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1.
Clin Chem ; 2020 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-33280026

RESUMO

BACKGROUND: Gene panel testing by massive parallel sequencing has increased the diagnostic yield but also the number of variants of uncertain significance. Clinical interpretation of genomic data requires expertise for each gene and disease. Heterozygous ATM pathogenic variants increase the risk of cancer, particularly breast cancer. For this reason, ATM is included in most hereditary cancer panels. It is a large gene, showing a high number of variants, most of them of uncertain significance. Hence, we initiated a collaborative effort to improve and standardize variant classification for the ATM gene. METHODS: Six independent laboratories collected information from 766 ATM variant carriers harboring 283 different variants. Data were submitted in a consensus template form, variant nomenclature and clinical information were curated, and monthly team conferences were established to review and adapt American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) criteria to ATM, which were used to classify 50 representative variants. RESULTS: Amid 283 different variants, 99 appeared more than once, 35 had differences in classification among laboratories. Refinement of ACMG/AMP criteria to ATM involved specification for twenty-one criteria and adjustment of strength for fourteen others. Afterwards, 50 variants carried by 254 index cases were classified with the established framework resulting in a consensus classification for all of them and a reduction in the number of variants of uncertain significance from 58% to 42%. CONCLUSIONS: Our results highlight the relevance of data sharing and data curation by multidisciplinary experts to achieve improved variant classification that will eventually improve clinical management.

2.
Front Oncol ; 10: 575909, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33216838

RESUMO

Background: Acute skin toxicity is a common and usually transient side-effect of breast radiotherapy although, if sufficiently severe, it can affect breast cosmesis, aftercare costs and the patient's quality-of-life. The aim of this study was to develop predictive models for acute skin toxicity using published risk factors and externally validate the models in patients recruited into the prospective multi-center REQUITE (validating pREdictive models and biomarkers of radiotherapy toxicity to reduce side-effects and improve QUalITy of lifE in cancer survivors) study. Methods: Patient and treatment-related risk factors significantly associated with acute breast radiation toxicity on multivariate analysis were identified in the literature. These predictors were used to develop risk models for acute erythema and acute desquamation (skin loss) in three Radiogenomics Consortium cohorts of patients treated by breast-conserving surgery and whole breast external beam radiotherapy (n = 2,031). The models were externally validated in the REQUITE breast cancer cohort (n = 2,057). Results: The final risk model for acute erythema included BMI, breast size, hypo-fractionation, boost, tamoxifen use and smoking status. This model was validated in REQUITE with moderate discrimination (AUC 0.65), calibration and agreement between predicted and observed toxicity (Brier score 0.17). The risk model for acute desquamation, excluding the predictor tamoxifen use, failed to validate in the REQUITE cohort. Conclusions: While most published prediction research in the field has focused on model development, this study reports successful external validation of a predictive model using clinical risk factors for acute erythema following radiotherapy after breast-conserving surgery. This model retained discriminatory power but will benefit from further re-calibration. A similar model to predict acute desquamation failed to validate in the REQUITE cohort. Future improvements and more accurate predictions are expected through the addition of genetic markers and application of other modeling and machine learning techniques.

3.
Hum Mutat ; 40(9): 1546-1556, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31294896

RESUMO

Testing for variation in BRCA1 and BRCA2 (commonly referred to as BRCA1/2), has emerged as a standard clinical practice and is helping countless women better understand and manage their heritable risk of breast and ovarian cancer. Yet the increased rate of BRCA1/2 testing has led to an increasing number of Variants of Uncertain Significance (VUS), and the rate of VUS discovery currently outpaces the rate of clinical variant interpretation. Computational prediction is a key component of the variant interpretation pipeline. In the CAGI5 ENIGMA Challenge, six prediction teams submitted predictions on 326 newly-interpreted variants from the ENIGMA Consortium. By evaluating these predictions against the new interpretations, we have gained a number of insights on the state of the art of variant prediction and specific steps to further advance this state of the art.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/diagnóstico , Biologia Computacional/métodos , Neoplasias Ovarianas/diagnóstico , Neoplasias da Mama/genética , Detecção Precoce de Câncer , Feminino , Predisposição Genética para Doença , Testes Genéticos , Variação Genética , Humanos , Modelos Genéticos , Neoplasias Ovarianas/genética
4.
Hum Mutat ; 40(12): 2296-2317, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31343793

