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1.
Hum Mutat ; 2021 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-34420246

RESUMO

Germline pathogenic variants in BRCA1 confer a high risk of developing breast and ovarian cancer. The BRCA1 exon 11 (formally exon 10) is one of the largest exons and codes for the nuclear localization signals of the corresponding gene product. This exon can be partially or entirely skipped during pre-mRNA splicing, leading to three major in-frame isoforms that are detectable in most cell types and tissue, and in normal and cancer settings. However, it is unclear whether the splicing imbalance of this exon is associated with cancer risk. Here we identify a common genetic variant in intron 10, rs5820483 (NC_000017.11:g.43095106_43095108dup), which is associated with exon 11 isoform expression and alternative splicing, and with the risk of breast cancer, but not ovarian cancer, in BRCA1 pathogenic variant carriers. The identification of this genetic effect was confirmed by analogous observations in mouse cells and tissue in which a loxP sequence was inserted in the syntenic intronic region. The prediction that the rs5820483 minor allele variant would create a binding site for the splicing silencer hnRNP A1 was confirmed by pull-down assays. Our data suggest that perturbation of BRCA1 exon 11 splicing modifies the breast cancer risk conferred by pathogenic variants of this gene.

3.
Virchows Arch ; 479(1): 221-226, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34100114

RESUMO

Salivary gland cancers (SGCs) are rare malignancies with highly heterogeneous histological features. Patients affected with SGCs are at increased risk of secondary malignancies, including breast cancer (BC). Previous studies enlightened a possible link between SGCs and hereditary predisposition to BC. Here, we searched for SGC-affected patients in 1796 high-risk BC families recruited at the Genetic Unit of the Istituto Nazionale dei Tumori of Milan, 516 of which carried pathogenic variants in BRCA1 and/or BRCA2, the main genetic risk factors for BC. We detected five families with an individual affected with SGC, including two male patients, one carrying a constitutional mutation in BRCA1 and the other in BRCA2. Loss of heterozygosity of BRCA wild-type alleles was assessed in the patients' tumour DNA. We conclude that our observations support the hypothesis that genetic factors associated with BC susceptibility might play a role also in at least a subset of SGCs.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Mutação , Neoplasias das Glândulas Salivares/genética , Adulto , Bases de Dados Factuais , Feminino , Predisposição Genética para Doença , Hereditariedade , Humanos , Itália , Perda de Heterozigosidade , Masculino , Pessoa de Meia-Idade , Linhagem
4.
Cancer Gene Ther ; 2020 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-33281191

RESUMO

Whereas 90% of patients with Wilms tumor (WT) reach cure, approximately half of patients developing a recurrent tumor die of the disease. Therefore, to disclose events leading to recurrence represents a clinical need. To study paired primary/recurrent tumor samples, being aware of the intra-tumoral heterogeneity, might help finding these answers. We previously suggested that mutations in SIX1 and DROSHA underlie WT recurrence. With the aim to better investigate this scenario, we collected 19 paired primary/recurrent tumors and 10 primary tumors from relapsing patients and searched for mutations in the SIX1/2 genes and microRNA processing genes (miRNAPGs). We found SIX1 mutation in one case, miRNAPGs mutations in seven cases, and the co-occurrence of SIX1 and miRNAPG mutations in one case. We could observe that, whereas in primary tumors the mutations could be heterogeneously present, in all cases they were positively selected and homogeneously present in the recurrent disease, as also indicated by a "moderate" and "almost perfect" agreement (according to the Landis and Koch classification criteria) between paired samples. Analysis of SIX1/2 genes and miRNAPGs in 50 non-relapsing WTs disclosed SIX2 mutation in one case and miRNAPGs mutations in seven. A borderline statistically significant association was observed between miRNAPGs mutations and the occurrence of relapse (p value: 0.05). These data suggest that SIX1 and miRNAPGs mutations may provide an advantage during tumor progression to recurrence and can represent oncogenic drivers in WT development.

