Mutation screening of the BRCA1 gene in early onset and familial breast/ovarian cancer in Moroccan population

Analysis of BRCA1 germline variants (exons 5, 11 and 20) in breast cancer families from Libya

Breast cancer (BC) is a leading cause of cancer deaths in Libyan women. BRCA1 variants differ globally due to the diversity of genetic makeup and populations history. Their distribution, prevalence, and significance in Libyans remain largely unexplored. This study investigated the characteristics and distribution of BRCA1 variants in exons 5, 11, and 20 in Libyan families with BC. Thirty-six BC patients at ≤ 45 years, between 46-50 years and with a family history of breast, ovarian, pancreatic or prostate cancer in close relatives, or with triple-negative BC, were selected from 33 unrelated families during 2018-2020 at the National Cancer Institute, Sabratha, Libya. From these 33 families, 20 women (18 BC patients and two unaffected) were screened for BRCA1 exons 5, 11 and 20 using Sanger sequencing. All families completed an epidemiology and family history questionnaire. Twenty-seven variants (26 in exon 11 and 1 in exon 20, minor allele frequency of < 0.01) were detected in 10 of 18 unrelated families (55.6%.) Among the 27 variants, 26 (96%) were heterozygous. A frameshift pathogenic variant, c.2643del, and one novel variant c.1366A>G were identified. Furthermore, seven variants with unknown clinical significance were detected: c.1158T>A, c.1346C>G, c.1174C>G, c.3630 G>T, c.3599A>T, and c.3400 G>C in exon 11, and c.5244T>A in exon 20. Six variants with conflicting pathogenicity interpretations, c. 3460T>A, c. 3572 G>A, c. 3700 G>C, c. 1246C>G, c. 1344C>G, and c. 1054 G>A, were also identified. Twelve benign/likely benign variants were identified. Rare BRCA1 variants that have not been reported in North Africa were found in Libyan patients. These findings provide preliminary insights into the BRCA1 variants that could contribute to hereditary BC risk in Libyans. Further functional, computational, and population analyses are essential to determine their significance and potential impact on BC risk, which could ultimately lead to more personalized management strategies.

Double Heterozygosity for Rare Deleterious Variants in the BRCA1 and BRCA2 Genes in a Hungarian Patient with Breast Cancer

Hereditary breast cancer is most commonly attributed to germline BRCA1 and BRCA2 gene variants. The vast majority of BRCA1 and BRCA2 mutation carriers are single heterozygotes, and double heterozygosity (DH) is a very rare finding. Here, we describe the case of a BRCA1/BRCA2 double heterozygous female proband diagnosed with breast cancer. Genetic testing for hereditary breast and ovarian cancer revealed two pathogenic variants in the BRCA1 (c.5095C>T, p.(Arg1699Trp)) and in BRCA2 genes (c.658_659delGT, p.(Val220Ilefs*4)) in heterozygous form. None of the variants were founder Jewish mutations; to our knowledge, these rare deleterious variants have not been previously described in DH patients in the literature. The patient had triple-negative unilateral breast cancer at the age of 36 and 44 years. Based on family studies, the BRCA1 variant was maternally inherited.

Immunohistochemical Detection of the Expressed BRCA1 and BRCA2 Proteins in Microenvironment of Malignant Breast Cancerous Tissues Infected with Human Mammary Tumor Virus

OBJECTIVE

The objective of the study was to examine the prevalence of HMTV infection, its associations with breast malignant tissues, and the expression of BRCA1 and BRCA2 proteins.

METHODS

One hundred archival breast tissues, 40 biopsies from female patients with breast cancer (BC), and 20 healthy breast tissues from the control group were used in the study. Immunohistochemical analysis was conducted to detect the expressed BRCA1 and BRCA2 proteins. Digoxigenin-labeled HMTV probes were used in chromogenic in situ hybridization for the identification of HMTV in breast tumor tissues. The complementary sequence sites of the HMTV probe sequences were stained by NBT/BCIP as blue signals.

RESULTS

There were 12 out of 40 (30%) benign breast tumorous tissues and 14 out of 40 (35%) BC tissues, while healthy control breast tissues were 10% (2 out of 20 tissues). Positive immunohistochemical (IHC) reactions for BRCA2 protein were observed in 12 out of 40 BC tissues (30.0%), 25% of benign breast tumorous tissues, and 5% of the control group. A significant (p < 0.05) statistical difference in the percentages of HMTV in the studied groups was found.

CONCLUSION

HMTV might contribute to the development of subsets of benign and malignant breast tumors. The observed rates of defective or mutated BRCA1 and BRCA2 genes in healthy tissues indicate a role in the development of breast tumors.

Challenges in periodic revision of genetic testing results: Comparison of the main classification guidelines and report of a retrospective analysis involving BRCA1/BRCA2 variants of uncertain significance

In the context of cancer predisposition syndromes, it is widely known that the correct interpretation of germline variants identified in multigene panel testing is essential for adequate genetic counseling and clinical decision making, in which variants of uncertain significance (VUS) are not considered actionable findings. Thus, their periodic re-evaluation using appropriate guidelines is notably important. In the present study, we compared the performance of the main variant classification guidelines (ACMG, Sherloc and ENIGMA) in variant reassessment, using as input a BRCA1/2 VUS case series (retrospective analysis) from Brazil, an ethnically diverse and admixed country with substantial challenges in VUS reclassification. As main findings, two of the 15 VUS analyzed were reclassified as likely pathogenic by the 3 guidelines, BRCA1 c.4987-3C > G (rs397509213) and BRCA2 c.7868A > G (rs80359012). Moreover, challenges in variant classification and reassessment are described and additional in silico data about structural impact of the variant BRCA2 c.7868A > G are provided. We hypothesize that the establishment of a framework to reassess VUS could improve this process in health centers that have not yet implemented this practice. Results of this study underscore that periodic monitoring of the functional, clinical, and bioinformatics data of a VUS by a multidisciplinary team are of utmost importance in clinical practice. When there is a specific guideline for a given gene, such as ENIGMA for BRCA1/2, it should be considered the first option for variant assessment. Finally, recruitment of VUS carriers and their relatives to participate in variant segregation studies and publication of VUS reclassification results in the international scientific literature should be encouraged.

Increased prevalence of the founder BRCA1 c.5309G>T and recurrent BRCA2 c.1310_1313delAAGA mutations in breast cancer families from Northerstern region of Morocco: evidence of geographical specificity and high relevance for genetic counseling

BACKGROUND

Inherited mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 (BRCA1/2) confer high risks of breast and ovarian cancer. Because the contribution of BRCA1/2 germline mutations to BC in the Northeastern population of Morocco remains largely unknown, we conducted this first study to evaluate the prevalence and the phenotypic spectrum of two BRCA1/2 pathogenic mutations (the founder BRCA1 c.5309G>T and BRCA2 c.1310_1313delAAGA). This choice was also argued by the presence of an apparent specific geographical connection of these mutations and the Northeastern region of Morocco.

METHODS

Screening for the germline mutations c.5309G>T and BRCA2 c.1310_1313delAAGA was performed by sequencing on a total of 184 breast cancer (BC) patients originated from the Northeastern region of Morocco. The likelihood of identifying a BRCA mutation is calculated using the Eisinger scoring model. The clinical and pathologic features were compared between the BRCA-positive and BRCA-negative groups of patients. Difference in survival outcomes was compared between mutation carriers and non-carriers.

RESULTS

BRCA1 c.5309G>T and BRCA2 c.1310_1313delAAGA are responsible for a significant proportion of all BC cases (12.5%) and at least 20% of familial BC. The screening of BRCA1/2 genes by NGS sequencing confirmed that there are no additional mutations detected among positive patients. The clinicopathological features in positive patients were in accordance with typical characteristics of BRCA pathogenic mutations. The mean features in the carriers were the early onset of the disease, familial history, triple negative status (for BRCA1 c.5309G>T) and worse prognosis in terms of overall surviving. Our study indicates that the Eisinger scoring model could be recommended to identify patients for referral to BRCA1/2 oncogenetic counseling.

CONCLUSION

Our findings suggest that BRCA1 c.5309G>T and BRCA2 c.1310_1313delAAGA mutations may have a strong founder and/or recurrent effect on breast cancer among the Northeastern Moroccan population. There contribution to breast cancer incidence is certainly substantial in this subgroup. Therefore, we believe that BRCA1 c.5309G>T and BRCA2 c.1310_1313delAAGA mutations have to be included in the array of tests aimed at revealing cancer syndrome carriers among subjects of Moroccan origin.

