BRCA1 Founder Research Articles

Genetic Predisposition to Breast Cancer Due to Mutations Other Than BRCA1 and BRCA2 Founder Alleles Among Ashkenazi Jewish Women

ImportanceAmong Ashkenazi Jewish women, 3 mutations in BRCA1 and BRCA2 severely increase the risk of breast and ovarian cancer. However, among Ashkenazi Jewish patients with breast cancer who do not carry one of these founder mutations, the likelihood of carrying another pathogenic mutation in BRCA1 or BRCA2 or another breast cancer gene is not known. This information would be valuable to the patient and family for cancer prevention and treatment.ObjectiveTo determine the frequency of cancer-predisposing mutations other than the BRCA1 and BRCA2 founder alleles among patients of Ashkenazi Jewish ancestry with breast cancer.Design, Setting, and ParticipantsIn this cohort study, genomic DNA of women from 12 major cancer centers with a first diagnosis of invasive breast cancer who identified themselves and all 4 grandparents as Ashkenazi Jewish and participated in the New York Breast Cancer Study (NYBCS) from 1996 to 2000 was sequenced for known and candidate breast cancer genes. Data analysis was performed from July 10, 2014, to March 10, 2017.Main Outcomes and MeasuresGenomic DNA from all 1007 NYBCS probands was sequenced for 23 known and candidate breast cancer genes using BROCA, a targeted multiplexed gene panel.ResultsOf the 1007 probands in the study, 903 probands had no founder mutations in BRCA1 or BRCA2; of these probands, 7 (0.8%) carried another pathogenic mutation in BRCA1 or BRCA2, and 31 (3.4%) carried a pathogenic mutation in another breast cancer gene (29 in CHEK2, and 1 each in BRIP1 and NBN). Of all inherited predispositions to breast cancer in the NYBCS, 73.8% (104 of 142) were due to a BRCA1 or BRCA2 founder allele, 4.9% (7 of 142) to another BRCA1 or BRCA2 mutation, and 21.8% (31 of 142) to a mutation in another gene. Overall, 14.1% (142 of 1007) of Ashkenazi Jewish patients with breast cancer in the NYBCS carried a germline mutation responsible for their disease: 11.0% (111 of 1007) in BRCA1 or BRCA2, and 3.1% (31 of 1007) in CHEK2 or another breast cancer gene. Of the 111 patients with BRCA1 or BRCA2 mutations, 57 (51.4%) had a mother or sister with breast or ovarian cancer and 54 patients (48.6%) did not.Conclusions and RelevanceComprehensive sequencing would provide complete relevant genetic information for Ashkenazi Jewish patients with breast cancer.

Erratum to: High Resolution Melting Analysis is Very Useful to IdentifyBRCA1c.4964_4982del19 (rs80359876) Founder Calabrian Pathogenic Variant on Peripheral Blood and Buccal Swab DNA.

Introduction Detection of pathogenic variants in hereditary breast and ovarian cancer-related breast cancer type 1 and type 2 susceptibility proteins (BRCA1/2) genes is an effective strategy in cancer prevention and treatment. Some ethnic and geographical regions show different BRCA1/2 mutation spectrum and prevalence. In Italy, elucidation of founder effect in BRCA1/2 genes can have an impact on the management of hereditary cancer families on a healthcare system level, making genetic testing more affordable and cost effective in certain regions. Methods The purpose of this paper is to develop a rapid, low-cost, high-throughput single-tube technology for genotyping the Italian founder mutation c.4964_4982del19 (rs80359876) in the BRCA1 gene, starting from peripheral blood and/or buccal swab DNA. Results Heterozygote samples for c.4964_4982del19 variant were easily and unambiguously identified by the altered shape of the melting curves and were clearly distinguished by a change in melting temperature that differed by approximately 5 °C. The same results were obtained both with DNA from peripheral blood than buccal swab. Conclusions We provide evidence about application of high-resolution melting analysis (HRMA) in unambiguously genotyping of the founder BRCA1 c.4964_4982del19 variant (rs80359876) in individuals from the Calabria region of Italy. In fact, HRMA was confirmed to be particularly suitable for the identification of BRCA1 c.4964_4982del19 variant, making this approach useful in clinical molecular diagnostics.

Abstract P5-16-02: Pathological complete response is associated with excellent outcomes in BRCA mutation associated triple negative breast cancer

