A Comparative Analysis of NOX4 Protein Expression in Malignant and Non-Malignant Thyroid Tumors.

The comparative analysis of the expression of the reactive oxygen species-generating NADPH oxidase NOX4 from TCGA data shows that the NOX4 transcript is upregulated in papillary thyroid carcinomas (PTC)-BRAFV600E tumors compared to PTC-BRAFwt tumors. However, a comparative analysis of NOX4 at the protein level in malignant and non-malignant tumors is missing. We explored NOX4 protein expression by immunohistochemistry staining in malignant tumors (28 classical forms of PTC (C-PTC), 17 follicular variants of PTC (F-PTC), and three anaplastic thyroid carcinomas (ATCs)) and in non-malignant tumors (six lymphocytic thyroiditis, four Graves' disease, ten goiters, and 20 hyperplasias). We detected the BRAFV600E mutation by Sanger sequencing and digital droplet PCR. The results show that NOX4 was found to be higher (score ≥ 2) in C-PTC (92.9%) compared to F-PTC (52.9%) and ATC (33.3%) concerning malignant tumors. Interestingly, all C-PTC-BRAFV600E expressed a high score for NOX4 at the protein level, strengthening the positive correlation between the BRAFV600E mutation and NOX4 expression. In addition, independent of the mutational status of BRAF, we observed that 90% of C-PTC infiltrating tumors showed high NOX4 expression, suggesting that NOX4 may be considered a complementary biomarker in PTC aggressiveness. Interestingly, NOX4 was highly expressed in non-malignant thyroid diseases with different subcellular localizations.

Germline mutations of B-Raf proto-oncogene and pathological implications in prostate cancer: observational study.

B-Raf proto-oncogene has been found in a variety of neoplasms. BRAF stimulation can promote tumour proliferation through the activation of the MAP/ERK kinase pathway. This study aimed to determine the germline spectra of BRAF and the association with pathological criteria of prostate tumours. Methods: Fifty blood samples from men treated with prostate cancer were analyzed for BRAF germline mutations and confirmed by Sanger sequencing, in addition, to establishing the frequencies and clinical correlations of frequent mutations in the BRAF gene for both exon 11 and exon 15. The frequency and distribution of high-frequency mutations were analyzed according to the pathological criteria of the patients. Results: Frameshift mutations: c.1628_1629insA and c.1624_1625insT with a frequency of (46%) and (18%), respectively, Nonsense mutations: c.1181C>A (p.Ser394Ter) was detected in one patient, missense mutations: c.1226A>G (p.Gln409Arg), c.1270T>C (p.Trp424Arg), c.1270_1271delins2 (p.Trp424Leu), with a frequency of (4%) were detected. There was no significant difference between mutation carriers and non-carriers regarding medical and surgical history, but prostate-specific antigen concentration was significantly different between the two groups. Conclusion: The results of this study elucidate the presence and involvement of germline mutations in prostate cancer, which could serve as a potential indicator for the diagnosis and therapeutic management of prostate cancer in the population studied.

Advanced Non-small Cell Lung Cancer: EGFR Mutation Analysis Using Pyrosequencing and the Fully Automated qPCR-Based IdyllaTM System.

BACKGROUND: Epidermal growth factor receptor (EGFR) mutation status is of a major clinical significance in non-small cell lung cancer (NSCLC) management, as it guides therapeutic decision making to target patients for a better response to therapy. This implicates the introduction of EGFR mutation analysis as the standard of care for Moroccan NSCLC patients, which in itself entails the implementation of targeted methods for routine EGFR mutation analysis in our laboratories. In this study, we aimed to present 2 targeted methods for EGFR mutation identification and to determine the prevalence and spectrum of EGFR mutations in NSCLC Moroccan patients. METHODS: A retrospective investigation of a cohort of 340 patients was undertaken to analyze somatic EGFR mutations in exons 18 to 21 using pyrosequencing and the IdyllaTM system. RESULTS: Of the enrolled patients, 70.9% were males and 29.1% were females. Predominately, 92% of cases had adenocarcinoma, and 53.7% of patients self-reported a history of smoking. Overall, 73 patients (21.7%) harbored an EGFR mutation, the most prevalent of which were the exon 19 deletions (53.4%) followed by exon 21 substitutions (31%). Exon 18 mutations and exon 20 alterations occurred in 8.1% and 6.7% of the positive EGFR mutation cases, respectively. Of the analyzed cases, all of the EGFR-mutated patients had adenocarcinoma. EGFR mutation prevalence was significantly higher in females (females vs males: 38.4% vs 14.5%, P < .001) and non-smokers (non-smokers vs non-smokers: 36% vs 10.3%, P < .001). The featured pyrosequencing and the IdyllaTM system are targeted methods endowed with high sensitivity and specificity as well as other compelling characteristics which make them great options for routine EGFR mutation testing for advanced NSCLC patients. CONCLUSION: These findings underline the imperious need for implementing quick and efficient targeted methods for routine EGFR mutation testing among NSCLC patients, which is particularly useful in determining patients who are more likely to benefit from targeted therapy.

