DNA, and some provided evidence of MSH2-independent correction. Biased crossover resolution was observed, consistent with asymmetry between DNA ends in earlier intermediates. Many crossover products yielded no heteroduplex DNA, suggesting dismantling by D-loop migration. Unlike the complexity of crossovers in yeast, these simple modifications of the original double-strand break repair model-asymmetry in recombination intermediates and D-loop migration-may be sufficient to explain most meiotic crossing over in mice while also addressing long-standing questions related to Holliday junction resolution.


Assuntos
Troca Genética/fisiologia , Recombinação Homóloga/fisiologia , Meiose/fisiologia , Animais , Segregação de Cromossomos/genética , Troca Genética/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , DNA Cruciforme/genética , DNA Cruciforme/metabolismo , Recombinação Homóloga/genética , Masculino , Meiose/genética , Camundongos , Camundongos Endogâmicos DBA , Proteína 2 Homóloga a MutS/genética , Proteína 2 Homóloga a MutS/metabolismo , Ácidos Nucleicos Heteroduplexes/genética
8.
Int J Clin Oncol ; 25(9): 1644-1652, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32430733

RESUMO

BACKGROUND: Risk factors for metachronous colorectal cancer (mCRC) in Lynch Syndrome (LS) patients are essential for colorectal cancer (CRC) treatment strategy to perform not only a curative but also preventive surgery. The aim of this study was to evaluate the risk factors for mCRC development in LS patients to define the patient subset that may benefit an extended curative and preventive surgical resection. METHODS: Patient's clinical history, oncological, molecular and follow-up were collected retrospectively from the Hereditary Digestive Tumors Registry at the National Cancer Institute of Milan. The age-related cumulative risk of mCRC was calculated using the Kaplan-Meier method. Factors significantly associated with mCRC were analyzed with a Cox regression model. Overall and specific competitive risks were also calculated. RESULTS: In a total of 1346 CRC patients, 159 (11.8%) developed a mCRC after a mean follow-up of 138 months from the primary tumor. The independent risk factors reported by a multivariate analysis were: pathogenetic variants in MLH1 and MSH2 (HR 2.96 and 1.91, respectively) and history of colorectal adenomas (HR 1.54); whereas female sex and extended surgery were protective (HR 0.59 and 0.79, respectively). CONCLUSIONS: Among a high-risk population for CRC, in particular LS, an extended surgery may be considered in CRC patients with specific risk factors (MLH1 or MSH2 germline pathogenic variants, history of colorectal adenomas) to reduce the risk of mCRC development.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/patologia , Neoplasias Colorretais/patologia , Neoplasias Colorretais/cirurgia , Segunda Neoplasia Primária/patologia , Adulto , Idoso , Neoplasias Colorretais/genética , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais Hereditárias sem Polipose/genética , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Segunda Neoplasia Primária/genética , Segunda Neoplasia Primária/mortalidade , Sistema de Registros , Estudos Retrospectivos , Fatores de Risco
9.
BMC Cancer ; 20(1): 191, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143595

RESUMO

BACKGROUND: This case represents the first report of malignant primary cardiac tumour in a patient with Lynch Syndrome associated with MSH2 pathogenic variant. CASE PRESENTATION: A 57-year-old woman with previous ovarian cystadenocarcinoma was admitted to the emergency room for hematic pericardial effusion. Multimodal diagnostic imaging revealed two solid pericardial vascularized masses. After pericardiectomy, the final histological diagnosis was poorly differentiated pleomorphic sarcomatoid carcinoma. During follow-up she developed an ampulla of Vater adenocarcinoma. Genetic analysis identified an MSH2 pathogenic variant. CONCLUSION: This case contributes to expand the tumour spectrum of Lynch syndrome, suggesting that MSH2 pathogenic variants cause a more complex multi-tumour cancer syndrome than the classic Lynch Syndrome. In MSH2 variant carriers, symptoms such as dyspnoea and chest discomfort might alert for rare tumours and a focused cardiac evaluation should be considered.