5.
Cancers (Basel) ; 12(12)2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-33266155

RESUMO

Women carriers of pathogenic variants (mutations) in the BRCA1/2 genes face a high lifetime risk of developing breast cancer (BC) and/or ovarian cancer (OC). However, metabolic factors may influence BRCA penetrance. We studied the association of metabolic factors with BRCA1/2 variants and the risk effect of metabolic exposures in relation to the position of the mutations within the BRCA1/2. Overall, 438 women carriers of BRCA1/2 mutations, aged 18-70, with or without a previous diagnosis of BC/OC and without metastases, who joined our randomized dietary trial, were included in the study. The pathogenic variants were divided, according to their predicted effect, into loss of function (LOF) and nonsynonymous variants. The association between metabolic exposures and variants were analyzed by a logistic regression model. LOF variant carriers showed higher levels of metabolic parameters compared to carriers of nonsynonymous variants. LOF variant carriers had significantly higher levels of plasma glucose and serum insulin than nonsynonymous variant carriers (p = 0.03 and p < 0.001, respectively). This study suggests that higher insulin levels are significantly associated with LOF variants. Further investigations are required to explore the association of metabolic factors with LOF variants and the mechanisms by which these factors may affect BRCA-related cancer risk.

6.
Eur J Ophthalmol ; : 1120672120940209, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32613861

RESUMO

PURPOSE: To analyze the anatomical and functional outcomes of a standardized scleral buckling approach in patients with noncomplex primary rhegmatogenous retinal detachment (RRD). METHODS: Retrospective institutional case series of 135 eyes of 131 patients diagnosed with noncomplex primary RRD. All patients underwent scleral buckling surgery with the placement of an encircling 5 mm oval sponge at 15 ± 2 mm posteriorly from the limbus, cryopexy, subretinal fluid drainage, and air tamponade. RESULTS: Final anatomical success at 12 months was achieved in all 135 eyes (100%). Primary anatomical surgical success was obtained in 127 out of 135 eyes (94%), while re-detachment occurred in eight out of 135 cases (6%). Primary anatomical success was significantly lower in pseudophakic eyes (p < 0.001). At the end of the follow-up period, no vision loss was observed in any patient and both sphere and cylinder refraction shift was mild. There was a low rate of postoperative complications. Nine out of 135 eyes (6.6%) developed full thickness macular hole, whether in 24 out of 135 eyes (17.8%) epiretinal membrane development was noticed. CONCLUSION: A standardized scleral buckling approach for primary noncomplex RRD may be effective. The technique is reproducible, easier, and quicker to perform if compared to classic scleral buckling procedures, suggesting that it may represent a valuable surgical option. Special care is needed in the management of pseudophakic RRD due to higher risk of RRD recurrence.

7.
Diagnostics (Basel) ; 9(4)2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600986

RESUMO

In Italy, 5200 new ovarian cancers were diagnosed in 2018, highlighting an increasing need to test women for BRCA1/2. The number of labs offering this test is continuously increasing. The aim of this study was to show the results coming from the intersociety survey coordinated by four different Clinical and Laboratory Italian Scientific Societies (AIOM, SIAPEC-IAP, SIBIOC, and SIGU). A multidisciplinary team belonging to the four scientific societies drew up two different questionnaires: One was targeted toward all Italian Departments of Medical Oncology, and the second toward laboratories of clinical molecular biology. This survey was implemented from September 2017 to March 2018. Seventy-seven out of 305 (25%) Departments of Medical Oncology filled our survey form. Indeed, 59 molecular laboratories were invited. A total of 41 laboratories (70%) filled in the questionnaire. From 2014 to 2017, 16 new molecular laboratories were activated. A total of 12,559 tests were performed in the year 2016, with a mean of 339 tests and a median of 254 tests per laboratory, showing a glimpse of an extreme low number of tests performed per year by some laboratories. In terms of the type and number of professionals involved in the pre- and post-test counseling, results among the onco-genetic team were heterogeneous. Our data show that the number of laboratories providing BRCA1/2 germline assays is significantly increased with further implementation of the somatic test coming soon. The harmonization of the complete laboratory diagnostic path should be encouraged, particularly in order to reduce the gap between laboratories with high and low throughput.

8.
Endocr Connect ; 8(8): 1224-1229, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31336362

RESUMO

Breast cancer in men is a rare and still poorly characterized disease. Inherited mutations in BRCA1, BRCA2 and PALB2 genes, as well as common polymorphisms, play a role in male breast cancer genetic predisposition. Male breast cancer is considered a hormone-dependent tumor specifically related to hyperestrogenism. Polymorphisms in genes involved in estrogen biosynthesis and metabolism pathways, such as CYP17A1 and CYP1B1, have been associated with breast cancer risk. Here, we aimed to investigate the role of CYP17A1 and CYP1B1 polymorphisms in male breast cancer risk. A series of 597 male breast cancer cases and 1022 male controls, recruited within the Italian Multicenter Study on male breast cancer, was genotyped for CYP17A1 rs743572, CYP1B1 rs1056836 and rs1800440 polymorphisms by allelic discrimination real-time PCR with TaqMan probes. Associations with male breast cancer risk were estimated using logistic regression. No statistically significant associations between male breast cancer risk and the three analyzed polymorphisms emerged. Similar results were obtained also when BRCA1/2 mutational status was considered. No significant differences in the distribution of the genotypes according to estrogen receptor status emerged. In conclusion, our study, based on a large series of male breast cancer cases, is likely to exclude a relevant role of CYP17A1 and CYP1B1 polymorphisms in male breast cancer predisposition. Overall, these results add new data to the increasing evidence that polymorphisms in these genes may not be associated with breast cancer risk.

