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Rao ND, Shirts BH. Using species richness calculations to model the global profile of unsampled pathogenic variants: Examples from BRCA1 and BRCA2. PLoS One 2023; 18:e0278010. [PMID: 36753473 PMCID: PMC9907816 DOI: 10.1371/journal.pone.0278010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/26/2023] [Indexed: 02/09/2023] Open
Abstract
There have been many surveys of genetic variation in BRCA1 and BRCA2 to identify variant prevalence and catalogue population specific variants, yet none have evaluated the magnitude of unobserved variation. We applied species richness estimation methods from ecology to estimate "variant richness" and determine how many germline pathogenic BRCA1/2 variants have yet to be identified and the frequency of these missing variants in different populations. We also estimated the prevalence of germline pathogenic BRCA1/2 variants and identified those expected to be most common. Data was obtained from a literature search including studies conducted globally that tested the entirety of BRCA1/2 for pathogenic variation. Across countries, 45% to 88% of variants were estimated to be missing, i.e., present in the population but not observed in study data. Estimated variant frequencies in each country showed a higher proportion of rare variants compared to recurrent variants. The median prevalence estimate of BRCA1/2 pathogenic variant carriers was 0.64%. BRCA1 c.68_69del is likely the most recurrent BRCA1/2 variant globally due to its estimated prevalence in India. Modeling variant richness using ecology methods may assist in evaluating clinical targeted assays by providing a picture of what is observed with estimates of what is still unknown.
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Affiliation(s)
- Nandana D. Rao
- Institute for Public Health Genetics, University of Washington, Seattle, Washington, United States of America
| | - Brian H. Shirts
- Institute for Public Health Genetics, University of Washington, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
- Brotman Baty Institute for Precision Medicine, Seattle, Washington, United States of America
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Molina-Zayas M, Garrido-Navas C, García-Puche JL, Barwell J, Pedrinaci S, Atienza MM, García-Linares S, de Haro-Muñoz T, Lorente JA, Serrano MJ, Poyatos-Andújar A. Identification of hereditary breast and ovarian cancer germline variants in Granada (Spain): NGS perspective. Mol Genet Genomics 2022; 297:859-871. [PMID: 35451682 PMCID: PMC9130174 DOI: 10.1007/s00438-022-01891-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 03/23/2022] [Indexed: 12/09/2022]
Abstract
The aim of this study was to assess the prevalence of germline variants in cancer-predisposing genes by either targeted (BRCA1/2) or multigene NGS panel in a high-risk Hereditary Breast and Ovarian Cancer (HBOC) cohort. Samples from 824 Caucasian probands were retrospectively collected and the impact of genetic diagnosis and genetic variants epidemiology in this cohort was evaluated. Performance of risk-reducing prophylactic measures, such as prophylactic mastectomy and/or prophylactic oophorectomy, was assessed through clinical follow-up of patients with a positive genetic result. Pathogenic variants predisposing to HBOC were identified in 11.9% (98/824) individuals at BRCA2 (47/98), BRCA1 (24/98), PALB2 (8/51), ATM (7/51), CHEK2 (6/51) MSH6, (2/51), RAD51C (2/51) and TP53 (2/386). Of them, 11 novel pathogenic variants and 12 VUS were identified, characterized, and submitted to ClinVar. Regarding clinical impact, the risk of developing basal or Her2 breast cancer was increased 15.7 times or 37.5 times for BRCA1 and MSH6 pathogenic variants respectively. On the contrary, the risk of developing basal or luminal A breast cancer was reduced to 81% or 77% for BRCA2 and BRCA1 pathogenic variants, respectively. Finally, 53.2% of individuals testing positive for class IV/V variants underwent prophylactic surgery (mastectomy, oophorectomy or both) being significantly younger at the cancer diagnosis than those undertaking prophylactic measures (p = 0.008). Of them, 8 carried a pathogenic/likely pathogenic variant in other genes different from BRCA1 and BRCA2, and the remaining (46.7%) decided to continue with clinical follow-up. No differences in pathogenicity or risk of developing cancer were found for BRCA1/2 between targeted and multigene sequencing strategies; however, NGS was able to resolve a greater proportion of high-risk patients.
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Affiliation(s)
- María Molina-Zayas
- UGC de Laboratorios, Hospital Universitario Clínico San Cecilio, Avda de la Investigación s/n, 18016, Granada, Spain
| | - Carmen Garrido-Navas
- Genetics Department, Faculty of Sciences, Universidad de Granada, 18071, Granada, Spain. .,CONGEN, Genetic Counselling Services, C/Albahaca 4, 18006, Granada, Spain.
| | - Jose Luis García-Puche
- Oncology Department, Vithas Granada Hospital, Avda de Santa María de La Alhambra, Granada, Spain
| | - Julian Barwell
- Leicestershire Clinical Genetics Service, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Susana Pedrinaci
- UGC de Laboratorios, Hospital Universitario Virgen de Las Nieves, Avda de Las Fuerzas Armadas, 2, 18014, Granada, Spain
| | - Margarita Martínez Atienza
- UGC de Laboratorios, Hospital Universitario Virgen de Las Nieves, Avda de Las Fuerzas Armadas, 2, 18014, Granada, Spain
| | - Susana García-Linares
- UGC de Laboratorios, Hospital Universitario Clínico San Cecilio, Avda de la Investigación s/n, 18016, Granada, Spain
| | - Tomás de Haro-Muñoz
- UGC de Laboratorios, Hospital Universitario Clínico San Cecilio, Avda de la Investigación s/n, 18016, Granada, Spain
| | - Jose Antonio Lorente
- Legal Medicine Department, Medicine School, Universidad de Granada, 18016, Granada, Spain
| | - M Jose Serrano
- Department of Medical Oncology, Bio-Health Research Institute (Instituto de Investigación Biosanitaria Ibs GRANADA), Hospital Universitario Virgen de Las Nieves Granada, University of Granada, Granada, Spain.,Department of Pathological Anatomy, Faculty of Medicine, Campus de Ciencias de la Salud, University of Granada, Granada, Spain
| | - Antonio Poyatos-Andújar
- UGC de Laboratorios, Hospital Universitario Clínico San Cecilio, Avda de la Investigación s/n, 18016, Granada, Spain.