Abstract Introduction: Pathological complete response (pCR) in unselected triple negative breast cancer (TNBC) is associated with excellent long-term survival. However, controversy remains as to whether pCR in BRCA mutation associated (BRCA[+]) TNBC is predictive of improved long-term outcome. A recent study suggests that pCR was not a surrogate for outcomes in BRCA1 associated TNBC. All of the patients in this study harbored an Ashkenazi Jewish founder BRCA1 mutation and the majority of mutation carriers underwent lumpectomy. Impact of pCR as it relates to BRCA status in a larger, heterogeneous TNBC cohort treated in a contemporary time frame is not known. Aim: Evaluate and compare the prognostic impact of pCR as it relates to the BRCA mutation status in patients enrolled in a prospective multisite TNBC registry. Methods: 453 patients with stage I-III TNBC were enrolled within a multisite registry between 2011- 2015, out of which 173 received neoadjuvant chemotherapy (NAC) and also underwent germline BRCA testing. pCR in the breast and axilla was evaluated and patients were followed for reoccurrence and survival. Recurrence free survival (RFS) was estimated according to the Kaplan-Meier method and compared among groups with log-rank statistic. Results: For the 173 eligible patients the median age was 49 years; African-American:14%; median tumor size:3 cm; 42%:Lymph node positive; and 18% (32/173) demonstrated BRCA mutation (BRCA1=28, BRCA2=4). All patients received anthracycline and/or taxane based NAC. pCR rates for BRCA[+] and wild type (BRCA[-]) patients was 72% and 46% respectively (p=0.01). 97% of BRCA[+] and 42% of BRCA[-] patients underwent bilateral mastectomy (p=0.001). The three year RFS was 92% and 81% in BRCA[+] and BRCA[-] patients, respectively (p=0.18). Attainment of pCR was associated with excellent 3 year RFS of 95% and 97% in BRCA[+] and BRCA[-] patients, respectively (p=0.85). Among BRCA[-] patients lack of pCR was associated with significantly worse 3 year RFS (70% RFS in patients without pCR, compared to 97% in patients with pCR; p=0.001). Among BRCA[+] patients lack of pCR was associated with numerically lower but not statistically significant worse 3 year RFS (83% RFS in patients without pCR, compared to 95% in patients with pCR; p=0.41). On multivariable Cox regression analysis, only stage III disease was associated with higher risk of relapse (p<0.001). Conclusions: Our observation of higher pCR in BRCA-carriers compared to wild-type TNBC patients is consistent with previously published literature. In this contemporary cohort of TNBC patients for whom the majority of BRCA[+] patients underwent bilateral mastectomy, attainment of pCR carried an excellent prognosis in both BRCA[+] and BRCA[-] patients. On the other hand, BRCA[+] patients who do not attain pCR may have better outcomes compared to BRCA[-] patients without pCR. Further research to explore the underlying biological mechanisms involved in tumor response and relapse in BRCA[+] and BRCA[-] TNBC patients is needed. Furthermore, given these observations, germline BRCA mutation status should be used as a stratification variable in studies evaluating pCR and long term outcomes with investigational therapies in TNBC. Citation Format: Prochaska LH, Godwin AK, Kimler BF, Lehn C, Klemp JR, O'Dea A, Elia M, Hoffmann MS, Crane G, McKittrick R, Sheehan M, Graff SL, Madhusudhana S, Khan QJ, Jensen RA, Sharma P. Pathological complete response is associated with excellent outcomes in BRCA mutation associated triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-16-02.

High Resolution Melting Analysis is Very Useful to Identify BRCA1 c.4964_4982del19 (rs80359876) Founder Calabrian Pathogenic Variant on Peripheral Blood and Buccal Swab DNA.

Detection of pathogenic variants in hereditary breast and ovarian cancer-related breast cancertype1 and type 2 susceptibility proteins (BRCA1/2) genes is an effective strategy in cancer prevention and treatment. Some ethnic and geographical regions show different BRCA1/2 mutation spectrum and prevalence. In Italy, elucidation of founder effect in BRCA1/2 genes can have an impact on the management of hereditary cancer families on a healthcare system level, making genetic testing more affordable and cost effective in certain regions. The purpose of this paper is to develop a rapid, low-cost, high-throughput single-tube technology for genotyping the Italian founder mutation c.4964_4982del19 (rs80359876) in the BRCA1 gene, starting from peripheral blood and/or buccal swab DNA. Heterozygote samples for c.4964_4982del19 variant were easily and unambiguously identified by the altered shape of the melting curves and were clearly distinguished by a change in melting temperature that differed by approximately 5°C. The same results were obtained both with DNA from peripheral blood than buccal swab. We provide evidence about application of high-resolution melting analysis (HRMA) in unambiguously genotyping of the founder BRCA1 c.4964_4982del19 variant (rs80359876) in individuals from the Calabria region of Italy. In fact, HRMA was confirmed to be particularly suitable for the identification of BRCA1 c.4964_4982del19 variant, making this approach useful in clinical molecular diagnostics.

