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1.
Genet Mol Biol ; 46(3 Suppl 1): e20230133, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38252059

RESUMO

The TP53 3'UTR variant rs78378222 A>C has been detected in different tumor types as a somatic alteration that reduces p53 expression through modification of polyadenylation and miRNA regulation. Its prevalence is not yet known in all tumors. Herein, we examine tumor tissue prevalence of rs7837822 in Brazilian cohorts of patients from south and southeast regions diagnosed with lung adenocarcinoma (LUAD, n=586), sarcoma (SARC, n=188) and uterine leiomyoma (ULM, n=41). The minor allele (C) was identified in heterozygosity in 6/586 LUAD tumors (prevalence = 1.02 %) and none of the SARC and ULM samples. Additionally, next generation sequencing analysis revealed that all variant-positive tumors (n=4) with sample availability had additional pathogenic or likely pathogenic somatic variants in the TP53 coding regions. Among them, 3/4 (75 %) had the same pathogenic or likely pathogenic sequence variant (allele frequency <0.05 in tumor DNA) namely c.751A>C (p.Ile251Leu). Our results indicate a low somatic prevalence of rs78378222 in LUAD, ULM and SARC tumors from Brazilian patients, which suggests that no further analysis of this variant in the specific studied regions of Brazil is warranted. However, these findings should not exclude tumor molecular testing of this TP53 3'UTR functional variant for different populations.

2.
Breast Cancer Res Treat ; 202(1): 57-65, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37578666

RESUMO

BACKGROUND: Neoadjuvant chemotherapy (NACT) is the mainstay of treatment of stages II and III triple-negative breast cancer (TNBC). This study aims to evaluate if the addition of carboplatin to NACT is associated with an increase in the pathological complete response (pCR) rates in TNBC. METHODS: We conducted an open-label phase II randomized clinical trial in a single center in Brazil. Patients with stage II and III TNBC were randomized to receive standard NACT with or without carboplatin. All the patients received doxorubicin (60 mg/m2) plus cyclophosphamide (600 mg/m2) both intravenously (i.v.) q21 days for four cycles. Patients were then randomized for additional treatment with weekly (wk) paclitaxel (80 mg/m2 i.v., for 12 cycles) plus wk carboplatin AUC 1.5 (experimental arm) or without wk carboplatin (control arm). Randomization was stratified according to gBRCA status, age, and AJCC 8th edition clinical stage (II vs. III). The primary endpoint was the pathologic complete response (pCR) rate. Secondary endpoints included recurrence-free survival and overall survival. RESULTS: Between 2017 and 2021, 146 patients were randomized, 73 on each arm. The median age was 45 years. Most patients (66.4%) had locally advanced stage III disease, 67.1% had T3/T4 tumors, and 56.2% had clinically positive axillary lymph nodes. Germline BRCA status was available for all patients, and 19.9% had pathogenic BRCA1/2 variants. The pCR rate (ypT0ypN0) was numerically increased by 13.7%, being 43.8% (31 of 73 patients) in the experimental and 30.1% (22 of 73 patients) in the control arm, not meeting the prespecified goal of increasing the pCR in 15% (p-value = 0.08). Survival outcomes are immature. CONCLUSION: The addition of carboplatin to standard NACT in stages II and III TNBC was associated with a non-statistically significant numerical increase in the pCR rate. Follow-up for survival outcomes and translational research initiatives are ongoing.


Assuntos
Neoplasias da Mama , Neoplasias de Mama Triplo Negativas , Humanos , Pessoa de Meia-Idade , Feminino , Carboplatina , Resultado do Tratamento , Proteína BRCA1 , Terapia Neoadjuvante , Neoplasias de Mama Triplo Negativas/patologia , Neoplasias da Mama/tratamento farmacológico , Proteína BRCA2 , Paclitaxel , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos
3.
Breast Cancer Res Treat ; 199(1): 127-136, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36881271