Assuntos
Adenocarcinoma/complicações , Ampola Hepatopancreática/patologia , Carcinoma/complicações , Neoplasias Colorretais Hereditárias sem Polipose/complicações , Neoplasias Cardíacas/complicações , Proteína 2 Homóloga a MutS/genética , Derrame Pericárdico/complicações , Pericárdio/patologia , Carcinoma/cirurgia , Neoplasias Colorretais Hereditárias sem Polipose/genética , Feminino , Seguimentos , Mutação em Linhagem Germinativa , Neoplasias Cardíacas/cirurgia , Humanos , Pessoa de Meia-Idade , Linhagem , Pericardiectomia , Pericárdio/cirurgia , Resultado do Tratamento
10.
Int J Gynecol Pathol ; 39(2): 136-140, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32039937

RESUMO

Muir-Torre syndrome is a rare subtype of Lynch syndrome characterized by coincidence of skin neoplasm and visceral malignancies. Here, we report a case of this rare disease, whose diagnosis of the syndrome was first suspected by the pathologist. This was a 60-yr-old woman who presented with an axillary skin nodule, which was diagnosed as basal cell carcinoma. Further inquiry revealed that she was hospitalized for evaluation of a recurrent vaginal stump endometrial carcinoma. Histologic workup and immunohistochemistry for mismatch repair proteins of both the skin and vaginal tumor suggested the possibility of Muir-Torre syndrome. NexGen sequencing identified a frame-shift mutation in the MSH2 gene. The patient was found to have a metachronous colorectal carcinoma, uterine endometrial carcinoma, and skin cancer from 1998 to 2016. Five family members had also suffered from colorectal cancer or glioma. This case report illustrates the importance of the multidisciplinary care approach, mismatch repair protein and gene testing, and detailed medical history taking into consideration the diagnosis of Muir-Torre syndrome.


Assuntos
Síndrome de Muir-Torre/genética , Proteína 2 Homóloga a MutS/genética , Feminino , Mutação da Fase de Leitura , Humanos , Pessoa de Meia-Idade , Síndrome de Muir-Torre/patologia , Neoplasias Primárias Múltiplas/genética , Neoplasias Primárias Múltiplas/patologia
11.
Jpn J Clin Oncol ; 50(3): 270-275, 2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-31958127

RESUMO

OBJECTIVE: The aim of this study was to investigate a magnetic resonance imaging-based definition of lower uterine segment carcinoma. METHODS: We retrospectively reviewed 587 consecutive patients with endometrial cancer who underwent hysterectomy. Lower uterine segment carcinoma was determined through pathological examination and magnetic resonance imaging assessment. For imaging assessment, the location of the inner lining of the uterus was classified into four equal parts on a sagittal section image. A tumor was defined as lower uterine segment carcinoma when its thickest part was located in the second or the third part from the uterine fundus. Lower uterine segment carcinoma was further divided into lower uterine segment in a narrow sense, upon which diagnosis was exclusively based on pathological findings, and lower uterine segment in a broad sense that were the remaining lower uterine segment carcinomas except lower uterine segment carcinomas in a narrow sense. The relationship between lower uterine segment carcinoma and probable Lynch syndrome was investigated. Patients with loss of MSH2, MSH6, and PMS2 expression or those with tumors with loss of MLH1 and absence of MLH1 promoter methylation were diagnosed as probable Lynch syndrome. RESULTS: Lower uterine segment carcinoma was identified in 59 (10.2%) patients. Twenty-eight (47.5%) patients were categorized as lower uterine segment in a narrow sense and 31 (52.5%) as lower uterine segment in a broad sense. Among them, probable Lynch syndrome was identified in 12 (20.3%) cases. There was no difference in clinical profiles, including the prevalence of probable Lynch syndrome between the two categories. CONCLUSIONS: A magnetic resonance imaging-based expanded definition of lower uterine segment carcinoma is likely to secure characteristics equivalent to a conventional pathology-based definition of lower uterine segment carcinoma. The novel definition of lower uterine segment carcinoma might improve the detection of probable Lynch syndrome.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico por imagem , Neoplasias Uterinas/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Imagem por Ressonância Magnética , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Regiões Promotoras Genéticas , Neoplasias Uterinas/patologia
12.
Gastroenterology ; 158(5): 1326-1333, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31926173