9.
Crit Rev Oncol Hematol ; 140: 67-72, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31176273

RESUMO

The current availability of new Poly(ADP-ribose) Polymerase (PARP)-inhibitors for the treatment of ovarian cancer patients independently of the presence of a BRCA pathogenic variant, together with the validation of somatic test for the analysis of BRCA1/2 genes, involves the need to optimise the guidelines for BRCA testing. The AIOM-SIGU-SIBIOC-SIAPEC-IAP Italian Scientific Societies, in this position paper, recommend the implementation of BRCA testing with 2 main objectives: the first is the identification of ovarian cancer patients with higher probability of benefit from specific anticancer treatments (test for response to therapy); the second goal, through BRCA testing in the family members of ovarian cancer patients, is the identification of carriers of pathogenic variant, who have inheredited predisposition to cancer development (test for cancer risk). These individuals with increased risk of cancer, should be encouraged to participate in dedicated high-risk surveillance clinics and specific risk-reducing measures (primary and/or secondary prevention programs).


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Testes Genéticos/normas , Mutação em Linhagem Germinativa , Neoplasias Ovarianas/genética , Sociedades Médicas , Bioquímica , Feminino , Genética , Humanos , Itália , Oncologia , Neoplasias Ovarianas/diagnóstico
10.
J Med Genet ; 56(6): 347-357, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30962250

RESUMO

The vocabulary currently used to describe genetic variants and their consequences reflects many years of studying and discovering monogenic disease with high penetrance. With the recent rapid expansion of genetic testing brought about by wide availability of high-throughput massively parallel sequencing platforms, accurate variant interpretation has become a major issue. The vocabulary used to describe single genetic variants in silico, in vitro, in vivo and as a contributor to human disease uses terms in common, but the meaning is not necessarily shared across all these contexts. In the setting of cancer genetic tests, the added dimension of using data from genetic sequencing of tumour DNA to direct treatment is an additional source of confusion to those who are not experienced in cancer genetics. The language used to describe variants identified in cancer susceptibility genetic testing typically still reflects an outdated paradigm of Mendelian inheritance with dichotomous outcomes. Cancer is a common disease with complex genetic architecture; an improved lexicon is required to better communicate among scientists, clinicians and patients, the risks and implications of genetic variants detected. This review arises from a recognition of, and discussion about, inconsistencies in vocabulary usage by members of the ENIGMA international multidisciplinary consortium focused on variant classification in breast-ovarian cancer susceptibility genes. It sets out the vocabulary commonly used in genetic variant interpretation and reporting, and suggests a framework for a common vocabulary that may facilitate understanding and clarity in clinical reporting of germline genetic tests for cancer susceptibility.


Assuntos
Predisposição Genética para Doença , Variação Genética , Classificação Internacional de Doenças , Neoplasias Embrionárias de Células Germinativas/diagnóstico , Neoplasias Embrionárias de Células Germinativas/genética , Biomarcadores Tumorais , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Genes BRCA1 , Genes BRCA2 , Mutação em Linhagem Germinativa , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Classificação Internacional de Doenças/normas , Terminologia como Assunto , Vocabulário Controlado
11.
Cancers (Basel) ; 11(3)2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30832263

RESUMO

Highly penetrant variants of BRCA1/2 genes are involved in hereditary predisposition to breast and ovarian cancer. The detection of pathogenic BRCA variants has a considerable clinical impact, allowing appropriate cancer-risk management. However, a major drawback is represented by the identification of variants of uncertain significance (VUS). Many VUS potentially affect mRNA splicing, making transcript analysis an essential step for the definition of their pathogenicity. Here, we characterize the impact on splicing of ten BRCA1/2 variants. Aberrant splicing patterns were demonstrated for eight variants whose alternative transcripts were fully characterized. Different events were observed, including exon skipping, intron retention, and usage of de novo and cryptic splice sites. Transcripts with premature stop codons or in-frame loss of functionally important residues were generated. Partial/complete splicing effect and quantitative contribution of different isoforms were assessed, leading to variant classification according to Evidence-based Network for the Interpretation of Mutant Alleles (ENIGMA) consortium guidelines. Two variants could be classified as pathogenic and two as likely benign, while due to a partial splicing effect, six variants remained of uncertain significance. The association with an undefined tumor risk justifies caution in recommending aggressive risk-reduction treatments, but prevents the possibility of receiving personalized therapies with potential beneficial effect. This indicates the need for applying additional approaches for the analysis of variants resistant to classification by gene transcript analyses.