RESUMO

BRCA1 and BRCA2 (BRCA1/2) genetic variants that disrupt messenger RNA splicing are commonly associated with increased risks of developing breast/ovarian cancer. The majority of splicing studies published to date rely on qualitative methodologies (i.e., Sanger sequencing), but it is necessary to incorporate semi-quantitative or quantitative approaches to accurately interpret the clinical significance of spliceogenic variants. Here, we characterize the splicing impact of 31 BRCA1/2 variants using semi-quantitative capillary electrophoresis of fluorescent amplicons (CE), Sanger sequencing and allele-specific assays. A total of 14 variants were found to disrupt splicing. Allelic-specific assays could be performed for BRCA1 c.302-1G>A and BRCA2 c.516+2T>A, c.1909+1G>A, c.8332-13T>G, c.8332-2A>G, c.8954-2A>T variants, showing a monoallelic contribution to full-length transcript expression that was concordant with semi-quantitative data. The splicing fraction of alternative and aberrant transcripts was also measured by CE, facilitating variant interpretation. Following Evidence-based Network for the Interpretation of Germline Mutant Alleles criteria, we successfully classified eight variants as pathogenic (Class 5), five variants as likely pathogenic (Class 4), and 14 variants as benign (Class 1). We also provide splicing data for four variants classified as uncertain (Class 3), which produced a "leaky" splicing effect or introduced a missense change in the protein sequence, that will require further assessment to determine their clinical significance.


Assuntos
Processamento Alternativo , Proteína BRCA1/genética , Proteína BRCA2/genética , Testes Genéticos/métodos , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Eletroforese Capilar , Feminino , Regulação Neoplásica da Expressão Gênica , Mutação em Linhagem Germinativa , Humanos , Polimorfismo Genético , RNA Mensageiro/genética , Análise de Sequência de DNA
5.
Hum Mutat ; 40(9): 1593-1611, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31112341

RESUMO

BRCA1 and BRCA2 (BRCA1/2) germline variants disrupting the DNA protective role of these genes increase the risk of hereditary breast and ovarian cancers. Correct identification of these variants then becomes clinically relevant, because it may increase the survival rates of the carriers. Unfortunately, we are still unable to systematically predict the impact of BRCA1/2 variants. In this article, we present a family of in silico predictors that address this problem, using a gene-specific approach. For each protein, we have developed two tools, aimed at predicting the impact of a variant at two different levels: Functional and clinical. Testing their performance in different datasets shows that specific information compensates the small number of predictive features and the reduced training sets employed to develop our models. When applied to the variants of the BRCA1/2 (ENIGMA) challenge in the fifth Critical Assessment of Genome Interpretation (CAGI 5) we find that these methods, particularly those predicting the functional impact of variants, have a good performance, identifying the large compositional bias towards neutral variants in the CAGI sample. This performance is further improved when incorporating to our prediction protocol estimates of the impact on splicing of the target variant.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/diagnóstico , Biologia Computacional/métodos , Neoplasias Ovarianas/diagnóstico , Neoplasias da Mama/genética , Simulação por Computador , Detecção Precoce de Câncer , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Modelos Genéticos , Mutação de Sentido Incorreto , Neoplasias Ovarianas/genética
6.
Radiother Oncol ; 138: 59-67, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31146072

RESUMO

PURPOSE: REQUITE aimed to establish a resource for multi-national validation of models and biomarkers that predict risk of late toxicity following radiotherapy. The purpose of this article is to provide summary descriptive data. METHODS: An international, prospective cohort study recruited cancer patients in 26 hospitals in eight countries between April 2014 and March 2017. Target recruitment was 5300 patients. Eligible patients had breast, prostate or lung cancer and planned potentially curable radiotherapy. Radiotherapy was prescribed according to local regimens, but centres used standardised data collection forms. Pre-treatment blood samples were collected. Patients were followed for a minimum of 12 (lung) or 24 (breast/prostate) months and summary descriptive statistics were generated. RESULTS: The study recruited 2069 breast (99% of target), 1808 prostate (86%) and 561 lung (51%) cancer patients. The centralised, accessible database includes: physician- (47,025 forms) and patient- (54,901) reported outcomes; 11,563 breast photos; 17,107 DICOMs and 12,684 DVHs. Imputed genotype data are available for 4223 patients with European ancestry (1948 breast, 1728 prostate, 547 lung). Radiation-induced lymphocyte apoptosis (RILA) assay data are available for 1319 patients. DNA (n = 4409) and PAXgene tubes (n = 3039) are stored in the centralised biobank. Example prevalences of 2-year (1-year for lung) grade ≥2 CTCAE toxicities are 13% atrophy (breast), 3% rectal bleeding (prostate) and 27% dyspnoea (lung). CONCLUSION: The comprehensive centralised database and linked biobank is a valuable resource for the radiotherapy community for validating predictive models and biomarkers. PATIENT SUMMARY: Up to half of cancer patients undergo radiation therapy and irradiation of surrounding healthy tissue is unavoidable. Damage to healthy tissue can affect short- and long-term quality-of-life. Not all patients are equally sensitive to radiation "damage" but it is not possible at the moment to identify those who are. REQUITE was established with the aim of trying to understand more about how we could predict radiation sensitivity. The purpose of this paper is to provide an overview and summary of the data and material available. In the REQUITE study 4400 breast, prostate and lung cancer patients filled out questionnaires and donated blood. A large amount of data was collected in the same way. With all these data and samples a database and biobank were created that showed it is possible to collect this kind of information in a standardised way across countries. In the future, our database and linked biobank will be a resource for research and validation of clinical predictors and models of radiation sensitivity. REQUITE will also enable a better understanding of how many people suffer with radiotherapy toxicity.