Molecular evaluation of human papillomavirus as an oncogenic biomarker in prostate cancer.

BACKGROUND: Prostate cancer (PCa) is one of the most common tumors in men, regardless of ethnicity and demographics. In many risk factors causing PCa, genes and viral infections are strong candidates for the development of prostate tumors. Indeed, tissue infections of PCa have been reported by the presence of several types of viruses including Human Papillomaviruses (HPV). OBJECTIVE: the present study was planned to determine whether HPV DNA could be detected in the blood of known men with prostate cancer and to assess the potential association between HPV infection and clinico-pathological characteristics of the patients. MATERIALS AND METHODS: In order to achieve our objectives, 150 liquid blood samples were taken from Moroccan patients, 100 patients with PCa, and 50 control cases. The viral DNA was extracted, calibrated and the target genes were amplified by PCR using specific primers and the use of 2% agarose gel with visualization under UV. RESULTS: Of the 100 samples tested, (10%) were infected with HPV), However, none of the control cases were infected with HPV. The analysis of the data made it possible to establish a correlation between the frequency of the viral infection of the human papilloma and the tumoral criteria. CONCLUSION: Therefore, this study strengthens the potential role of HPV as a cofactor in prostate cancer development, and we propose that infection with this virus may be involved in the development of PCa metastases.

Prevalence and patterns of mutations in RAS/RAF/MEK/ERK/MAPK signaling pathway in colorectal cancer in North Africa.

BACKGROUND: Our review discuss (i) the findings from analyzed data that have examined KRAS, NRAS and BRAF mutations in patients with colorectal cancer (CRC) in North Africa and to compare its prevalence with that shown in other populations and (ii) the possible role of dietary and lifestyle factors with CRC risk.  METHODS: Using electronic databases, a systematic literature search was performed for the KRAS, NRAS, and BRAF mutations in CRC patients from Morocco, Tunisia, Algeria and Lybia.  RESULTS: Seventeen studies were identified through electronic searches with six studies conducted in Morocco, eight in Tunisia, two in Algeria, and one in Libya. A total of 1843 CRC patients were included 576 (31.3%) in Morocco, 641 (34.8%) in Tunisia, 592 (32.1%) in Algeria, and 34 (1.8%) in Libya. Overall, the average age of patients was 52.7 years old. Patients were predominantly male (56.6%). The mutation rates of KRAS, NRAS and BRAF were 46.4%, 3.2% and 3.5% of all patients, respectively. A broad range of reported KRAS mutation frequencies have been reported in North Africa countries. The KRAS mutation frequency was 23.9% to 51% in Morocco, 23.1% to 68.2% in Tunisia, 31.4% to 50% in Algeria, and 38.2% in Libya. The G12D was the most frequently identified KRAS exon 2 mutations (31.6%), followed by G12V (25.4%), G13D (15.5%), G12C (10.2%), G12A (6.9%), and G12S (6.4%). G12R, G13V, G13C and G13R are less than 5%. There are important differences among North Africa countries. In Morocco and Tunisia, there is a higher prevalence of G12D mutation in KRAS exon 2 (≈50%). The most frequently mutation type in KRAS exon 3 was Q61L (40%). A59T and Q61E mutations were also found. In KRAS exon 4, the most common mutation was A146T (50%), followed by K117N (33.3%), A146P (8.3%) and A146V (8.3%). CONCLUSION: KRAS mutated CRC patients in North Africa have been identified with incidence closer to the European figures. Beside established anti-CRC treatment, better understanding of the causality of CRC can be established by combining epidemiology and genetic/epigenetic on CRC etiology. This approach may be able to significantly reduce the burden of CRC in North Africa.