Guideline-Based, Multi-Gene Panel Germline Genetic Testing for at-Risk Patients with Breast Cancer

Background

Genetic testing for at-risk patients with breast cancer should be routinely offered. Knowledge generated may influence both treatment decisions and cancer prevention strategies among the patients themselves and their relatives. In this study, we report on the prevalence and patterns of germline mutations, using commercially available next-generation sequencing (NGS)-based multi-gene panels (MGP).

Patients and Methods

Consecutive at-risk breast cancer patients, as determined by international guidelines, were offered germline genetic testing using a 20-gene NGS-based panel at a reference lab. Samples of peripheral blood were obtained for DNA extraction and genetic variants were classified as benign/likely benign (negative), pathogenic/likely pathogenic (positive) or variants of uncertain significance (VUS).

Results

A total of 1310 patients, median age (range) 43 (19-82) years, were enrolled. Age ≤45 years (n = 800, 61.1%) was the most common indication for testing. Positive family history of breast, ovarian, pancreatic or prostate cancers, and triple-negative disease were among the common indications. Among the whole group, 184 (14.0%) patients had pathogenic/likely pathogenic variants; only 90 (48.9%) were in BRCA1 or BRCA2, while 94 (51.9%) others had pathogenic variants in other genes; mostly in APC, TP53, CHEK2 and PALB2. Mutation rates were significantly higher among patients with positive family history (p = 0.009); especially if they were 50 years or younger at the time of breast cancer diagnosis (p < 0.001). Patients with triple-negative disease had relatively higher rate (17.5%), and mostly in BRCA1/2 genes (71.4%). Variants of uncertain significance (VUS) were reported in 559 (42.7%) patients; majority (90.7%) were in genes other than BRCA1 or BRCA2.

Conclusion

Pathogenic mutations in genes other than BRCA1/2 are relatively common and could have been missed if genetic testing was restricted to BRCA1/2. The significantly high rate of VUS associated with multi-gene panel testing can be disturbing.

Screening of BRCA1/2 variants in Mauritanian breast cancer patients

Background and study aim

Carrying a pathogenic BRCA1/2 variant increases greatly young women’s risk of developing breast cancer (BC). This study aimed to provide the first genetic data on BC in Mauritania.

Methods

Using NGS based screening; we searched for BRCA1/2 variants in DNA samples from 137 patients diagnosed for hereditary BC.

Results

We identified 16 pathogenic or likely pathogenic (PV) variants carried by 38 patients. Two predominant BRCA1 PV variants were found: c.815_824dup and c.4986 + 6 T > C in 13 and 7 patients, respectively. Interestingly, three novels BRCA1/2 predicted pathogenic variants have also been detected. Notably, no specific distribution of BRCA1/2 variants was observed regarding triple negative breast cancer (TNBC) or patient gender status.

Conclusions

In this first genetic profiling of BC in Mauritania, we identified a substantial number of BRCA1/2 pathogenic variants. This finding could be important in the future diagnosis and prevention policy of hereditary BC in Mauritania.

Mutational spectrum of BRCA1/2 genes in Moroccan patients with hereditary breast and/or ovarian cancer, and review of BRCA mutations in the MENA region

PURPOSE

Breast cancer (BC) is the most common form of female cancer around the world. BC is mostly sporadic, and rarely hereditary. These hereditary forms are mostly BRCA1- and BRCA2-associated hereditary breast and ovarian cancer syndrome. BRCA1 and BRCA2 genes are large and had some recurrent mutations specific to some populations. Through this work we analyze the most recurrent mutations in Moroccan population and compared them to a large review of other BRCA1/2 spectrum mutations in the MENA region.

METHODS

We report in this work a series of 163 unrelated patients (the largest series of Moroccan patients) with familial breast and/or ovarian cancer, selected among patients referred to our oncogenetic outpatient clinic, from 2006 to 2021. To identify genetic variants in these two genes, different genetic analysis strategies have been carried out, using Sanger Sequencing DNA or Target Panel Sequencing.

RESULTS

Pathogenic variants were identified in 27.6% of patients. The most frequent mutation identified in our patients was the c.1310_1313delAAGA, BRCA2 (33%), and three other mutations seem more frequent in the Moroccan population (33%) of all reported patients: c.798_799delTT, BRCA1; and c.3279delC, BRCA1; and c.7234_7235insG in BRCA2 gene.

CONCLUSION

Through this work, we emphasize the importance of screening for BRCA1 and BRCA2 recurrent mutations in Moroccan patients. Other MENA (MENA: English-language acronym referring to the Middle East and North Africa region) countries had also some recurrent BRCA mutations, which will allow a fast and unexpensive first line genetic analysis and a precise molecular diagnosis. This will allow an adapted follow-up of the patients and a pre-symptomatic diagnosis of their relatives.

Prevalence of Clinically Relevant Germline BRCA Variants in a Large Unselected South African Breast and Ovarian Cancer Cohort: A Public Sector Experience

Breast cancer is a multifaceted disease that currently represents a leading cause of death in women worldwide. Over the past two decades (1998–2020), the National Health Laboratory Service’s Human Genetics Laboratory in central South Africa screened more than 2,974 breast and/or ovarian cancer patients for abnormalities characteristic of the widely known familial breast cancer genes, Breast Cancer gene 1 (BRCA1) and Breast Cancer gene 2 (BRCA2). Patients were stratified according to the presence of family history, age at onset, stage of the disease, ethnicity and mutation status relative to BRCA1/2. Collectively, 481 actionable (likely-to pathogenic) variants were detected in this cohort among the different ethnic/racial groups. A combination of old (pre-2014) and new (post-2014) laboratory techniques was used to identify these variants. Additionally, targeted genotyping was performed as translational research revealed the first three recurrent South African pathogenic variants, namely BRCA1 c.1374del (legacy name 1493delC), BRCA1 c.2641G&gt;T (legacy name E881X) and BRCA2 c.7934del (legacy name 8162delG). This initial flagship study resulted in a cost-effective diagnostic test that enabled screening of a particular ethnic group for these variants. Since then, various non-Afrikaner frequent variants were identified that were proven to represent recurrent variants. These include BRCA2 c.5771_5774del (legacy name 5999del4) and BRCA2 c.582G&gt;A, both Black African founder mutations. By performing innovative translational research, medical science in South Africa can adopt first-world technologies into its healthcare context as a developing country. Over the past two decades, the progress made in the public sector enabled a pivotal shift away from population-directed genetic testing to the screening of potentially all breast and ovarian cancer patients, irrespective of ethnicity, family history or immunohistochemical status. The modifications over the years complied with international standards and guidelines aimed at universal healthcare for all. This article shares all the cohort stratifications and the likely-to pathogenic variants detected.

Case Report Series: Aggressive HR Deficient Colorectal Cancers Related to BRCA1 Pathogenic Germline Variants

Objective

The link between BRCA1 and homologous recombination deficiency (HRD) in cancer has gained importance with the emergence of new targeted cancer treatments, while the available data on the role of the gene in colorectal cancer (CRC) remain contradictory. The aim of this case series was to elucidate the role of known pathogenic BRCA1 variants in the development of early-onset CRC.

Design

Patients were evaluated using targeted next generation sequencing, exome sequencing and chromosomal microarray analysis of the paired germline and tumor samples. These results were used to calculate the HRD score and the frequency of mutational signatures in the tumors.

Results

Three patients with metastatic CRC were heterozygous for a previously known BRCA1 nonsense variant. All tumors showed remarkably high HRD scores, and the HRD-related signature 3 had the second highest contribution to the somatic pattern of variant accumulation in the samples (23% in 1 and 2, and 13% in sample 3).

Conclusions

A BRCA1 germline pathogenic variant can be involved in CRC development through HRD. Thus, BRCA1 testing should be considered in young patients with a personal history of microsatellite stable CRC as this could further allow a personalized treatment approach.

Prevalence of specific and recurrent/founder pathogenic variants in BRCA genes in breast and ovarian cancer in North Africa

Background

Elucidation of specific and recurrent/founder pathogenic variants (PVs) in BRCA (BRCA1 and BRCA2) genes can make the genetic testing, for breast cancer (BC) and/or ovarian cancer (OC), affordable for developing nations.

Methods

To establish the knowledge about BRCA PVs and to determine the prevalence of the specific and recurrent/founder variants in BRCA genes in BC and/or OC women in North Africa, a systematic review was conducted in Morocco, Algeria, and Tunisia.