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Vargas E, de Deugd R, Villegas VE, Gil F, Mora L, Viaña LF, Bruges R, Gonzalez A, Galvis JC, Hamann U, Torres D. OUP accepted manuscript. Oncologist 2022; 27:e151-e157. [PMID: 35641219 PMCID: PMC8895486 DOI: 10.1093/oncolo/oyab026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 09/08/2021] [Indexed: 11/13/2022] Open
Abstract
Background Pathogenic germline mutations in the BRCA1 and BRCA2 (BRCA1/2) genes contribute to hereditary breast/ovarian cancer (OC) in White/mestizo Colombian women. As there is virtually no genetic data on breast cancer (BC) in Colombians of African descent, we conducted a comprehensive BRCA1/2 mutational analysis of 60 Afro-Colombian families affected by breast/OC. Materials and Methods Mutation screening of the complete BRCA1/2 genes for small-scale mutations and large genomic alterations was performed in these families using next-generation sequencing and multiplex ligation-dependent probe amplification analysis. Results Four pathogenic germline mutations, including one novel mutation, were identified, comprising 3 in BRCA1 and one in BRCA2. The prevalence of BRCA1/2 mutations, including one BRCA1 founder mutation (c.5123C>A) previously identified in this sample set, was 3.9% (2/51) in female BC-affected families and 33.3% (3/9) in those affected by both breast and OC. Haplotype analysis of 2 BRCA2_c.2701delC carriers (one Afro-Colombian and one previously identified White/mestizo Colombian patient with BC) suggested that the mutation arose in a common ancestor. Conclusion Our data showed that 2/5 (40%) mutations (including the one previously identified in this sample set) are shared by White/mestizo Colombian and Afro-Colombian populations. This suggests that these 2 populations are closely related. Nevertheless, variations in the BRCA1/2 mutational spectrum among Afro-Colombian subgroups from different regions of the country were observed, suggesting that specific genetic risk assessment strategies need to be developed.
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Affiliation(s)
- Elizabeth Vargas
- Institute of Human Genetics, Pontificia Universidad Javeriana, Bogota, Colombia
- Molecular Genetics of Breast Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Victoria E Villegas
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
- Victoria E. Villegas, Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia; Tel: +57(1) 2970200;
| | - Fabian Gil
- Unit of Clinical Epidemiology and Biostatistics, Pontificia Universidad Javeriana, Bogota, Colombia
| | - Lina Mora
- Institute of Human Genetics, Pontificia Universidad Javeriana, Bogota, Colombia
| | | | - Ricardo Bruges
- Centro Javeriano de Oncología, Pontificia Universidad Javeriana, Bogota, Colombia
| | - Alejandro Gonzalez
- Centro Javeriano de Oncología, Pontificia Universidad Javeriana, Bogota, Colombia
| | - Juan Carlos Galvis
- Centro Javeriano de Oncología, Pontificia Universidad Javeriana, Bogota, Colombia
| | - Ute Hamann
- Molecular Genetics of Breast Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Diana Torres
- Institute of Human Genetics, Pontificia Universidad Javeriana, Bogota, Colombia
- Molecular Genetics of Breast Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Corresponding author: Diana Torres, Institute of Human Genetics, Pontificia Universidad Javeriana, Bogota, Colombia; Tel: +57(1) 3208320;
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Pajares B, Porta J, Porta JM, Sousa CFD, Moreno I, Porta D, Durán G, Vega T, Ortiz I, Muriel C, Alba E, Márquez A. Hereditary breast and ovarian cancer in Andalusian families: a genetic population study. BMC Cancer 2018; 18:647. [PMID: 29884136 PMCID: PMC5994127 DOI: 10.1186/s12885-018-4537-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 05/21/2018] [Indexed: 11/24/2022] Open
Abstract
Background The BRCA1/2 mutation profile varies in Spain according to the geographical area studied. The mutational profile of BRCA1/2 in families at risk for hereditary breast and ovarian cancer has not so far been reported in Andalusia (southern Spain). Methods We analysed BRCA1/2 germline mutations in 562 high-risk cases with breast and/or ovarian cancer from Andalusian families from 2010 to 2015. Results Among the 562 cases, 120 (21.4%) carried a germline pathogenic mutation in BRCA1/2; 50 in BRCA1 (41.7%) and 70 in BRCA2 (58.3%). We detected 67 distinct mutations (29 in BRCA1 and 38 in BRCA2), of which 3 in BRCA1 (c.845C > A, c.1222_1223delAC, c.2527delA) and 5 in BRCA2 (c.293 T > G, c.5558_5559delGT, c.6034delT, c.6650_6654delAAGAT, c.6652delG) had not been previously described. The most frequent mutations in BRCA1 were c.5078_5080delCTG (10%) and c.5123C > A (10%), and in BRCA2 they were c.9018C > A (14%) and c.5720_5723delCTCT (8%). We identified 5 variants of unknown significance (VUS), all in BRCA2 (c.5836 T > C, c.6323G > T, c.9501 + 3A > T, c.8022_8030delGATAATGGA, c.10186A > C). We detected 76 polymorphisms (31 in BRCA1, 45 in BRCA2) not associated with breast cancer risk. Conclusions This is the first study reporting the mutational profile of BRCA1/2 in Andalusia. We identified 21.4% of patients harbouring BRCA1/2 mutations, 58.3% of them in BRCA2. We also characterized the clinical data, mutational profile, VUS and haplotype profile. Electronic supplementary material The online version of this article (10.1186/s12885-018-4537-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bella Pajares
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain.
