Association between ABCB1 C3435T polymorphism and breast cancer risk: a Moroccan case-control study and meta-analysis.

BACKGROUND: Breast cancer is the most common cause of cancer death among women. Several studies have investigated the relationship between the C3435T polymorphism of ABCB1 gene and risk of breast cancer; but the results are conflicting. In the present study, we sought to assess the relationship between the C3435T polymorphism in ABCB1 gene and the risk of breast cancer in a sample of the Moroccan population. METHODS: A case control study was performed on 60 breast cancer patients and 68 healthy women. The ABCB1 C3435T polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Furthermore, a meta-analysis including 16 studies with 6094 cases of breast cancer and 8646 controls was performed. RESULTS: Genotype frequencies were 50 % for CC, 33.3 % for CT and 16.7 % for TT in patients and 41.2 % for CC, 48.5 % for CT and 10.3 % for TT respectively in the control group. This difference was not statistically significant. The same trend as observed in the allele distribution between patients and controls (P = 0.84). Findings from the meta-analysis showed that the ABCB1 C3435T polymorphism was not associated with an increased risk of breast cancer in the dominant model (OR = 0.907; 95 % CI = 0.767-1.073; P = 0.25) as well as in the recessive model (OR = 1.181; 95 % CI = 0.973-1.434; P = 0.093) and in the allele contrast model (OR = 1.098; 95 % CI = 0.972-1.240; P = 0.133). However, the stratification of studies on ethnic basis showed that the TT genotype was associated with the risk of breast cancer in Asians (OR = 1.405; 95 % CI = 1.145-1.725; P = 0.001), Caucasians (OR = 1.093; 95 % CI = 1.001-1.194; P = 0.048) and North African (OR = 2.028; 95 % CI = 1.220-3.371; P = 0.006). CONCLUSIONS: We have noted that the implication of C3435T variant on the risk of breast cancer was ethnicity-dependent. However, there is no evidence that ABCB1 C3435T polymorphism could play a role in susceptibility to breast cancer in Morocco. Further studies with a larger sample size, extended to other polymorphisms are needed to understand the influence of ABCB1 genetic variants on the risk of breast cancer.

Association of TP53 PIN3 polymorphism with breast cancer in Moroccan population.

TP53 is a tumor suppressor gene involved in cell cycle progression control, DNA damage repair, genomic stability, and apoptosis. Some polymorphisms in this gene have been associated with the development of a number of cancers including breast carcinoma. PIN3 Ins16bp polymorphism has been widely studied in different populations for an association with breast cancer risk. In most case-control studies, a duplicated allele has been more frequent in cases rather than controls but there are also inconsistent results. The present study aimed to assess the association of PIN3 Ins16bp polymorphism of p53 with breast cancer risk in Moroccan population. This case-control study was performed on 105 female patients with confirmed breast cancer and 114 healthy controls. The genotype frequency was 69.5 % (A1A1), 26.7 % (A1A2), and 3.8 % (A2A2) in patients and 68.4 % (A1A1), 24.6 % (A1A2), and 7 % (A2A2) in controls. No statistically significant association was observed between PIN3 Ins16bp polymorphism and breast cancer risk with odds ratio of 1.07 (confidence interval (CI) = 0.58-1.97, p = 0.83) for the heterozygous A1A2 and 0.53 (CI = 0.15-1.85, p = 0.32) for mutated homozygous A2A2.According to our preliminary genetic analysis, PIN3 Ins16pb polymorphism could not be assessed as a marker of risk factor for predisposition to breast cancer in Moroccan population. However, a high frequency of A2 allele (19.3 %) in our population suggested that PIN3 Ins16pb polymorphism may be a valuable marker for study in other cancers with larger groups.

A novel SCN8A variant of unknown significance in pediatric epilepsy: a case report.

Variants in SCN8A are associated with several diseases, including developmental and epileptic encephalopathy, intermediate epilepsy or mild-to-moderate developmental and epileptic encephalopathy, self-limited familial infantile epilepsy, neurodevelopmental delays with generalized epilepsy, neurodevelopmental disorder without epilepsy, hypotonia, and movement disorders. Herein, we report an 8-year-old Moroccan boy with intermediate epilepsy of unknown origin, intellectual disability, autism spectrum disorder, and hyperactivity. The patient presented a normal 46, XY karyotype and a normal comparative genomic hybridization profile. Whole-exome sequencing was performed, and heterozygous variants were identified in KCNK4 and SCN8A. The SCN8A variant [c.4499C > T (p.Pro1500Leu)] was also detected in the healthy mother and was classified as a variant of uncertain clinical significance. This variant occurs in a highly conserved domain, which may affect the function of the encoded protein. More studies are needed to confirm the pathogenicity of this novel variant to establish the effective care, management, and genetic counselling of affected individuals.

