BRCA1 and BRCA2 germline mutations in Moroccan breast/ovarian cancer families: novel mutations and unclassified variants

P53 marker expression in epithelial ovarian tumours in a centre in Nigeria - a descriptive study

BACKGROUND

p53 is a tumor suppressor gene. p53 expression in epithelial ovarian tumors (EOTs) is correlated with their biological behavior and predicts patient overall survival. However, there is a dearth of knowledge regarding p53 expression in these tumors among women from southwest Nigeria. Our study aimed to determine the patterns of p53 expression in various types of epithelial ovarian tumours.

METHODS

We conducted a retrospective study of epithelial ovarian tumours. We retrieved formalin-fixed, paraffin-embedded (FFPE) tissue blocks of previously diagnosed epithelial tumors from the departmental archive. We performed immunohistochemical analysis using p53 antibodies. We scored the expression and staining intensity of p53 as follows: negative (0), focal/weakly positive (1 +), and diffuse/strongly positive (2 +) on the basis of the recommended Cytomation scoring system.

RESULTS

The spectrum of p53 expression in the 51 histologically diagnosed cases revealed that 29 cases had no expression, consisting of 21 benign EOTs, two borderline EOTs, and six malignant EOTs. Nine cases exhibited wild-type expression, including six serous carcinomas, two mucinous carcinomas, and one signet ring cell carcinoma. p53 overexpression was observed in 13 patients overall, with 12 having serous carcinomas and one having endometrioid carcinoma. Among the 21 serous carcinoma patients, 28.6% (6 patients) presented with wild-type p53 expression, 57.1% (12 patients) presented with p53 overexpression, and 14.3% (three patients) presented negative p53 expression. There was a significant association between p53 expression and the histological grade of serous carcinoma.

CONCLUSION

Most epithelial ovarian carcinomas in our hospital are high grade, with many serous carcinomas showing either p53 overexpression or loss of expression. This may contribute to the poor patient survival rate.

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.

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>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>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.

Deregulated miRNA clusters in ovarian cancer: Imperative implications in personalized medicine

Ovarian cancer (OC) is one of the most common and fatal types of gynecological cancer. OC is usually detected at the advanced stages of the disease, making it highly lethal. miRNAs are single-stranded, small non-coding RNAs with an approximate size ranging around 22 nt. Interestingly, a considerable proportion of miRNAs are organized in clusters with miRNA genes placed adjacent to one another, getting transcribed together to result in miRNA clusters (MCs). MCs comprise two or more miRNAs that follow the same orientation during transcription. Abnormal expression of the miRNA cluster has been identified as one of the key drivers in OC. MC exists both as tumor-suppressive and oncogenic clusters and has a significant role in OC pathogenesis by facilitating cancer cells to acquire various hallmarks. The present review summarizes the regulation and biological function of MCs in OC. The review also highlights the utility of abnormally expressed MCs in the clinical management of OC.

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.

Next-generation sequencing of BRCA1 and BRCA2 genes in Moroccan prostate cancer patients with positive family history

Prostate cancer is the most common male cancer in Morocco. Although sporadic forms account for a large proportion of patients, familial forms of prostate cancer are observed in 20% of cases and about 5% are due to hereditary transmission. Indeed, germline mutations in BRCA1/2 genes have been associated with prostate cancer risk. However, the spectrum of these mutations was not investigated in Moroccan Prostate cancer patients. Thereby, the aim of this study was to characterize and to estimate the prevalence of germline BRCA1/2 mutations and large rearrangements in Moroccan patients with familial prostate cancer. The entire coding regions and intron/exon boundaries of BRCA1 and BRCA2 genes have been analyzed by next generation sequencing (NGS) in a total of 30 familial prostate cancer patients. Three pathogenic mutations were detected in four unrelated patients (13.3%). One BRCA1 mutation (c.1953_1956delGAAA) and two BRCA2 mutations (c.7234_7235insG and BRCA2ΔE12). In addition, sixty-three distinct polymorphisms and unclassified variants have been found. Early identification of germline BRCA1/2 mutations may be relevant for the management of Moroccan prostate cancer patients.

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.

Screening of germline mutations in young Rwandan patients with breast cancers

Background

In Sub‐Saharan Africa breast cancer is commonly detected at younger age and the profile is more aggressive with a high mortality rate compared to the European countries. It is suggested that African‐specific genetic background plays a key role in this matter. The present study aimed at understanding the role of genetic factors in breast cancer development in young Rwandan.

