Hereditary breast cancer next-generation sequencing panel evaluation in the south region of Brazil: A novel BRCA2 candidate pathogenic variant is reported.

BACKGROUND: In this article, we delineate a loosely selected cohort comprising patients with a history of early-onset breast cancer and/or a familial occurrence of cancer. The aim of this study was to gain insights into the presence of breast cancer-related gene variants in a population from a micro-region in southern Brazil, specifically the Metropolitan Region of Curitiba. This area exhibits a highly genetically mixed population, mirroring the general characteristics of the Brazilian people. METHODS: Comprehensive next-generation sequencing (NGS) multigene panel testing was conducted on 12 patients from the region, utilizing three different library preparation methods. RESULTS: Two pathogenic variants and one candidate pathogenic variant were identified: BRCA2 c.8878C>T, p.Gln2960Ter; CHEK2 c.1100del, p.Thr367Metfs15, and BRCA2 c.3482dup, p.Asp1161Glufs3. CONCLUSION: BRCA2 c.3482dup, a novel candidate pathogenic variant, previously unpublished, is reported. The prevalence of pathogenic variants in this small cohort is similar to that described in the literature. All different library preparation methods were equally proficient in enabling the detection of these variants.

Germline rare variants in HER2-positive breast cancer predisposition: a systematic review and meta-analysis.

Introduction: Approximately 10% of breast cancer (BC) cases result from hereditary causes. Genetic testing has been widely implemented in BC care to determine hereditary cancer syndromes and personalized medicine. Thus, identification of individuals carrying germline pathogenic variants could be useful to provide appropriate prophylactic or screening measures for each BC subtype, however, there are few formal recommendations for genetic testing in this sense so far. In this study, we assessed rare germline variants in a specific group of genes in order to determine the association with human epidermal growth factor 2 enriched (HER2+) BC phenotype through a systematic review and meta-analysis comparing subtypes overexpressing HER2 with other clinically recognized subtypes of BC. This review was registered with PROSPERO (ID: CRD42023447571). Methods: We conducted an online literature search in PubMed (MEDLINE), Scopus, and EMBASE databases. We included original studies that investigated germline variants in HER2+ BC patients and selected the studies that reported only rare and/or pathogenic germline variants. We assessed the risk of bias and quality of the studies using the Joanna Briggs Institute Critical Appraisal checklists and the Modified Newcastle-Ottawa Scale for Genetic Studies, respectively. Considering hormone receptor and HER2 expression status, we compared gene-based risks initially in HR-HER2-, HR+HER2-, HR+HER2+, and HR-HER2+ groups, conducting separate meta-analyses using the random effects model for each comparison, and within them for each gene. Results: Of the total 36 studies describing germline variants, 11 studies provided information on the prevalence of variants in the different clinically relevant BC subtypes and allowed comparisons. Germline variants within eight genes showed significant differences when meta-analyzed between the BC groups: BRCA1, BRCA2, TP53, ATM, CHEK2, PALB2, RAD51C, and BARD1. Notably, TP53, ATM, and CHEK2 germline variants were identified as predisposing factors for HER2+ subtypes, whereas BRCA1, BRCA2, PALB2, RAD51C, and BARD1 germline variants were associated with a predisposition to low HER2 expression. Main concerns about bias and quality assessment were the lack of confounding factors control; and comparability or outcome assessment, respectively. Discussion: Our findings underscore the connection between germline variants and differential expression of the HER2 protein and BC subtypes. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023447571.

Adherencia de pacientes de alto riesgo heredo-familiar de cáncer de mama a "Programa de Vigilancia Activa": experiencia de la Clínica de Alto Riesgo de Cáncer de Mama del Centro Mamario del Hospital Universitario Austral / Adherence of patients with high hereditary-familial risk of breast cancer to the "Active Surveillance Program": experience of the High Risk Breast Cancer Clinic of the Breast Center of the Austral University Hospital