| | - Javier Porta
- Genologica, Paseo de la Farola 16, 29016, Malaga, Spain
| | | | - Cristina Fernández-de Sousa
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain
| | - Ignacio Moreno
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain
| | - Daniel Porta
- Genologica, Paseo de la Farola 16, 29016, Malaga, Spain
| | - Gema Durán
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain
| | - Tamara Vega
- Genologica, Paseo de la Farola 16, 29016, Malaga, Spain
| | | | - Carolina Muriel
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain
| | - Emilio Alba
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain
| | - Antonia Márquez
- Clinical Oncology Unit Hospitales Universitarios Regional y Virgen de la Victoria. Instituto de Investigación Biomédica de Málaga (IBIMA), Campus Teatinos s/n. 29010, Malaga, Spain
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Alvarez C, Tapia T, Perez-Moreno E, Gajardo-Meneses P, Ruiz C, Rios M, Missarelli C, Silva M, Cruz A, Matamala L, Carvajal-Carmona L, Camus M, Carvallo P. BRCA1 and BRCA2 founder mutations account for 78% of germline carriers among hereditary breast cancer families in Chile. Oncotarget 2017; 8:74233-74243. [PMID: 29088781 PMCID: PMC5650336 DOI: 10.18632/oncotarget.18815] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/12/2017] [Indexed: 11/25/2022] Open
Abstract
Identifying founder mutations in BRCA1 and BRCA2 in specific populations constitute a valuable opportunity for genetic screening. Several studies from different populations have reported recurrent and/or founder mutations representing a relevant proportion of BRCA mutation carriers. In Latin America, only few founder mutations have been described. We screened 453 Chilean patients with hereditary breast cancer for mutations in BRCA1 and BRCA2. For recurrent mutations, we genotyped 11 microsatellite markers in BRCA1 and BRCA2 in order to determine a founder effect through haplotype analysis. We found a total of 25 mutations (6 novel) in 71 index patients among which, nine are present exclusively in Chilean patients. Our analysis revealed the presence of nine founder mutations, 4 in BRCA1 and 5 in BRCA2, shared by 2 to 10 unrelated families and spread in different regions of Chile. Our panel contains the highest amount of founder mutations until today and represents the highest percentage (78%) of BRCA1 and BRCA2 mutation carriers. We suggest that the dramatic reduction of Amerindian population due to smallpox and wars with Spanish conquerors, a scarce population increase during 300 years, and the geographic position of Chile constituted a favorable scenario to establish founder genetic markers in our population.
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Affiliation(s)
- Carolina Alvarez
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Teresa Tapia
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Elisa Perez-Moreno
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Patricia Gajardo-Meneses
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Catalina Ruiz
- Centro de Cáncer, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mabel Rios
- Unidad de Patología Mamaria, Hospital Base de Valdivia, Valdivia, Chile
| | | | - Mariela Silva
- Unidad de Patología Mamaria, Hospital Base de Valdivia, Valdivia, Chile
| | - Adolfo Cruz
- Unidad de Patología Mamaria, Hospital Barros Luco Trudeau, Santiago, Chile
| | - Luis Matamala
- Unidad de Patología Mamaria, Hospital Regional de Antofagasta, Antofagasta, Chile
| | - Luis Carvajal-Carmona
- Genome Center and Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, California, USA
| | - Mauricio Camus
- Centro de Cáncer, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pilar Carvallo
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Molecular characterization and clinical interpretation of BRCA1/BRCA2 variants in families from Murcia (south-eastern Spain) with hereditary breast and ovarian cancer: clinical–pathological features in BRCA carriers and non-carriers. Fam Cancer 2017; 16:477-489. [DOI: 10.1007/s10689-017-9985-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Lynce F, Graves KD, Jandorf L, Ricker C, Castro E, Moreno L, Augusto B, Fejerman L, Vadaparampil ST. Genomic Disparities in Breast Cancer Among Latinas. Cancer Control 2017; 23:359-372. [PMID: 27842325 DOI: 10.1177/107327481602300407] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Breast cancer is the most common cancer diagnosed among Latinas in the United States and the leading cause of cancer-related death among this population. Latinas tend to be diagnosed at a later stage and have worse prognostic features than their non-Hispanic white counterparts. Genetic and genomic factors may contribute to observed breast cancer health disparities in Latinas. METHODS We provide a landscape of our current understanding and the existing gaps that need to be filled across the cancer prevention and control continuum. RESULTS We summarize available data on mutations in high and moderate penetrance genes for inherited risk of breast cancer and the associated literature on disparities in awareness of and uptake of genetic counseling and testing in Latina populations. We also discuss common genetic polymorphisms and risk of breast cancer in Latinas. In the treatment setting, we examine tumor genomics and pharmacogenomics in Latina patients with breast cancer. CONCLUSIONS As the US population continues to diversify, extending genetic and genomic research into this underserved and understudied population is critical. By understanding the risk of breast cancer among ethnically diverse populations, we will be better positioned to make treatment advancements for earlier stages of cancer, identify more effective and ideally less toxic treatment regimens, and increase rates of survival.