RESUMO

BACKGROUND & AIMS: Lynch syndrome is caused by variants in DNA mismatch repair (MMR) genes and associated with an increased risk of colorectal cancer (CRC). In patients with Lynch syndrome, CRCs can develop via different pathways. We studied associations between Lynch syndrome-associated variants in MMR genes and risks of adenoma and CRC and somatic mutations in APC and CTNNB1 in tumors in an international cohort of patients. METHODS: We combined clinical and molecular data from 3 studies. We obtained clinical data from 2747 patients with Lynch syndrome associated with variants in MLH1, MSH2, or MSH6 from Germany, the Netherlands, and Finland who received at least 2 surveillance colonoscopies and were followed for a median time of 7.8 years for development of adenomas or CRC. We performed DNA sequence analyses of 48 colorectal tumors (from 16 patients with mutations in MLH1, 29 patients with mutations in MSH2, and 3 with mutations in MSH6) for somatic mutations in APC and CTNNB1. RESULTS: Risk of advanced adenoma in 10 years was 17.8% in patients with pathogenic variants in MSH2 vs 7.7% in MLH1 (P < .001). Higher proportions of patients with pathogenic variants in MLH1 or MSH2 developed CRC in 10 years (11.3% and 11.4%) than patients with pathogenic variants in MSH6 (4.7%) (P = .001 and P = .003 for MLH1 and MSH2 vs MSH6, respectively). Somatic mutations in APC were found in 75% of tumors from patients with pathogenic variants in MSH2 vs 11% in MLH1 (P = .015). Somatic mutations in CTNNB1 were found in 50% of tumors from patients with pathogenic variants in MLH1 vs 7% in MSH2 (P = .002). None of the 3 tumors with pathogenic variants in MSH6 had a mutation in CTNNB1, but all had mutations in APC. CONCLUSIONS: In an analysis of clinical and DNA sequence data from patients with Lynch syndrome from 3 countries, we associated pathogenic variants in MMR genes with risk of adenoma and CRC, and somatic mutations in APC and CTNNB1 in colorectal tumors. If these findings are confirmed, surveillance guidelines might be adjusted based on MMR gene variants.


Assuntos
Adenoma/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Proteínas de Ligação a DNA/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Adenoma/diagnóstico , Adenoma/genética , Proteína da Polipose Adenomatosa do Colo/genética , Adulto , Colonoscopia , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA , Análise Mutacional de DNA , Feminino , Finlândia/epidemiologia , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Países Baixos/epidemiologia , Estudos Prospectivos , beta Catenina/genética
13.
Gynecol Oncol ; 156(3): 669-675, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31924330

RESUMO

OBJECTIVE: Mismatch repair (MMR) deficiency and Bethesda panel microsatellite instability (MSI) are increasingly analyzed to identify tumors that might benefit from immune checkpoint inhibitors, but tumor heterogeneity is a potential obstacle for such analyses. In ovarian cancer, data on intratumoral heterogeneity of MMR deficiency/MSI are lacking. METHODS: N = 582 ovarian cancers were screened for MMR deficiency by immunohistochemistry (IHC) on a tissue microarray. 10 cases suspect for MMR deficiency were identified among 478 interpretable cancers and repeated IHC on large sections combined with polymerase chain reaction (PCR)-based MSI analysis validated MMR deficiency/MSI in 9 of these tumors. RESULTS: MMR deficiency/MSI was predominantly seen in endmetrioid cancers (8 of 35, 23%) and also in 1 of 358 serous carcinomas (0.3%), but was absent in 34 mucinous carcinomas, 23 clear cell carcinomas, 17 malignant mixed Mullerian tumors (carcinosarcomas), and 11 mixed carcinomas. MMR deficiency involed protein loss of PMS2/MLH1 in 6 cases and of MSH2 and/or MSH6 in 3 cases. 7 MMR deficient cancers were MSI-high (all endometrioid), one was MSI-low (endometrioid) and one cancer with unequivocal MMR protein loss exhibited microsatellite stability (serous). MLH1 promotor methylation was observed in 4 of 5 endometrioid cancers with MLH1 protein loss. Immunostaining of all available cancer-containing tissue blocks (n = 114) of tumors with confirmed MMR deficiency/MSI revealed uniform MMR status throughout the entire tumor mass. CONCLUSIONS: Our data show that MSI is present in a substantial proportion of endometrioid ovarian cancers but can also occur in other tumor subtypes. MMR deficiency/MSI typically involves the entire tumor mass, suggesting that MMR inactivation occurs early in tumorigenesis in a subset of ovarian cancers.