Methods

We performed a massive parallel sequencing on Illumina MiSeq NGS system for the screening of 26 genes associated with hereditary breast cancer from 40 patients under 35 years old from two University Teaching Hospitals in Kigali, Rwanda. Sanger sequencing was used to confirm pathogenic and likely pathogenic mutations.

Results

Five patients out of 40 (12.5%) presented with pathogenic mutations including four patients (10%) carrying BRCA1 or BRCA2 pathogenic variants. One patient showed a missense likely pathogenic TP53 variant. We have also detected additional missense, intronic, and 3’UTR variants of unknown significance in all study participants.

Conclusion

This preliminary study suggests that the frequency of germline mutations in young Rwandan patients with breast cancer is similar to the observations made in Caucasians. However, further large studies including patients and controls are needed to better understand the impact of genetic factors as well as the environmental risk factors in the development of breast cancer in young Rwandans.

Screening of germline mutations in Rwandan young patients with breast cancer. The next generation sequencing detected pathogenic BRCA 1 and 2 mutations in 6 patients. We have also detected additional missense, intronic, and 3’UTR variants of unknown significance in all study participants.

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.

Novel BRCA2 pathogenic variant c.5219 T > G; p.(Leu1740Ter) in a consanguineous Senegalese family with hereditary breast cancer

Background

Pathogenic variants associated with hereditary breast cancer have been reported for BRCA1 and BRCA2 (BRCA1/2) genes in patients from multiple ethnicities, but limited information is available from sub-Saharan African populations. We report a BRCA2 pathogenic variant in a Senegalese family with hereditary breast cancer.

Methods

An index case from a consanguineous family and nineteen healthy female relatives were recruited after informed consent. Along with this family, 14 other index cases with family history of breast cancer were also recruited. For the control populations we recruited 48 healthy women with no cancer diagnosis and 48 women diagnosed with sporadic breast cancer without family history. Genomic DNA was extracted from peripheral blood. All BRCA2 exons were amplified by PCR and sequenced. Sequences were compared to the BRCA2 GenBank reference sequence (NM_000059.3) using Alamut Software.

Results

We identified a novel nonsense pathogenic variant c.5219 T > G; p.(Leu1740Ter) in exon 11 of BRCA2 in the index case. The pathogenic variant was also identified in three sisters and one daughter, but was absent in the controls and unrelated cases.

Conclusions

This is the first report of a novel BRCA2 pathogenic variant in a Senegalese family with hereditary breast cancer. This result confirms the diversity of hereditary breast cancer pathogenic variants across populations and extends our knowledge of genetic susceptibility to breast cancer in Africa.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0814-y) contains supplementary material, which is available to authorized users.

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.

Novel Associations between BRCA1 Variants C.181 T>G (Rs28897672) and Ovarian Crisk in Saudi Females

BACKGROUND

Mutations in BRCA1 gene have been implicated in ovarian cancers, and BRCA testing may be conducted in high-risk women. This study was designed to determine the frequency of three single nucleotide polymorphisms (SNPs) variants in BRCA1 gene and BRCA1 expression in Saudi females with ovarian cancer.

METHODS

Expression levels of mRNA of BRCA1 gene were studied in 10 ovarian cancer and 10 normal ovarian tissues, by quantitative real time polymerase chain reaction (qPCR). The study also included 28 females who had suffered from ovarian cancer and had been successfully operated upon and 90 healthy females with no history of cancer. Blood was drawn in EDTA tubes and used for extraction of DNA. The genotyping was carried out using Taqman® SNP Genotyping kit by RT-PCR. The variants investigated included c.871 T>C (rs799917), c.1040 G>A (rs4986852), c.181 T>G (rs28897672) in BRCA1 gene.

RESULTS

The c.181 T>G (rs28897672) showed significantly different genotype and allele frequencies between the patients and the control subjects (p value = 0.002 and 0.02, respectively). The genotype TG was significantly protective (OR = 0.36, p value = 0.024). The mRNA expression of BRCA1 gene was found to be low in the ovarian cancer tissues.

CONCLUSIONS

This study showed that c.181 T>G in BRCA1 genes is associated with the development of ovarian cancer in Saudis. More studies are needed to unveil other SNPs that may be associated with ovarian cancer and to understand the mechanism(s) involved in reducing the expression of BRCA1 gene in ovarian cancer tissues.