Abstract B59: Analysis of High-Grade Serous Ovarian Cancer in a Cohort of Women diagnosed Epithelial Ovarian Cancer at University of Miami/Jackson Memorial Hospital

Abstract Background: High-grade serous ovarian (HGSC) cancer is the most common and aggressive histotype of epithelial ovarian cancer in women, accounting for 75% of epithelial ovarian carcinomas. Most women present at advanced stages III/IV at diagnosis and 5-year survival for patients with advanced stage disease is approximately 20-30%. However, for patients with stage I disease, five-year survival rates exceed 90%. Ovarian cancer risk factors include nulliparity, early age of menarche, late age of menopause, hormone replacement, obesity and strong family history of hereditary breast and ovarian cancer (HBOC). It is estimated that about 1 in 500 Americans have a mutation in BRCA1 or BRCA2. In women with a germline mutation there is a lifetime risk of: 40%-60% (BRCA1) and 11%-27% (BRCA2), of developing ovarian cancer. Recent studies of different immigrant populations in the United States and in their respective countries of origin have identified pockets of women who bare a similarly high genetic burden as the Ashkenazi Jewish population. Women of Bahamian and Trinidadian heritage are estimated to have 27.1% of breast cancer cases due to BRCA founder mutations. The ovarian cancer burden in these isolated high-risk populations is still unclear, but likely to be as high as those women of Ashkenazi descent. South Florida has the highest Caribbean immigrant community in the US and nearly 4 out of 10 immigrants in Florida were born in the Caribbean. We sought to elucidate the patient demographic, pathologic, and outcome within a university health system between the safety net hospital - Jackson Memorial Hospital (JMH) and the Sylvester comprehensive cancer center (SCCC). Methods: We conducted a retrospective chart review study of women diagnosed with epithelial ovarian cancer with the high-grade serous carcinoma histotype at Sylvester Comprehensive Cancer Center/Jackson Memorial Hospital between 2011 and 2015. We collected data including date of diagnosis, age, body mass index (BMI), country of birth, ethnicity, germ-line and somatic genetic tests results, medical insurance, treatment and vital status. SPSS software was used to analyze using independent samples t-tests when parametric and using Wilcoxon-Mann-Whitney tests when non-parametric; and Chi-squared tests for categorical and binary data. Results: 374 patients were diagnosed and treated for high-grade serous ovarian cancer (HGSC). 50.8% were non-Hispanic, 47.9% Hispanic and 1.3% Unknown. 12.% of the patient population was Black with a significantly higher BMI (39.1 vs 27.9, p=0.004). Mean age was 58 (Hispanic white 57.7yrs (17-93), non-Hispanic white 58.5yrs (17-93) and Black (53.7yrs (18-78), p=0.019)) compared to US national average of 63. At least 32.3% of patients were born in the US while, 60% of patients were born in Latin America and the Caribbean. 72.3% of patients born outside the US were diagnosed and treated at JMH (p<0.001). In a subset analysis of 102 patients, 31% had genetic or somatic testing, of these, 2 patients were Black, not of Afro-Caribbean descent. Patients at JMH presented with 8% Stage I vs 74.7% Stage III/IV, compared to 16.3% Stage I vs 73% Stage IV at SCCC. They had more advanced stage V - 42.7% vs 16.3% at SCCC. JMH patients were more likely to be on Medicaid or uninsured (68% vs 14.2%, p<0.001). Median survival was 47.0 months (44.1-49.9) at SCCC compared to 45.0 months (37.6-52.3) for women at JMH (p=0.392). Conclusion: The majority of women sought care at the SCCC when diagnosed with HGSC had a higher likelihood of early stage diagnosis, were insured and born in the USA, there was no difference in outcome between patients treated at JMH versus SCCC. Genetic testing within the Black population was low compared to Hispanic and non-Hispanic white patients. This data indicate that the quality of care received in this university health system is similar at both sites. Further studies are indicated to explore uptake of genetic testing, disparities between safety net systems and comprehensive cancer centers, particularly with the shift toward targeted disease prevention and personalized therapy. Note: This abstract was not presented at the conference. Citation Format: Sophia HL George, Marilyn Huang, Leah Dodds, Raleigh Butler, Sean Oldak, Moraima Batista, Judith Hurley, Joseph Pearson, Erin Kobetz, Brian Slomovitz. Analysis of High-Grade Serous Ovarian Cancer in a Cohort of Women diagnosed Epithelial Ovarian Cancer at University of Miami/Jackson Memorial Hospital. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr B59.

Early onset breast cancer in Ashkenazi women carriers of founder BRCA1/2 mutations: beyond 10years of follow-up.

This study uncovers disease characteristics by long-term follow-up in Ashkenazi early onset breast cancer (EOBC) patients, carriers of founder BRCA1/2 mutations compared to non-carriers of such mutations. An archives-retrospective design was conducted to study the pathological and clinical characteristics of 149 Ashkenazi Jewish EOBC patients (<42years) who were referred consecutively to the oncogenetic clinic by the oncology centre at Rambam HealthCare Campus, as from 1995, with a mean follow-up of 13.61years. Of 149 patients, 33 (22.1%) and 15 (10.1%) carried the founder BRCA1 (185delAG; 5382insC) and BRCA2 (6174delT) mutations, respectively; and 101 (67.8%) were non-carriers of these mutations. Contralateral breast-cancer was predominant among BRCA1/2 carriers compared to non-carriers (14, 58.3%; 6, 60%; 7, 8.1%; respectively, p<.001). Ovarian cancer was diagnosed in two BRCA1 carriers and one non-carrier. Oestrogen and/or progesterone receptor negative tumours were majorly detected in BRCA1 carriers (n=16, 57.1%) compared to BRCA2 carriers (n=4, 30.8%) and non-carriers (n=23, 25.3%) (p=.007). BRCA1 carriers and non-carriers developed contralateral breast cancer at an earlier age than BRCA2 carriers. BRCA2 carriers portrayed similar tumour characteristics to non-carriers. EOBC BRCA1/2 carriers are at risk to develop bilateral disease; however, they are similarly susceptible for local recurrence, distant metastases and mortality.