RESUMO

We determined the frequency and mutational spectrum of BRCA1 and BRCA2 in a series of patients at high risk for developing breast cancer from Brazil. A total of 1267 patients were referred for BRCA genetic testing, and no obligation of fulfilling criteria of mutation probability methods for molecular screening was applied. Germline deleterious mutations in BRCA1/2 (i.e., pathogenic/likely pathogenic variants) were identified in 156 out of 1267 patients (12%). We confirm recurrent mutations in BRCA1/2, but we also report three novel mutations in BRCA2, not previously reported in any public databases or other studies. Variants of unknown significance (VUS) represent only 2% in this dataset and most of them were detected in BRCA2. The overall mutation prevalence in BRCA1/2 was higher in patients diagnosed with cancer at age > 35 years old, and with family history of cancer. The present data expand our knowledge of BRCA1/2 germline mutational spectrum, and it is a valuable clinical resource for genetic counseling and cancer management programs in the country.


Assuntos
Proteína BRCA1 , Proteína BRCA2 , Neoplasias da Mama , Adulto , Feminino , Humanos , Brasil/epidemiologia , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Mutação , Neoplasias Ovarianas/genética
4.
Genet Med ; 24(1): 119-129, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34906479

RESUMO

PURPOSE: Germline genetic testing for BRCA1 and BRCA2 variants has been a part of clinical practice for >2 decades. However, no studies have compared the cancer risks associated with missense pathogenic variants (PVs) with those associated with protein truncating (PTC) variants. METHODS: We collected 582 informative pedigrees segregating 1 of 28 missense PVs in BRCA1 and 153 pedigrees segregating 1 of 12 missense PVs in BRCA2. We analyzed 324 pedigrees with PTC variants in BRCA1 and 214 pedigrees with PTC variants in BRCA2. Cancer risks were estimated using modified segregation analysis. RESULTS: Estimated breast cancer risks were markedly lower for women aged >50 years carrying BRCA1 missense PVs than for the women carrying BRCA1 PTC variants (hazard ratio [HR] = 3.9 [2.4-6.2] for PVs vs 12.8 [5.7-28.7] for PTC variants; P = .01), particularly for missense PVs in the BRCA1 C-terminal domain (HR = 2.8 [1.4-5.6]; P = .005). In case of BRCA2, for women aged >50 years, the HR was 3.9 (2.0-7.2) for those heterozygous for missense PVs compared with 7.0 (3.3-14.7) for those harboring PTC variants. BRCA1 p.[Cys64Arg] and BRCA2 p.[Trp2626Cys] were associated with particularly low risks of breast cancer compared with other PVs. CONCLUSION: These results have important implications for the counseling of at-risk women who harbor missense PVs in the BRCA1/2 genes.


Assuntos
Neoplasias da Mama , Neoplasias Ovarianas , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Feminino , Genes BRCA1 , Genes BRCA2 , Predisposição Genética para Doença , Testes Genéticos/métodos , Mutação em Linhagem Germinativa/genética , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/genética
5.
Hum Mutat ; 42(3): 290-299, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33326660

RESUMO

The current study aimed to identify new breast and/or ovarian cancer predisposition genes. For that, whole-exome sequencing (WES) was performed in the germline DNA of 52 non-BRCA1/BRCA2/TP53 mutation carrier women at high-risk for hereditary breast and ovarian cancer (HBOC). All variants were classified using information from population and disease specific databases, in silico prediction tools and the American College of Medical Genetics and Genomics (ACMG) criteria. Loss of heterozygosity (LOH) of tumor samples and segregation analyses were performed whenever possible. The variants identified were investigated in a second, independent cohort of 17 BC cases. Pathogenic/Likely Pathogenic variants were identified in known cancer genes such as CHEK2, MUTYH, PMS2, and RAD51C. Rare and potentially pathogenic variants were identified in DNA repair genes (FAN1, POLQ, and RAD54L) and other cancer-related genes such as DROSHA and SLC34A2. Interestingly, the variant c.149T>G in the FAN1 gene was identified in two unrelated families, and exhibited LOH in the tumor tissue of one of them. In conclusion, this is the largest Brazilian WES study involving families at high-risk for HBOC which has brought novel insights into the role of potentially new genetic risk factors for hereditary breast and ovarian cancer.