Assuntos
Neoplasias da Mama/radioterapia , Neoplasias Pulmonares/radioterapia , Neoplasias da Próstata/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
7.
Int J Cancer ; 145(10): 2682-2691, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30927264

RESUMO

Multigene panels provide a powerful tool for analyzing several genes simultaneously. We evaluated the frequency of pathogenic variants (PV) in customized predefined panels according to clinical suspicion by phenotype and compared it to the yield obtained in the analysis of our clinical research gene panel. We also investigated mutational yield of opportunistic testing of BRCA1/2 and mismatch repair (MMR) genes in all patients. A total of 1,205 unrelated probands with clinical suspicion of hereditary cancer were screened for germline mutations using panel testing. Overall, 1,048 females and 157 males were analyzed, mean age at cancer diagnosis was 48; 883 had hereditary breast/ovarian cancer-suspicion, 205 hereditary nonpolyposis colorectal cancer (HNPCC)-suspicion, 73 adenomatous-polyposis-suspicion and 44 with other/multiple clinical criteria. At least one PV was found in 150 probands (12%) analyzed by our customized phenotype-driven panel. Tumoral MMR deficiency predicted for the presence of germline MMR gene mutations in patients with HNPCC-suspicion (46/136 vs. 0/56 in patients with and without MMR deficiency, respectively). Opportunistic testing additionally identified five MSH6, one BRCA1 and one BRCA2 carriers (0.6%). The analysis of the extended 24-gene panel provided 25 additional PVs (2%), including in 4 out of 51 individuals harboring MMR-proficient colorectal tumors (2 CHEK2 and 2 ATM). Phenotype-based panels provide a notable rate of PVs with clinical actionability. Opportunistic testing of MMR and BRCA genes leads to a significant straightforward identification of MSH6, BRCA1 and BRCA2 mutation carriers, and endorses the model of opportunistic testing of genes with clinical utility within a standard genetic counseling framework.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Predisposição Genética para Doença , Testes Genéticos/métodos , Síndromes Neoplásicas Hereditárias/diagnóstico , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Reparo de Erro de Pareamento de DNA , Feminino , Genes Supressores de Tumor , Mutação em Linhagem Germinativa , Humanos , Masculino , Anamnese , Pessoa de Meia-Idade , Síndromes Neoplásicas Hereditárias/genética , Linhagem , Fenótipo
8.
Int J Cancer ; 145(2): 401-414, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30623411

RESUMO

A subset of genetic variants found through screening of patients with hereditary breast and ovarian cancer syndrome (HBOC) and Lynch syndrome impact RNA splicing. Through target enrichment of the transcriptome, it is possible to perform deep-sequencing and to identify the different and even rare mRNA isoforms. A targeted RNA-seq approach was used to analyse the naturally-occurring splicing events for a panel of 8 breast and/or ovarian cancer susceptibility genes (BRCA1, BRCA2, RAD51C, RAD51D, PTEN, STK11, CDH1, TP53), 3 Lynch syndrome genes (MLH1, MSH2, MSH6) and the fanconi anaemia SLX4 gene, in which monoallelic mutations were found in non-BRCA families. For BRCA1, BRCA2, RAD51C and RAD51D the results were validated by capillary electrophoresis and were compared to a non-targeted RNA-seq approach. We also compared splicing events from lymphoblastoid cell-lines with those from breast and ovarian fimbriae tissues. The potential of targeted RNA-seq to detect pathogenic changes in RNA-splicing was validated by the inclusion of samples with previously well characterized BRCA1/2 genetic variants. In our study, we update the catalogue of normal splicing events for BRCA1/2, provide an extensive catalogue of normal RAD51C and RAD51D alternative splicing, and list splicing events found for eight other genes. Additionally, we show that our approach allowed the identification of aberrant splicing events due to the presence of BRCA1/2 genetic variants and distinguished between complete and partial splicing events. In conclusion, targeted-RNA-seq can be very useful to classify variants based on their putative pathogenic impact on splicing.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Processamento de RNA , Análise de Sequência de RNA/métodos , Proteína BRCA1/genética , Proteína BRCA2/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/genética , Eletroforese Capilar , Feminino , Predisposição Genética para Doença , Humanos , Mutação
9.
Breast Cancer Res Treat ; 174(2): 543-550, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30552643