Introducción: Las mujeres con predisposición genética-familiar presentan un riesgo más elevado de desarrollar cáncer de mama. La vigilancia es una de las estrategias más efectivas para ofrecer a este subgrupo de mujeres, sin embargo la adherencia a la misma puede ser dificultosa. Objetivo: Analizar la adherencia de las pacientes con Alto Riesgo Heredo-Familiar (ARHF) al programa específico de "Seguimiento de pacientes de Alto Riesgo" del Hospital Universitario Austral. Material y método: Se revisaron de forma retrospectiva datos de 104 mujeres sanas con ARHF que ingresaron al programa de vigilancia: "Seguimiento de pacientes de Alto Riesgo" del Hospital Universitario Austral en el período comprendido entre junio de 2016 a febrero de 2022. Resultados: La adherencia al programa fue total en 38 pacientes (36,54%) y parcial en 42 (40,38%). Se observó falta de adherencia en 24 pacientes (23,07%). La causa más prevalente fue la incomodidad al realizar la resonancia (54,16%). Analizando la adherencia según el año de ingreso al programa se observa una caída significativa a partir del 3er año de seguimiento y solo 48,98% completaron la sexta ronda. Conclusiones: La falta de adherencia observada fue significativa. Los datos demostrados apuntan a una necesidad de continuar desarrollando estrategias que faciliten el seguimiento(AU)

Introduction: Women with a genetic-familial predisposition have a higher risk of developing breast cancer. Surveillance is one of the most effective strategies to offer this subgroup of women, however adherence to it can be difficult. Objetive: To analize the adherence of patients with High Risk of Familial-Hereditary (HRFH) breast cancer to a specific program: "Follow-up in High Risk patients" of the Austral University Hospital. Material and method: Data from 104 women with HRFH who were admitted to the surveillance program: "Follow-up in High Risk patients" of the Austral University Hospital in the period from june 2016 to february 2022 were retrospectively reviewed. Results: Adherence to the program was complete in 38 patients (36,54%) and partial in 42 (40,38%). 24 (23,07%) patients had lack of adherence. The most prevalent cause was discomfort when performing the resonance (54,16%). When we analyze adherence according to the year of admission to the program, a significant drop is observed from de 3rd year of follow-up and only 48,98% completed round six. Conclusions: The observed lack of adherence was significant. The demonstrated data points to a need to continue developing strategies that facilitate monitoring(AU)

Double heterozygous pathogenic variants prevalence in a cohort of patients with hereditary breast cancer.

Hereditary breast cancer (BC) corresponds to 5% of all BC and a larger parcel of early-onset disease. The incorporation of next-generation sequencing (NGS) techniques reduced the cost of molecular testing and allowed the inclusion of additional cancer predisposition genes in panels that are more comprehensive. This enabled the identification of germline pathogenic variants in carriers and the introduction of risk-reducing strategies. It also resulted in the identification of the co-occurrence of more than one germline pathogenic variant in BC genes in some families. This is a rare event, and there are few reports on its impact on cancer risk. We conducted a single-institution retrospective study in which 1,156 women with early onset BC and/or a family history of cancer were tested by a germline multi-gene hereditary cancer panel. Germline pathogenic variants in high- and/or moderate-penetrance BC genes were identified in 19.5% of the individuals (n = 226). The most frequent variants were found in TP53 (69 of 226; 55 of them represented by p.R337H), BRCA1 (47 of 226), and BRCA2 (41 of 226). Double heterozygous (DH) variants were detected in 14 cases, representing 1.2% of all individuals assessed. There were no significant differences in age of BC onset and risk for bilateral BC in DH carriers when compared with those with one germline variant.

Training promotores to lead virtual hereditary breast cancer education sessions for Spanish-speaking individuals of Latin American heritage in California.