Abstract 2550: Identification of novel BRCA founder mutations in middle eastern breast cancer patients using capture and sanger sequencing analysis

Abstract Ethnic differences of breast cancer genomics have prompted us to investigate the spectra of BRCA1 and BRCA2 mutations in different populations. The prevalence and effect of BRCA 1 and BRCA 2 mutations in Saudi population is not fully explored. We conducted this study to characterize the prevalence of BRCA mutations in Middle Eastern breast cancer patients from Saudi Arabia. A total of 486 clinically high risk breast cancer patients were recruited from the King Faisal Specialist Hospital &amp; Research Centre from 1990 and 2011. Comprehensive BRCA1 and BRCA2 mutation screening was performed using capture sequencing and/or Sanger Sequencing of all coding exons of BRCA1 and BRCA2 in 190 cases. Thereafter, the validation was done using a panel of detected mutations in an additional 296 high risk breast cancer cases. Among the total 486 cases analyzed, 9 deleterious BRCA mutations were identified in 28 (5.8%) cases, comprising 25 cases in BRCA 1 and three cases in BRCA 2. The six BRCA 1 recurrent mutations (c. 1140dupG, c.4065_4068delTCAA, c.4136_4137delCT, c.4524G&amp;gt;A, c.5251C&amp;gt;T and c.5530delC) accounted for 96% (24/25) of all BRCA 1 mutant cases in this cohort. The one recurrent BRCA 2 mutation (c.7007G&amp;gt;A) accounted for 66.6% (2/3) of all BRCA2 mutant cases. Haplotype analysis was performed to confirm two BRCA1 recurrent mutations are novel putative founder mutation. In this study our findings suggest that BRCA mutations account for substantial proportion of high risk breast cancer cases in Middle Eastern population. Knowing the spectrum and frequency of founder mutation in this population will help in developing cost-effective rapid screening assay which can facilitate genetic testing and counseling for breast cancer risk assessment. Citation Format: Rong Bu, Abdul K. Siraj, Khadija A. S. Al-Obaisi, Shaham Beg, Mohsen Al Hazmi, Yan Kong, Dahish Ajarim, Fouad Al-Dayel, Khawla S. Al-Kuraya. Identification of novel BRCA founder mutations in middle eastern breast cancer patients using capture and sanger sequencing analysis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2550.

Abstract 2928: Accumulation of tumor cells with retained heterozygous BRCA1 status during platinum therapy: A probable mechanism of attenuation of tumor response in BRCA1-driven ovarian cancer

Abstract Approximately 15-25% ovarian cancer (OC) patients carry germ-line mutation in BRCA1 or BRCA2 genes. BRCA deficiency underlies the pronounced sensitivity of tumor cells to platinum-containing cytotoxic therapy. However, significant variations in platinum sensitivity are observed even within BRCA1/2 mutation-driven carcinomas. It has been shown, that chemoresistant tumor tissues could be characterized by the restoration of the BRCA1 function via additional somatic genetic events. This investigation aimed to analyze the role of BRCA status within the group of patients receiving preoperative platinum-based therapy. We addressed the question, whether intratumoral LOH status of BRCA1 gene may be altered during neoadjuvant therapy. At first, we tested for Slavic founder BRCA mutations 225 ovarian cancer patients, who started their treatment with a few cycles of platinum-based therapy, and underwent debulking surgery afterwards. 34 BRCA1 and 1 BRCA2 mutation carriers were identified. Complete clinical response was documented in 12/35 (34%) mutation carriers and 8/190 (4%) non-carriers (P = 0.000002). Histopathologic response was observed in 16/35 (46%) women with the germ-line mutation versus 42/169 (25%) patients with the wild-type genotype (P = 0.02). Surprisingly, somatic loss of heterozygosity (LOH) for the remaining wild-type BRCA1 allele was detected only in 7/24 (29%) post-neoadjuvant therapy residual tumor tissues as compared to 9/11 (82%) BRCA1-associated OC, which were not exposed to systemic treatment before the surgery (P = 0.009). We hypothesize that the low frequency of LOH is related to the selection of tumor clones with somatically preserved BRCA1 gene during the therapy. We obtained for the LOH-analysis paired biological specimens from 8 patients; the pairs included cytological slides prepared at diagnosis and corresponding surgical material removed after neoadjuvant therapy. The restoration of BRCA1 heterozygosity was revealed in 4 out of 6 post-treatment tumor samples presenting with LOH at diagnosis. Another two ovarian carcinomas did not demonstrate somatic LOH before the treatment, and their status did not change during the neoadjuvant therapy. Thus, even though chemonaive OC specimens demonstrate somatic loss of the wild-type BRCA1 allele, the intratumoral BRCA1 heterozygosity could be restored in the platinum-exposed tissue, probably via expansion of LOH-negative clones. Conclusion: The obtained data confirm high sensitivity of BRCA-driven ovarian cancer to platinating agents and provide evidence for a rapid selection of tumor cell clones without LOH during the platinum-based therapy. Citation Format: Ekaterina Sh. Kuligina, Tatyana V. Gorodnova, Anna P. Sokolenko, Aleksandr O. Ivantsov, Aglaya G. Iyevleva, Evgeny N. Imyanitov. Accumulation of tumor cells with retained heterozygous BRCA1 status during platinum therapy: A probable mechanism of attenuation of tumor response in BRCA1-driven ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2928.