RESUMO

PURPOSE: Disruption of splicing motifs by genetic variants can affect the correct generation of mature mRNA molecules leading to aberrant transcripts. In some cases, variants may alter the physiological transcription profile composed of several transcripts, and an accurate in vitro evaluation is crucial to establish their pathogenicity. In this study, we have characterized a novel PALB2 variant c.3201+5G>T identified in a breast cancer family. METHODS: Peripheral blood RNA was analyzed in two carriers and ten controls by RT-PCR and Sanger sequencing. The splicing profile was also characterized by semi-quantitative capillary electrophoresis and quantitative PCR. RAD51 foci formation and PALB2 LOH status were evaluated in primary breast tumor samples from the carriers. RESULTS: PALB2 c.3201+5G>T disrupts intron 11 donor splice site and modifies the abundance of several alternative transcripts (∆11, ∆12, and ∆11,12), also present in control samples. All transcripts are predicted to encode for non-functional proteins. Semi-quantitative and quantitative analysis of PALB2 full-length transcript indicated haploinsufficiency in carriers. One tumor exhibited PALB2 LOH and RAD51 assay indicated homologous recombination deficiency in both tumors. CONCLUSIONS: Our results support a pathogenic classification for PALB2 c.3201+5G>T, highlighting the impact of variants causing an imbalanced expression of natural RNA isoforms in cancer susceptibility.


Assuntos
Processamento Alternativo , Neoplasias da Mama/genética , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Mutação em Linhagem Germinativa , Polimorfismo de Nucleotídeo Único , Feminino , Perfilação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Perda de Heterozigosidade , Pessoa de Meia-Idade , Linhagem , Análise de Sequência de RNA
10.
J Med Genet ; 56(2): 63-74, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30472649

RESUMO

BACKGROUND: Genetic analysis of BRCA1 and BRCA2 for the diagnosis of hereditary breast and ovarian cancer (HBOC) is commonly restricted to coding regions and exon-intron boundaries. Although germline pathogenic variants in these regions explain about ~20% of HBOC cases, there is still an important fraction that remains undiagnosed. We have screened BRCA1/2 deep intronic regions to identify potential spliceogenic variants that could explain part of the missing HBOC susceptibility. METHODS: We analysed BRCA1/2 deep intronic regions by targeted gene sequencing in 192 high-risk HBOC families testing negative for BRCA1/2 during conventional analysis. Rare variants (MAF <0.005) predicted to create/activate splice sites were selected for further characterisation in patient RNA. The splicing outcome was analysed by RT-PCR and Sanger sequencing, and allelic imbalance was also determined when heterozygous exonic loci were present. RESULTS: A novel transcript was detected in BRCA1 c.4185+4105C>T variant carrier. This variant promotes the inclusion of a pseudoexon in mature mRNA, generating an aberrant transcript predicted to encode for a non-functional protein. Quantitative and allele-specific assays determined haploinsufficiency in the variant carrier, supporting a pathogenic effect for this variant. Genotyping of 1030 HBOC cases and 327 controls did not identify additional carriers in Spanish population. CONCLUSION: Screening of BRCA1/2 intronic regions has identified the first BRCA1 deep intronic variant associated with HBOC by pseudoexon activation. Although the frequency of deleterious variants in these regions appears to be low, our study highlights the importance of studying non-coding regions and performing comprehensive RNA assays to complement genetic diagnosis.