12.
Eur J Epidemiol ; 34(6): 591-600, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30737679

RESUMO

Observational studies suggest that higher birth weight (BW) is associated with increased risk of breast cancer in adult life. We conducted a two-sample Mendelian randomisation (MR) study to assess whether this association is causal. Sixty independent single nucleotide polymorphisms (SNPs) known to be associated at P < 5 × 10-8 with BW were used to construct (1) a 41-SNP instrumental variable (IV) for univariable MR after removing SNPs with pleiotropic associations with other breast cancer risk factors and (2) a 49-SNP IV for multivariable MR after filtering SNPs for data availability. BW predicted by the 41-SNP IV was not associated with overall breast cancer risk in inverse-variance weighted (IVW) univariable MR analysis of genetic association data from 122,977 breast cancer cases and 105,974 controls (odds ratio = 0.86 per 500 g higher BW; 95% confidence interval 0.73-1.01). Sensitivity analyses using four alternative methods and three alternative IVs, including an IV with 59 of the 60 BW-associated SNPs, yielded similar results. Multivariable MR adjusting for the effects of the 49-SNP IV on birth length, adult height, adult body mass index, age at menarche, and age at menopause using IVW and MR-Egger methods provided estimates consistent with univariable analyses. Results were also similar when all analyses were repeated after restricting to estrogen receptor-positive or -negative breast cancer cases. Point estimates of the odds ratios from most analyses performed indicated an inverse relationship between genetically-predicted BW and breast cancer, but we are unable to rule out an association between the non-genetically-determined component of BW and breast cancer. Thus, genetically-predicted higher BW was not associated with an increased risk of breast cancer in adult life in our MR study.


Assuntos
Peso ao Nascer , Neoplasias da Mama/epidemiologia , Peso ao Nascer/genética , Feminino , Humanos , Análise da Randomização Mendeliana , Polimorfismo de Nucleotídeo Único , Medição de Risco
13.
Int J Cancer ; 145(2): 390-400, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30613976

RESUMO

Breast cancer (BC) in men is rare and genetic predisposition is likely to play a relevant role in its etiology. Inherited mutations in BRCA1/2 account for about 13% of all cases and additional genes that may contribute to the missing heritability need to be investigated. In our study, a well-characterized series of 523 male BC (MBC) patients from the Italian multicenter study on MBC, enriched for non-BRCA1/2 MBC cases, was screened by a multigene custom panel of 50 cancer-associated genes. The main clinical-pathologic characteristics of MBC in pathogenic variant carriers and non-carriers were also compared. BRCA1/2 pathogenic variants were detected in twenty patients, thus, a total of 503 non-BRCA1/2 MBC patients were examined in our study. Twenty-seven of the non-BRCA1/2 MBC patients were carriers of germline pathogenic variants in other genes, including two APC p.Ile1307Lys variant carriers and one MUTYH biallelic variant carrier. PALB2 was the most frequently altered gene (1.2%) and PALB2 pathogenic variants were significantly associated with high risk of MBC. Non-BRCA1/2 pathogenic variant carriers were more likely to have personal (p = 0.0005) and family (p = 0.007) history of cancer. Results of our study support a central role of PALB2 in MBC susceptibility and show a low impact of CHEK2 on MBC predisposition in the Italian population. Overall, our data indicate that a multigene testing approach may benefit from appropriately selected patients with implications for clinical management and counseling of MBC patients and their family members.