Assuntos
Neoplasias da Mama , Síndrome Hereditária de Câncer de Mama e Ovário , Neoplasias Ovarianas , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/patologia , Feminino , Genes BRCA2 , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Humanos , Perda de Heterozigosidade , Mutação , Neoplasias Ovarianas/genética , Sequenciamento do Exoma
6.
BMC Cancer ; 20(1): 143, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32087690

RESUMO

BACKGROUND: MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene expression regulation and have been described as key regulators of carcinogenesis. Aberrant miRNA expression has been frequently reported in sporadic breast cancers, but few studies have focused on profiling hereditary breast cancers. In this study, we aimed to identify specific miRNA signatures in hereditary breast tumors and to compare with sporadic breast cancer and normal breast tissues. METHODS: Global miRNA expression profiling using NanoString technology was performed on 43 hereditary breast tumors (15 BRCA1, 14 BRCA2, and 14 BRCAX), 23 sporadic breast tumors and 8 normal breast tissues. These normal breast tissues derived from BRCA1- and BRCA2- mutation carriers (n = 5) and non-mutation carriers (n = 3). Subsequently, we performed receiver operating characteristic (ROC) curve analyses to evaluate the diagnostic performance of differentially expressed miRNAs. Putative target genes of each miRNAs considered as potential biomarkers were identified using miRDIP platform and used for pathway enrichment analysis. RESULTS: miRNA expression analyses identified several profiles that were specific to hereditary breast cancers. A total of 25 miRNAs were found to be differentially expressed (fold change: > 2.0 and p < 0.05) and considered as potential biomarkers (area under the curve > 0.75) in hereditary breast tumors compared to normal breast tissues, with an expressive upregulation among BRCAX cases. Furthermore, bioinformatic analysis revealed that these miRNAs shared target genes involved in ErbB, FoxO, and PI3K-Akt signaling pathways. CONCLUSIONS: Our results showed that miRNA expression profiling can differentiate hereditary from sporadic breast tumors and normal breast tissues. These miRNAs were remarkably deregulated in BRCAX hereditary breast cancers. Therefore, miRNA signatures can be used as potential novel diagnostic biomarkers for the prediction of BRCA1/2- germline mutations and may be useful for future clinical management.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Biomarcadores Tumorais/genética , Neoplasias da Mama/patologia , Regulação Neoplásica da Expressão Gênica , Mutação em Linhagem Germinativa , MicroRNAs/genética , Adulto , Idoso , Brasil , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Pessoa de Meia-Idade , Curva ROC
7.
Psychooncology ; 29(4): 681-687, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31984583

RESUMO

OBJECTIVE: There is a lack of information describing Brazilian women at risk of hereditary breast and ovarian cancer syndrome (HBOC) who undergo genetic cancer risk assessment (GCRA). This study aims to characterize the psychosocial profile of women at risk for HBOC at their first GCRA to obtain an overview of their families' profiles and the challenges of the oncogenetics setting. METHODS: This was a cross-sectional study in which interviews were conducted with 83 cancer-affected women at their first GRCA appointment after the pedigree draw. Tools to evaluate psychological outcomes were applied. The pedigree genogram and ecomap were constructed and analyzed with content analysis using the "life course perspective" theory. RESULTS: Individuals perceived their breast/ovarian cancer risk to be equal to that of the general population, although they were highly concerned about developing cancer. No evidence of anxiety or depressive symptoms was identified. Participants used the coping strategy of searching for religiosity. The genograms and ecomaps resulted in five major themes: support and social support; attitudes, feelings and emotions; cancer causes; communication; and relationships with relatives. Individuals between 20-29 years of age and those with no family history of cancer tended not to communicate with relatives, which may indicate future problems in the GCRA process regarding genetic testing. CONCLUSIONS: This study demonstrated that knowing the families who undergo the GCRA process can help professionals provide more individualized and thorough attention during GCRA and genetic testing, which results in better follow-up and prevention strategies.