Assuntos
Proteína BRCA1/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Íntrons , Adulto , Proteína BRCA2/genética , Neoplasias da Mama Masculina/genética , Estudos de Casos e Controles , Simulação por Computador , Éxons , Feminino , Regulação da Expressão Gênica , Frequência do Gene , Testes Genéticos , Mutação em Linhagem Germinativa , Humanos , Masculino , Processamento de RNA , RNA Mensageiro/genética
11.
EMBO Mol Med ; 10(12)2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30377213

RESUMO

Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) are effective in cancers with defective homologous recombination DNA repair (HRR), including BRCA1/2-related cancers. A test to identify additional HRR-deficient tumors will help to extend their use in new indications. We evaluated the activity of the PARPi olaparib in patient-derived tumor xenografts (PDXs) from breast cancer (BC) patients and investigated mechanisms of sensitivity through exome sequencing, BRCA1 promoter methylation analysis, and immunostaining of HRR proteins, including RAD51 nuclear foci. In an independent BC PDX panel, the predictive capacity of the RAD51 score and the homologous recombination deficiency (HRD) score were compared. To examine the clinical feasibility of the RAD51 assay, we scored archival breast tumor samples, including PALB2-related hereditary cancers. The RAD51 score was highly discriminative of PARPi sensitivity versus PARPi resistance in BC PDXs and outperformed the genomic test. In clinical samples, all PALB2-related tumors were classified as HRR-deficient by the RAD51 score. The functional biomarker RAD51 enables the identification of PARPi-sensitive BC and broadens the population who may benefit from this therapy beyond BRCA1/2-related cancers.


Assuntos
Antineoplásicos/administração & dosagem , Neoplasias da Mama/diagnóstico , Resistencia a Medicamentos Antineoplásicos , Xenoenxertos/patologia , Ftalazinas/administração & dosagem , Piperazinas/administração & dosagem , Inibidores de Poli(ADP-Ribose) Polimerases/administração & dosagem , Rad51 Recombinase/análise , Animais , Biomarcadores Tumorais/análise , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Feminino , Recombinação Homóloga , Humanos , Camundongos
12.
J Cancer Res Clin Oncol ; 144(12): 2495-2513, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30306255

RESUMO

PURPOSE: Few and small studies have been reported about multigene testing usage by massively parallel sequencing in European cancer families. There is an open debate about what genes should be tested, and the actionability of some included genes is under research. METHODS: We investigated a panel of 34 known high/moderate-risk cancer genes, including 16 related to breast or ovarian cancer (BC/OC) genes, and 63 candidate genes to BC/OC in 192 clinically suspicious of hereditary breast/ovarian cancer (HBOC) Spanish families without pathogenic variants in BRCA1 or BRCA2 (BRCA1/2). RESULTS: We identified 16 patients who carried a high- or moderate-risk pathogenic variant in eight genes: 4 PALB2, 3 ATM, 2 RAD51D, 2 TP53, 2 APC, 1 BRIP1, 1 PTEN and 1 PMS2. These findings led to increased surveillance or prevention options in 12 patients and predictive testing in their family members. We detected 383 unique variants of uncertain significance in known cancer genes, of which 35 were prioritized in silico. Eighteen loss-of-function variants were detected in candidate BC/OC genes in 17 patients (1 BARD1, 1 ERCC3, 1 ERCC5, 2 FANCE, 1 FANCI, 2 FANCL, 1 FANCM, 1 MCPH1, 1 PPM1D, 2 RBBP8, 3 RECQL4 and 1 with SLX4 and XRCC2), three of which also carry pathogenic variants in known cancer genes. CONCLUSIONS: Eight percent of the BRCA1/2 negative patients carry pathogenic variants in other actionable genes. The multigene panel usage improves the diagnostic yield in HBOC testing and it is an effective tool to identify potentially new candidate genes.


Assuntos
Biomarcadores Tumorais , Genes BRCA1 , Genes BRCA2 , Síndrome Hereditária de Câncer de Mama e Ovário/diagnóstico , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Adulto , Alelos , Biologia Computacional/métodos , Feminino , Predisposição Genética para Doença , Testes Genéticos , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Análise de Sequência de DNA , Espanha , Adulto Jovem
13.
Front Genet ; 9: 366, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30233647