BRCA1 and BRCA2 Germline Mutation Analysis in Hereditary Breast/Ovarian Cancer Families from the Aures Region (Eastern Algeria): First Report

Breast cancer is currently the leading cause of cancer morbidity and mortality among Algerian women. In this study, we aimed to investigate the mutation spectrum of BRCA1 and BRCA2 genes in hereditary breast/ovarian cancer (HBOC) families from the Aures region (eastern Algeria). High risk breast/ovarian cancer families were selected from overall 1162 consecutive patients collected from cancer registry of anticancer center of Batna. Breast cancers were diagnosed between 2011 and 2015. Recurrent mutations on BRCA1 and BRCA2 previously found in Algerian patients were screened using PCR-direct sequencing in 113 HBOC families. In addition, for the first time in Algeria, HBOC patients were analyzed by NGS using a cancer panel of 30 hereditary cancer genes or BRCA1/2 genetic test. Six distinct deleterious mutations in BRCA1 and BRCA2 and a new VUS in PALB2 were detected in ten patients. Two distinct BRCA2 pathogenic variants c.1813dupA and c.8485C > T detected in two young female triple negative breast cancer (TNBC) patients, respectively, with a family history of male breast cancer, are reported here for the first time in Algerian population. Interestingly, we also detected a BRCA exon 15 deletion in two unrelated young female TNBC patients with strong family history of breast/ovarian cancer. Our study showed differences in the distribution of the mutation spectrum of BRCA genes between the Aures region and the north central region of Algeria. Our results will contribute in the implementation of genetic counseling and testing for patients and families at risk of hereditary breast and ovarian cancer.

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.

Investigating of variations in BRCA1 gene in Iranian families with breast cancer

Background: Breast cancer is one of the most common cancers among Iranian women whose relationship with mutation status in BRCA1 is previously approved. Therefore, screening of the most mutated exons in BRCA1 in hereditary breast cancer patients provides beneficial information about the main disease-causing reason. Methods: A total of 14 Iranian hereditary breast cancer patients participated in this case series study. DNA was extracted from patients' blood samples for PCR assay. The quality of PCR products was determined using horizontal electrophoresis. Then, sequencing and analysis of the sequencing results were performed to investigate variation status in the sequences. Results: Five variants in 4 patients were found, including 1 pathogenic variant in exon 16 (H1686Q, NM_007294.3:c.5058T>A) and 4 novel intronic variants of uncertain significance (NC_000017.11:41228314G>T, NC_000017.11:41228309C>T, NC_000017.11:41228317G>T, and NC_000017.11:41203042G>A) in BRCA1. This study was the first to report 1 rare pathogenic variant in BRCA1 (H1686Q, NM_007294.3: c.5058T>A) in an Iranian family as the main disease-causing reason. Another interesting finding was non-existence of variations in almost all globally-reported and mutated exons in BRCA1. Conclusion: Investigation of these exons in BRCA1 showed the uniqueness of mutation pattern in Iranian breast cancer patients compared to other world regions. Due to the existence of other BRCA1 exons and also other predisposing genes in breast cancer, the main cause of cancer development in other participants might have been put in those exons and genes. We concluded that the most mutated exons in BRCA1 in Iranian population may not be the same as those found in other parts of the world.

Global Inequities in Precision Medicine and Molecular Cancer Research

Precision medicine based upon molecular testing is heralded as a revolution in how cancer is prevented, diagnosed, and treated. Large efforts across the world aim to conduct comprehensive molecular profiling of disease to inform preclinical models, translational research studies and clinical trials. However, most studies have only been performed in patients from high-income countries. As the burden on non-communicable diseases increases, cancer will become a pressing burden across the world, disproportionately affecting low-middle income settings. There is emerging evidence that the molecular landscape of disease differs geographically and by genetic ancestry, which cannot be explained by environmental factors alone. There is a lack of good quality evidence that characterises the molecular landscape of cancers found in low-middle income countries. As cancer medicine becomes increasingly driven by molecular alterations in high-income settings, low-income settings may become left behind. Further efforts on an international scale must be made by researchers, funders, and policymakers to ensure cancer research addresses disease across the world, so models are not limited to subtypes of disease found in high-income countries. In this review, we discuss differences found in the molecular profiles of tumours worldwide and the implication this has for the future of global cancer care. Finally, we identify several barriers currently limiting progress in this field and innovative solutions, which may address these shortcomings.