BRCA1 and BRCA2 rearrangements in Brazilian individuals with Hereditary Breast and Ovarian Cancer Syndrome.

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.

Identification of a founder BRCA1 mutation in the Moroccan population.

Breast cancer (BC) is the most frequent cancer among women in Morocco. However, the role of the most prevalent BC-predisposing genes, BRCA1 and BRCA2, has been largely unexplored. To help define the role of BRCA1 in BC in Morocco, we characterized the first potential BRCA1 founder mutation in this population. Genetic testing of BRCA1 and BRCA2 in BC high-risk families identified mutation BRCA1 c.5309G>T, p.(Gly1770Val) or G1770V in five independent families from Morocco, suggesting a founder effect. To confirm this hypothesis, haplotype construction was performed using seven intragenic and flanking BRCA1 microsatellite markers. Clinical data were also compiled. Clinical data from carriers of mutation G1770V correspond to data from carriers of BRCA1 pathogenic mutations. Microsatellite analysis showed a common haplotype for the five families in a region comprising 1.54 Mb, confirming G1770V as the first specific founder BRCA1 mutation in the Moroccan population. Our findings contribute to a better understanding of BC genetics in the Moroccan population. Nevertheless, comprehensive studies of mutation G1770V in large series of BC patients from Morocco are needed to assess the real prevalence of this mutation and to improve genetic testing and risk assessment in this population.

Novel germline mutations and unclassified variants of BRCA1 and BRCA2 genes in Chinese women with familial breast/ovarian cancer.

BackgroundGermline mutations in the BRCA1 and BRCA2 genes greatly increase a woman’s risk of developing breast and/or ovarian cancer. The prevalence and distribution of such mutations differ across races/ethnicities. Several studies have investigated Chinese women with high-risk breast cancer, but the full spectrum of the mutations in these two genes remains unclear.MethodsIn this study, 133 unrelated Chinese women with familial breast/ovarian cancer living in Zhejiang, eastern China, were enrolled between the years 2008 and 2014. The complete coding regions and exon-intron boundaries of BRCA1 and BRCA2 were screened by PCR-sequencing assay. Haplotype analysis was performed to confirm BRCA1 and BRCA2 founder mutations. In silico predictions were performed to identify the non-synonymous amino acid changes that were likely to disrupt the functions of BRCA1 and BRCA2.ResultsA total of 23 deleterious mutations were detected in the two genes in 31 familial breast/ovarian cancer patients with a total mutation frequency of 23.3 % (31/133). The highest frequency of 50.0 % (8/16) was found in breast cancer patients with a history of ovarian cancer. The frequencies of BRCA1 and BRCA2 mutations were 13.5 % (18/133) and 9.8 % (13/133), respectively. We identified five novel deleterious mutations (c.3295delC, c.3780_3781delAG, c.4063_4066delAATC, c.5161 > T and c.5173insA) in BRCA1 and seven (c.1-40delGA, c.4487delC, c.469_473delAAGTC, c.5495delC, c.6141T > A, c.6359C > G and c.7588C > T) in BRCA2, which accounted for 52.2 % (12/23) of the total mutations. Six recurrent mutations were found, including four (c.3780_3781delAG, c.5154G > A, c.5468-1del8 and c.5470_5477del8) in BRCA1 and two (c.3109C > T and c.5682C > G) in BRCA2. Two recurrent BRCA1 mutations (c.5154G > A and c.5468-1del8) were identified as putative founder mutations. We also found 11 unclassified variants, and nine of these are novel. The possibility was that each of the non-synonymous amino acid changes would disrupt the function of BRCA1 and BRCA2 varied according to the different algorithms used.ConclusionsBRCA1 and BRCA2 mutations accounted for a considerable proportion of hereditary breast/ovarian cancer patients from eastern China and the spectrum of the mutations of these two genes exhibited some unique features. The two BRCA1 putative founder mutations may provide a cost-effective option to screen Chinese population, while founder effects of the two mutations should be investigated in a lager sample size of patients.

Breast cancer in high-risk Afrikaner families: Is BRCA founder mutation testing sufficient?