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Affiliation(s)
- Filipa Lynce
- Health Outcomes and Behavior Program, Moffitt Cancer Center, Tampa, FL, USA.
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Kobayashi Y, Yang S, Nykamp K, Garcia J, Lincoln SE, Topper SE. Pathogenic variant burden in the ExAC database: an empirical approach to evaluating population data for clinical variant interpretation. Genome Med 2017; 9:13. [PMID: 28166811 PMCID: PMC5295186 DOI: 10.1186/s13073-017-0403-7] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/13/2017] [Indexed: 12/25/2022] Open
Abstract
Background The frequency of a variant in the general population is a key criterion used in the clinical interpretation of sequence variants. With certain exceptions, such as founder mutations, the rarity of a variant is a prerequisite for pathogenicity. However, defining the threshold at which a variant should be considered “too common” is challenging and therefore diagnostic laboratories have typically set conservative allele frequency thresholds. Methods Recent publications of large population sequencing data, such as the Exome Aggregation Consortium (ExAC) database, provide an opportunity to characterize with accuracy and precision the frequency distributions of very rare disease-causing alleles. Allele frequencies of pathogenic variants in ClinVar, as well as variants expected to be pathogenic through the nonsense-mediated decay (NMD) pathway, were analyzed to study the burden of pathogenic variants in 79 genes of clinical importance. Results Of 1364 BRCA1 and BRCA2 variants that are well characterized as pathogenic or that are expected to lead to NMD, 1350 variants had an allele frequency of less than 0.0025%. The remaining 14 variants were previously published founder mutations. Importantly, we observed no difference in the distributions of pathogenic variants expected to be lead to NMD compared to those that are not. Therefore, we expanded the analysis to examine the distributions of NMD expected variants in 77 additional genes. These 77 genes were selected to represent a broad set of clinical areas, modes of inheritance, and penetrance. Among these variants, most (97.3%) had an allele frequency of less than 0.01%. Furthermore, pathogenic variants with allele frequencies greater than 0.01% were well characterized in publications and included many founder mutations. Conclusions The observations made in this study suggest that, with certain caveats, a very low allele frequency threshold can be adopted to more accurately interpret sequence variants. Electronic supplementary material The online version of this article (doi:10.1186/s13073-017-0403-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuya Kobayashi
- Invitae Corporation, 1400 16th St., San Francisco, CA, 94103, USA.
| | - Shan Yang
- Invitae Corporation, 1400 16th St., San Francisco, CA, 94103, USA
| | - Keith Nykamp
- Invitae Corporation, 1400 16th St., San Francisco, CA, 94103, USA
| | - John Garcia
- Invitae Corporation, 1400 16th St., San Francisco, CA, 94103, USA
| | | | - Scott E Topper
- Invitae Corporation, 1400 16th St., San Francisco, CA, 94103, USA
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de Juan Jiménez I, García Casado Z, Palanca Suela S, Esteban Cardeñosa E, López Guerrero JA, Segura Huerta Á, Chirivella González I, Sánchez Heras AB, Juan Fita MJ, Tena García I, Guillen Ponce C, Martínez de Dueñas E, Romero Noguera I, Salas Trejo D, Goicoechea Sáez M, Bolufer Gilabert P. Novel and recurrent BRCA1/BRCA2 mutations in early onset and familial breast and ovarian cancer detected in the Program of Genetic Counseling in Cancer of Valencian Community (eastern Spain). Relationship of family phenotypes with mutation prevalence. Fam Cancer 2014; 12:767-77. [PMID: 23479189 DOI: 10.1007/s10689-013-9622-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
During the first 6 years of the Program of Genetic Counselling in Cancer of Valencia (eastern Spain), 310 mutations (155 in BRCA1 and 155 in BRCA2) in 1,763 hereditary breast (BC) and ovarian cancer (OC) families were identified. Of the mutations found 105 were distinct (53 in BRCA1 and 52 in BRCA2), eight new and 37 recurrent. Two of the novel mutations were frame-shift placed in exons 2 and 11 of BRCA1 and the remaining six were placed in BRCA2; four frame-shift (three in exon 11 and one in exon 23), one deletion of the entire exon 19 and one in the intervening sequence of exon 22. The BRCA1 mutations with higher recurrence were c.66_68delAG, c.5123C > A, c.1961delA, c.3770_3771delAG and c.5152+5G > A that covered 45.2% of mutations of this gene. The age of onset of BCs of c.68_69delAG mutation carriers occurs later than for the other recurrent mutations of this gene (45 vs. 37 years; p = 0.008). The BRCA2 mutations with higher recurrence were c.9026_9030delATCAT, c.3264insT and c.8978_8991del14 which represented 43.2% of all mutations in this gene, being the most recurrent mutation by far c.9026_9030delATCAT that represents 21.3% of BRCA2 mutations and 10.6% of all mutations. Probands with family histories of BC and OC, or OC and/or BC in at least two first degree relatives, were the more likely to have BRCA1/BRCA2 mutations (35.2% of the total mutations). And that most BRCA1mutations (73.19% mutations) occurred in probands with early-onset BC or with family history of OC.