Assuntos
Adaptação Psicológica , Testes Genéticos , Síndrome Hereditária de Câncer de Mama e Ovário/psicologia , Medição de Risco , Apoio Social , Adulto , Brasil , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Adulto Jovem
8.
Genet Mol Biol ; 43(2): e20190097, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32325485

RESUMO

In Brazil, the population in general has little knowledge about genetic risks, as well as regarding the role and importance of the Cancer Genetic Counseling (CGC). The goal of this study was to evaluate cancer-related worry and cancer risk perception during CGC sessions in Brazilian women at-risk for hereditary breast cancer. This study was performed in 264 individuals seeking CGC for hereditary breast cancer. Both cancer-affected and unaffected individuals were included. As results, individuals with and without cancer reported different motivations for seeking CGC and undergoing genetic testing. A correlation was observed between age at the first CGC session and age at which the closest relative was diagnosed with cancer. Multivariate analysis showed that educational level, cancer risk discussion within the family, and number of deaths by cancer among first-degree relatives influenced positively the cancer risk perception. In conclusion, the results of this study indicate that cancer-related worry and cancer risk perception are significant aspects of morbidity in individuals seeking CGC, whether they are cancer-affected or unaffected. CGC has an important role in health education and cancer prevention for its potential of promoting an accurate perception of the risk.

9.
Genet Mol Biol ; 43(2): e20190072, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32453342

RESUMO

Specific pathogenic mutations associated with breast cancer development can vary between ethnical groups. One example is BRCA1 c.5266dupC that was first described as a founder mutation in the Ashkenazi Jewish population, but was later also found in other populations. In Brazil, this mutation corresponds to 20% of pathogenic BRCA1 variants reported. Our objective was to investigate the haplotype component of a group of Brazilian families who inherited c.5266dupC in the BRCA1 gene and to verify the ancestry contribution from European, African, and Amerindian origins. Fourteen probands carrying c.5266dupC and 16 relatives (carriers and non-carriers) were investigated. The same haplotype was observed segregating within all the families analyzed, revealing no recombinants in a region of 0.68 Mb. Ancestry analysis demonstrated that the European component was predominant among probands. The BRCA1 c.5266dupC analysis indicates that there was a founder effect in the Brazilian population.

10.
Hum Mutat ; 40(10): 1781-1796, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31112363

RESUMO

BRCA1 and BRCA2 (BRCA1/2) pathogenic sequence variants (PSVs) confer elevated risks of multiple cancers. However, most BRCA1/2 PSVs reports focus on European ancestry individuals. Knowledge of the PSV distribution in African descent individuals is poorly understood. We undertook a systematic review of the published literature and publicly available databases reporting BRCA1/2 PSVs also accessed the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) database to identify African or African descent individuals. Using these data, we inferred which of the BRCA PSVs were likely to be of African continental origin. Of the 43,817 BRCA1/2 PSV carriers in the CIMBA database, 469 (1%) were of African descent. Additional African descent individuals were identified in public databases (n = 291) and the literature (n = 601). We identified 164 unique BRCA1 and 173 unique BRCA2 PSVs in individuals of African ancestry. Of these, 83 BRCA1 and 91 BRCA2 PSVs are of likely or possible African origin. We observed numerous differences in the distribution of PSV type and function in African origin versus non-African origin PSVs. Research in populations of African ancestry with BRCA1/2 PSVs is needed to provide the information needed for clinical management and decision-making in African descent individuals worldwide.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , População Negra/genética , Predisposição Genética para Doença , Variação Genética , Alelos , Feminino , Estudos de Associação Genética , Humanos , Mutação , Vigilância da População
11.
Int J Cancer ; 145(2): 318-326, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-30303536