RESUMO

In silico tools for splicing defect prediction have a key role to assess the impact of variants of uncertain significance. Our aim was to evaluate the performance of a set of commonly used splicing in silico tools comparing the predictions against RNA in vitro results. This was done for natural splice sites of clinically relevant genes in hereditary breast/ovarian cancer (HBOC) and Lynch syndrome. A study divided into two stages was used to evaluate SSF-like, MaxEntScan, NNSplice, HSF, SPANR, and dbscSNV tools. A discovery dataset of 99 variants with unequivocal results of RNA in vitro studies, located in the 10 exonic and 20 intronic nucleotides adjacent to exon-intron boundaries of BRCA1, BRCA2, MLH1, MSH2, MSH6, PMS2, ATM, BRIP1, CDH1, PALB2, PTEN, RAD51D, STK11, and TP53, was collected from four Spanish cancer genetic laboratories. The best stand-alone predictors or combinations were validated with a set of 346 variants in the same genes with clear splicing outcomes reported in the literature. Sensitivity, specificity, accuracy, negative predictive value (NPV) and Mathews Coefficient Correlation (MCC) scores were used to measure the performance. The discovery stage showed that HSF and SSF-like were the most accurate for variants at the donor and acceptor region, respectively. The further combination analysis revealed that HSF, HSF+SSF-like or HSF+SSF-like+MES achieved a high performance for predicting the disruption of donor sites, and SSF-like or a sequential combination of MES and SSF-like for predicting disruption of acceptor sites. The performance confirmation of these last results with the validation dataset, indicated that the highest sensitivity, accuracy, and NPV (99.44%, 99.44%, and 96.88, respectively) were attained with HSF+SSF-like or HSF+SSF-like+MES for donor sites and SSF-like (92.63%, 92.65%, and 84.44, respectively) for acceptor sites. We provide recommendations for combining algorithms to conduct in silico splicing analysis that achieved a high performance. The high NPV obtained allows to select the variants in which the study by in vitro RNA analysis is mandatory against those with a negligible probability of being spliceogenic. Our study also shows that the performance of each specific predictor varies depending on whether the natural splicing sites are donors or acceptors.

14.
Hum Mutat ; 39(12): 2025-2039, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30204945

RESUMO

The widespread use of next generation sequencing for clinical testing is detecting an escalating number of variants in noncoding regions of the genome. The clinical significance of the majority of these variants is currently unknown, which presents a significant clinical challenge. We have screened over 6,000 early-onset and/or familial breast cancer (BC) cases collected by the ENIGMA consortium for sequence variants in the 5' noncoding regions of BC susceptibility genes BRCA1 and BRCA2, and identified 141 rare variants with global minor allele frequency < 0.01, 76 of which have not been reported previously. Bioinformatic analysis identified a set of 21 variants most likely to impact transcriptional regulation, and luciferase reporter assays detected altered promoter activity for four of these variants. Electrophoretic mobility shift assays demonstrated that three of these altered the binding of proteins to the respective BRCA1 or BRCA2 promoter regions, including NFYA binding to BRCA1:c.-287C>T and PAX5 binding to BRCA2:c.-296C>T. Clinical classification of variants affecting promoter activity, using existing prediction models, found no evidence to suggest that these variants confer a high risk of disease. Further studies are required to determine if such variation may be associated with a moderate or low risk of BC.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Mutação em Linhagem Germinativa , Regiões Promotoras Genéticas , Regiões 5' não Traduzidas , Idade de Início , Proteína BRCA1/química , Proteína BRCA1/metabolismo , Proteína BRCA2/química , Proteína BRCA2/metabolismo , Fator de Ligação a CCAAT/metabolismo , Linhagem Celular Tumoral , Feminino , Predisposição Genética para Doença , Humanos , Células MCF-7 , Fator de Transcrição PAX5/metabolismo , Ligação Proteica
15.
Hum Mutat ; 39(9): 1155-1160, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29969168

RESUMO

Many BRCA1 and BRCA2 (BRCA1/2) genetic variants have been studied at mRNA level and linked to hereditary breast and ovarian cancer due to splicing alteration. In silico tools are reliable when assessing variants located in consensus splice sites, but we may identify variants in complex genomic contexts for which bioinformatics is not precise enough. In this study, we characterize BRCA2 c.7976 + 5G > T variant located in intron 17 which has an atypical donor site (GC). This variant was identified in three unrelated Spanish families and we have detected exon 17 skipping as the predominant transcript occurring in carriers. We have also detected several isoforms (Δ16-18, Δ17,18, Δ18, and ▼17q224 ) at different expression levels among carriers and controls. This study remarks the challenge of interpreting genetic variants when multiple alternative isoforms are present, and that caution must be taken when using in silico tools to identify potential spliceogenic variants located in GC-AG introns.