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Affiliation(s)
- Inmaculada de Juan Jiménez
- Laboratory of Molecular Biology, Service of Clinical Analysis, Escuela de Enfermería 7ª, Hospital Universitario La Fe, Avd. Campanar 21, 46009, Valencia, Spain
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Large genomic rearrangements of BRCA1 and BRCA2 among patients referred for genetic analysis in Galicia (NW Spain): delimitation and mechanism of three novel BRCA1 rearrangements. PLoS One 2014; 9:e93306. [PMID: 24686251 PMCID: PMC3970959 DOI: 10.1371/journal.pone.0093306] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 02/28/2014] [Indexed: 11/19/2022] Open
Abstract
In the Iberian Peninsula, which includes mainly Spain and Portugal, large genomic rearrangements (LGRs) of BRCA1 and BRCA2 have respectively been found in up to 2.33% and 8.4% of families with hereditary breast and/or ovarian cancer (HBOC) that lack point mutations and small indels. In Galicia (Northwest Spain), the spectrum and frequency of BRCA1/BRCA2 point mutations differs from the rest of the Iberian populations. However, to date there are no Galician frequency reports of BRCA1/BRCA2 LGRs. Here we used multiplex ligation-dependent probe amplification (MLPA) to screen 651 Galician index cases (out of the 830 individuals referred for genetic analysis) without point mutations or small indels. We identified three different BRCA1 LGRs in four families. Two of them have been previously classified as pathogenic LGRs: the complete deletion of BRCA1 (identified in two unrelated families) and the deletion of exons 1 to 13. We also identified the duplication of exons 1 and 2 that is a LGR with unknown pathogenicity. Determination of the breakpoints of the BRCA1 LGRs using CNV/SNP arrays and sequencing identified them as NG_005905.2:g.70536_180359del, NG_005905.2:g.90012_97270dup, and NC_000017.10:g.41230935_41399840delinsAluSx1, respectively; previous observations of BRCA1 exon1-24del, exon1-2dup, and exon1-13del LGRs have not characterized them in such detail. All the BRCA1 LGRs arose from unequal homologous recombination events involving Alu elements. We also detected, by sequencing, one BRCA2 LGR, the Portuguese founder mutation c.156_157insAluYa5. The low frequency of BRCA1 LGRs within BRCA1 mutation carriers in Galicia (2.34%, 95% CI: 0.61-7.22) seems to differ from the Spanish population (9.93%, 95% CI: 6.76-14.27, P-value = 0.013) and from the rest of the Iberian population (9.76%, 95% CI: 6.69-13.94, P-value = 0.014).
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Palanca S, de Juan I, Perez-Simó G, Barragán E, Chirivella I, Martínez E, Fuster O, Bolufer P. The deletion of exons 3-5 of BRCA1 is the first founder rearrangement identified in breast and/or ovarian cancer Spanish families. Fam Cancer 2013; 12:119-23. [PMID: 23117300 DOI: 10.1007/s10689-012-9579-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We recently described a novel g.8097_22733del14637 deletion encompassing exons 3-5 in BRCA1 gene. This rearrangement was detected in 3 of 15 (20 %) breast and/or ovarian cancer families of Eastern Spain. This finding made us suspect that the newly identified deletion could be a founder mutation. To confirm this hypothesis we studied 18 subjects belonging to the three families under study, 11 deletion carriers and 7 non-carriers. We performed a haplotype analysis using two BRCA1 intragenic microsatellite markers and two markers surrounding the BRCA1 locus. The segregation analysis showed one common particular haplotype established by D17S1325, D17S1323, D17S855 and D17S1320 markers detected in the deletion carriers but absent in the non-carriers. Our study sustain that the deletion of exons 3-5 of BRCA1, g.8097_22733del14637, identified in families of southeastern of the Valencian Community is the first founder rearrangement until now reported in Spanish population, confirming the hypothesis that this mutation could have Iberian ancestry.
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Affiliation(s)
- Sarai Palanca
- Laboratorio de Biología Molecular, Escuela de Enfermería 7ª planta, Hospital Universitario La Fe, Avd. Campanar 21, 46009, Valencia, Spain
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12
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Blay P, Santamaría I, Pitiot AS, Luque M, Alvarado MG, Lastra A, Fernández Y, Paredes A, Freije JMP, Balbín M. Mutational analysis of BRCA1 and BRCA2 in hereditary breast and ovarian cancer families from Asturias (Northern Spain). BMC Cancer 2013; 13:243. [PMID: 23683081 PMCID: PMC3662577 DOI: 10.1186/1471-2407-13-243] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/14/2013] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The prevalence of BRCA1 and BRCA2 mutations in Spain is heterogeneous and varies according to geographical origin of studied families. The contribution of these mutations to hereditary breast and ovarian cancer has not been previously investigated in Asturian populations (Northern Spain). METHODS In the present work, 256 unrelated high-risk probands with breast and/or ovarian cancer from families living in Asturias were analyzed for the presence of a BRCA1 or BRCA2 gene mutation from October 2007 to May 2012. The entire coding sequences and each intron/exon boundaries of BRCA1/2 genes were screened both by direct sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA). RESULTS A total of 59 families (23%) were found to carry a pathogenic germ line mutation, 39 in BRCA1 and 20 in BRCA2. Twenty nine additional families (12%) carried an unknown significance variant. We detected 28 distinct pathogenic mutations (16 in BRCA1 and 12 in BRCA2), of which 3 mutations in BRCA1 (c.1674delA, c.1965C>A and c.2900_2901dupCT) and 5 in BRCA2 (c.262_263delCT, c.2095C>T, c.3263dupC, c.4030_4035delinsC, c.8042_8043delCA) had not been previously described.The novel mutations c.2900_2901dupCT in BRCA1 and c.4030_4035delinsC in BRCA2 occurred in 8 and 6 families respectively and clustered in two separated small geographically isolated areas suggesting a founder effect. These 2 mutations, together with the Galician BRCA1 mutation c.211A>G (9 families), and the common BRCA1 mutation c.3331_3334delCAAG (6 families), account for approximately 50% of all affected families. By contrast, very frequent mutations in other Spanish series such as the BRCA1 Ashkenazi founder mutation c.68_69delAG, was found in only one family. CONCLUSIONS In this study we report the BRCA1 and BRCA2 spectrum of mutations and their geographical distribution in Asturias, which largely differ from other areas of Spain. Our findings may help design a first step recurrent mutation panel for screening high-risk breast and/or ovarian cancer families from this specific area.