Germline pathogenic mutations in cancer susceptibility genes result in inherited cancer syndromes. In the Afrikaner population of South Africa (SA), three founder mutations in the BRCA genes that lead to hereditary breast and ovarian cancer syndrome (HBOCS) have been identified. To investigate the uptake and type of molecular testing performed on patients for HBOCS, to determine the prevalence of the three Afrikaner founder BRCA mutations as well as non-founder BRCA mutations in the study population, and to analyse the utility of two mutation prediction models (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) and Manchester scoring method) in assisting with the decision for the most cost-effective testing option. A retrospective file review was performed on counsellees of self-reported Afrikaner ancestry from Johannesburg, SA (2001 - 2014), with a personal or family history of breast and/or ovarian cancer. Demographic and family history information was recorded and Manchester and BOADICEA scores were calculated for each patient. Of 86 unrelated counsellees whose files were reviewed, 54 (62.8%) underwent BRCA genetic testing; 18 (33.3%) tested positive for a mutation, and 14 of these (77.8%) for an Afrikaner founder mutation. Twelve counsellees had the BRCA2 c.7934delG mutation. Four non-founder mutations were identified. BOADICEA scores were significantly higher in counsellees who tested positive for a mutation than in those who tested negative. Founder mutation testing should be performed as a first-line option. BOADICEA is very useful in identifying counsellees at high risk for a BRCA mutation and also assists with the decision to pursue further testing following a negative founder mutation result. These findings assist in guiding an informed genetic counselling service for at-risk individuals with an Afrikaner background.

BRCA1 founder mutations do not contribute to increased risk of gastric cancer in the Polish population

BackgroundGastric cancer (GC) is part of the spectrum of diseases linked to BRCA1 and BRCA2 mutations that increase the risk of breast and ovarian cancer. Data suggesting an increased risk of developing GC among BRCA1 and BRCA2 mutation carriers are based almost exclusively on indirect studies. The objective was to assess in a direct study whether there is a relationship between GC and selected recurrent BRCA1 and BRCA2 mutations in the Polish population.MethodsThree hundred seventeen GC patients (193 males and 124 females; mean age 59.5 ± 12.8 y) diagnosed at the Department of Gastroenterology at the Pomeranian Medical University were included in this retrospective study. All patients were genotyped for 3 BRCA1 Polish founder mutations (5382insC, C61G and 4153delA) as well as for 9 known recurrent mutations in BRCA1 and BRCA2 genes. Genotyping was performed using allele-specific oligonucleotide polymerase chain reaction (ASA-PCR) for 4153delA and 5382insC, restriction fragment length polymorphism (PCR-RFLP) for C61G and TaqMan real-time PCR for 185delAG, 3819del5, 3875del4, 5370C > T, 886delGT, 4075delGT, 5467insT, 6174delT and 8138del5.ResultsAmong tested mutations one founder BRCA1 mutation 5382insC was detected in two of 317 (0.63 %) GC cases. A comparison of frequency of detected BRCA1 founder mutations in GC patients to previously described 4570 Polish controls (0.63 % vs. 0.48 %) failed to indicate an increased risk of GC in the mutation carriers (OR = 1.3; 95 % CI 0.3-5.6, p = 0.71). A comparison of frequency of GC male cases and male controls (1.0 % vs. 0.43 %,OR = 1.5; 95 % CI 0.3-6.4, p = 0.61) allowed to formulate the same conclusion that there is no increased risk for GC for males. None of the 9 recurrent BRCA1 and BRCA2 mutations has been detected in tested GC patients.ConclusionThe current study indicates that founder BRCA1 mutations reported in Polish breast/ovarian cancer patients do not contribute to increased GC risk. The nine tested recurrent BRCA1 and BRCA2 mutations were not detected in GC patients which may suggests that they are rare in GC patients in the Polish population. Further analyses, including sequencing of entire sequences of BRCA1 and BRCA2 genes, are necessary to ultimately determine the role of these two genes in GC in Poland.

High response rates to neoadjuvant platinum-based therapy in ovarian cancer patients carrying germ-line BRCA mutation

Preoperative therapy provides an advantage for clinical drug assessment, as it involves yet untreated patients and facilitates access to the post-treatment biological material. Testing for Slavic founder BRCA mutations was performed for 225 ovarian cancer (OC) patients, who were treated by platinum-based neoadjuvant therapy. 34 BRCA1 and 1 BRCA2 mutation carriers were identified. Complete clinical response was documented in 12/35 (34%) mutation carriers and 8/190 (4%) non-carriers (P = 0.000002). Histopathologic response was observed in 16/35 (46%) women with the germ-line mutation versus 42/169 (25%) patients with the wild-type genotype (P = 0.02). Somatic loss of heterozygosity (LOH) for the remaining wild-type BRCA1 allele was detected only in 7/24 (29%) post-neoadjuvant therapy residual tumor tissues as compared to 9/11 (82%) BRCA1-associated OC, which were not exposed to systemic treatment before the surgery (P = 0.009). Furthermore, comparison of pre- and post-treatment tumor material obtained from the same patients revealed restoration of BRCA1 heterozygosity in 2 out of 3 sample pairs presenting with LOH at diagnosis. The obtained data confirm high sensitivity of BRCA-driven OC to platinating agents and provide evidence for a rapid selection of tumor cell clones without LOH during the course of therapy.