Assuntos
Processamento Alternativo/genética , Proteína BRCA2/genética , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Mutação/genética , Idoso , Idoso de 80 Anos ou mais , Proteína BRCA1/genética , Simulação por Computador , Éxons/genética , Feminino , Variação Genética/genética , Síndrome Hereditária de Câncer de Mama e Ovário/patologia , Humanos , Íntrons/genética , Isoformas de Proteínas , Sítios de Splice de RNA/genética
16.
Nat Commun ; 9(1): 967, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29511213

RESUMO

BRCA1 is a tumor suppressor that regulates DNA repair by homologous recombination. Germline mutations in BRCA1 are associated with increased risk of breast and ovarian cancer and BRCA1 deficient tumors are exquisitely sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors. Therefore, uncovering additional components of this DNA repair pathway is of extreme importance for further understanding cancer development and therapeutic vulnerabilities. Here, we identify EDC4, a known component of processing-bodies and regulator of mRNA decapping, as a member of the BRCA1-BRIP1-TOPBP1 complex. EDC4 plays a key role in homologous recombination by stimulating end resection at double-strand breaks. EDC4 deficiency leads to genome instability and hypersensitivity to DNA interstrand cross-linking drugs and PARP inhibitors. Lack-of-function mutations in EDC4 were detected in BRCA1/2-mutation-negative breast cancer cases, suggesting a role in breast cancer susceptibility. Collectively, this study recognizes EDC4 with a dual role in decapping and DNA repair whose inactivation phenocopies BRCA1 deficiency.


Assuntos
Proteína BRCA1/metabolismo , Neoplasias da Mama/metabolismo , Reparo do DNA , Proteínas/metabolismo , Proteína BRCA1/genética , Neoplasias da Mama/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Recombinação Homóloga , Humanos , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Ligação Proteica , Proteínas/genética , Capuzes de RNA/genética , Capuzes de RNA/metabolismo
17.
Radiother Oncol ; 121(3): 431-439, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27443449

RESUMO

PURPOSE: Several small studies have indicated that the ATM rs1801516 SNP is associated with risk of normal tissue toxicity after radiotherapy. However, the findings have not been consistent. In order to test this SNP in a well-powered study, an individual patient data meta-analysis was carried out by the International Radiogenomics Consortium. MATERIALS AND METHODS: The analysis included 5456 patients from 17 different cohorts. 2759 patients were given radiotherapy for breast cancer and 2697 for prostate cancer. Eight toxicity scores (overall toxicity, acute toxicity, late toxicity, acute skin toxicity, acute rectal toxicity, telangiectasia, fibrosis and late rectal toxicity) were analyzed. Adjustments were made for treatment and patient related factors with potential impact on the risk of toxicity. RESULTS: For all endpoints except late rectal toxicity, a significantly increased risk of toxicity was found for carriers of the minor (Asn) allele with odds ratios of approximately 1.5 for acute toxicity and 1.2 for late toxicity. The results were consistent with a co-dominant pattern of inheritance. CONCLUSION: This study convincingly showed a significant association between the ATM rs1801516 Asn allele and increased risk of radiation-induced normal tissue toxicity.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/genética , Neoplasias da Mama/radioterapia , Neoplasias da Próstata/radioterapia , Lesões por Radiação/genética , Alelos , Neoplasias da Mama/genética , Feminino , Predisposição Genética para Doença , Genótipo , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Polimorfismo de Nucleotídeo Único , Neoplasias da Próstata/genética , Lesões por Radiação/etiologia , Tolerância a Radiação/genética , Radioterapia/efeitos adversos , Fatores de Risco
18.
J Med Genet ; 53(8): 548-58, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27060066

RESUMO

BACKGROUND: BRCA1 and BRCA2 are the two principal tumour suppressor genes associated with inherited high risk of breast and ovarian cancer. Genetic testing of BRCA1/2 will often reveal one or more sequence variants of uncertain clinical significance, some of which may affect normal splicing patterns and thereby disrupt gene function. mRNA analyses are therefore among the tests used to interpret the clinical significance of some genetic variants. However, these could be confounded by the appearance of naturally occurring alternative transcripts unrelated to germline sequence variation or defects in gene function. To understand which novel splicing events are associated with splicing mutations and which are part of the normal BRCA2 splicing repertoire, a study was undertaken by members of the Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium to characterise the spectrum of naturally occurring BRCA2 mRNA alternate-splicing events. METHODS: mRNA was prepared from several blood and breast tissue-derived cells and cell lines by contributing ENIGMA laboratories. cDNA representing BRCA2 alternate splice sites was amplified and visualised using capillary or agarose gel electrophoresis, followed by sequencing. RESULTS: We demonstrate the existence of 24 different BRCA2 mRNA alternate-splicing events in lymphoblastoid cell lines and both breast cancer and non-cancerous breast cell lines. CONCLUSIONS: These naturally occurring alternate-splicing events contribute to the array of cDNA fragments that may be seen in assays for mutation-associated splicing defects. Caution must be observed in assigning alternate-splicing events to potential splicing mutations.