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Affiliation(s)
- Pilar Blay
- Unidad de Cáncer Familiar, Servicio de Oncología Médica, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Hospital Universitario Central de Asturias (HUCA), Calle de Celestino Villamil, Oviedo 33006, Spain.
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13
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Karami F, Mehdipour P. A comprehensive focus on global spectrum of BRCA1 and BRCA2 mutations in breast cancer. BIOMED RESEARCH INTERNATIONAL 2013; 2013:928562. [PMID: 24312913 PMCID: PMC3838820 DOI: 10.1155/2013/928562] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/31/2013] [Accepted: 08/15/2013] [Indexed: 02/05/2023]
Abstract
Breast cancer (BC) is the most common cancer of women all over the world. BRCA1 and BRCA2 gene mutations comprise the most important genetic susceptibility of BC. Except for few common mutations, the spectrum of BRCA1 and BRCA2 mutations is heterogeneous in diverse populations. 185AGdel and 5382insC are the most important BRCA1 and BRCA2 alterations which have been encountered in most of the populations. After those Ashkenazi founder mutations, 300T>G also demonstrated sparse frequency in African American and European populations. This review affords quick access to the most frequent alterations among various populations which could be helpful in BRCA screening programs.
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Affiliation(s)
- Fatemeh Karami
- Department of Medical Genetics, Tehran University of Medical Sciences, School of Medicine, Tehran, Iran
| | - Parvin Mehdipour
- Department of Medical Genetics, Tehran University of Medical Sciences, School of Medicine, Tehran, Iran
- *Parvin Mehdipour:
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14
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Wang F, Fang Q, Ge Z, Yu N, Xu S, Fan X. Common BRCA1 and BRCA2 mutations in breast cancer families: a meta-analysis from systematic review. Mol Biol Rep 2011; 39:2109-18. [DOI: 10.1007/s11033-011-0958-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 05/26/2011] [Indexed: 10/18/2022]
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15
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Mahfoudh W, Bouaouina N, Ahmed SB, Gabbouj S, Shan J, Mathew R, Uhrhammer N, Bignon YJ, Troudi W, Elgaaied ABA, Hassen E, Chouchane L. Hereditary breast cancer in Middle Eastern and North African (MENA) populations: identification of novel, recurrent and founder BRCA1 mutations in the Tunisian population. Mol Biol Rep 2011; 39:1037-46. [PMID: 21603858 PMCID: PMC3249560 DOI: 10.1007/s11033-011-0829-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 05/03/2011] [Indexed: 01/20/2023]
Abstract
Germ-line mutations in BRCA1 breast cancer susceptibility gene account for a large proportion of hereditary breast cancer families and show considerable ethnic and geographical variations. The contribution of BRCA1 mutations to hereditary breast cancer has not yet been thoroughly investigated in Middle Eastern and North African populations. In this study, 16 Tunisian high-risk breast cancer families were screened for germline mutations in the entire BRCA1 coding region and exon-intron boundaries using direct sequencing. Six families were found to carry BRCA1 mutations with a prevalence of 37.5%. Four different deleterious mutations were detected. Three truncating mutations were previously described: c.798_799delTT (916 delTT), c.3331_3334delCAAG (3450 delCAAG), c.5266dupC (5382 insC) and one splice site mutation which seems to be specific to the Tunisian population: c.212 + 2insG (IVS5 + 2insG). We also identified 15 variants of unknown clinical significance. The c.798_799delTT mutation occurred at an 18% frequency and was shared by three apparently unrelated families. Analyzing five microsatellite markers in and flanking the BRCA1 locus showed a common haplotype associated with this mutation. This suggests that the c.798_799delTT mutation is a Tunisian founder mutation. Our findings indicate that the Tunisian population has a spectrum of prevalent BRCA1 mutations, some of which appear as recurrent and founding mutations.