RESUMO

Colorectal cancer (CRC) is one of the most common cancers in Latin America and the Caribbean, with the highest rates reported for Uruguay, Brazil and Argentina. We provide a global snapshot of the CRC patterns, how screening is performed, and compared/contrasted to the genetic profile of Lynch syndrome (LS) in the region. From the literature, we find that only nine (20%) of the Latin America and the Caribbean countries have developed guidelines for early detection of CRC, and also with a low adherence. We describe a genetic profile of LS, including a total of 2,685 suspected families, where confirmed LS ranged from 8% in Uruguay and Argentina to 60% in Peru. Among confirmed LS, path_MLH1 variants were most commonly identified in Peru (82%), Mexico (80%), Chile (60%), and path_MSH2/EPCAM variants were most frequently identified in Colombia (80%) and Argentina (47%). Path_MSH6 and path_PMS2 variants were less common, but they showed important presence in Brazil (15%) and Chile (10%), respectively. Important differences exist at identifying LS families in Latin American countries, where the spectrum of path_MLH1 and path_MSH2 variants are those most frequently identified. Our findings have an impact on the evaluation of the patients and their relatives at risk for LS, derived from the gene affected. Although the awareness of hereditary cancer and genetic testing has improved in the last decade, it is remains deficient, with 39%-80% of the families not being identified for LS among those who actually met both the clinical criteria for LS and showed MMR deficiency.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Detecção Precoce de Câncer , Feminino , Fidelidade a Diretrizes , Humanos , América Latina/epidemiologia , Masculino , Guias de Prática Clínica como Assunto , Medição de Risco
12.
Genes Chromosomes Cancer ; 57(7): 350-358, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29520894

RESUMO

Inactivating mutations in the MLH1 gene cause the cancer predisposition Lynch syndrome, but for small coding genetic variants it is mostly unclear if they are inactivating or not. Nine such MLH1 variants have been identified in South American colorectal cancer (CRC) patients (p.Tyr97Asp, p.His112Gln, p.Pro141Ala, p.Arg265Pro, p.Asn338Ser, p.Ile501del, p.Arg575Lys, p.Lys618del, p.Leu676Pro), and evidence of pathogenicity or neutrality was not available for the majority of these variants. We therefore performed biochemical laboratory testing of the variant proteins and compared the results to protein in silico predictions on structure and conservation. Additionally, we collected all available clinical information of the families to come to a conclusion concerning their pathogenic potential and facilitate clinical diagnosis in the affected families. We provide evidence that four of the alterations are causative for Lynch syndrome, four are likely neutral and one shows compromised activity which can currently not be classified with respect to its pathogenic potential. The work demonstrates that biochemical testing, corroborated by congruent evolutionary and structural information, can serve to reliably classify uncertain variants when other data are insufficient.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Predisposição Genética para Doença , Proteína 1 Homóloga a MutL/genética , Mutação , Neoplasias Colorretais Hereditárias sem Polipose/etnologia , Simulação por Computador , Células HEK293 , Humanos , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL/química , Conformação Proteica , América do Sul
13.
Hum Mutat ; 39(5): 593-620, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29446198

RESUMO

The prevalence and spectrum of germline mutations in BRCA1 and BRCA2 have been reported in single populations, with the majority of reports focused on White in Europe and North America. The Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) has assembled data on 18,435 families with BRCA1 mutations and 11,351 families with BRCA2 mutations ascertained from 69 centers in 49 countries on six continents. This study comprehensively describes the characteristics of the 1,650 unique BRCA1 and 1,731 unique BRCA2 deleterious (disease-associated) mutations identified in the CIMBA database. We observed substantial variation in mutation type and frequency by geographical region and race/ethnicity. In addition to known founder mutations, mutations of relatively high frequency were identified in specific racial/ethnic or geographic groups that may reflect founder mutations and which could be used in targeted (panel) first pass genotyping for specific populations. Knowledge of the population-specific mutational spectrum in BRCA1 and BRCA2 could inform efficient strategies for genetic testing and may justify a more broad-based oncogenetic testing in some populations.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Internacionalidade , Mutação/genética , Bases de Dados Genéticas , Família , Geografia , Humanos
16.
BMC Cancer ; 17(1): 623, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28874130