BACKGROUND: Awareness about hereditary breast cancer and the preventative steps to minimize disease risk is lower in Hispanic/Latina individuals than non-Hispanic White women in the United States. For this reason, we developed a promotor-based hereditary breast cancer education and risk identification program for self-identified Hispanic/Latina women, which included training promotores in basic genetics and hereditary breast cancer. This study explored promotores' experiences receiving training and participating in virtual practice sessions as well as changes in knowledge about hereditary breast cancer. METHODS: A total of ten promotores underwent a two-week basic training led by the promotores organization and an eight-hour in person hereditary breast cancer training workshop. Demographic information along with pre- and post-training surveys were completed by ten promotores who participated in the training workshop. Surveys were given to determine changes in knowledge of hereditary breast cancer and genetics. Of the ten promotores, two were selected to lead community education sessions and participated in 6 semi-structured interviews. All interviews and practice sessions were conducted using a virtual platform. RESULTS: The data revealed that after the 8-h workshop and practice sessions, promotores felt confident about their ability to conduct virtual education sessions with the community. Interviews identified key facilitators to success such as a supportive environment, practice presentations, and personal motivation. Learning the online platform was considered the biggest challenge by the promotores, as opposed to learning complex genetics topics. CONCLUSIONS: These results provide further evidence supporting promotores' willingness and ability to provide health education on relatively complex topics. It also offers insight into the challenges of presenting information to vulnerable populations using an online platform and the additional support that is required to ensure a positive outcome.

Breast Cancer Phenotype Associated With Li-Fraumeni Syndrome: A Brazilian Cohort Enriched by TP53 p.R337H Carriers.

Breast cancer (BC) is the most prevalent malignancy in women with Li-Fraumeni syndrome (LFS). The literature on BC in LFS is limited due to its rarity worldwide. A TP53 founder pathogenic variant (c.1010G>A; p.R337H) is responsible for the higher prevalence of this syndrome among women of Brazilian ancestry. Purpose: The aim of the study was to describe the BC phenotype expressed by Brazilian female LFS carriers and compare the data between p.R337H and other TP53 germline pathogenic/likely pathogenic variants (non-p.R337H carriers). Methods: We searched for cases of TP53 germline pathogenic/likely pathogenic variant carriers affected by BC included between 2015 and 2020 in the BLiSS (Brazilian Li-Fraumeni Study) registry at the Sírio-Libanês Hospital. Results: Among 163 adult female carriers from the registry, 91 (56%) had received a BC diagnosis, including 72 p.R337H carriers. BC was the first cancer diagnosed in 90% of cases. Early onset BC (age ≤45 years) was diagnosed in 78.2% of cases (11.5% <31 years; 66.7% 31-45 years; 21.8% >45 years). The median age of BC diagnosis for p.R337H carriers was 39.5 years (range 20-69 years) compared to 34 years (range 21-63 years) for non-p.R337H carriers (p = 0.009). In total, 104 breast tumors were observed in 87 women. Bilateral BC was observed in 29.3% of cases. Histology was available for 96 tumors, comprising 69 invasive breast carcinomas, which were mostly invasive ductal carcinomas (95.6%), 25 ductal in situ carcinomas and 2 soft-tissue sarcomas. Overall, 90.5% of invasive breast carcinomas were hormone receptor (HR)-positive, 39.5% were human epidermal growth factor receptor 2 (HER2)-positive, and 32.8% showed HR and HER2 co-expression. In addition, 55.4% of patients opted for contralateral prophylactic mastectomy after a first BC diagnosis. There were no significant differences in the risk of developing contralateral BC or in the immunohistochemical profile between p.R337H and non-p.R337H groups. Conclusions: The expressed phenotype of p.R337H is similar to that of other TP53 pathogenic/likely pathogenic variants, except for an average older age at the onset of disease; however, this is still younger than the general population.

Genetic Landscape of Male Breast Cancer.

Male breast cancer (MBC) is now considered molecularly different from female breast cancer (FBC). Evidence from studies indicates that common genetic and epigenetic features of FBC are not shared with those diagnosed in men. Genetic predisposition is likely to play a significant role in the tumorigenesis of this rare disease. Inherited germline variants in BRCA1 and BRCA2 account for around 2% and 10% of MBC cases, respectively, and the lifetime risk of breast cancer for men harboring BRCA1 and BRCA2 mutations is 1.2% and 6.8%. As for FBC, pathogenic mutations in other breast cancer genes have also been recently associated with an increased risk of MBC, such as PALB2 and CHEK2 mutations. However, while multigene germline panels have been extensively performed for BC female patients, the rarity of MBC has resulted in limited data to allow the understanding of the magnitude of risk and the contribution of recently identified moderate penetrance genes of FBC for MBC predisposition. This review gathers available data about the germline genetic landscape of men affected by breast cancer, estimated risk associated with these genetic variants, and current guidelines for clinical management.