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.

Clonal lineage of high grade serous ovarian cancer in a patient with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is caused by mutations in the NF1 gene encoding neurofibromin, which negatively regulates Ras signaling. NF1 patients have an increased risk of developing early onset breast cancer, however, the association between NF1 and high grade serous ovarian cancer (HGSOC) is unclear. Since most NF1-related tumors exhibit early biallelic inactivation of NF1, we evaluated the evolution of genetic alterations in HGSOC in an NF1 patient. Somatic variation analysis of whole exome sequencing of tumor samples from both ovaries and a peritoneal metastasis showed a clonal lineage originating from an ancestral clone within the left adnexa, which exhibited copy number (CN) loss of heterozygosity (LOH) in the region of chromosome 17 containing TP53, NF1, and BRCA1 and mutation of the other TP53 allele. This event led to biallelic inactivation of NF1 and TP53 and LOH for the BRCA1 germline mutation. Subsequent CN alterations were found in the dominant tumor clone in the left ovary and nearly 100% of tumor at other sites. Neurofibromin modeling studies suggested that the germline NF1 mutation could potentially alter protein function. These results demonstrate early, biallelic inactivation of neurofibromin in HGSOC and highlight the potential of targeting RAS signaling in NF1 patients.

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.

Monoallelic characteristic-bearing heterozygous L1053X in BRCA2 gene among Sudanese women with breast cancer

Background

Breast cancer (BC) is the most common type of cancer in women. Among many risk factors of BC, mutations in BRCA2 gene were found to be the primary cause in 5–10% of cases. The majority of deleterious mutations are frameshift or nonsense mutations. Most of the reported BRCA2 mutations are protein truncating mutations.

Methods

The study aimed to describe the pattern of mutations including single nucleotide polymorphisms (SNPs) and variants of the BRCA2 (exon11) gene among Sudanese women patients diagnosed with BC. In this study a specific region of BRCA2 exon 11 was targeted using PCR and DNA sequencing.

Results

Early onset cases 25/45 (55.6%) were premenopausal women with a mean age of 36.6 years. Multiparity was more frequent within the study amounting to 30 cases (66.6%), with a mean parity of 4.1. Ductal type tumor was the predominant type detected in 22 cases (48.8%) among the reported histotypes. A heterozygous monoallelic nonsense mutation at nucleotide 3385 was found in four patients out of 9, where TTA codon was converted into the stop codon TGA.

Conclusion

This study detected a monoallelic nonsense mutation in four Sudanese female patients diagnosed with early onset BC from different families. Further work is needed to demonstrate its usefulness in screening of BC.

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.

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.

Clinical and pathological features of BRCA1/2 tumors in a sample of high-risk Moroccan breast cancer patients

BACKGROUND

BRCA1 and BRCA2 genes explain a large part of hereditary breast cancer. Several studies have shown that BRCA1 and BRCA2 tumors exhibit some specific morphological and immunohistochemical characteristics. The aim of our study is to compare the clinicopathological characteristics between Moroccan breast cancers associated or not with BRCA1 and BRCA2 mutations. Previously, we had identified 11 BRCA carriers in a series of 40 selected breast cancer patients at increased risk for carrying a mutation in the BRCA1 and BRCA2 genes. The clinical and pathological features of patients carrying BRCA1 or BRCA2 mutation (n = 11) were evaluated and compared to those of non-mutated patients (n = 29).

RESULTS

In comparison with non carriers, women with BRCA1/2 mutation present younger mean age at diagnosis (37.90 vs. 44.48 years, p = 0.05), younger mean age of 1st menarche (13.08 vs. 14.24 years, p = 0.05) and shorter duration of breastfeeding (8.71 vs. 19.35 months, p = 0.05). Moreover, 63.6 and 62.5% of BRCA1/2 carriers present SBR grade III and triple negative tumors respectively (p = 0.02).

CONCLUSIONS

In this first Moroccan study comparing clinical and pathological characteristics of women carrying or not BRCA1/2 mutation, patients with BRCA mutation tend to develop early breast cancer with high-grade and triple negative tumors. However, further large scale research including more data is needed to better characterize BRCA1/2 cases and to evaluate the survival rate associated with these mutations in our population tumors. Moreover, it would be more interesting to study women with BRCA1 and BRCA2 mutations separately in order to determine if they exhibit distinct characteristics.

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.