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Affiliation(s)
- Wijden Mahfoudh
- Department of Molecular Immuno-Oncology, Faculty of Medicine, 5019 Monastir, Tunisia
| | - Noureddine Bouaouina
- Department of Molecular Immuno-Oncology, Faculty of Medicine, 5019 Monastir, Tunisia
- Department of Radiation Oncology, CHU Farhat Hached, 4000 Sousse, Tunisia
| | - Slim Ben Ahmed
- Department of Medical Oncology, CHU Farhat Hached, 4000 Sousse, Tunisia
| | - Sallouha Gabbouj
- Department of Molecular Immuno-Oncology, Faculty of Medicine, 5019 Monastir, Tunisia
| | - Jingxuan Shan
- Department of Genetic Medicine, Weill Cornell Medical College in Qatar, P.O. Box 24144, Doha, Qatar
| | - Rebecca Mathew
- Department of Genetic Medicine, Weill Cornell Medical College in Qatar, P.O. Box 24144, Doha, Qatar
| | - Nancy Uhrhammer
- Laboratoire Diagnostic Génétique et Moléculaire, Centre Jean Perrin, Clermont-Ferrand, France
| | - Yves-Jean Bignon
- Laboratoire Diagnostic Génétique et Moléculaire, Centre Jean Perrin, Clermont-Ferrand, France
| | - Wafa Troudi
- Laboratory of Genetics, Immunology and Human Pathology at the Faculty of Sciences of Tunis, University El Manar I, 1060 Tunis, Tunisia
| | - Amel Ben Ammar Elgaaied
- Laboratory of Genetics, Immunology and Human Pathology at the Faculty of Sciences of Tunis, University El Manar I, 1060 Tunis, Tunisia
| | - Elham Hassen
- Department of Molecular Immuno-Oncology, Faculty of Medicine, 5019 Monastir, Tunisia
| | - Lotfi Chouchane
- Department of Genetic Medicine, Weill Cornell Medical College in Qatar, P.O. Box 24144, Doha, Qatar
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Genomic rearrangements of the BRCA1 gene in Chilean breast cancer families: an MLPA analysis. Breast Cancer Res Treat 2011; 128:845-53. [PMID: 21327469 DOI: 10.1007/s10549-011-1382-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 01/31/2011] [Indexed: 10/18/2022]
Abstract
Point mutations and small deletions and insertions in BRCA1 and BRCA2 genes are responsible of about 20% of hereditary breast cancer cases in Chilean population. Studies in other populations have identified the amplification and/or deletion of one or more exons in these genes as the cause of the disease. In this study the authors determined the presence of these types of alterations in BRCA1 and BRCA2, in 74 Chilean families with breast/ovarian cancer that were negative for germline mutations in these genes. Since these alterations are not detectable using the conventional PCR-based methods, the authors use MLPA (multiplex ligation-dependent probe amplification) to detect amplifications and/or deletions in BRCA1 and BRCA2 genes. The authors identified two different alterations in BRCA1: exon 10 duplication in one family and amplification of exons 3, 5, and 6 in two families. Duplication of exon 10 contains intronic adjacent sequences suggesting gene duplication. The second rearrangement consist of a 4 times amplification of a fragment containing exons 3, 5, and 6 joined together with no introns, suggesting the presence of a processed pseudogene. No alterations were detected in BRCA2. In order to validate the MLPA results and characterize the genomic alterations the authors performed qPCR, long range PCR, and sequencing.
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17
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Konecny M, Milly M, Zavodna K, Weismanova E, Gregorova J, Mlkva I, Ilencikova D, Kausitz J, Bartosova Z. Comprehensive genetic characterization of hereditary breast/ovarian cancer families from Slovakia. Breast Cancer Res Treat 2011; 126:119-30. [PMID: 21203900 DOI: 10.1007/s10549-010-1325-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 12/20/2010] [Indexed: 12/15/2022]
Abstract
Germline mutations in the BRCA1/2 genes account for the majority of hereditary breast ovarian cancer (HBOC). Identification of causal mutations may have significant impact on clinical management of such families. Despite high mutation detection rate, many HBOC cases remain without identified cause. These cases warrant use of several analysis methods, such as those for large genomic rearrangements and DNA copy number changes, or analysis other genes, shown to be associated with increased HBOC risk. We assessed 585 Slovak HBOC for the presence of mutations in BRCA genes. Sequencing revealed mutations in 100 families, representing 17.1% (88 and 12% of mutations were located in BRCA1 and BRCA2, respectively). Four of the mutations, c.80+4del4, c.1938_1947del10 and c.1166delG in BRCA1 and c.6589delA in BRCA2 gene have been described only in Slovak population. Using MLPA analysis, we detected two large genomic rearrangements in three families, a deletion of exons 21 and 22, and a rare deletion of a whole BRCA1 gene. Twenty-seven different variants of uncertain clinical effect (four novel) and 14 distinct SNP BRCA1 haplotypes were detected. Their potential effect was considered using the prediction software packages Align-GVGD, Pmut and Polyphen. We observed that the best clinical criterion for the initiation of BRCA1 analysis is the presence of breast cancer at 40 years of age in the association with the presence of ovarian cancer diagnosed around the age of 50. Conversely, the best clinical criterion for starting with BRCA2 analysis is the presence of breast cancer diagnosed in older age (above 50), or the presence of breast cancer in conjunction with carcinomas at different sites e.g., prostate, colorectum, ovary and uterus. Finally we have seen that the analyses of other HBOC risk gene TP53 and specific mutation in CHEK2*c.1100delC in Slovak HBOC families were not efficient since no mutations were found in these genes.
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Affiliation(s)
- Michal Konecny
- Department of Clinical Genetics, St. Elizabeth Cancer Institute, Bratislava, Slovakia.
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18
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Heterogeneous prevalence of recurrent BRCA1 and BRCA2 mutations in Spain according to the geographical area: implications for genetic testing. Fam Cancer 2010; 9:187-91. [PMID: 19941167 DOI: 10.1007/s10689-009-9301-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BRCA1 and BRCA2 genes have a high allelic heterogeneity. The knowledge of the most prevalent mutations and their geographical distribution can be useful in designing efficient mutational screening. In the present work we reviewed the frequency of BRCA1 and BRCA2 recurrent mutations in seven geographic areas of Spain to evaluate the effects of their heterogeneous prevalence in genetic testing. We observed that prevalence of recurrent mutations vary according to the geographical origin of the studied families, and accounted for a variable number of positive families depending on the series. Therefore, more upcoming data of larger Spanish population cohorts collected from different areas in the country will allow to design a wider comprehensive panel of recurrent mutations that may be applicable worldwide to families with Hispanic origin.