Identification of Variants (rs11571707, rs144848, and rs11571769) in the BRCA2 Gene Associated with Hereditary Breast Cancer in Indigenous Populations of the Brazilian Amazon.

Estimates show that 5-10% of breast cancer cases are hereditary, caused by genetic variants in autosomal dominant genes; of these, 16% are due to germline mutations in the BRCA1 and BRCA2 genes. The comprehension of the mutation profile of these genes in the Brazilian population, particularly in Amazonian Amerindian groups, is scarce. We investigated fifteen polymorphisms in the BRCA1 and BRCA2 genes in Amazonian Amerindians and compared the results with the findings of global populations publicly available in the 1000 Genomes Project database. Our study shows that three variants (rs11571769, rs144848, and rs11571707) of the BRCA2 gene, commonly associated with hereditary breast cancer, had a significantly higher allele frequency in the Amazonian Amerindian individuals in comparison with the African, American, European, and Asian groups analyzed. These data outline the singular genetic profiles of the indigenous population from the Brazilian Amazon region. The knowledge about BRCA1 and BRCA2 variants is critical to establish public policies for hereditary breast cancer screening in Amerindian groups and populations admixed with them, such as the Brazilian population.

Differential Profile of BRCA1 vs. BRCA2 Mutated Families: A Characterization of the Main Differences and Similarities in Patients.

The identification of families at-risk for hereditary breast cancer (BC) is important because affected individuals present a much higher cancer risk than the general population. The aim of this study was to identify the most important factors associated with the presence of a pathogenic BRCA1/BRCA2 mutation. Family history (FH), histopathological and immunohistochemical characteristics were compared among BC women with pathogenic BRCA1/BRCA2 variants; VUSs in BRCA1/BRCA2; BRCA1/BRCA2 WT and sporadic BC. The most significative differences observed concerned the molecular subtype of the tumors, age at cancer diagnosis and FH of cancer. The presence of bilateral breast cancer (BBC), number of BC cases and the presence of ovarian cancer (OC) increased (respectively) 5.797, 5.033 and 4.412 times the risk of being a BRCA1/BRCA2 mutation carrier. Besides, women with BRCA1 or BRCA2 mutations presented different tumor and FH profiles. The main characteristics associated with a BRCA1 mutation were triple negativity (OR: 17.31), BBC history (OR: 4.96) and occurrence of OC (OR: 4.32). There were no major discerning components associated with BRCA2 mutations. Thus, we conclude that tumor pathology and FH of cancer might be considered together at the time of genetic testing mainly in countries where access to genetic testing is still restricted.

Hereditary Breast Cancer Risk Analysis in Uninsured Mexican-Origin Women Living in the U.S.-Mexico Border Region.

PURPOSE: This article describes the risk of hereditary breast cancer (HBC) in low-income Hispanic women living on the U.S.-Mexico border using the Pedigree Assessment Tool (PAT). METHOD: The PAT was administered as part of the El Paso and Hudspeth County Breast Cancer Education, Screening and NavigaTion program (BEST). Baseline data (n = 1,966) from this program was used to analyze risk factors for HBC. Analysis was conducted to determine significant covariates associated with the presence of any PAT risk factors. RESULTS: The PAT identified 17% (95% CI [15%, 19%]) of the women in the study as having some risk of HBC. Having had a mammogram within 3 years was significantly associated with having any PAT risk factors (odds ratio [OR] = 1.79, p = .006). Women who immigrated to the United States during childbearing age (OR = 0.610, p = .009) or during peri/menopause (OR = 0.637, p = .024) were significantly less likely to have any PAT risk factors. DISCUSSION: The PAT instrument detected a substantial pool of women who may be at risk for HBC. A significant proportion of these women were not up to date mammogram. CONCLUSIONS: The PAT is an effective tool to identify women at risk for HBC and encourage regular screening.