Assuntos
Reparo de Erro de Pareamento de DNA , Enzimas Reparadoras do DNA/deficiência , Neoplasias Ovarianas/enzimologia , Neoplasias Ovarianas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Endometrioide/genética , Enzimas Reparadoras do DNA/genética , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Imuno-Histoquímica , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/deficiência , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/deficiência , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/deficiência , Proteína 2 Homóloga a MutS/genética , Análise Serial de Tecidos , Adulto Jovem
14.
Nat Commun ; 11(1): 139, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949146

RESUMO

Mismatch repair deficient (dMMR) gastro-oesophageal adenocarcinomas (GOAs) show better outcomes than their MMR-proficient counterparts and high immunotherapy sensitivity. The hypermutator-phenotype of dMMR tumours theoretically enables high evolvability but their evolution has not been investigated. Here we apply multi-region exome sequencing (MSeq) to four treatment-naive dMMR GOAs. This reveals extreme intratumour heterogeneity (ITH), exceeding ITH in other cancer types >20-fold, but also long phylogenetic trunks which may explain the exquisite immunotherapy sensitivity of dMMR tumours. Subclonal driver mutations are common and parallel evolution occurs in RAS, PIK3CA, SWI/SNF-complex genes and in immune evasion regulators. MSeq data and evolution analysis of single region-data from 64 MSI GOAs show that chromosome 8 gains are early genetic events and that the hypermutator-phenotype remains active during progression. MSeq may be necessary for biomarker development in these heterogeneous cancers. Comparison with other MSeq-analysed tumour types reveals mutation rates and their timing to determine phylogenetic tree morphologies.


Assuntos
Reparo de Erro de Pareamento de DNA , Neoplasias Esofágicas/genética , Heterogeneidade Genética , Neoplasias Gástricas/genética , Adenocarcinoma/genética , Proteínas de Ligação a DNA/genética , Exoma , Genes Neoplásicos/genética , Humanos , Evasão da Resposta Imune , Imunoterapia , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Mutação , Fenótipo , Filogenia
15.
J Med Genet ; 57(1): 62-69, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31391288

RESUMO

BACKGROUND: Pathogenic variants in mismatch repair (MMR) genes (MLH1, MSH2, MSH6 and PMS2) increase risk for Lynch syndrome and related cancers. We quantified tumour characteristics to assess variant pathogenicity for germline MMR genes. METHODS: Among 4740 patients with cancer with microsatellite instability (MSI) and immunohistochemical (IHC) results, we tested MMR pathogenic variant association with MSI/IHC status, and estimated likelihood ratios which we used to compute a tumour characteristic likelihood ratio (TCLR) for each variant. Predictive performance of TCLR in combination with in silico predictors, and a multifactorial variant prediction (MVP) model that included allele frequency, co-occurrence, co-segregation, and clinical and family history information was assessed. RESULTS: Compared with non-carriers, carriers of germline pathogenic/likely pathogenic (P/LP) variants were more likely to have abnormal MSI/IHC status (p<0.0001). Among 150 classified missense variants, 73.3% were accurately predicted with TCLR alone. Models leveraging in silico scores as prior probabilities accurately classified >76.7% variants. Adding TCLR as quantitative evidence in an MVP model (MVP +TCLR Pred) increased the proportion of accurately classified variants from 88.0% (MVP alone) to 98.0% and generated optimal performance statistics among all models tested. Importantly, MVP +TCLR Pred resulted in the high yield of predicted classifications for missense variants of unknown significance (VUS); among 193 VUS, 62.7% were predicted as P/PL or benign/likely benign (B/LB) when assessed according to American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines. CONCLUSION: Our study demonstrates that when used separately or in conjunction with other evidence, tumour characteristics provide evidence for germline MMR missense variant assessment, which may have important implications for genetic testing and clinical management.