Results

Search of the databases yielded 25 relevant references, including eleven studies in Morocco, five in Algeria, and nine in Tunisia. Overall, 15 studies investigated both BRCA1 and BRCA2 genes, four studies examined the entire coding region of the BRCA1 gene, and six studies in which the analysis was limited to a few BRCA1 and/or BRCA2 exons. Overall, 76 PVs (44 in BRCA1 and32 in BRCA2) were identified in 196 BC and/or OC patients (129 BRCA1 and 67 BRCA2 carriers). Eighteen of the 76 (23.7%) PVs [10/44 (22.7%) in BRCA1 and 8/32 (25%) in BRCA2] were reported for the first time and considered to be novel PVs. Among those identified as unlikely to be of North African origin, the BRCA1 c.68_69del and BRCA1 c.5266dupC Jewish founder alleles and PVs that have been reported as recurrent/founder variants in European populations (ex: BRCA1 c.181T>G, BRCA1 c1016dupA). The most well characterized PVs are four in BRCA1 gene [c.211dupA (14.7%), c.798_799detTT (14%), c.5266dup (8.5%), c.5309G>T (7.8%), c.3279delC (4.7%)] and one in BRCA2 [c.1310_1313detAAGA (38.9%)]. The c.211dupA and c.5309G>T PVs were identified as specific founder variants in Tunisia and Morocco, accounting for 35.2% (19/54) and 20.4% (10/49) of total established BRCA1 PVs, respectively. c.798_799delTT variant was identified in 14% (18/129) of all BRCA1 North African carriers, suggesting a founder allele. A broad spectrum of recurrent variants including BRCA1 3279delC, BRCA1 c.5266dup and BRCA2 c.1310_1313detAAGA was detected in 42 patients. BRCA1 founder variants explain around 36.4% (47/129) of BC and outnumber BRCA2 founder variants by a ratio of ≈3:1.

Conclusions

Testing BC and/or OC patients for the panel of specific and recurrent/founder PVs might be the most cost-effective molecular diagnosis strategy.

Identification of a novel pathogenic variant in PALB2 and BARD1 genes by a multigene sequencing panel in triple negative breast cancer in Morocco

Pathogenic variants (PVs) in BRCA genes have been mainly associated with an increasing risk of triple negative breast cancer (TNBC). The contribution of PVs in non-BRCA genes to TNBC seems likely since the processing of homologous recombination repair of double-strand DNA breaks involves several genes. Here, we investigate the susceptibility of genetic variation of the BRCA and non-BRCA genes in 30 early-onset Moroccan women with TNBC. Methods: Targeted capture-based next generation sequencing (NGS) method was performed with a multigene panel testing (MGPT) for variant screening. Panel sequencing was performed with genes involved in hereditary predisposition to cancer and candidate genes whose involvement remains unclear using Illumina MiSeq platform. Interpretation was conducted by following the American College of Medical Genetics and Genomics-Association for Molecular Pathology (ACMG-AMP) criteria. Results: PVs were identified in 20% (6/30) of patients with TNBC. Of these, 16.7% (5/30) carried a BRCA PV [10% (3/30) in BRCA1, 6.7% (2/30) in BRCA2] and 6.6% (2/30) carried a non-BRCA PV. The identified PVs in BRCA genes (BRCA1 c.798_799delTT, BRCA1 c.3279delC, BRCA2 c.1310_1313del, and BRCA2 c.1658T>G) have been reported before and were classified as pathogenic. The identified founder PVs BRCA1 c.798_799del and BRCA2 c.1310_1313delAAGA represented 10% (3/30). Our MGPT allowed identification of several sequence variations in most investigated genes, among which we found novel truncating variations in PALB2 and BARD1 genes. The PALB2 c.3290dup and BARD1 c.1333G>T variants are classified as pathogenic. We also identified 42 variants of unknown/uncertain significance (VUS) in 70% (21/30) of patients with TNBC, including 50% (21/42) missense variants. The highest VUS rate was observed in ATM (13%, 4/30). Additionally, 35.7% (15/42) variants initially well-known as benign, likely benign or conflicting interpretations of pathogenicity have been reclassified as VUS according to ACMG-AMP. Conclusions: PALB2 and BARD1 along with BRCA genetic screening could be helpful for a larger proportion of early-onset TNBC in Morocco.

Tracing ovarian cancer research in Morocco: A bibliometric analysis

BACKGROUND

The burden of ovarian cancer (OC) in low-income countries continues to increase annually. This gynecological cancer, known for its poor survival outcomes, has not attracted much interest in medical research as compared to other women's malignancies such as breast cancer. This bibliometric study was conducted to better depict the global map and the future directions of scientific productivity in the area of OC research in Morocco.

METHODS

Publication trends on OC were retrospectively analyzed using a number of bibliometric parameters based on the Pubmed database and other resources.

RESULTS

During the time period (1900-2018), a total number of 74 publications responding to the inclusion criteria were found and incorporated in the bibliometric analysis. This was dominated by case reports and case series on rare ovarian tumors (n = 60). In the core cluster, only 10 original studies and 3 reviews on OC were published by Moroccan researchers. After full-text appraisal for study population, only two clinical original articles included OC patients. The other clinical studies included breast cancer patients only or were suggestive of inherited OC. In addition, 3 preclinical in vitro studies were found during the literature search. The majority of these publications were covered by Pubmed and Web of Science core collection and all published in English language. The H-index of top 10 Moroccan scientists in this area didn't exceed 10. Importantly, research and review articles were frequently published in influential journals. However, the number of publications as compared to other African countries was very low. Moreover, a similar trend in terms of article per each newly diagnosed OC case, GDP per capita and per million was also noticed. For gender distribution, female scientists were first authors in the majority of these papers but less represented as leading last authors. In the complementary cluster of other article types on rare ovarian tumors, 70% of the items were published in French and approximately 60% were indexed on Pubmed. During the last five years, a marked acceleration of publishing this research category with little impact in the evidence-based practice was noticed.

CONCLUSIONS

This research area in gynecologic oncology seems to be neglected and needs to be prioritized in future research projects in Morocco particularly given the aggressive behavior of this women's cancer and the few available therapeutic options. There is an unmet need for studies on OC in all fields particularly epidemiology, clinic-pathological characteristics, and survival outcomes.

A Review of Cancer Genetics and Genomics Studies in Africa

Cancer is the second leading cause of death globally and is projected to overtake infectious disease as the leading cause of mortality in Africa within the next two decades. Cancer is a group of genomic diseases that presents with intra- and inter-population unique phenotypes, with Black populations having the burden of morbidity and mortality for most types. At large, the prevention and treatment of cancers have been propelled by the understanding of the genetic make-up of the disease of mostly non-African populations. By the same token, there is a wide knowledge gap in understanding the underlying genetic causes of, and genomic alterations associated with, cancer among black Africans. Accordingly, we performed a review of the literature to survey existing studies on cancer genetics/genomics and curated findings pertaining to publications across multiple cancer types conducted on African populations. We used PubMed MeSH terms to retrieve the relevant publications from 1990 to December 2019. The metadata of these publications were extracted using R text mining packages: RISmed and Pubmed.mineR. The data showed that only 0.329% of cancer publications globally were on Africa, and only 0.016% were on cancer genetics/genomics from Africa. Although the most prevalent cancers in Africa are cancers of the breast, cervix, uterus, and prostate, publications representing breast, colorectal, liver, and blood cancers were the most frequent in our review. The most frequently reported cancer genes were BRCA1, BRCA2, and TP53. Next, the genes reported in the reviewed publications’ abstracts were extracted and annotated into three gene ontology classes. Genes in the cellular component class were mostly associated with cell part and organelle part, while those in biological process and molecular function classes were mainly associated with cell process, biological regulation, and binding, and catalytic activity, respectively. Overall, this review highlights the paucity of research on cancer genomics on African populations, identified gaps, and discussed the need for concerted efforts to encourage more research on cancer genomics in Africa.

BRCA1 and BRCA2 truncating mutations and variants of unknown significance in Egyptian female breast cancer patients

BACKGROUND

Breast cancer is the most common malignancy among women worldwide and the leading cause of cancer death in economically developing countries. We sought to study the contribution of BRCA1/2 mutations to the burden of breast cancer in Egypt.

PATIENTS AND METHODS

103 Egyptian female breast cancer patients, unselected for age of onset or family history, were included in the study. Mutational screening of some exons of BRCA1/2 genes was performed using High Resolution Melting analysis followed by direct sequencing of detected variants.

RESULTS

Twenty sequence variants were identified. According to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) guidelines, 8 variants were classified as pathogenic (Class 5), 1 as likely pathogenic and 11 as variants of unknown significance (Class 3). The pathogenic variants comprised 5 novel frameshift mutations; BRCA1 c.5205delA and BRCA2 (c.3641delT, c.3291dupT, c.3292delA, and c.787dupA) mutations; 1 novel nonsense mutation (BRCA2 c.3280A>T) and 2 previously described missense mutations (BRCA1 c.117T>G, c.110C>A).

CONCLUSION

This study provides the results of our attempt to delineate the genetic aspect of breast cancer among the Egyptian population and emphasizes the necessity of implementing screening strategies for early diagnosis and counseling for breast cancer in Egypt.