RESUMO

BACKGROUND: Genetic counselling and testing for Lynch syndrome (LS) have recently been introduced in several Latin America countries. We aimed to characterize the clinical, molecular and mismatch repair (MMR) variants spectrum of patients with suspected LS in Latin America. METHODS: Eleven LS hereditary cancer registries and 34 published LS databases were used to identify unrelated families that fulfilled the Amsterdam II (AMSII) criteria and/or the Bethesda guidelines or suggestive of a dominant colorectal (CRC) inheritance syndrome. RESULTS: We performed a thorough investigation of 15 countries and identified 6 countries where germline genetic testing for LS is available and 3 countries where tumor testing is used in the LS diagnosis. The spectrum of pathogenic MMR variants included MLH1 up to 54%, MSH2 up to 43%, MSH6 up to 10%, PMS2 up to 3% and EPCAM up to 0.8%. The Latin America MMR spectrum is broad with a total of 220 different variants which 80% were private and 20% were recurrent. Frequent regions included exons 11 of MLH1 (15%), exon 3 and 7 of MSH2 (17 and 15%, respectively), exon 4 of MSH6 (65%), exons 11 and 13 of PMS2 (31% and 23%, respectively). Sixteen international founder variants in MLH1, MSH2 and MSH6 were identified and 41 (19%) variants have not previously been reported, thus representing novel genetic variants in the MMR genes. The AMSII criteria was the most used clinical criteria to identify pathogenic MMR carriers although microsatellite instability, immunohistochemistry and family history are still the primary methods in several countries where no genetic testing for LS is available yet. CONCLUSION: The Latin America LS pathogenic MMR variants spectrum included new variants, frequently altered genetic regions and potential founder effects, emphasizing the relevance implementing Lynch syndrome genetic testing and counseling in all of Latin America countries.


Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Adulto , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/genética , Biologia Computacional/métodos , Reparo de Erro de Pareamento de DNA , Feminino , Efeito Fundador , Aconselhamento Genético , Predisposição Genética para Doença , Testes Genéticos , Variação Genética , Mutação em Linhagem Germinativa , Humanos , América Latina/epidemiologia , Masculino , Pessoa de Meia-Idade , Vigilância da População , Splicing de RNA , Sistema de Registros , Fatores de Risco
17.
Artigo em Inglês | MEDLINE | ID: mdl-26770289

RESUMO

INTRODUCTION: Breast cancer (BC) is an important public health problem worldwide. In Brazil, breast cancer is the most frequently diagnosed tumor and the leading cause of cancer death in women. Hereditary cancer represents approximately 5 to 10 % of BC cases. Even outside the hereditary cancer context, the presence of polymorphisms acting as genetic modifiers may contribute to a better or worse prognosis. Not much is known about the hereditary BC epidemiology in Brazil or about the influence of polymorphisms on hereditary predisposition. OBJECTIVE: This study examined the role of five different polymorphisms in four groups of women with BC: Group 1: women with a germline mutation in the BRCA1/2 genes; Group 2: women with variants of uncertain significance in BRCA1/2 and Group 3: women with no mutations in BRCA1/2. PATIENTS AND METHODS: The women included in groups 1, 2 and 3 were patients from the Department of Oncogenetics of the Barretos Cancer Hospital who had undergone genetic testing because of a clinical suspicion of hereditary predisposition syndrome. The constitutive DNA was analyzed for the presence of polymorphisms at rs2981582 (FGFR2 gene); rs3803662 (TNRC9); rs889312 (MAP3K1); rs3817198 (LSP1 gene); and rs13281615 (8q24). The analyses were performed using PCR amplification and bi-directional sequencing. RESULTS: No differences were identified in the frequency of the polymorphisms that were analyzed among the three groups. However, some associations were identified, such as the occurrence of bilateral breast cancer and homozygosity for the G allele in rs13281615 as well as the correlation between the SNPs rs2981582 and rs13281615 and the number of cancer cases in the family. Regarding the G allele of rs13281615, we observed that the proportion of individuals who were homozygous for this allele increased with the number of generations affected by cancer, regardless of the group where the patients were included. Concerning the rs2981582 we could observe that individuals from group 1 and homozygous CC had fewer cancer (and also fewer breast cancer) cases. Regarding the hormone receptors, we observed an increased frequency in C homozygotes (rs3803662) among estrogen receptor-negative individuals from groups 1 and 3. For rs2981582 (FGFR2), we observed an increased frequency of the T allele in women who were positive for the estrogen and progesterone receptors regardless of the BRCA1/2 mutational status (p = 0.020 and p = 0.014, respectively). CONCLUSION: The results presented here provide interesting data on the modifying effect of polymorphisms on a family history of cancer; this may be a variable to consider in the analysis of tumor diversity, and of the family history observed in families with hereditary breast cancer (even in those harboring the same type of genetic alteration).