Family history predictors of BRCA1/BRCA2 mutation status among Tunisian breast/ovarian cancer families

BACKGROUND

With the increasing request for BRCA1/BRCA2 mutation tests, several risk models have been developed to predict the presence of mutation in these genes; in this study, we have developed an efficient BRCA genetic testing strategy.

METHOD

As first step, to identify predictor variables associated with BRCA status, we have undertaken a cumulative mutation analysis including data from three Tunisian studies. Then, we have developed a logistic regression model for predicting the likelihood of harboring a BRCA mutation. Using receiver operating characteristic curves (ROC), an effective evaluation was performed. A total of 92 Tunisian families were included. Overall, 27 women were positive for BRCA1/BRCA2 deleterious mutations.

RESULTS

Tow recurrent mutations (c.211dupA and c.5266dupC) explained 76 % of BRCA1-related families and three recurrent mutations (c.1310_1313del, c.1542_1547delAAGA and c.7887_7888insA) explained 90 % of BRCA2-related families. Early age at diagnosis of breast cancer, ovarian cancer, bilateral breast cancer were associated with BRCA1, whereas male breast cancer and four or more breast cancer cases in the family were associated with BRCA2. The area under the receiver operating characteristic curve of the risk score was 0.802 (95 % confidence interval = 0.0699-0. 905).

CONCLUSION

Logistic regression reported particular profiles related to BRCA germline mutation carriers in our population, as well as an efficient prediction model that may be a useful tool for increasing the cost-effectiveness of genetic testing strategy.

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.

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 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.

Screening of exon 11 of BRCA1 gene using the high resolution melting approach for diagnosis in Moroccan breast cancer patients

Background

Identification of specific mutations in cancer patients may lead to the discovery of genes, which can affect susceptibility and/or prognosis. It has previously been reported that mutations in BRCA1 and BRCA2 genes are linked to breast cancer. Here, we evaluated the use of the High Resolution Melting (HRM) approach to screen for mutations in exon 11 of BRCA1 gene in Moroccan patients.

Methods

HRM analysis was used to screen exon 11 from 71 breast cancer patients in order to detect different variants. Conventional Sanger sequencing was used to confirm the presence of possible mutations. Distribution of different SNPs was determined by SNaPshot analysis software.

Results

In order to assess the efficacy of the HRM approach to screen for mutations, especially in diagnosis, we first used two samples with previously known mutations, “2924delA and 3398delC”. Indeed, these previously known sequence variants were detected by the HRM approach and yielded melting curves with atypical shape relative to wild-type control sequences. We then analyzed, 69 samples from breast cancer patients using the HRM method, and were able to detect two samples with atypical curves. Sequencing of the two samples, using the conventional Sanger approach, confirmed the presence of the same SNP (c.2612C > T) in both samples.

Conclusions

Our results strongly suggest that the HRM approach represents a reliable and highly sensitive method for mutation scanning, especially in diagnosis.

The CHEK2 1100delC allelic variant is not present in familial and sporadic breast cancer cases from Moroccan population

Purpose

The cell-cycle checkpoint kinase 2 (CHEK2) is an important signal transducer of cellular responses to DNA damage, whose defects has been associated with increased risk for breast cancer. The CHEK2 1100delC mutation has been reported to confer a twofold increased risk of breast cancer among carriers. The frequency of the mutation varies among populations. The highest frequency has been described in Northern and Eastern European countries. However, the 1100delC mutation has been investigated in different case-control studies and none in Moroccan population. The aim of this study was to evaluate the prevalence of this variant and determine its contribution to the development of breast cancer in sporadic cases and also in members of breast cancer families who tested negative or positive for a deleterious mutation in BRCA1/BRCA2.

Methods

In this case-control study we performed the CHEK2 1100delC mutation analysis by ASO-PCR in 134 breast cancer patients and 114 unaffected control individuals. Most of these families had several cases of breast cancer or ovarian cancer (or both).

Results

No CHEK2 1100delC mutations were detected in any of 134 individuals, including 59 women diagnosed with breast cancer at an early age (<40 years), 10 women with bilateral breast cancer, and 6 women with ovarian cancer.

Conclusion

Our preliminary genetic analysis are consistent with the reported very low frequency of CHEK2 1100delC mutation in North American populations (compared with Northern Europe), rendering CHEK2 1100delC such as an unlikely to be major breast cancer susceptibility genes.