[Prognostic value of residual disease detection in acute myeloid leukemia with normal karyotype and negative FLT3-ITD]. / Intérêt pronostique de la détection de la maladie résiduelle dans les leucémies aiguës myéloïdes avec caryotype normal et FLT3-ITD négatif.

INTRODUCTION: Complete remission (CR) in patients with acute myeloid leukemia (AML) is still morphologicaly defined, thus corresponding to a wide range of tumor burden. OBJECTIVES: we aimed to evaluate the residual disease (MRD) status in patients with AML, as well as perform a molecular analysis of the FLT3/ITD gene in patients with normal karyotype. MATERIAL AND METHODS: adult patients with AML, diagnosed according to the WHO 2016 criteria, were included. MRD was detected using flow cytometric techniques after induction treatment resulting in CR. RESULTS: thirty patients met our inclusion criteria. 83 % of them had an intermediate risk status, 67 % of which (20/30) having a normal karyotype. MRD and leukemic stem cell (LSC) positivity in this group was predominant with considerable decrease in benign progenitor count. The relapse-free survival (RFS) in the group of MRD negative patients with normal cytogenetics and non-mutated FLT3 gene was better than the RFS in all of our patients studied. CONCLUSION: MRD and LSC are powerful prognostic factors for relapse. They should be routinely integrated to guide better management of AML.

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

OBJECTIVE: Breast cancer is the most common female cancer in Morocco. About 5 to 10% are due to hereditary predisposition and mutations in BRCA1 and BRCA2 genes are responsible for an important proportion of high-risk breast/ovarian cancer families. The relevance of BRCA1/2 mutations in the Moroccan population was not studied. The main objective of this study is to investigate the spectrum of BRCA1 and BRCA2 germline mutations in early onset and familial breast/ovarian cancer among Moroccan women. METHODS: We screened the entire coding sequences and intron/exon boundaries of BRCA1 and BRCA2 genes in 40 patients by direct sequencing. RESULTS: Nine pathogenic mutations were detected in ten unrelated families, five deleterious mutations in BRCA1 gene and four mutations in BRCA2 gene. Four novel mutations were found: one in BRCA1 (c.2805delA/2924delA) and three in BRCA2 (c.3381delT/3609delT; c.7110delA/7338delA and c.7235insG/7463insG). We also identified 51 distinct polymorphisms and unclassified variants (three described for the first time). CONCLUSIONS: Our data suggest that BRCA1 and BRCA2 mutations are responsible for a significant proportion of familial breast cancer in Moroccan patients. Therefore full BRCA1/2 screening should be offered to patients with a family history of breast/ovarian cancer.

R306X Mutation in the MECP2 Gene Causes an Atypical Rett Syndrome in a Moroccan Patient: A Case Report.

Rett syndrome (RTT) is a rare X-linked syndrome that predominantly affects girls. It is characterized by a severe and progressive neurodevelopmental disorder with neurological regression and autism spectrum features. The Rett syndrome is associated with a broad phenotypic spectrum. It ranges from a classical Rett syndrome defined by well-established criteria to atypical cases with symptoms similar to other syndromes, such as Angelman syndrome. The first case of a Moroccan female child carrying a R306X mutation in the MECP2 (Methyl-CpG-Binding Protein 2) gene, with an unusual manifestation of Rett syndrome, is presented here. She showed autistic regression, behavioral stagnation, epilepsy, unmotivated laughter, and craniofacial dysmorphia. Whole exome sequencing revealed a nonsense mutation (R306X), resulting in a truncated, nonfunctional MECP2 protein. The overlapping phenotypic spectrums between Rett and Angelman syndromes have been described, and an interaction between the MECP2 gene and the UBE3A (Ubiquitin Protein Ligase E3A) gene pathways is possible but has not yet been proven. An extensive genetic analysis is highly recommended in atypical cases to ensure an accurate diagnosis and to improve patient management and genetic counseling.