Tests genéticos brca1/2 y otros genes de predisposición al cáncer de mama: análisis retrospectivo de 106 pacientes / Genetic studies for brca1/2 and other genes related to predisposition in breast cancer: retrospective analysis of 106 patients

Introducción Si bien el cáncer de mama hereditario representa entre el 5-10% del total de los cánceres de mama, es importante la detección de pacientes portadoras de mutaciones patogénicas en genes brca1/2 y otros genes relacionados con el cáncer de mama ya que esta información permitirá tomar conductas adecuadas de prevención y/o tratamiento tanto en la paciente portadora como en sus familiares. Objetivo Llevar a cabo un análisis retrospectivo de 106 pacientes que realizaron estudios genéticos para genes brca1/2 y otros genes relacionados con el cáncer de mama. Resultados Del total de 106 pacientes, encontramos: 17 (16,03%) con mutación patogénica; 38 (35,85%) con vus (Variantes de significado incierto) informadas en el reporte original; y 51 (48,11%) con estudios negativos. De los 38 informes con vus, 7 (6,6%) fueron reclasificadas como vus verdaderas a junio de 2018. De las 17 mutaciones patogénicas encontradas, 16 correspondieron a mutaciones en los genes brca1/2 (15,09%) y 1 a mutación en el chek2 (3,77%). Conclusiones Los estudios genéticos de predisposición en cáncer de mama son, en la actualidad, una herramienta fundamental para la atención multidisciplinaria de la paciente de alto riesgo en un consultorio de patología mamaria. Es un deber del mastólogo pensar en la indicación de un estudio genético de predisposición al cáncer de mama y derivar al genetista para identificar correctamente al paciente que se va a beneficiar de esta información

Introduction Although hereditary breast cáncer represents 5-10% of all breast cancers, it is important to detect patients carrying pathogenic mutations in brca1/2 genes and other genes related to breast cáncer as this information will allow take appropriate prevention and / or treatment behaviors in both the patient carrier and their family members. Objective To make a retrospective analysis of 106 patients who carried out genetic studies for brca1/2 genes and other genes related to breast cancer. Results From 106 patients we found 17 (16.03%) with pathogenic mutations, 38 (35.85%) with vus (variant of unknown significance) in the original report, and 51 (48.11%) negatives. From 35 vus, we reclasified as true vus only 7 (6,6%) in June 2018. From 17 pathogenic mutations in 106 patients studied (16.03%), we found 16 in the brca1/2 genes (15.09%) and 1 mutation in chek2 (3.77%). Conclusions Genetic predisposition tests in breast cáncer are a fundamental tool for multidisciplinary care of the high-risk patient in a breast center query. The mastologist has to think in the first place about the indication of a genetic testing ofbreast cancer predisposition, and refer to the geneticist for a prompt consultation for patients benefit

Low Prevalence of the Four Common Colombian Founder Mutations in BRCA1 and BRCA2 in Early-Onset and Familial Afro-Colombian Patients with Breast Cancer.

BACKGROUND: Inherited mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 (BRCA1/2) confer high risks of breast and ovarian cancer. In Colombian Hispanic families, four common BRCA1/2 founder mutations have previously been identified. Because nothing is known about the contribution of BRCA1/2 germline mutations to early-onset and hereditary breast and/or ovarian cancer in Afro-Colombians, we conducted the first study on 60 patients with early-onset and familial breast cancer in this population. MATERIALS AND METHODS: Screening for the four Colombian founder mutations BRCA1/c.3331_3334delCAAG, BRCA1/c.5123C>A, BRCA2/c.2806_2809delAAAC, and BRCA2/c.1763_1766delATAA was performed using mismatch polymerase chain reaction (PCR) analysis, PCR-based restriction fragment length polymorphism analysis, and qualitative real-time PCR. Mutations were confirmed by direct DNA sequencing. RESULTS: The BRCA1 founder mutation c.5123C>A was identified in one family with breast and ovarian cancer (1/60, 1.7%). Three women were diagnosed with breast cancer, including one with bilateral disease, at the ages of 30, 30/33, and 52 years, and one woman was diagnosed with ovarian cancer at the age of 60 years. CONCLUSION: Our data showed a low prevalence of the BRCA1/2 founder mutations in Colombians of African descent, implying that these mutations should not be recommended for genetic screening programs in the Afro-Colombian population. IMPLICATIONS FOR PRACTICE: Risk reduction intervention programs are needed for women who are found to carry a BRCA1/2 mutation, as is the implementation of prevention programs for patients with inherited breast cancer, to reduce the burden of inherited diseases. With the aim of reducing racial disparities in breast cancer prevention, this study focused on genetic testing and treatment for patients in a minority population with BRCA1/2 mutations.