Clinical Significance of Somatic Mutations in RAS/RAF/MAPK Signaling Pathway in Moroccan and North African Colorectal Cancer Patients.

BACKGROUND: Mutations in RAS (KRAS, NRAS) and BRAF genes are the main biomarker predicting response to anti-EGFR monoclonal antibodies in targeted therapy in colorectal cancer (CRC). OBJECTIVE: Our study aims to evaluate the frequencies of KRAS, NRAS and BRAF mutations and their possible associations with clinico-pathological features in CRC patients from Morocco. METHODS: DNA was extracted from 80 FFPE samples using the QIAamp DNA FFPE-kit. RAS and BRAF mutations were assessed by pyrosequencing assays using Qiagen, KRAS Pyro®kit 24.V1, Ras-Extension Pyro®kit 24.V1 and BRAF Pyro®Kit 24.V1, respectively, and carried out in the PyroMark-Q24. RESULTS: RAS mutations were identified in 57.5% (56.2% in KRAS, 8.8% in NRAS). In KRAS gene, exon 2 mutations accounted for 93.3% (68.9% in codon 12, 24.4% in codon 13). Within codon 12, G12D was the most prevalent mutation (37.7%), followed by G12C (13.4%), G12S (8.9%) and G12V (6.6%). Within codon 13, the most frequently observed mutation was G13D (22.3%). The mutation rates of exon 3 and 4 were 15.6% and 13.3%, respectively. In exon 3 codon 61, 2.3% patients were detected with two concurrent mutations (Q61R, Q61H), and 4.4% with three concurrent mutations (Q61R, Q61H, Q61L). In NRAS gene, the mutation rates of exon 2, 3 and 4 were 57.1%, 28.6%, and 14.3%, respectively. G13A and Q61H were the most common mutations, accounting for 42.9% and 28.5%, respectively. There were 13% patients with concurrent KRAS/NRAS mutation and 4.3% wt KRAS with NRAS mutations. No mutations were identified in BRAF gene. In both sexes, KRAS codon 12 mutations were associated with higher stage III/IV tumors. Moreover, Patients whose tumor is in the proximal colon (56.3%) are more likely to harbor KRAS mutations than those tumor located in rectum (25%). CONCLUSION: RAS mutations could be useful in future target anti-EGFR therapy and molecular CRC screening strategy in Morocco.

Molecular characterization of human papillomavirus and mouse mammary tumor virus-like infections in prostate cancer tissue and relevance with tumor characteristics.

The suspected roles of human Papillomavirus (HPV) and mouse mammary tumor virus (MMTV) infections in prostate tumor development were recently reported. To detect the frequency of HPV and MMTV-like infections and clinical correlates of tumor characteristics, DNA samples from 50 men treated at Teaching Hospital of Rabat City (Morocco) between June 2017 and February 2019, were genotyped and confirmed by Sanger sequencing. Eight infections of HPV18 and two infections of MMTV-like were detected, and 50% of patients were at a Gleason score of 6. A significant association between Gleason score and HPV or MMTV-like infection was noted (P=0.0008); 90% of patients with viral infections presented with T1 and T2 pathological stage tumors. Yet, no significant differences were found between infected and noninfected men regarding other pathological parameters including prostate-specific antigen (PSA), tumor histological stage, age at diagnosis and radical prostatectomy treatment (P=0.2179, 0.4702, 0.8101, and 0.9644, respectively). The molecular evolution of HPV and MMTV in comparison with previously aligned sequences was discussed. Our findings provide a highlight on the correlations between the clinical-pathological parameters of prostate tumors and HPV and MMTV infections. Prospective studies with a wide sample size are needed for more statistical clarification of the association between viral infections with prostate tumor criteria.

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.

The Biological Significance of Long noncoding RNAs Dysregulation and their Mechanism of Regulating Signaling Pathways in Cervical Cancer.