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19
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Kang P, Mariapun S, Phuah SY, Lim LS, Liu J, Yoon SY, Thong MK, Mohd Taib NA, Yip CH, Teo SH. Large BRCA1 and BRCA2 genomic rearrangements in Malaysian high risk breast-ovarian cancer families. Breast Cancer Res Treat 2010; 124:579-84. [PMID: 20617377 DOI: 10.1007/s10549-010-1018-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 06/23/2010] [Indexed: 12/11/2022]
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20
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Esteban Cardeñosa E, Bolufer Gilabert P, de Juan Jimenez I, Palanca Suela S, Barragán González E, Chirivella González I, Segura Huerta A, Guillén Ponce C, Martínez de Dueñas E. Broad BRCA1 and BRCA2 mutational spectrum and high incidence of recurrent and novel mutations in the eastern Spain population. Breast Cancer Res Treat 2009; 121:257-60. [PMID: 20033483 DOI: 10.1007/s10549-009-0680-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 12/05/2009] [Indexed: 11/26/2022]
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21
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del Valle J, Feliubadaló L, Nadal M, Teulé A, Miró R, Cuesta R, Tornero E, Menéndez M, Darder E, Brunet J, Capellà G, Blanco I, Lázaro C. Identification and comprehensive characterization of large genomic rearrangements in the BRCA1 and BRCA2 genes. Breast Cancer Res Treat 2009; 122:733-43. [DOI: 10.1007/s10549-009-0613-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 10/20/2009] [Indexed: 11/25/2022]
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22
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Infante M, Durán M, Acedo A, Pérez-Cabornero L, Sanz DJ, García-González M, Beristain E, Esteban-Cardeñosa E, de la Hoya M, Teulé A, Vega A, Tejada MI, Lastra E, Miner C, Velasco EA. BRCA1 5272-1G>A and BRCA2 5374delTATG are founder mutations of high relevance for genetic counselling in breast/ovarian cancer families of Spanish origin. Clin Genet 2009; 77:60-9. [PMID: 19912264 DOI: 10.1111/j.1399-0004.2009.01272.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The distribution of BRCA1 and BRCA2 germ line mutations in breast/ovarian cancer families varies among different populations, which typically present a wide spectrum of unique mutations. Splicing mutation 5272-1G>A of BRCA1 and frameshift mutation 5374delTATG of BRCA2 are highly prevalent mutations in Castilla-León (Spain), accounting for 18.4% and 13.6% of BRCA1 and BRCA2 positive families, respectively. To test the presence of founder effects, 9 Spanish 5272-1G>A and 13 5374delTATG families were genotyped with polymorphic markers linked to BRCA1 or BRCA2. All the 5272-1G>A families shared a common haplotype in eight markers (1.1 Mb region) and the mutation age was estimated in 15 generations (approximately 380 years). A conserved haplotype associated to 5374delTATG was observed in four markers (0.82 Mb). The mutation occurred approximately 48 generations ago (approximately 1200 years). Each mutation likely arose from a common ancestor that could be traced to a small area of Castilla-León and expanded to other Spanish regions. They can have a significant impact on the clinical management of asymptomatic carriers as well as on the genetic screening strategy to be followed in populations with Spanish ancestries.
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Affiliation(s)
- M Infante
- Grupo de Genética del Cáncer, Instituto de Biología y Genética Molecular (UVa-CSIC), Valladolid
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Analysis of BRCA1/BRCA2 genes' contribution to breast cancer susceptibility in high risk Jewish Ashkenazi women. Fam Cancer 2008; 8:127-33. [PMID: 18798010 DOI: 10.1007/s10689-008-9216-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 09/03/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND Three mutations in BRCA1 (185delAG 5382InsC) and BRCA2 (6174delT) can be detected in a substantial proportion of Jewish Ashkenazi breast/ovarian cancer families. Family-specific pathogenic mutations in both genes can be detected in up to 5% of high risk Ashkenazim. The contribution of major gene rearrangements and seemingly pathogenic missense mutations to inherited breast cancer predisposition has never been systematically evaluated in Ashkenazim. MATERIAL AND METHODS High risk, Jewish Ashkenazi women, non-carriers of the predominant Jewish BRCA1/BRCA2 mutations, were genotyped for major gene rearrangements in BRCA1/BRCA2 using Multiplex ligation-dependent probe amplification (MLPA), and for the occurrence rate of 6 seemingly pathogenic missense mutations in BRCA1 (R866C, R331S, R841W, Y179C, C61G, M1008I) using a modified restriction enzyme assay. RESULTS Overall, 105 Jewish Ashkenazi high risk women, participated in the study: 104 with breast cancer [age at diagnosis (mean +/- SD) 51.05 +/- 11.13 years], one was affected with ovarian cancer (61 years). Two were found to carry the M1008I mutation in BRCA1 and none harbored any of the other missense mutations. MLPA reveled four changes (amplifications of exons 5, 17, 19 and 21) in BRCA1 in five patients, and six patients exhibited 4 MLPA-detectable abnormalities in BRCA2 (amplifications in exons 1b, 2, and deletions in exons 11a and 25). None of these abnormalities could be confirmed using quantitative PCR (qPCR) analysis. CONCLUSIONS Major gene rearrangements involving BRCA1 BRCA2 contribute little to the burden of inherited predisposition of breast cancer in Ashkenazi Jews.
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