Non-Coding Variants in BRCA1 and BRCA2 Genes: Potential Impact on Breast and Ovarian Cancer Predisposition.

BRCA1 and BRCA2 are major breast cancer susceptibility genes whose pathogenic variants are associated with a significant increase in the risk of breast and ovarian cancers. Current genetic screening is generally limited to BRCA1/2 exons and intron/exon boundaries. Most identified pathogenic variants cause the partial or complete loss of function of the protein. However, it is becoming increasingly clear that variants in these regions only account for a small proportion of cancer risk. The role of variants in non-coding regions beyond splice donor and acceptor sites, including those that have no qualitative effect on the protein, has not been thoroughly investigated. The key transcriptional regulatory elements of BRCA1 and BRCA2 are housed in gene promoters, untranslated regions, introns, and long-range elements. Within these sequences, germline and somatic variants have been described, but the clinical significance of the majority is currently unknown and it remains a significant clinical challenge. This review summarizes the available data on the impact of variants on non-coding regions of BRCA1/2 genes and their role on breast and ovarian cancer predisposition.

Gynecological-endocrinological aspects in women carriers of BRCA1/2 gene mutations.

Women carriers of mutations in the genes BRCA1 and BRCA2 coding for tumor suppressor proteins are at high risk of developing breast and ovarian cancers. Hereditary breast and ovarian cancers due to BRCA pathogenic mutations occur at earlier ages: mean age 43 years at diagnosis of breast cancer for BRCA1 mutations; onset of ovarian cancer up to 10-21% by age 50 years. Preventive strategies are then defined in the reproductive years. The National Comprehensive Cancer Network (NCCN) guidelines define that BRCA1/2 genetic testing should begin with the affected cancer individual (BRCA1/2 full sequencing); then, family members should be tested for the specific gene mutation found. A woman known to be a carrier needs a strict specific surveillance strategy to achieve early diagnosis. The NCCN proposes breast imageneological surveillance beginning at age 25 years; ovarian surveillance beginning at age 30-35 years. Concomitantly, risk-reducing strategies should be analyzed: surgical or pharmacological. When prophylactic bilateral salpingo-oophorectomy is performed before menopause, estrogen replacement therapy could be required. For BRCA, we review the risks of cancer in mutations carriers, criteria for genetic testing, surveillance and risk-reduction strategies, and the safety of prescribing hormone therapy when needed.

Comprehensive Analysis of Germline Variants in Mexican Patients with Hereditary Breast and Ovarian Cancer Susceptibility.

Hereditary breast and ovarian cancer syndrome (HBOC) represents 5⁻10% of all patients with breast cancer and is associated with high-risk pathogenic alleles in BRCA1/2 genes, but only for 25% of cases. We aimed to find new pathogenic alleles in a panel of 143 cancer-predisposing genes in 300 Mexican cancer patients with suspicion of HBOC and 27 high-risk patients with a severe family history of cancer, using massive parallel sequencing. We found pathogenic variants in 23 genes, including BRCA1/2. In the group of cancer patients 15% (46/300) had a pathogenic variant; 11% (33/300) harbored variants with unknown clinical significance (VUS) and 74% (221/300) were negative. The high-risk group had 22% (6/27) of patients with pathogenic variants, 4% (1/27) had VUS and 74% (20/27) were negative. The most recurrent mutations were the Mexican founder deletion of exons 9-12 and the variant p.G228fs in BRCA1, each found in 5 of 17 patients with alterations in this gene. Rare VUS with potential impact at the protein level were found in 21 genes. Our results show for the first time in the Mexican population a higher contribution of pathogenic alleles in other susceptibility cancer genes (54%) than in BRCA1/2 (46%), highlighting the high locus heterogeneity of HBOC and the necessity of expanding genetic tests for this disease to include broader gene panels.