Contribution of BRCA1 and BRCA2 germline mutations to early onset breast cancer: a series from north of Morocco

BACKGROUND

To date, the contribution of BRCA1/2 mutations in Moroccan early onset breast cancer patients remains unknown. Here we assess these genetic alterations for the first time in a cohort from North of Morocco.

METHODS

Thirty-three patients diagnosed with breast cancer at the age of ≤40 years were recruited irrespective of breast and/or ovarian cancer family history. Coding regions and intron-exon boundaries of BRCA1 and BRCA2 genes were sequenced from peripheral blood DNA using Ion Proton (Thermo Fisher Scientific) next generation sequencing platform.

RESULTS

Overall, five BRCA germline mutations were identified (15.1%). The frequency of mutations among patients with family history of breast cancer was 16.7%. Three mutations were found in BRCA1 (9%) and two within the BRCA2 gene (6%). These are three frameshift mutations (c.798_799del, c.2125_2126insA, c.5116_5119delAATA), one missense (c.116G > A) and one nonsense mutation (c.289G > T). The mutation c.5116_5119delAATA has a founder effect in North Africa. Moreover, one variant of unknown significance was identified in BRCA2 (c.4090A > G). Most BRCA mutations carriers (80%) had no family history of breast cancer.

CONCLUSION

Our data do not support the hypothesis that BRCA mutations alone explain the higher frequency of breast cancer in Moroccan young women. The young age (≤40 years) for breast cancer diagnosis seems to be strongly predictive of BRCA mutation status in Moroccan patients. These results will help in decision making with regard to genetic counseling and testing in the national scale.

Screening of BRCA1/2 genes mutations and copy number variations in patients with high risk for hereditary breast and ovarian cancer syndrome (HBOC)

Background

Hereditary breast and ovarian cancer (HBOC) is an autosomal dominant inherited cancer susceptibility disorder. Both BRCA1 and BRCA2 genes are considered as high penetrance genes of this syndrome. The identification of BRCA1/2 genetic alterations before cancer development, grant patients the chance to benefit from various medical cancer prevention approaches. Therefore, the appearance of recent advanced technologies in molecular analysis such as next generation sequencing has simplified full BRCA1/2 analysis.

Many attempts took place in hope of understanding the molecular germline spectrum of these two genes in Moroccan HBOC patients. However, most of the past projects focused only on young breast cancer cases, lacked ovarian cancer cases in their cohort and only a limited number of these studies were able to analyze the entire exons or copy number variations for both genes.

In attempt of gaining more information regarding the molecular profile of BRCA1/2 in HBOC, we conducted a study in which we analyze their molecular profile on selected Moroccan patients suspected of having HBOC syndrome.

Methods

In this study we obtained blood samples from 64 selected Moroccan patients, who suffered from Breast and/or ovarian cancer and had a strong family history for cancer. To analyze BRCA1/2 punctual variants and copy number variations, we used the Ion Personal Genome Machine (PGM) and Oncomine BRCA1/2 research assay panel. Afterward, we correlated the molecular results with the clinic-pathologic data using IBM SPSS Statistics ver 2.

Results

From the 64 selected cases, Forty-six had breast cancer, fifteen had ovarian cancer and three had both breast and ovarian cancer. The molecular analysis revealed that 18 patients from the 64 harbored a pathogenic variant (28%). Twelve had six different BRCA1 pathogenic variants and six had six different BRCA2 pathogenic variants. In this study, we report four pathogenic variants that to the best of our knowledge has never been reported in the Moroccan population before. Regarding copy number variation analysis, No CNV was detected in both genes for all the 64 successfully sequenced and analyzed patients in our cohort.

Conclusion

Work like the present has an important implication on public health and science. It is critical that molecular profiling studies are performed on underserved and understudied population like Morocco.

Patterns and Prevalence of Germline BRCA1 and BRCA2 Mutations among High-Risk Breast Cancer Patients in Jordan: A Study of 500 Patients

Purpose

Knowledge of BRCA1 and BRCA2 mutations has a significant clinical impact on the management and prevention of breast cancer. In this study, we evaluate the pattern and prevalence of germline mutations in BRCA1 and BRCA2 among high-risk Jordanian breast cancer patients selected as per international guidelines.

Methods

BRCA1 and BRCA2 testing were performed at a reference genetic lab. Mutations were classified as pathogenic/likely pathogenic and variant of uncertain significance (VUS).

Results

A total of 517 patients, median age: 39 (range: 19–78) years, were enrolled. Among the whole group, 72 (13.9%) patients had pathogenic or likely pathogenic BRCA1 (n = 24, 4.6%) or BRCA2 (n = 48, 9.3%) mutations, while 53 (10.3%) others had VUS. Among 333 younger (≤40 years) patients, mutations were observed in 44 (13.2%). Positive mutations were found in 40 (16.5%) patients with one or more close relatives with breast cancer and in 20 (35.1%) of the 57 patients with triple-negative disease. Multivariate analysis showed that a triple-negative status, history of two or more close relatives with breast cancer, and history of one or more close relatives with invasive ovarian cancer were associated with significant high odds ratios (OR) of carrying a pathogenic variant, with an OR (95% CI) of 5.08 (2.66–9.67), 3.24 (1.78–5.89), and 2.97 (1.04–8.52), respectively.

Conclusions

BRCA1 and BRCA2 mutations are not uncommon among Jordanian patients. Young age has the weakest association with positive mutations, while patients with triple-negative disease, especially those with an additional positive family history, have the highest mutation rate.

Association between hereditary predisposition to common cancers and congenital multimalformations

In a previous article we reported that mutations favoring cancer at adulthood seemed to improve fertility and limit miscarriages. Because spontaneous abortion may result from anomalies in embryo, we questioned if an increased frequency of congenital malformation could be evidenced among cancer-prone families. Oncogenetics database (≈193 000 members) of the comprehensive cancer center Jean Perrin was crossed with regional registry of congenital malformations (≈10 000). Among children born between 1986 and 2011, 176 children with malformation matched in both databases. In breast/ovaries cancer-prone families, the risk for malformations was multiplied by 2.4 [1.2-4.5] in case of a BRCA1 mutation. Frequencies of malformation in BRCA2 and MMR mutated families were similar to families without a cancer syndrome. In comparison to malformations concerning a unique anatomical system, multimalformations were significantly more frequent in case of BRCA or MMR mutations: compared to families without cancer syndrome, the risk of multimalformations was multiplied by 4.1 [0.8-21.7] for cancer-prone families but with no known deleterious mutation, by 6.9 [1.2-38.6] in families with a known mutation but an unknown parental mutational status and by 10.4 [2.3-46.0] when one parent carried the familial mutation. No association with the type of anatomical system was found, nor with multiple births. These results suggest that BRCA and MMR genes play an important role in human embryogenesis and that if their function is lowered because of heterozygote mutations, congenital malformations are either more likely (BRCA1 mutations) and/or more susceptible to concern several anatomical systems.

Correlation between Candidate Single Nucleotide Variants and Several Clinicopathological Risk Factors Related to Breast Cancer in Jordanian Women: A Genotype-Phenotype Study

This study aim to investigate the association of breast cancer risk and prognostic factors with single nucleotide variants of the BRCA1, BRCA2, DAPK1, MMP9, TOX3, and TP53 genes in Jordanian women. Blood samples were collected from 230 Jordanian breast cancer patients for use in DNA extraction followed by genotyping and subsequent statistical analysis. We found that two single nucleotide variants (SNVs) of the BRCA2 gene, namely rs1799944 and rs766173, were significantly associated with breastfeeding status. Likewise, the rs11141901 and rs1041326 SNVs of the DAPK1 gene were linked with co-morbidity (p-value = 0.002) and family history of BC (p-value = 0.015), while the rs1045042 SNV of the same gene was associated with both allergy (p-value = 0.001) and family history of BC (p-value = 0.02). Tumor differentiation was correlated with the DAPK1 SNVs rs11141901 (p-value = 0.041) and rs1041326 (p-value = 0.005). Additionally, the rs2250889 SNV of the MMP9 gene was significantly associated with HER2 status, whereas the TP53 SNVs rs12951053 and rs1042522 were associated with age at menarche (p-value = 0.043) and breastfeeding status (p-value = 0.013), respectively. In contrast, the TP53 SNV rs2287497 was significantly linked to age at first pregnancy (p-value = 0.001), smoking (p-value = 0.041), and axillary lymph node status (p-value = 6e^-4). No such association was found for the BRCA1 and TOX3 SNVs. The current findings suggest significant associations between certain SNVs and breast cancer risk and prognosis in Jordanian women.