18.
Genet Mol Biol ; 39(2): 210-22, 2016 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-27223485

RESUMO

In Brazil, breast cancer is a public health care problem due to its high incidence and mortality rates. In this study, we investigated the prevalence of hereditary breast cancer syndromes (HBCS) in a population-based cohort in Brazils southernmost capital, Porto Alegre. All participants answered a questionnaire about family history (FH) of breast, ovarian and colorectal cancer and those with a positive FH were invited for genetic cancer risk assessment (GCRA). If pedigree analysis was suggestive of HBCS, genetic testing of the BRCA1, BRCA2, TP53, and CHEK2 genes was offered. Of 902 women submitted to GCRA, 214 had pedigrees suggestive of HBCS. Fifty of them underwent genetic testing: 18 and 40 for BRCA1/BRCA2 and TP53 mutation screening, respectively, and 7 for CHEK2 1100delC testing. A deleterious BRCA2 mutation was identified in one of the HBOC probands and the CHEK2 1100delC mutation occurred in one of the HBCC families. No deleterious germline alterations were identified in BRCA1 or TP53. Although strict inclusion criteria and a comprehensive testing approach were used, the suspected genetic risk in these families remains unexplained. Further studies in a larger cohort are necessary to better understand the genetic component of hereditary breast cancer in Southern Brazil.

19.
Genet Mol Biol ; 39(2): 223-31, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27303907

RESUMO

Approximately 5-10% of breast cancers are caused by germline mutations in high penetrance predisposition genes. Among these, BRCA1 and BRCA2, which are associated with the Hereditary Breast and Ovarian Cancer (HBOC) syndrome, are the most frequently affected genes. Recent studies confirm that gene rearrangements, especially in BRCA1, are responsible for a significant proportion of mutations in certain populations. In this study we determined the prevalence of BRCA rearrangements in 145 unrelated Brazilian individuals at risk for HBOC syndrome who had not been previously tested for BRCA mutations. Using Multiplex Ligation-dependent Probe Amplification (MLPA) and a specific PCR-based protocol to identify a Portuguese founder BRCA2 mutation, we identified two (1,4%) individuals with germline BRCA1 rearrangements (c.547+240_5193+178del and c.4675+467_5075-990del) and three probands with the c.156_157insAlu founder BRCA2 rearrangement. Furthermore, two families with false positive MLPA results were shown to carry a deleterious point mutation at the probe binding site. This study comprises the largest Brazilian series of HBOC families tested for BRCA1 and BRCA2 rearrangements to date and includes patients from three regions of the country. The overall observed rearrangement frequency of 3.44% indicates that rearrangements are relatively uncommon in the admixed population of Brazil.

20.
Genet Mol Biol ; 39(2): 168-77, 2016 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-27192127

RESUMO

The identification of families at-risk for hereditary cancer is extremely important due to the prevention potential in those families. However, the number of Brazilian genetic services providing oncogenetic care is extremely low for the continental dimension of the country and its population. Therefore, at-risk patients do not receive appropriate assistance. This report describes the creation, structure and management of a cancer genetics service in a reference center for cancer prevention and treatment, the Barretos Cancer Hospital (BCH). The Oncogenetics Department (OD) of BCH offers, free of charge, to all patients/relatives with clinical criteria, the possibility to perform i) genetic counseling, ii) preventive examinations and iii) genetic testing with the best quality standards. The OD has a multidisciplinary team and is integrated with all specialties. The genetic counseling process consists (mostly) of two visits. In 2014, 614 individuals (371 families) were seen by the OD. To date, over 800 families were referred by the OD for genetic testing. The support provided by the Oncogenetics team is crucial to identify at-risk individuals and to develop preventive and personalized behaviors for each situation, not only to the upper-middle class population, but also to the people whose only possibility is the public health system.

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