The role of germline mutations in the BRCA1/2 and mismatch repair genes in men ascertained for early-onset and/or familial prostate cancer.

Prostate cancer (PrCa) is one of the most common cancers diagnosed worldwide and 5-10 % of all cases are estimated to be associated with inherited predisposition. Even though there is strong evidence that the genetic component is significant in PrCa, the genetic etiology of familial and early-onset disease is largely unknown. Although it has been suggested that men from families with hereditary breast/ovarian cancer (HBOC) and, more recently, with Lynch syndrome may have an increased risk for PrCa, the contribution of these syndromes to PrCa predisposition in families ascertained for early-onset and/or familial PrCa, independently of the presence of other cancers in the family, is uncertain. To quantify the contribution of genes associated with HBOC and Lynch syndromes to PrCa predisposition, we have tested for germline mutations 460 early-onset and/or familial PrCa patients. All patients were screened for the six mutations that are particularly common in Portugal and 38 of them were selected for complete sequencing of BRCA1/2 and/or MLH1, MSH2 and MSH6. Two patients were found to harbor the same MSH2 mutation and a third patient carried a Portuguese BRCA2 founder mutation. None of the alterations were identified in 288 control subjects. Furthermore, we reviewed the 62 PrCa diagnoses in all HBOC (n = 161) and Lynch syndrome (n = 124) families previously diagnosed at our department, and found five other BRCA2 mutation carriers and two additional MSH2 mutation carriers. The clinicopathological characteristics of mutation carriers are in concordance with earlier data suggesting an aggressive PrCa phenotype and support the hypothesis that mutation carriers might benefit from targeted screening according to the gene mutated in the germline.

Prevalence of founder mutations in the BRCA1 and BRCA2 genes among unaffected women from the Bahamas.

Population-based testing for BRCA1/2 mutations detects a high proportion of carriers not identified by cancer family history-based testing. We sought to determine whether population-based testing is an effective approach to genetic testing in the Bahamas, where 23% of women with breast cancer carry one of seven founder mutations in the BRCA1 or BRCA2 gene. We determined the prevalence of founder BRCA mutations in 1847 Bahamian women without a personal history of breast or ovarian cancer, unselected for age or family history. We found that 2.8% (20/705) of unaffected women with a family history of breast/ovarian cancer and 0.09% (1/1089) of unaffected women without a family history carry a BRCA mutation. A total of 38% of unaffected women with a known mutation in the family were found to carry the familial mutation. We previously suggested that all Bahamian women with breast or ovarian cancer be offered genetic testing. These current data suggest that additionally all unaffected Bahamian women with a family history of breast/ovarian cancer should be offered genetic testing for the founder BRCA mutations.

Abstract 1292: Identification of BRCA1 and BRCA2 founder mutations in population isolates from Colombia

Abstract Breast cancer (BC) is the most common malignancy in women. Germline mutations in breast cancer risk genes, such as BRCA1 and BRCA2, account for a large portion of hereditary breast cancer families. The contribution of mutations in breast cancer susceptibility genes has been poorly investigated in minority populations, such as in Hispanics from South America. While mutations in BRCA1 and BRCA2 display a heterogeneous mutation spectrum, specific mutations often occur in population isolates. Using the KASP genotyping technology, we screened 476 unselected Colombian breast cancer patients for three common BRCA1 and one BRCA2 founder mutations in the Hispanic population. The BRCA2 c.2806_2809delAAAC founder mutation was identified in 3 of the 476 BC cases (0.6%). Strikingly, 24 out of 476 cases (5.0%) harbored the BRCA1 founder mutation c.3331_3334delCAAG, which has also been reported in Southern European populations, including Spain and Portugal. The clinical data and family history of these patients have highlighted a distinct geographic region from where these cases originate. This finding potentially represents one of the most remarkable founder effects reported in human populations. To date the arrival of the BRCA1 c.3331_3334delCAAG mutation to Colombia, we are completing haplotype analysis of the patients and their families, along with BC cases from Spain and Portugal that harbor the same mutation. Interestingly, haplotype analyses of our BC cases have revealed a haplotype larger than 3.5 cM. In the future, we aim to perform haplotype analysis of family members of the mutation carriers and BC cases from Portugal and Spain to further study the haplotype around this BRCA1 mutation, which will allow us to date the origin of the mutation. By understanding the prevalence of mutations in known breast cancer risk genes in minority populations, cancer disparities can be better addressed and breast cancer screening can be improved. Furthermore, the ability to identify such strong founder effects highlights an advantage of using this Colombian population isolate in facilitating the identification of novel BC risk genes. Citation Format: Anna Marie D. Tuazon, Carolina Ramírez, Mabel Bohorquez, Rodrigo Prieto, Jorge Castro, Gilbert Mateus, Alejandro Velez, Magdalena Echeverry, Luis G. Carvajal-Carmona. Identification of BRCA1 and BRCA2 founder mutations in population isolates from Colombia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1292. doi:10.1158/1538-7445.AM2014-1292