Characterization of BRCA1 and BRCA2 genetic variants in a cohort of Bahraini breast cancer patients using next-generation sequencing

Background

Breast cancer is the most common malignancy in women worldwide. About 5%–10% are due to hereditary predisposition. The contribution of BRCA1/2 mutations to familial breast cancer in Bahrain has not been explored. The objective of this study was to investigate the spectrum of BRCA1/2 genetic variants and estimate their frequencies in familial breast cancer. We also aim to test the efficiency of the next‐generation sequencing (NGS) as a powerful tool for detecting genetic variation within BRCA1/2 genes.

Methods

Twenty‐five unrelated female patients diagnosed with familial breast cancer were screened for BRCA1/2 variants. All targeted coding exons and exon–intron boundaries of BRCA1/2 genes were amplified with 167 pairs of primers by NGS.

Results

We have identified two deleterious BRCA1/2 variants in two patients, one in BRCA1 gene (c.4850C>A) and other in BRCA2 gene (c.67+2T>C). In addition to the deleterious variants, we identified 24 distinct missense variants of uncertain significance, 10 of them are seen to confer minor but cumulatively significant risk of breast cancer.

Conclusion

Our data suggest that BRCA1/2 variants may contribute to the pathogenesis of familial breast cancer in Bahrain. It also shows that NGS is useful tool for screening BRCA1/2 genetic variants of probands and unaffected relatives.

Prevalence of BRCA mutations among hereditary breast and/or ovarian cancer patients in Arab countries: systematic review and meta-analysis

Background

To systematically assess the prevalence of BRCA1 and BRCA2 gene mutations in women with Hereditary Breast and/or Ovarian Cancer (HBOC) in Arab countries and to describe the variability in the BRCA gene mutations in different regions of the Arab world.

Methods

Observational studies reporting prevalence of BRCA mutations from 22 Arab countries were systematically searched in databases including PUBMED, EMBASE, Web of Science, and Google Scholar. Two reviewers independently screened the studies and extracted data and assessed the risk of bias. Hoy’s risk of Bias tool was used to assess the biases in individual studies. Due to substantial heterogeneity, pooled weighted estimates were calculated using Quality Effect Models (QEM) that adjust for bias, while the Random Effect Models (REM) estimates served as the sensitivity estimates.

Results

Fourteen studies reporting prevalence of BRCA were included. The pooled estimate of BRCA among HBOC was 20% (95% CI: 7–36%). Subgroup analysis including only those with low risk of bias provided an estimate of 11% (95% CI: 1–27%). Levant region had higher prevalence 28% (95% CI: 11–49%) compared to Arabian Gulf region and North Africa but differences are not statistically significant, when tested using Z-test for proportions.

Conclusion

Given the pooled estimates vary widely with substantial heterogeneity, larger, well-designed studies are warranted to better understand the frequency and the impact of BRCA gene mutations among Arab women.

Trial registration

International Prospective Register of Systematic Reviews (PROSPERO) registration number: CRD42018095905.

BRCA1/2 germline missense mutations: a systematic review

Hereditary breast and ovarian cancer is an inherited syndrome associated with BRCA1/2 germline defects. The identified mutations are classified as missense, large deletion, insertion, nonsense and splice-site variants with a deleterious impact on BRCA1/2 function. Part of these forms the well-documented truncating mutations, and missense variants represent a clinical dilemma as the pathogenic role is yet to be clearly shown. In this systematic review, we collected these missense variations with a documented deleterious function. We focused on English language articles from MEDLINE. This study included all BRCA1/2 germline missense mutations identified in breast and ovarian cancer patients. The method of this study followed the 'PRISMA statement for reporting systematic reviews and meta-analyses'. A total of 61 BRCA1/2 germline and pathogenic missense mutations were identified: 70.5% affected BRCA1 and 29.5% BRCA2, respectively. In BRCA1, the majority of mutations were located in the BRCA C-terminus (48.8%), leading to a disruption of function. Conversely, no specific associations were verified between mutations and the BRCA2 gene. The European population was the most affected by BRCA1 and the Asian population by BRCA2 mutant patterns. The identification of novel BRCA1/2 missense mutations requires specific genetic tests to assess pathogenicity. With this systematic review, we are, to the best of our knowledge, the first to collect the overall amount of data on these pathogenic mutants with the aim of improving the management of carriers and their kindred.

Genetic epidemiology of ovarian cancer in the 22 Arab countries: A systematic review

Ovarian cancer (OC) is a common disease among Arabs, with one of the highest incidences in the world. OC is underdiagnosed, underreported, and mostly reported with breast cancer. This study aimed to conduct a systematic review to estimate the published knowledge about the genetic epidemiology of OC in the 22 Arab countries. Therefore, we systematically searched seven literature databases (Web of science, PubMed, Science Direct, ProQuest, Embase, Scopus, and Google scholar) from the time of inception until June 2018 to collect all the information related to the incidence and pathogenic mutations spectrum for OC among Arabs. Our search strategy identified 3645 studies, of which 44 studies met our inclusion criteria, which cover the past 25 years (1993-2018). OC incidence among Arabs ranged from a low of 0.9/100,000/year in Saudi Arabia to a high of 8.0/100,000/year in Sudan. The total number of OC patients captured was 802; of these, 53 and five families carry 22 mutations in BRCA1/2 genes. Of these, eight mutations were unique to the Arab populations, and five mutations were commonly circulated among Arabs (BRCA1: c.5266dupC, c.5095C>T, c.68_69delAG, and c.4041_4042delAG; BRCA 2 c.1310_1313delAAGA). The ratio of BRCA1 (77.3%) mutations was higher than BRCA2 mutations (22.7%). This is the first systematic review to focus on the genetic epidemiology of only OC as an understudied disease that is common among Arabs. This study is expected to serve as a platform for further well-controlled genetic epidemiological studies for OC in the Arab world.

BRCA1 c.68_69delAG (exon2), c.181T>G (exon5), c.798_799delTT and 943ins10 (exon11) mutations in Burkina Faso

The worldwide variation of BRCA mutations is well known. The c.68_69delAG, c.181T>G, c.798_799delTT mutations in BRCA1 were observed in Moroccan, Algerian and Tunisian Breast Cancer families and were described founder mutation in Northern Africa. The 943ins10 is also recognized a founder mutation in West Africa. To our knowledge no study has been published on BRCA1/2 germline mutations and hereditary breast cancer (HBC) in population of Burkina Faso. The aim of the present study (first in Burkina Faso) was to screen for these four mutations in 15 unrelated patients with HBC. Mutation analysis was performed by Sanger sequencing of coding exon2, Exon5 and exon11A sequences of the BRCA1 gene. Blood specimens of 15 patients from Burkina Faso, with HBC were collected at the University Hospital Yalgado OUEDRAOGO (CHU-YO) of Ouagadougou in Burkina Faso. c.68_69delAG (exon2), c.181T>G (exon5), c.798_799delTT and 943ins10 (exon11) mutations were not detected in any of the 15 women diagnosed with family breast cancer history. Genetic analysis in this study, we show that targeting relevant exons in BRCA1 genes did not allow detection of mutations in the population of Burkina Faso. Therefore, such an approach may be of interest to perfom a complete sequencing of BRCA1 and BRCA2 genes in families at a high risk of developing breast cancer in Burkina Faso.

Genetics of breast cancer in African populations: a literature review

Breast cancer (BC) is one of the most complex, diverse and leading cause of death in women worldwide. The present investigation aims to explore genes panel associated with BC in different African regions, and compare them to those studied worldwide.

We extracted relevant information from 43 studies performed in Africa using the following criteria: case-control study, association between genetic variations and BC risk. Data were provided on mutations and polymorphisms associated with BC without fixing a specific date. Case-only studies and clinical trials were excluded.

Our study revealed that the majority of African BC genetic studies remain restricted to the investigation of BRCA1 and BRCA2 genes and differences in their mutations spectrum. Therefore, it is necessary to encourage African researchers to characterize more genes involved in BC using methods generating global information such as next-generation sequencing in order to guide specific and more effective therapeutic strategies for the African community.

Significant association between ERCC2 and MTHR polymorphisms and breast cancer susceptibility in Moroccan population: genotype and haplotype analysis in a case-control study

Background

Genetic determinants of breast cancer (BC) remained largely unknown in the majority of Moroccan patients. The purpose of this study was to explore the association of ERCC2 and MTHFR polymorphisms with genetic susceptibility to breast cancer in Moroccan population.

Methods

We genotyped ERCC2 polymorphisms (rs1799793 (G934A) and rs13181 (A2251C)) and MTHFR polymorphisms (rs1801133 (C677T) and rs1801131 (A1298C)) using TaqMan SNP Genotyping Assays. Genotypes were compared in 151 BC cases and 156 population-matched controls. Allelic, genotypic and haplotype associations with the risk and clinicopathological features of BC were assessed using logistic regression analyses.