Assuntos
Neoplasias da Mama Masculina/genética , Quinase do Ponto de Checagem 2/genética , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Mutação , Análise de Sequência de DNA/métodos , Proteína da Polipose Adenomatosa do Colo/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , DNA Glicosilases/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Adulto Jovem
14.
Cancers (Basel) ; 11(2)2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30696104

RESUMO

Genetic testing for BRCA1 and BRCA2 genes has led to the identification of many unique variants of uncertain significance (VUS). Multifactorial likelihood models that predict the odds ratio for VUS in favor or against cancer causality, have been developed, but their use is conditioned by the amount of necessary data, which are difficult to obtain if a variant is rare. As an alternative, variants mapping to the coding regions can be examined using in vitro functional assays. BRCA1 and BRCA2 proteins promote genome protection by interacting with different proteins. In this study, we assessed the functional effect of two sets of variants in BRCA genes by exploiting the green fluorescent protein (GFP)-reassembly in vitro assay, which was set-up to test the BRCA1/BARD1, BRCA1/UbcH5a, and BRCA2/DSS1 interactions. Based on the findings observed for the validation panels of previously classified variants, BRCA1/UbcH5a and BRCA2/DSS1 binding assays showed 100% sensitivity and specificity in identifying pathogenic and non-pathogenic variants. While the actual efficiency of these assays in assessing the clinical significance of BRCA VUS has to be verified using larger validation panels, our results suggest that the GFP-reassembly assay is a robust method to identify variants affecting normal protein functioning and contributes to the classification of VUS.

16.
Br J Ophthalmol ; 103(4): 481-487, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-29945896

RESUMO

PURPOSE: To investigate the incidence, clinical features and risk factors of premacular membrane (PMM) formation after primary rhegmatogenous retinal detachment (RRD) repair with scleral buckling (SB) alone. METHODS: This institutional, prospective and consecutive case series included phakic eyes with RRD, treated with SB alone within 7 days from the occurrence of symptoms, with a follow-up of 6 months. Spectral-domain optical coherence tomography images were reviewed. The association of PMM development and morphology with preoperative and intraoperative RRD features was analysed. RESULTS: Ninety-two patients with a mean age of 56±13 years completed the 6 months follow-up period. Postoperatively, eyes with any PMM stage were 30 out of 92 (32.6%) at 1 month and 47 out of 92 (51,1%) at both 3 months and 6 months. Over the follow-up period, 17 out of 47 PMMs (36.2%) progressed to later stages. Progression of PMMs to later stages were observed only in RRDs involving the macular region (17 out of 35 eyes, 48.5%), while none of the PMMs in macula-sparing detachments progressed to later stages (p=0.020). The risk factors significantly associated with postoperative new onset of PMM were preoperative RRDs involving the macular region (p=0.001), cryopexy time (p=0.045), presence of horseshoe tears (p=0.003), worse preoperative visual acuity (p=0.004) and subretinal fluid drainage (p=0.047). CONCLUSION: The incidence of postoperative PMM formation after RRD repair with SB alone was high. In retinal detachments involving the macular region PMM were more severe, tending to anatomical progression and functional deterioration. Activation of foveal Müller cell in detachments involving the macula may be a key factor in PMM progression.


Assuntos
Macula Lutea/patologia , Complicações Pós-Operatórias/epidemiologia , Descolamento Retiniano/cirurgia , Recurvamento da Esclera/efeitos adversos , Tomografia de Coerência Óptica/métodos , Acuidade Visual , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Incidência , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Estudos Prospectivos , Descolamento Retiniano/diagnóstico , Adulto Jovem
17.
Front Oncol ; 8: 583, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30564557

RESUMO

Inherited mutations in BRCA1, and, mainly, BRCA2 genes are associated with increased risk of male breast cancer (MBC). Mutations in PALB2 and CHEK2 genes may also increase MBC risk. Overall, these genes are functionally linked to DNA repair pathways, highlighting the central role of genome maintenance in MBC genetic predisposition. MUTYH is a DNA repair gene whose biallelic germline variants cause MUTYH-associated polyposis (MAP) syndrome. Monoallelic MUTYH variants have been reported in families with both colorectal and breast cancer and there is some evidence on increased breast cancer risk in women with monoallelic variants. In this study, we aimed to investigate whether MUTYH germline variants may contribute to MBC susceptibility. To this aim, we screened the entire coding region of MUTYH in 503 BRCA1/2 mutation negative MBC cases by multigene panel analysis. Moreover, we genotyped selected variants, including p.Tyr179Cys, p.Gly396Asp, p.Arg245His, p.Gly264Trpfs*7, and p.Gln338His, in a total of 560 MBC cases and 1,540 male controls. Biallelic MUTYH pathogenic variants (p.Tyr179Cys/p.Arg241Trp) were identified in one MBC patient with phenotypic manifestation of adenomatous polyposis. Monoallelic pathogenic variants were identified in 14 (2.5%) MBC patients, in particular, p.Tyr179Cys was detected in seven cases, p.Gly396Asp in five cases, p.Arg245His and p.Gly264Trpfs*7 in one case each. The majority of MBC cases with MUTYH pathogenic variants had family history of cancer including breast, colorectal, and gastric cancers. In the case-control study, an association between the variant p.Tyr179Cys and increased MBC risk emerged by multivariate analysis [odds ratio (OR) = 4.54; 95% confidence interval (CI): 1.17-17.58; p = 0.028]. Overall, our study suggests that MUTYH pathogenic variants may have a role in MBC and, in particular, the p.Tyr179Cys variant may be a low/moderate penetrance risk allele for MBC. Moreover, our results suggest that MBC may be part of the tumor spectrum associated with MAP syndrome, with implication in the clinical management of patients and their relatives. Large-scale collaborative studies are needed to validate these findings.