Assuntos
Reparo de Erro de Pareamento de DNA , Mutação de Sentido Incorreto , Neoplasias/genética , Neoplasias Colorretais Hereditárias sem Polipose , Simulação por Computador , Proteínas de Ligação a DNA/genética , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Neoplasias/metabolismo
16.
Genes Chromosomes Cancer ; 59(2): 111-118, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31433521

RESUMO

Interpretation of missense variants remains a major challenge for genetic diagnosis, even in well-known genes such as the DNA-mismatch repair (MMR) genes involved in Lynch syndrome. We report the characterization of a variant in MSH2: c.1022T>C, which was identified in 20 apparently unrelated families living in the North of France. A total of 150 patients from 20 families were included in this study. Family segregation studies, tumor analyses and functional analyses at both the RNA and protein levels were performed. Founder effect was evaluated by haplotype analysis.We show that MSH2 c.1022T>C is a missense variant (p.Leu341Pro) that affects protein stability. This variant is frequent in the North of France (7.7% of pathogenic variations identified in MMR genes), and is located on an ancestral haplotype. It is associated with a high risk of a broad tumor spectrum including brain and cutaneous cancers. The MSH2 c.1022T>C variant is a pathogenic founder variation associated with a high risk of cancer. These findings have important implications for genetic counseling and management of variant carriers.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Proteína 2 Homóloga a MutS/genética , Adulto , Idoso , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Reparo de Erro de Pareamento de DNA , Éxons , Feminino , Efeito Fundador , França/epidemiologia , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Haplótipos , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Proteína 2 Homóloga a MutS/metabolismo , Mutação de Sentido Incorreto , Linhagem , Polimorfismo de Nucleotídeo Único
17.
Eur J Med Genet ; 63(3): 103753, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31491536

RESUMO

Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome (LS), is a common cancer-predisposing syndrome. This study aimed to investigate the spectrum of germ-line mutations in Russian LS patients. LS-related mismatch repair (MMR) genes were analyzed in 16 patients, who were forwarded to genetic testing due to strong clinical features of LS and had high-level microsatellite instability (MSI-H) in the tumor (n = 14) or unknown MSI status (n = 2). In addition, 672 consecutive colorectal cancer (CRC) cases were screened for family history; 15 patients were younger than 50 years and reported 2 or more instances of LS-related cancers in 1st- or 2nd-degree relatives. Seven of these cases demonstrated MSI-H and therefore were subjected to DNA germ-line testing. Overall, 17/23 (74%) subjects carried LS-associated gene variants (MLH1: 10; MSH2: 4; MSH6: 2; PMS2: 1), with 2 alleles (MLH1 c.677G > T and MSH2 с.1906G > C) detected twice. Testing for recurrent mutations of 30 consecutive MSI-H CRCs led to the identification of 2 additional subjects with LS. The analysis of all relevant publications identified 28 unrelated LS patients presented in Russian medical literature and 3 unrelated Russian LS subjects described in international journals. Overall, 15/49 (31%) genetic defects revealed in Russian LS patients were represented by six recurrent alleles (MLH1: c.350C > T, c.677G > T, c.1852_1854del; MSH2: c.942+3A > T, c.1861C > T, с.1906G > C). We conclude that the founder effect for LS in Russia is seemingly less pronounced than the one for hereditary breast-ovarian cancer syndrome, however testing for recurrent LS mutations may be considered feasible in some circumstances.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Adulto , Alelos , Reparo de Erro de Pareamento de DNA/genética , Proteínas de Ligação a DNA/genética , Feminino , Efeito Fundador , Testes Genéticos , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Mutação , Federação Russa , Análise de Sequência de DNA
18.
Genet Med ; 22(1): 15-25, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31337882

RESUMO

PURPOSE: Pathogenic variants affecting MLH1, MSH2, MSH6, and PMS2 cause Lynch syndrome and result in different but imprecisely known cancer risks. This study aimed to provide age and organ-specific cancer risks according to gene and gender and to determine survival after cancer. METHODS: We conducted an international, multicenter prospective observational study using independent test and validation cohorts of carriers of class 4 or class 5 variants. After validation the cohorts were merged providing 6350 participants and 51,646 follow-up years. RESULTS: There were 1808 prospectively observed cancers. Pathogenic MLH1 and MSH2 variants caused high penetrance dominant cancer syndromes sharing similar colorectal, endometrial, and ovarian cancer risks, but older MSH2 carriers had higher risk of cancers of the upper urinary tract, upper gastrointestinal tract, brain, and particularly prostate. Pathogenic MSH6 variants caused a sex-limited trait with high endometrial cancer risk but only modestly increased colorectal cancer risk in both genders. We did not demonstrate a significantly increased cancer risk in carriers of pathogenic PMS2 variants. Ten-year crude survival was over 80% following colon, endometrial, or ovarian cancer. CONCLUSION: Management guidelines for Lynch syndrome may require revision in light of these different gene and gender-specific risks and the good prognosis for the most commonly associated cancers.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Proteínas de Ligação a DNA/economia , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Mutação , Adulto , Idoso , Neoplasias Colorretais Hereditárias sem Polipose/mortalidade , Reparo de Erro de Pareamento de DNA , Bases de Dados Genéticas , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Penetrância , Estudos Prospectivos , Medição de Risco , Caracteres Sexuais , Análise de Sobrevida
19.
J Clin Pathol ; 73(5): 273-277, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31662440