Results

ERCC2-rs1799793-AA genotype was associated with high risk of BC compared to wild type genotype (recessive model: OR: 2.90, 95% CI: 1.34–6.26, p = 0.0069) even after Bonferroni correction (p < 0,0125). MTHFR rs1801133-TT genotype was associated with increased risk of BC (recessive model, OR: 2.49, 95% CI: 1.17–5.29, p = 0.017) but the association turned insignificant after Bonferroni correction. For the rest of SNPs, no statistical associations to BC risk were detected.

Significant association with clinical features was detected for MTHFR-rs1801133-TC genotype with early age at diagnosis and familial BC. Following Bonferroni correction, only association with familial BC remained significant. MTHFR-rs1801131-CC genotype was associated with sporadic BC. ERCC2-rs1799793-AA genotype correlated with ER+ and PR+ breast cancer. ERCC2-rs13181-CA genotype was significantly associated large tumors (T ≥ 3) in BC patients. None of these associations passed Bonferroni correction.

Haplotype analysis showed that ERCC2 A-C haplotype was significantly associated with increased BC risk (OR: 3.71, 95% CI: 1.7–8.12, p = 0.0002 and p = 0.0008 before and after Bonferroni correction, respectively) and positive expression of ER and PR in BC patients. ERCC2 G-C haplotype was correlated with PR negative and larger tumor (T4). We did not find any MTHFR haplotypes associated with BC susceptibility. However, the less common haplotype MTHFR T-C was more frequent in young patients and in familial breast cancer, while MTHFR C-C haplotype was associated with sporadic BC form.

Conclusions

Our findings are a first observation of association between ERCC2 SNPs and breast cancer in Moroccan population. The results suggested that ERCC2 and MTHFR polymorphisms may be reliable for assessing risk and prognosis of BC in Moroccan population.

Germline BRCA1/BRCA2 mutations among high risk breast cancer patients in Jordan

Background

Breast cancer is the most common malignancy and the leading cause of cancer-related deaths among Jordanian women. With a median age of 50 years at diagnosis, a higher prevalence of hereditary breast cancer may be expected. The objective of this pilot study is to evaluate, for the first time, the contribution of germline mutations in BRCA1/2 to breast cancer among Jordanian patients.

Methods

Jordanian breast cancer women with a selected high risk profile were invited to participate. Peripheral blood samples were obtained for DNA extraction. A detailed 3-generation family history was also collected. BRCA sequencing was performed at a reference laboratory. Mutations were classified as deleterious, suspected deleterious, variant of uncertain significance or favor polymorphisms. Patients’ medical records were reviewed for extraction of clinical and tumor pathology data.

Results

One hundred patients were enrolled to the study. Median age was 40 (22–75) years. In total, 20 patients had deleterious and 7 suspected deleterious mutations in BRCA1 or BRCA2 genes. Seven variants of uncertain significance were also detected. After excluding patients tested subsequent to the index case in their families, highest mutation rates were observed among triple negatives (9/16, 56.3%) especially among those with positive family history of breast and/or ovarian cancer (9/13, 69.2%), patients with bilateral or second primary breast cancer (10/15, 66.7%) and those with family history of male breast cancer (2/5, 40.0%).

Conclusions

BRCA1/2 mutations are not uncommon among selected Jordanian females with breast cancer. The contribution of these findings to much younger age at diagnosis is debatable.

Although small, our selected patient cohort shows an important incidence of deleterious and suspected deleterious BRCA1/2 mutations suggesting that genetic testing should be offered to patients with certain high risk features.

BRCA1 mutation spectrum, functions, and therapeutic strategies: The story so far

BRCA1 gene mutations account for about 25-28% of hereditary Breast Cancer as BRCA1 is included in the category of high penetrance genes. Except for few commonmutations, there is a heterogenous spectrum of BRCA1 mutations in various ethnic groups. 185AGdel and 5382ins Care the most common BRCA1 alterations (founder mutations) which have been identified in most of the population. This review has been compiled with an aim to consolidate the information on genetic variants reported in BRCA1 found in various ethnic groups, their functional implications if known; involvement of BRCA1 in various cellular pathways/processes and potential BRCA1 targeted therapies. The pathological variations of BRCA1 vary among different ethical groups. A systematic search in PubMed and Google scholar for the literature on BRCA1 gene was carried out to figure out structure and function of BRCA1 gene. BRCA1 is a large protein having 1863 amino acids with multiple functional domains and interacts with multiple proteins to carry out various crucial cellular processes. BRCA1 plays a major role in maintaining genome integrity, transcription regulation, chromatin remodeling, cell cycle checkpoint control, DNA damage repair, chromosomal segregation, and apoptosis. Studies investigating the phenotypic response of mutant BRCA1 protein and comparing it to wildtype BRCA1 protein are clinically important as they are involved in homologous recombination and other repair mechanisms. These studies may help in developing more targetted therapies, detecting novel interacting partners, identification of new signaling pathways that BRCA1 is a part of or downstream target genes that BRCA1 affects.

Clinicopathologic and prognostic features of breast cancer in young women: a series from North of Morocco

BACKGROUND

Literature data reported a higher frequency of breast cancer in young women (BCYW) in developing countries. BCYW is associated with delayed diagnosis, aggressive biology and poor prognosis. However, our knowledge of biological profile, treatment received and outcome of young patients is still limited in Morocco. We propose to analyze clinicopathologic, therapeutic and prognostic features of BCYW among a series of patients native and/or inhabitant of North of Morocco.

METHODS

We carried out a retro-prospective study of 331 infiltrating breast cancer cases registered between January 2010 and December 2015. Details of tumor pathology, treatment and outcome were collected. Disease-Free Survival (DFS) and Overall Survival (OS) were assessed by Kaplan-Meier analysis.

RESULTS

A total of 82 patients were diagnosed with breast cancer at the age of 40 or younger (24.8%). Median age was 36 years. More than one quarter (26%) of patients had family history of breast or ovarian cancer. Advanced stages accounted for 34.2% of cases. Median tumor diameter was 2.8 cm. Intermediate and high-grade tumors represented 47.6% and 40.2%, respectively. Nodal involvement was present in 58.5% and lymphovascular invasion was found in 47.7% of the patients. About two thirds (66.2%) of tumors were hormone receptor positive, 29.2% over-expressed HER2 receptor and 23% were triple negative. Patients underwent breast conserving surgery in 38.2% of cases, 61.7% were offered adjuvant chemotherapy and 84.6% received hormone therapy. Five-year DFS and OS were respectively 88.9% and 75.6%. Locoregional recurrence occurred in 2.8% of cases and 8.3% of patients developed distant metastases.

CONCLUSION

Our findings are in accordance with previous studies that have shown a higher frequency of breast cancer among Moroccan young women. In line with literature data, clinicopathologic profile seems to be aggressive and prognosis is pejorative in our series.

Characterization of BRCA1 and BRCA2 variants found in a Norwegian breast or ovarian cancer cohort

Germline mutations in BRCA1 and BRCA2 cause hereditary breast and ovarian cancer. Molecular screening of these two genes in patients with a family history of breast or ovarian cancer has revealed pathogenic variants as well as genetic variants of unknown significance (VUS). These VUS may cause a challenge in the genetic counseling process regarding clinical management of the patient and the family. We investigated 32 variants previously detected in 33 samples from patients with a family history of breast or ovarian cancer. cDNA was analyzed for alternative transcripts and selected missense variants located in the BRCT domains of BRCA1 were assessed for their trans-activation ability. Although an extensive cDNA analysis was done, only three of the 32 variants appeared to affect the splice-process (BRCA1 c.213-5T>A, BRCA1 c.5434C>G and BRCA2 c.68-7T>A). In addition, two variants located in the BRCT domains of BRCA1 (c.5075A>C p.Asp1692Ala and c.5513T>G p.Val1838Gly) were shown to abolish the BRCT domain trans-activation ability, whereas BRCA1 c.5125G>A p.Gly1709Arg exhibited equal trans-activation capability as the WT domain. These functional studies may offer further insights into the pathogenicity of certain identified variants; however, this assay is only applicable for a subset of missense variants.

High frequency of the recurrent c.1310_1313delAAGA BRCA2 mutation in the North-East of Morocco and implication for hereditary breast-ovarian cancer prevention and control

Background

To date, a limited number of BRCA1/2 germline mutations have been reported in hereditary breast and/or ovarian cancer in the Moroccan population. Less than 20 different mutations of these two genes have been identified in Moroccan patients, and recently we reported a further BRCA2 mutation (c.1310_1313delAAGA; p.Lys437IlefsX22) in three unrelated patients, all from the North-East of the country. We aimed in this study to evaluate the frequency and geographic distribution of this BRCA2 frameshift mutation, in order to access its use as the first-line BRCA genetic testing strategy for Moroccan patients. We enrolled in this study 122 patients from different regions of Morocco, with suggestive inherited predisposition to breast and ovarian cancers. All subjects gave written informed consent to BRCA1/2 genetic testing. According to available resources of our lab and enrolled families, 51 patients were analyzed by the conventional individual exon-by-exon Sanger sequencing, 23 patients were able to benefit from a BRCA next generation sequencing and a target screening for exon 10 of BRCA2 gene was performed in 48 patients.