Arab gene geography: From population diversities to personalized medical genomics

Genetic disorders are not equally distributed over the geography of the Arab region. While a number of disorders have a wide geographical presence encompassing 10 or more Arab countries, almost half of these disorders occur in a single Arab country or population. Nearly, one-third of the genetic disorders in Arabs result from congenital malformations and chromosomal abnormalities, which are also responsible for a significant proportion of neonatal and perinatal deaths in Arab populations. Strikingly, about two-thirds of these diseases in Arab patients follow an autosomal recessive mode of inheritance. High fertility rates together with increased consanguineous marriages, generally noticed in Arab populations, tend to increase the rates of genetic and congenital abnormalities. Many of the nearly 500 genes studied in Arab people revealed striking spectra of heterogeneity with many novel and rare mutations causing large arrays of clinical outcomes. In this review we provided an overview of Arab gene geography, and various genetic abnormalities in Arab populations, including disorders of blood, metabolic, circulatory and neoplasm, and also discussed their associated molecules or genes responsible for the cause of these disorders. Although studying Arab-specific genetic disorders resulted in a high value knowledge base, approximately 35% of genetic diseases in Arabs do not have a defined molecular etiology. This is a clear indication that comprehensive research is required in this area to understand the molecular pathologies causing diseases in Arab populations.

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.

Novel nonsense mutation of BRCA2 gene in a Moroccan man with familial breast cancer

BACKGROUND

Breast cancer is the most common cancer in women worldwide. About 5 to 10% of cases are due to an inherited predisposition in two major genes, BRCA1 and BRCA2, transmitted as an autosomal dominant form. Male breast cancer is rare and is mainly due to BRCA2 than BRCA1 germline mutations.

OBJECTIVE

Molecular study of BRCA2 gene in man with familial breast cancer.

METHODS

PCR and direct sequencing of BRCA2 gene.

RESULTS

Identification of novel heterozygous germline mutation c.6428C>A ; p.Ser2143Stop of BRCA2 gene.

Mutation spectrum and prevalence of BRCA1 and BRCA2 genes in patients with familial and early-onset breast/ovarian cancer from Tunisia

The contribution of BRCA1/BRCA2 mutations to hereditary breast cancer in the Tunisian population has not been accurately estimated. The purpose of our study was to estimate the incidence and spectrum of pathogenic mutations in BRCA1/2 genes in early onset and familial breast/ovarian cancer among Tunisian women. To identify predictive factors for BRCA1/2 mutations, we screened the entire coding sequences and intron/exon boundaries of BRCA1/BRCA2 genes in 48 patients by direct sequencing. Twelve pathogenic mutations were detected (25%); three in BRCA1 (c.211dupA in four families, c.5266dupC in three families and c.1504_1508delTTAAA in one family) and two novel mutations in BRCA2 (c.1313dupT in two families and c.7654dupT in two families). We also identified 23 different polymorphisms and unclassified variants. These results indicate that our population has a spectrum of recurrent BRCA mutations.

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

Worldwide variation in the distribution of BRCA mutations is well recognised, and for the Moroccan population no comprehensive studies about BRCA mutation spectra or frequencies have been published. We therefore performed mutation analysis of the BRCA1 gene in 121 Moroccan women diagnosed with breast cancer. All cases completed epidemiology and family history questionnaires and provided a DNA sample for BRCA testing. Mutation analysis was performed by direct DNA sequencing of all coding exons and flanking intron sequences of the BRCA1 gene. 31.6 % (6/19) of familial cases and 1 % (1/102) of early-onset sporadic (< 45 years)were found to be associated with BRCA1 mutations. The pathogenic mutations included two frame-shift mutations (c.798_799delTT, c.1016dupA), one missense mutation (c.5095C>T),and one nonsense mutation (c.4942A>T). The c.798_799delTT mutation was also observed in Algerian and Tunisian BC families, suggesting the first non-Jewish founder mutation to be described in Northern Africa. In addition, ten different unclassified variants were detected in BRCA1, none of which were predicted to affect splicing. Most unclassified variants were placed in Align-GVGD classes suggesting neutrality. c.5117G>C involves a highly conserved amino acid suggestive of interfering with function (Align-GVGD class C55), but has been observed in conjunction with a deleterious mutation in a Tunisian family. These findings reflect the genetic heterogeneity of the Moroccan population and are relevant to genetic counselling and clinical management. The role of BRCA2 in BC is also under study.

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.