BRCA1 gene-related hereditary susceptibility to breast and ovarian cancer in Latvia

PurposeIn this report, we summarise data on BRCA1 gene analysis in Latvia to characterise criteria of genetic testing for breast and ovarian cancer susceptibility. Material/methodsAnalysis by SSCP/HD, MALDI-TOF mass spectrometry or DNA sequencing was used for mutation detection. Mutations identified were confirmed by direct DNA sequencing. ResultsOut of 1068 breast and 231 ovarian cancer patients from different families: 58 carried the c.5266dupC and 43 carried the c.4035delA mutations. Every 4th patient in our study did not report cancer in the family. The breast cancer was diagnosed earlier in carriers of the c.5266dupC than in carriers of the c.4035delA (p=0.003). The incidence of breast or ovarian cancer does not differ among the 2 mutation carriers in our patient group. The nature of the c.5266dupC mutation might be more deleterious. ConclusionsWe recommend the screening of 4 founder BRCA1 mutations in all breast and ovarian cancer patients in Latvia at diagnosis of disease regardless of family history or age. The BRCA1 screening can be carried out efficiently using the MALDI-TOF mass spectrometry mutation detection method developed in the Biomedical Research and Study Centre (Riga, Latvia).

Abstract P2-07-03: High-throughput germline mutation screening for hereditary breast cancer in southern Chinese patients by massively parallel DNA sequencing

Abstract Introduction: Breast cancer is the most common malignancy and 3rd leading cause of deaths among the female population in Hong Kong. Since the establishment of The Hong Kong Hereditary Breast Cancer Family Registry in 2007, 1344 patients with breast and/or ovarian cancer who met the selection criteria were recruited for genetic testing in Hong Kong. Since 2011 we started to employ next-generation DNA sequencing (NGS) to expedite the analysis workflow and expand the panel of genes for sequencing. Aim: To evaluate the workflow of NGS in mutation screening of BRCA1, BRCA2, TP53 and PTEN genes, and compared with the sequence data obtained by Sanger sequencing. Methods: We sequenced BRCA1, BRCA2, TP53 and PTEN genes in peripheral blood samples of 410 patients, 53 positive controls and 107 healthy local individuals using 454 GS Junior System. Generation of barcoded amplicon libraries was streamlined by microfluidic PCR using Fluidigm Access Array System. Sequencing data were analyzed by an in-house developed fully automatic bioinformatics pipeline, which mainly consists of GS Amplicon Variant Analyzer, SAMtools and Ensembl Variant Effect Predictor. All putative mutations identified were validated by Sanger sequencing. Furthermore, the frequency of BRCA1, BRCA2 and PTEN missense variants of unknown significance (VUS) identified in the cohort were compared among 107 healthy local individuals and 1000 Genomes project samples. The VUS were also subjected to a panel of in silico prediction methods including PolyPhen and SIFT. Results: Among 410 patients, there were 7 in BRCA1, 6 in BRCA2 and 1 in TP53 mutations found, including 1 novel recurrent BRCA2 (c.7007G&amp;gt;T) and 1 novel founder BRCA2 (c.5164_5165delAG) mutations. Based on multiple criteria, 12 in BRCA1, 12 in BRCA2 and 1 in PTEN VUS could be prioritized for further investigation. The bioinformatics pipeline was extensively evaluated with Sanger-validated controls. The evaluation determined minimum sequencing coverage needed in this sequencing platform for accurate analysis. The pipeline accuracy was demonstrated by successful detecting mutations from 53 positive controls, including single nucleotide variants, insertions and deletions in different sequence context. Conclusion: BRCA1, BRCA2, TP53 and PTEN mutation screening of 410 patients were expedited by high-throughput DNA sequencing. This method could detect 14 positive cases, including recurrent mutations, in a shorter period of time when compared with Sanger full gene sequencing. High-risk patients who are negative for the gene panel may need further investigation other than screening for BRCA1/2. The in-house developed bioinformatics pipeline was validated to detect various types of mutations and potentially become a conventional platform for genetic screening. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-07-03.

Large BRCA1 and BRCA2 genomic rearrangements in Polish high-risk breast and ovarian cancer families

BRCA1 and BRCA2 are two major genes associated with familial breast and ovarian cancer susceptibility. In Poland standard BRCA gene test is usually limited to Polish founder BRCA1 mutations: 5382insC, C61G and 4153delA. To date, just a few single large genomic rearrangements (LGRs) of BRCA1 gene have been reported in Poland. Here we report the first comprehensive analysis of large mutations in BRCA1 and BRCA2 genes in this country. We screened LGRs in BRCA1 and BRCA2 genes by multiplex ligation-dependent probe amplification in 200 unrelated patients with strong family history of breast/ovarian cancers and negative for BRCA1 Polish founder mutations. We identified three different LGRs in BRCA1 gene: exons 13-19 deletion, exon 17 deletion and exon 22 deletion. No LGR was detected in BRCA2 genes. Overall, large rearrangements accounted for 3.7% of all BRCA1 mutation positive families in our population and 1.5% in high-risk families negative for Polish founder mutation.