Results

Overall, and among the 122 patients analyzed for at least the exon 10 of the BRCA2 gene, the c.1310_1313delAAGA frameshift mutation was found in 14 patients. Genealogic investigation revealed that all carriers of this mutation shared the same geographic origin and were descendants of the North-East of Morocco.

Discussion

In this study, we highlighted that c.1310_1313delAAGA mutation of BRCA2 gene is recurrent with high frequency in patients from the North-East region of Morocco. Therefore, we propose to use, in public health strategies, the detection of this mutation as the first-line screening tests in patients with breast and ovarian cancer originated from this region.

A new case of "de novo" BRCA1 mutation in a patient with early-onset breast cancer

Most of the de novo BRCA1/2 mutations have been identified in patients with early‐onset breast cancer and without family history of the disease. The identification of these alterations could play a prominent role in the prevention and treatment strategies and may influence clinical management of patients.

Comparison between CaGene 5.1 and 6.0 for BRCA1/2 mutation prediction: a retrospective study of 150 BRCA1/2 genetic tests in 517 families with breast/ovarian cancer

During the past years, several empirical and statistical models have been developed to discriminate between carriers and non-carriers of germline BRCA1/BRCA2 (breast cancer 1, early onset/breast cancer 2, early onset) mutations in families with hereditary breast or ovarian cancer. Among these, the BRCAPRO or CaGene model is commonly used during genetic counseling, and plays a central role in the identification of potential carriers of BRCA1/2 mutations. We compared performance and clinical applicability of BRCAPRO version 5.1 vs version 6.0 in order to assess diagnostic accuracy of updated version. The study was carried out on 517 pedigrees of patients with familial history of breast or ovarian cancer, 150 of which were submitted to BRCA1/2 mutation screening, according to BRCAPRO evaluation or to criteria based on familial history. In our study, CaGene 5.1 was more sensitive than CaGene 6.0, although the latter showed a higher specificity. Both BRCAPRO versions better discriminate BRCA1 than BRCA2 mutations. This study evidenced similar performances in the two BRCAPRO versions even if the CaGene 6.0 has underestimated the genetic risk prediction in some BRCA mutation-positive families. Genetic counselors should recognize this limitation and during genetic counseling would be advisable to use a set of criteria in order to improve mutation carrier prediction.

First application of next-generation sequencing in Moroccan breast/ovarian cancer families and report of a novel frameshift mutation of the BRCA1 gene

At present, breast cancer is the most common type of cancer in females. The majority of cases are sporadic, but 5-10% are due to an inherited predisposition to develop breast and ovarian cancers, which are transmitted as an autosomal dominant form with incomplete penetrance. The beneficial effects of clinical genetic testing, including next generation sequencing (NGS) for BRCA1/2 mutations, is major; in particular, it benefits the care of patients and the counseling of relatives that are at risk of breast cancer, in order to reduce breast cancer mortality. BRCA genetic testing was performed in 15 patients with breast cancer and a family with positivity for the heterozygous c.6428C>A mutation of the BRCA2 gene. Informed consent was obtained from all the subjects. Genomic DNAs were extracted and the NGS for genes was performed using the Ion Torrent Personal Genome Machine (PGM) with a 316 chip. The reads were aligned with the human reference HG19 genome to elucidate variants in the BRCA1 and BRCA2 genes. Mutations detected by the PGM platform were confirmed by target direct Sanger sequencing on a second patient DNA sample. In total, 4 BRCA variants were identified in 6 families by NGS. Of these, 3 mutations had been previously reported: c.2126insA of BRCA1, and c.1310_1313delAAGA and c.7235insG of BRCA2. The fourth variant, c.3453delT in BRCA1, has, to the best of our knowledge, never been previously reported. The present study is the first to apply NGS of the BRCA1 and BRCA2 genes to a Moroccan population, prompting additional investigation into local founder mutations and variant characteristics in the region. The variants with no clear clinical significance may present a diagnostic challenge when performing targeted resequencing. These results confirm that an NGS approach based on Ampliseq libraries and PGM sequencing is a highly efficient, speedy and high-throughput mutation detection method, which may be preferable in lower income countries.

Migrant breast cancer patients and their participation in genetic counseling: results from a registry-based study

Certain ethnic groups seem to have less access to cancer genetic counseling. Our study was to investigate the participation in cancer genetic counseling among migrant breast cancer patients of Turkish and Moroccan origin. Hospital medical records of Turkish and Moroccan and of a comparative group of non-Turkish/Moroccan newly diagnosed breast cancer patients were studied. All women were diagnosed between 2007 and 2012. Eligibility for genetic counseling was assessed with a checklist. A total of 156 Turkish/Moroccan patients were identified, and 321 patients were assigned to the comparative group. About one third (35%) of the Turkish/Moroccan patients fulfilled criteria for breast cancer genetic counseling, compared to 21% of the comparative group (P = 0.001); this was largely due to a relatively young age at diagnosis in the migrant group (26% <40 years vs 5% in the comparative group, P = 0.0001). Uptake of genetic counseling among eligible patients was 47% in the migrant group and 56% in the comparative group; differences in uptake were seen among the patients diagnosed before 40 years of age (48% in the migrant group vs 81% in the comparative group; P = 0.021). When adjusted for age at diagnosis, ethnicity was associated with discussing referral to genetic counseling and its actual uptake. The Turkish/Moroccan ethnicity appears to be associated with a lower uptake of genetic counseling, mainly caused by the lower uptake in the young age-group. The major barrier to participation in genetic counseling seems to lie within the referral process.

Contribution of BRCA1 and BRCA2 Germline Mutations to Early Algerian Breast Cancer

Breast cancer is the most common female malignancy and the leading cancer mortality cause among Algerian women. Germline mutations in the BRCA1 and BRCA2 genes in patients with early-onset breast cancer have not been clearly identified within the Algerian population. It is necessary to study the BRCA1/2 genes involvement in the Algerian breast cancer occurrence. We performed this study to define germline mutations in BRCA1/2 and their implication in breast cancer among young women from eastern Algeria diagnosed or treated with primary invasive breast cancer at the age of 40 or less who were referred to Anti-Cancer Center of Setif, Algeria. Case series were unselected for family history. Eight distinct pathogenic mutations were identified in eight unrelated families. Three deleterious mutations and one large genomic rearrangement involving deletion of exon 2 were found in BRCA1 gene. In addition, four mutations within the BRCA2 gene and one large genomic rearrangement were identified. Novel mutation was found among Algerian population. Moreover, five variants of uncertain clinical significance and favor polymorphisms were identified. Our data suggest that BRCA1/2 mutations are responsible for a significant proportion of breast cancer in Algerian young women.

BRCA Mutations Increase Fertility in Families at Hereditary Breast/Ovarian Cancer Risk

BACKGROUND

Deleterious mutations in the BRCA genes are responsible for a small, but significant, proportion of breast and ovarian cancers (5 - 10 %). Proof of de novo mutations in hereditary breast/ovarian cancer (HBOC) families is rare, in contrast to founder mutations, thousands of years old, that may be carried by as much as 1 % of a population. Thus, if mutations favoring cancer survive selection pressure through time, they must provide advantages that compensate for the loss of life expectancy.

METHOD

This hypothesis was tested within 2,150 HBOC families encompassing 96,325 individuals. Parameters included counts of breast/ovarian cancer, age at diagnosis, male breast cancer and other cancer locations. As expected, well-known clinical parameters discriminated between BRCA-mutated families and others: young age at breast cancer, ovarian cancer, pancreatic cancer and male breast cancer. The major fertility differences concerned men in BRCA-mutated families: they had lower first and mean age at paternity, and fewer remained childless. For women in BRCA families, the miscarriage rate was lower. In a logistic regression including clinical factors, the different miscarriage rate and men's mean age at paternity remained significant.

RESULTS

Fertility advantages were confirmed in a subgroup of 746 BRCA mutation carriers and 483 non-carriers from BRCA mutated families. In particular, female carriers were less often nulliparous (9.1 % of carriers versus 16.0 %, p = 0.003) and had more children (1.8 ± 1.4 SD versus 1.5 ± 1.3, p = 0.002) as well as male carriers (1.7 ± 1.3 versus 1.4 ± 1.3, p = 0.024).