A portrait of germline mutation in Brazilian at-risk for hereditary breast cancer.

PURPOSE: Knowledge about the germline mutational spectrum among Brazilian with hereditary breast and ovarian cancer (HBOC) is limited. Only five studies have performed comprehensive BRCA sequencing, corresponding to 1041 individuals among a Brazilian population of over 207 million people. Herein we aimed to determine the clinical and molecular characteristics of Brazilian patients who underwent oncogenetic counseling and genetic testing of a panel of high-risk and moderate-risk genes from 2009 to 2017. METHODS: Massively parallel sequencing was applied in 157 individuals (132 breast cancer-affected and 25 breast cancer-unaffected individuals) selected according NCCN criteria for hereditary breast cancer. Analysis of mutation segregation in family members was performed by capillary bidirectional sequencing, clinical response after treament and survival analysis was estimated by Kaplan-Meier. RESULTS: Nineteen germline variants were identified,15 pathogenic and 4 VUS (Variants of Uncertain Significance) in 27 individuals (27/157; 17% P < 0.0001) distributed among 7 genes. Sixty-eight percent of patients (13/19) harbor mutation in BRCA genes and 32% (6/19) in moderate risk genes. This is the first study reporting ATR deleterious germline mutation in association with hereditary breast cancer. Cancer-affected patients with moderate- risk mutation present a more aggressive phenotype, with bilateral cancer (25% vs. 13%, P = 0.0305), high-grade tumors (79.2% vs. 46.3%, P = 0.0001) and triple-negative (50% vs. 22.4%, P < 0.0001). However, no difference in the 5 years overall survival was observed between BRCA and moderate risk groups. CONCLUSIONS: This work highlights the benefits of large-scale sequencing for oncogenetic counseling and extends our understanding about the genetics of hereditary breast cancer in the multi-ethnic Brazilian population.

Complex Landscape of Germline Variants in Brazilian Patients With Hereditary and Early Onset Breast Cancer.

Pathogenic variants in known breast cancer (BC) predisposing genes explain only about 30% of Hereditary Breast Cancer (HBC) cases, whereas the underlying genetic factors for most families remain unknown. Here, we used whole-exome sequencing (WES) to identify genetic variants associated to HBC in 17 patients of Brazil with familial BC and negative for causal variants in major BC risk genes (BRCA1/2, TP53, and CHEK2 c.1100delC). First, we searched for rare variants in 27 known HBC genes and identified two patients harboring truncating pathogenic variants in ATM and BARD1. For the remaining 15 negative patients, we found a substantial vast number of rare genetic variants. Thus, for selecting the most promising variants we used functional-based variant prioritization, followed by NGS validation, analysis in a control group, cosegregation analysis in one family and comparison with previous WES studies, shrinking our list to 23 novel BC candidate genes, which were evaluated in an independent cohort of 42 high-risk BC patients. Rare and possibly damaging variants were identified in 12 candidate genes in this cohort, including variants in DNA repair genes (ERCC1 and SXL4) and other cancer-related genes (NOTCH2, ERBB2, MST1R, and RAF1). Overall, this is the first WES study applied for identifying novel genes associated to HBC in Brazilian patients, in which we provide a set of putative BC predisposing genes. We also underpin the value of using WES for assessing the complex landscape of HBC susceptibility, especially in less characterized populations.

Genetic alterations detected by comparative genomic hybridization in BRCAX breast and ovarian cancers of Brazilian population.