Assuntos
Processamento Alternativo/genética , Proteína BRCA2/genética , RNA Mensageiro/genética , Proteína BRCA1/genética , Neoplasias da Mama/genética , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Predisposição Genética para Doença/genética , Testes Genéticos/métodos , Humanos , Células MCF-7 , Mutação/genética , Neoplasias Ovarianas/genética , Sítios de Splice de RNA/genética
19.
Apoptosis ; 20(3): 371-82, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25398538

RESUMO

We tested apoptosis levels in in vitro irradiated T-lymphocytes from breast cancer (BC) patients with radiotherapy-induced late effects. Previous results reported in the literature were revised. We also examined the effect of TP53 Arg72Pro polymorphism on irradiation-induced apoptosis (IA). Twenty BC patients, ten with fibrosis and/or telangiectasias and ten matched controls with no late reactions, were selected from those receiving radiotherapy between 1993 and 2007. All patients were followed-up at least 6 years after radiotherapy. Using the combination of both CD3 and CD8 antibodies the in vitro IA was measured in CD3, CD8 and CD4 T-lymphocytes, and CD8 natural killer lymphocytes (CD8 NK) by flow cytometry. The TP53 Arg72Pro genotype was determined by sequencing. Patients with late radiotherapy toxicity showed less IA for all T-lymphocytes except for the CD8 NK. CD8 NK showed the highest spontaneous apoptosis and the lowest IA. IA in patients with toxicity appears to be lower than the control patients only in TP53 Arg/Arg patients (P = 0.077). This difference was not present in patients carrying at least one Pro allele (P = 0.8266). Our data indicate that late side effects induced by radiotherapy of BC are associated to low levels of IA. CD8 NK cells have a different response to in vitro irradiation compared to CD8 T-lymphocytes. It would be advisable to distinguish the CD8 NK lymphocytes from the pool of CD8+ lymphocytes in IA assays using CD8+ cells. Our data suggest that the 72Pro TP53 allele may influence the IA of patients with radiotherapy toxicity.


Assuntos
Neoplasias da Mama/radioterapia , Linfócitos T CD4-Positivos/efeitos da radiação , Linfócitos T CD8-Positivos/efeitos da radiação , Raios gama/efeitos adversos , Células Matadoras Naturais/efeitos da radiação , Subpopulações de Linfócitos/efeitos da radiação , Polimorfismo Genético , Proteína Supressora de Tumor p53/genética , Adulto , Apoptose/efeitos da radiação , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Estudos de Casos e Controles , Células Cultivadas , Feminino , Fibrose , Expressão Gênica , Humanos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/patologia , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/patologia , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Tolerância a Radiação , Telangiectasia/genética , Telangiectasia/metabolismo , Telangiectasia/patologia , Resultado do Tratamento , Proteína Supressora de Tumor p53/metabolismo
20.
Breast Cancer Res Treat ; 147(1): 133-43, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25086635

RESUMO

BRCA1 and BRCA2 are the most well-known breast and ovarian cancer susceptibility genes. Additional genes involved in DNA repair have been identified as predisposing to breast cancer. Recently, RAD51C, a new Fanconi Anemia gene, essential for homologous recombination repair, has been reported to be a rare hereditary breast and ovarian cancer susceptibility gene. Indeed, several pathogenic mutations have been identified in BRCA1/BRCA2-negative hereditary breast and ovarian cancer families. Here, we present the results of the screening of RAD51C mutations in a large series of 516 BRCA1/BRCA2-negative Spanish patients from breast and/or ovarian cancer families, and the evaluation of these results in the context of all RAD51C carriers. RAD51C mutation screening was performed by DNA analysis for all index cases. All the genetic variants identified were analyzed in silico for splicing and protein predictions. cDNA analysis was performed for three selected variants. All previous RAD51C mutation studies on breast and/or ovarian cancer were reviewed. We identified three inactivating RAD51C mutations. Two mutations were found in breast and ovarian cancer families and one mutation in a site-specific breast cancer family. Based on the mean age of ovarian cancer diagnosis in RAD51C carriers, we would recommend prophylactic bilateral salpingo-ophorectomy in premenopausal RAD51C mutation carriers. Our results support that RAD51C is a rare breast and ovarian cancer susceptibility gene and may contribute to a small fraction of families including breast and ovarian cancer cases and families with only breast cancer. Thus, RAD51C testing should be offered to hereditary breast and/or ovarian cancer families without selecting for specific cancer origin.


Assuntos
Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa/genética , Neoplasias Ovarianas/genética , Adulto , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Família , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/epidemiologia , Prognóstico , Espanha/epidemiologia
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