CONCLUSION

Although BRCA mutations shorten the reproductive period due to cancer mortality, they compensate by improving fertility both in male and female carriers.

Screening for common mutations in BRCA1 and BRCA2 genes: interest in genetic testing of Tunisian families with breast and/or ovarian cancer

BACKGROUND

In the Tunisian population, as yet a limited number of BRCA1/2 germline mutations have been reported in hereditary breast and/or ovarian cancer. These mutations are located in a few exons of BRCA1/2. The aim of the present study was to search for these mutations in 66 unrelated patients with hereditary breast and/or ovarian cancer in order to assess the interest in such a targeted approach for genetic testing in Tunisia.

MATERIALS AND METHODS

Blood specimens from the 66 Tunisian patients, with family history of breast and/or ovarian cancer, were collected at the Salah Azaiz Cancer Institute of Tunis. The exons 5, 20 and part of exon 11 of BRCA1 as well as part of exons 10 and 11 of BRCA2 were analyzed by Sanger sequencing.

RESULTS

12 patients had deleterious mutations in the BRCA1 or BRCA2 genes (18%), including a novel frame-shift mutation of BRCA1 (c.3751dup; 3780insT). Four distinct BRCA1 mutations were detected eight patients: c.5266dup (5382insC) and c.211dup (330insA) each in three patients, c.3751dup (3870insT) and c.4041_4042del (4160delAG) each in one patient. The four remaining cases all carried the same BRCA2 mutation, c.1310_1313del (1538delAAGA). Besides these deleterious mutations, eight polymorphisms and unclassified variants were detected, one of them being never reported (BRCA1c.3030T>G, p.Pro1010Pro).

CONCLUSION

In this study, we show that targeting relevant exons in BRCA1 and BRCA2 genes allows detection of a substantial percentage of mutations in the Tunisian population. Therefore such an approach may be of interest in genetic testing of high-risk breast and ovarian cancer families in Tunisia.

BRCA1 and BRCA2 mutations in ethnic Lebanese Arab women with high hereditary risk breast cancer

PURPOSE

Breast cancer is the most common malignancy among women in Lebanon and in Arab countries, with 50% of cases presenting before the age of 50 years.

METHODS

Between 2009 and 2012, 250 Lebanese women with breast cancer who were considered to be at high risk of carrying BRCA1 or BRCA2 mutations because of presentation at young age and/or positive family history (FH) of breast or ovarian cancer were recruited. Clinical data were analyzed statistically. Coding exons and intron-exon boundaries of BRCA1 and BRCA2 were sequenced from peripheral blood DNA. All patients were tested for BRCA1 rearrangements using multiplex ligation-dependent probe amplification (MLPA). BRCA2 MLPA was done in selected cases.

RESULTS

Overall, 14 of 250 patients (5.6%) carried a deleterious BRCA mutation (7 BRCA1, 7 BRCA2) and 31 (12.4%) carried a variant of uncertain significance. Eight of 74 patients (10.8%) aged ≤40 years with positive FH and only 1 of 74 patients (1.4%) aged ≤40 years without FH had a mutated BRCA. Four of 75 patients (5.3%) aged 41-50 years with FH had a deleterious mutation. Only 1 of 27 patients aged >50 years at diagnosis had a BRCA mutation. All seven patients with BRCA1 mutations had grade 3 infiltrating ductal carcinoma and triple-negative breast cancer. Nine BRCA1 and 17 BRCA2 common haplotypes were observed.

CONCLUSION

Prevalence of deleterious BRCA mutations is lower than expected and does not support the hypothesis that BRCA mutations alone cause the observed high percentage of breast cancer in young women of Lebanese and Arab descent. Studies to search for other genetic mutations are recommended.

BRCA1 and BRCA2 mutations in Iranian breast cancer patients: A systematic review

BACKGROUND

BRCA1/2 genes mutation prevalence varies among ethnic groups and may be influenced by founder mutations. Understanding BRCA1/2 genes mutations is important for reducing breast cancer (BC) incidence, accurate risk assessment and counseling. This systematic review of the literature was conducted to addressing BRCA1/2 mutations in Iranian BC patients.

MATERIALS AND METHODS

A search for relevant articles was run on before January 2014 using MedLine, PubMed, Science Iranian Database, Google, and Web sites related to the study topic. The key words included: BC and Iran with Genes, BRCA Genes, BRCA1 and BRCA2; "Cancer Genes," and "Iran."

RESULTS

Thirteen articles retrieved from this search strategy were eligible for this review. The overall BRCA1 mutation rate for Iranian female BC patients was detected 31.8% (377/1183). Although this gene mutation rate for male patients is <0.01%. Eight BRCA1 mutations (c. 4837A > G, c. 3419G > A, c. 3119G > A, c. 2612C > T, c. 3113A > G, c. 2311T > C, c. 4301T > C and c. 4308T > C in BRCA1, and one BRCA2 mutation (c. 6494G > C) were found in multiple case subjects and represent candidate founder mutations.

CONCLUSION

According to these studies, there is heterogeneity in BRCA mutations in Iranian BC patients.

BRCA genetic screening in Middle Eastern and North African: mutational spectrum and founder BRCA1 mutation (c.798_799delTT) in North African

BACKGROUND

The contribution of BRCA1 mutations to both hereditary and sporadic breast and ovarian cancer (HBOC) has not yet been thoroughly investigated in MENA.

METHODS

To establish the knowledge about BRCA1 mutations and their correlation with the clinical aspect in diagnosed cases of HBOC in MENA populations. A systematic review of studies examining BRCA1 in BC women in Cyprus, Jordan, Egypt, Lebanon, Morocco, Algeria, and Tunisia was conducted.

RESULTS

Thirteen relevant references were identified, including ten studies which performed DNA sequencing of all BRCA1 exons. For the latter, 31 mutations were detected in 57 of the 547 patients ascertained. Familial history of BC was present in 388 (71%) patients, of whom 50 were mutation carriers. c.798_799delTT was identified in 11 North African families, accounting for 22% of total identified BRCA1 mutations, suggesting a founder allele. A broad spectrum of other mutations including c.68_69delAG, c.181T>G, c.5095C>T, and c.5266dupC, as well as sequence of unclassified variants and polymorphisms, was also detected.

CONCLUSION

The knowledge of genetic structure of BRCA1 in MENA should contribute to the assessment of the necessity of preventive programs for mutation carriers and clinical management. The high prevalence of BC and the presence of frequent mutations of the BRCA1 gene emphasize the need for improving screening programs and individual testing/counseling.

Breast cancer in Morocco: a literature review

In Morocco, breast cancer is the most prevalent cancer in women and a major public health problem. Several Moroccan studies have focused on studying this disease, but more are needed, especially at the genetic and molecular levels. It is therefore interesting to establish the genetic and molecular profile of Moroccan patients with breast cancer. In this paper, we will highlight some pertinent hypotheses that may enhance breast cancer care in Moroccan patients. This review will give a precise description of breast cancer in Morocco and propose some new markers for detection and prediction of breast cancer prognosis.

BRCA1 gene exon 11 mutations in Uighur and Han women with early-onset sporadic breast cancer in the northwest region of China

The prevalence of BRCA1 gene mutations in breast cancer differs between diverse ethnic groups. Relatively little information is known about patterns of BRCA1 mutations in early-onset breast cancer in women of Uighur or Han descent, the major ethnic populations of the Xinjiang region in China. The aim of this study was to identify BRCA1 mutations in Uighur and Han patients with early-onset (age <35 years), and sporadic breast cancer for genetic predisposition to breast cancer. For detection of BRCA1 mutations, we used a polymerase chain reaction single-stranded conformation polymorphism approach, followed by direct DNA sequencing in 22 Uighur and 13 Han women with early-onset sporadic breast cancer, and 32 women with benign breast diseases. The prevalence of BRCA1 mutations in this population was 22.9% (8/35) among early-onset sporadic breast cancer cases. Of these, 31.8% (7/22) of Uighur patients and 7.69% (1/13) of Han patients were found to have BRCA1 mutations. In 7 Uighur patients with BRCA1 mutations, there were 11 unique sequence alterations in the BRCA1 gene, including 4 clearly disease-associated mutations on exon 11 and 3 variants of uncertain clinical significance on exon 11, meanwhile 4 neutral variants on intron 20 or 2. None of the 11 BRCA1 mutations identified have been previously reported in the Breast Cancer Information Core database. These findings reflect the prevalence of BRCA1 mutations in Uighur women with early-onset and sporadic breast cancer, which will allow for provision of appropriate genetic counseling and treatment for Uighur patients in the Xinjiang region.

A comprehensive focus on global spectrum of BRCA1 and BRCA2 mutations in breast cancer

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.