18.
Front Oncol ; 8: 480, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30410870

RESUMO

PALB2 (partner and localizer of BRCA2) was initially identified as a binding partner of BRCA2. It interacts also with BRCA1 forming a complex promoting DNA repair by homologous recombination. Germline pathogenic variants in BRCA1, BRCA2 and PALB2 DNA repair genes are associated with high risk of developing breast cancer. Mutation screening in these breast cancer predisposition genes is routinely performed and allows the identification of individuals who carry pathogenic variants and are at risk of developing the disease. However, variants of uncertain significance (VUSs) are often detected and establishing their pathogenicity and clinical relevance remains a central challenge for the risk assessment of the carriers and the clinical decision-making process. Many of these VUSs are missense variants leading to single amino acid substitutions, whose impact on protein function is uncertain. Typically, VUSs are rare and due to the limited genetic, clinical, and pathological data the multifactorial approaches used for classification cannot be applied. Thus, these variants can only be characterized through functional analyses comparing their effect with that of normal and mutant gene products used as positive and negative controls. The two missense variants BRCA2:c.91T >G (p.Trp31Gly) and PALB2:c.3262C >T (p.Pro1088Ser) were detected in two breast cancer probands originally ascertained at Breast Cancer Units of Institutes located in Milan and Bergamo (Northern Italy), respectively. These variants were located in the BRCA2-PALB2 interacting domains, were predicted to be deleterious by in silico analyses, and were very rare and clinically not classified. Therefore, we initiate to study their functional effect by exploiting a green fluorescent protein (GFP)-reassembly in vitro assay specifically designed to test the BRCA2-PALB2 interaction. This functional assay proved to be easy to develop, robust and reliable. It also allows testing variants located in different genes. Results from these functional analyses showed that the BRCA2:p.Trp31Gly and the PALB2:p.Pro1088Ser prevented the BRCA2-PALB2 binding. While caution is warranted when the interpretation of the clinical significance of rare VUSs is based on functional studies only, our data provide initial evidences in favor of the possibility that these variants are pathogenic.

19.
Oncotarget ; 9(75): 34079-34089, 2018 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-30344923

RESUMO

Wilms tumour (WT), the most frequent malignant childhood renal tumour, shows a high degree of genetic and epigenetic heterogeneity. Loss of imprinting on chromosome 11p15 is found in a large fraction of cases and mutations in a few genes, including WT1, CTNNB1, WTX, TP53 and, more recently, SIX1, SIX2 and micro RNA processing genes (miRNAPGs), have been observed. However, these alterations are not sufficient to describe the entire spectrum of genetic defects underlying WT development. We inspected data obtained from a previously performed genome-wide single nucleotide polymorphism (SNP) array analysis on 96 WT samples. By selecting focal regions commonly involved in chromosomal anomalies, we identified genes with a possible role in WT development, based on the prior knowledge of their biological relevance, including MYCN, DIS3L2, MIR562, HACE1, GLI3, CDKN2A and CDKN2B, PALB2, and CHEK2. The MYCN hotspot mutation c.131C>T was detected in seven cases (7.3%). Full sequencing of the remaining genes disclosed 16 rare missense variants and a splicing mutation. Most of these were present at the germline level. Promoter analysis of HACE1, CDKN2A and CDKN2B disclosed partial methylation affecting HACE1 in a consistent fraction of cases (85%). Interestingly, of the four missense variants identified in CHEK2, three were predicted to be deleterious by in silico analyses, while an additional variant was observed to alter mRNA splicing, generating a functionally defective protein. Our study adds additional information on putative WT genes, and adds evidences involving CHEK2 in WT susceptibility.

20.
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
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