BACKGROUND: About 5-10% of breast/ovarian cancers are hereditary. However, for a large proportion of cases (around 50%), the genetic cause remains unknown. These cases are grouped in a separated BRCAX category. The aim of this study was to identify genomic alterations in BRCA1/BRCA2 wild-type tumor samples from women with family history strongly suggestive of hereditary breast/ovarian cancer. RESULTS: A cohort of 31 Brazilian women was included in the study. Using the GISTIC algorithm, we identified 20 regions with genomic gains and 31 with losses. The most frequent altered regions were 1q21.2, 6p22.1 and 8p23.3 in breast tumors and Xq26 and Xp22.32-22.31 among the ovarian cancer cases. An interesting association identified was the loss of 22q13.31-13.32 and the presence of ovarian cancer cases. Among the genes present in the frequently altered regions, we found FGFR1, NSMCE2, CTTN, CRLF2, ERBB2, STARD3, MIR3201 and several genes of RAET and ULBP family. CONCLUSIONS: In conclusion, our results suggest that alterations on chromosomes 1, 6, 8 and X are common on BRCAX tumors and that the loss on 22q can be associated with the presence of ovarian cancer. METHODS: DNA copy number alterations were analyzed by 60K array comparative genomic hybridization in breast and ovarian FFPE tumors.

Genetic and epigenetic characterization of the BRCA1 gene in Brazilian women at-risk for hereditary breast cancer.

This study aimed to characterize women at-risk for hereditary BC regarding their clinical and molecular characteristics (mutation and methylation in the BRCA1 gene) and correlate the gene expression levels with histopathological, clinical and family history information. BRCA1 real time qPCR was performed to evaluate methylation status and gene expression. The study included 88 women grouped according to the BRCA1 mutational status: 23 BRCA1 mutated, 22 with a Variant of Unknown Significance (VUS) in BRCA1 and 43 BRCA1 WT. Most BRCA1 mutated tumors were triple negative (69.6%) and had histologic grade III (61.0%). Patients with VUS/WT BRCA1 were predominantly of luminal B subtype with histological grades I and II. Regarding the methylation profile, BRCA1 hypermethylation was observed in only two patients (both WT) and none had association with pathogenic BRCA1 mutation. In one patient methylation was present in both, tumor and normal tissues. Hypermethylated tumors had ductal histology, negativity for ER and occurred in < 50 years patients. Gene expression profile showed in all groups lower BRCA1 mRNA levels in tumor tissue compared to the adjacent breast tissue, thereby indicating the loss/decrease of gene function. No association was found between the levels of BRCA1 gene expression and family history of cancer. In summary, our findings suggested that methylation at the BRCA1 gene is not the "second" event in the development of BC in patients with germline mutations in BRCA1 and, although rare, BRCA1 epimutations can constitute an explanation for a fraction of HBOC families.

Prevalence of BRCA1/BRCA2 mutations in a Brazilian population sample at-risk for hereditary breast cancer and characterization of its genetic ancestry.

BACKGROUND: There are very few data about the mutational profile of families at-risk for hereditary breast and ovarian cancer (HBOC) from Latin America (LA) and especially from Brazil, the largest and most populated country in LA. RESULTS: Of the 349 probands analyzed, 21.5% were BRCA1/BRCA2 mutated, 65.3% at BRCA1 and 34.7% at BRCA2 gene. The mutation c.5266dupC (former 5382insC) was the most frequent alteration, representing 36.7% of the BRCA1 mutations and 24.0% of all mutations identified. Together with the BRCA1 c.3331_3334delCAAG mutation, these mutations constitutes about 35% of the identified mutations and more than 50% of the BRCA1 pathogenic mutations. Interestingly, six new mutations were identified. Additionally, 39 out of the 44 pathogenic mutations identified were not previously reported in the Brazilian population. Besides, 36 different variants of unknown significance (VUS) were identified. Regarding ancestry, average ancestry proportions were 70.6% European, 14.5% African, 8.0% Native American and 6.8% East Asian. MATERIALS AND METHODS: This study characterized 349 Brazilian families at-risk for HBOC regarding their germline BRCA1/BRCA2 status and genetic ancestry. CONCLUSIONS: This is the largest report of BRCA1/BRCA2 assessment in an at-risk HBOC Brazilian population. We identified 21.5% of patients harboring BRCA1/BRCA2 mutations and characterized the genetic ancestry of a sample group at-risk for hereditary breast cancer showing once again how admixed is the Brazilian population. No association was found between genetic ancestry and mutational status. The knowledge of the mutational profile in a population can contribute to the definition of more cost-effective strategies for the identification of HBOC families.