Large-scale meta-analysis of genetic studies in ischemic stroke: Five genes involving 152,797 individuals.

BACKGROUND: Ischemic stroke descent has a genetic basis. Stroke represents a complex trait, which is assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies. MATERIALS AND METHODS: We performed a literature-based systematic review of genetic association studies in stroke abound several populations. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for each gene-disease association. Following a review of 300 manuscripts, five candidate gene variants were analyzed among 152,797 individuals (45,433 cases and 107,364 controls). RESULTS: For these five candidate genes studied, the prothrombin OR is 1,57 (1,23-2,89), the factor V Leiden OR is 1,43 (0,67-6,24), the mean OR of angiotensin I converting enzyme (ACE) insertion/deletion (I/D) polymorphism is 1,11 (1,02-1,25), the summary OR for the C677T variant of 5,10-methylenetetrahydrofolate reductase (MTHFR) is 1,23 (0,61-1,47) and the pooled OR for the apolipoprotein E (APOE) gene is 0,95 (0,77-1,14) . CONCLUSION: These data suggest the genetic associations of some genes with ischemic stroke and it is necessary to compete with other genes. Our findings could represent an epidemiological base and a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

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.

BRCA Mutational Status is a Promising Predictive Biomarker for Platinum- based Chemotherapy in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) can be distinguished from other breast malignancies by the lack of expression of estrogen receptors (ER), progesterone receptors (PR) as well as human epidermal growth factor receptor 2 (HER2). TNBC is associated with adverse clinical outcomes and high risk of metastasis. Currently, several clinical and translational reports are focusing on developing targeted therapies for this aggressive cancer. In addition to approved targeted drugs such as poly(ADP-ribose) polymerase inhibitors (PARPi) and immune-checkpoint inhibitors, platinum-based chemotherapy is still a cornerstone therapeutic option in TNBC. However, despite the observed improved outcomes with platinum- based chemotherapy in TNBC, there is still a large proportion of patients who do not respond to this treatment, hence, the need for predictive biomarkers to stratify TNBC patients and therefore, avoiding unwanted toxicities of these agents. With the emergence of genetic testing, several recent studies suggested mutations in breast cancer susceptibility gene (BRCA) in TNBC patients as important predictors of outcomes. These mutations alter the homologous recombination repair (HRR) mechanisms leading to genomic instability. Consequently, sensitivity to platinum-based treatments in this subpopulation of TNBC patients may be explained by cell death enhanced by deoxyribonucleic acid (DNA) damage induced by these potent anticancer drugs. Through this paper, we review several recent studies on this topic to better understand the mechanisms and discuss the potential of BRCA mutational status as a predictive biomarker of platinum-based chemotherapy in TNBC.

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.

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.

Relationship between family history of breast cancer and clinicopathological features in Moroccan patients.

BACKGROUND: Breast cancer is the most common cancer affecting women all over the world. In addition to hormonal and environmental causes, family history is emerging as an important risk factor in the etiology of this disease. The aim of the present study is thus to compare the clinico-pathological features of familial and sporadic breast cancer in Moroccan patients. METHODS: A comparative retrospective cohort study was conducted on 570 women with familial and sporadic breast cancer who were diagnosed and treated in the Oncology Center of Ibn Rochd University Hospital in 2009. Data on breast cancer risk factors and clinico-pathological characteristics of the tumors were extracted from patients' medical records. RESULTS: Familial cases represented 18.4% of breast cancer patients. The age of onset appears to be earlier in familial breast cancers (P=0.0024). There were no significant differences between familial and sporadic groups according to histological type, tumor size and estrogen receptor status. However, Scarff-Bloom-Richardson grade III was found in 43.8% of familial cases vs 26.7% of sporadic cases (P=0.0127) and the lymph node involvement was observed in 72.4% of familial cases vs 58.9% in sporadic cases (P=0.0213). Moreover, familial breast cancer patients present especially progesterone receptor-negative tumors (P=0.0380). CONCLUSIONS: Our initial significant findings show that familial breast cancer seems to affect young women and tends to present high Scarff-Bloom-Richardson grade tumors with lymph node involvement and absence of progesterone receptors. These preliminary results may be useful as clinical marker to identify familial breast cancer allowing the development of careful follow-up for this patients subtype.