RESUMO

AIMS: The aim of this study was to evaluate the mismatch repair gene expression and their correlation with NF-kB in patients with oral squamous cell carcinoma (SCC). METHODS: Total RNA was isolated from 28 biopsy samples. A control group was composed of 20 volunteers. Differential expression of hMSH2, hMSH6 and NF-kB genes was accessed by quantitative PCR. RESULTS: There is increased expression of all the analysed genes when the patients were smokers and alcoholics. In addition, there is increased expression of hMSH2 when SCC was removed from the base of the tongue. There was a correlation between NF-kB and hMSH2 and hMSH6 as well as between repair genes hMSH2 and hMSH6 expression levels. There is increased expression of the hMSH2 gene in patients with SCC, especially in the alcoholics. CONCLUSIONS: There is a strong indication that NF-kB gene was expressed along with the studied repair genes, evidencing the possibility that this system can be activated by the inflammatory pathway.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Neoplasias Bucais/metabolismo , Proteína 2 Homóloga a MutS/metabolismo , NF-kappa B/metabolismo , Adulto , Idoso , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/etiologia , Carcinoma de Células Escamosas/genética , Estudos de Casos e Controles , Proteínas de Ligação a DNA/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Bucais/diagnóstico , Neoplasias Bucais/etiologia , Neoplasias Bucais/genética , Proteína 2 Homóloga a MutS/genética , Reação em Cadeia da Polimerase , Fatores de Risco
20.
J Surg Oncol ; 121(5): 906-916, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31650563

RESUMO

BACKGROUND AND OBJECTIVES: DNA repair is a new and important pathway that explains colorectal carcinogenesis. This study will evaluate the prognostic value of molecular modulation of double-strand break repair (XRCC2 and XRCC5); DNA damage tolerance/translesion synthesis (POLH, POLK, and POLQ), and interstrand crosslink repair (DCLRE1A) in sporadic colorectal cancer (CRC). METHODS: Tumor specimens and matched healthy mucosal tissues from 47 patients with CRC who underwent surgery were assessed for gene expression of XRCC2, XRCC5, POLH, POLK, POLQ, and DCLRE1A; protein expression of Polk, Ku80, p53, Ki67, and mismatch repair MLH1 and MSH2 components; CpG island promoter methylation of XRCC5, POLH, POLK, POLQ, and DCLRE1A was performed. RESULTS: Neoplastic tissues exhibited induction of POLK (P < .001) and DCLRE1A (P < .001) expression and low expression of POLH (P < .001) and POLQ (P < .001) in comparison to healthy paired mucosa. Low expression of POLH was associated with mucinous histology and T1-T2 tumors (P = .038); low tumor expression of POLK was associated with distant metastases (P = .042). CRC harboring POLK promoter methylation exhibited better disease-free survival (DFS) (P = .005). CONCLUSIONS: This study demonstrated that low expression or unmethylated POLH and POLK were related to worse biological behavior tumors. However, POLK methylation was associated with better DFS. POLK and POLH are potential prognostic biomarkers in CRC.


Assuntos
Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Idoso , Biomarcadores/metabolismo , Estudos de Casos e Controles , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Neoplasias Colorretais/metabolismo , Ilhas de CpG , Dano ao DNA , Metilação de DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , Intervalo Livre de Doença , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/metabolismo , Feminino , Expressão Gênica , Humanos , Autoantígeno Ku/genética , Autoantígeno Ku/metabolismo , Masculino , Proteína 1 Homóloga a MutL/genética , Proteína 1 Homóloga a MutL/metabolismo , Proteína 2 Homóloga a MutS/genética , Proteína 2 Homóloga a MutS/metabolismo , Metástase Neoplásica/genética , Prognóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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