Despite the remarkable decrease in cervical cancer incidence due to the availability of the HPV vaccine and implementation of screening programs for early detection in developed countries, this cancer remains a major health problem globally, especially in developing countries where most of the cases and mortality occur. Therefore, more understanding of molecular mechanisms of cervical cancer development might lead to the discovery of more effective diagnosis and treatment options. Research on long noncoding RNAs (lncRNAs) demonstrates the important roles of these molecules in many physiological processes and diseases, especially cancer. In the present review, we discussed the significance of lncRNAs altered expression in cervical cancer, highlighting their roles in regulating highly conserved signaling pathways, such as mitogen-activated protein kinase (MAPK), Wnt/ß-catenin, Notch, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathways and their association with the progression of cervical cancer in order to bring more insight and understanding of this disease and their potential implications in cancer diagnosis and therapy.

Visceral Crisis Means Short Survival Among Patients With Luminal A Metastatic Breast Cancer: A Retrospective Cohort Study.

BACKGROUND: Patients with visceral crisis from luminal metastatic breast cancer (mBC) are often treated with palliative chemotherapy. No studies have analyzed the aggressiveness of the care in visceral crisis from luminal mBC patients. The objective of this study was to assess practices in this setting in a university medical oncology department. METHODS: This retrospective study included all patients who were managed for luminal mBC between January 2013 and April 2016. The analysis focused on the characteristics of the patients, the modalities of cancer treatment and delays between visceral crisis and death. RESULTS: Thirty-five patients pre-treated with two hormonal therapy lines were enrolled retrospectively. Worse performance status and a higher proportion of severe organ dysfunction for luminal mBC were observed among patients with visceral crisis. Sixty-five percent of patients received cytotoxic treatment. One cycle of chemotherapy was administrated in the majority of patients. Palliative care was performed in 35% of patients. Chemotherapy did not have any significant effect on patient outcome in the present study. The mean time between visceral crisis and death was 4.7 weeks (standard deviation = 1.9). CONCLUSION: Our study showed that visceral crisis in patients with luminal mBC is a complex problem. We need more comprehension of molecular pathogenesis to visceral crisis disease to propose efficacious treatments for these patients and to identify subgroup of patients who need chemotherapy followed by maintenance endocrine therapy.

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.

The single nucleotide polymorphism +936 C/T VEGF is associated with human epidermal growth factor receptor 2 expression in Moroccan breast cancer women.

The vascular endothelial growth factor (VEGF), a potent regulator of angiogenesis, is involved in the development and progression of breast cancer (BC). The functional +936 C/T polymorphism of the VEGF-A gene has been implicated in BC susceptibility; however, published data are conflicting. In the current case-control study, we analyzed the association of the +936 C/T polymorphism with BC risk and tumor markers expression, human epidermal growth factor receptor 2 (HER2/neu) and caner antigen 15.3 (CA 15.3) in Moroccan women. We genotyped the DNA of 70 BC patients and 70 healthy women by TaqMan SNP assays. The χ(2) test and Fisher's exact test were used for statistical analyses. The overall results revealed that there is no association between the +936 C/T polymorphism and BC risk [p = 0.8; OR 0.87, 95 % CI (0.32-2.42)]. However, when we stratified the group of patients according to the status of tumor markers, a statistical significant association of +936 C/T SNP and HER2/neu expression was observed (p = 0.009). In contrast, no association with the other tumor marker, CA 15.3, was found (p = 0.090). Thus, the +936 C/T polymorphism seems to have a correlation with HER/neu expression in BC disease.

Investigating the association of vascular endothelial growth factor polymorphisms with breast cancer: a Moroccan case-control study.

The main mediator of breast cancer (BC) angiogenesis is the vascular endothelial growth factor (VEGF). Variation of VEGF-A gene may influence the BC susceptibility. The present case-control study investigated the association of the four commonly studied single nucleotide polymorphisms (SNP) of VEGF-A, namely: -1154A/G (rs1570360), -2578C/A (rs699947), -634G/C (rs2010963) and -460T/C (rs833061) with BC susceptibility and aggressiveness in Moroccan women. After genomic DNA extraction, genotyping was performed by TaqMan SNP assays on 70 BC patients and 70 healthy women. The χ2 test was used to detect differences in the genotype frequencies of VEGF between the groups and to stratify genotypes by the clinico-pathological characteristics in patient's group. Women carriers of -1154AG + AA and -2578AC + AA VEGF genotypes had a reduced risk to develop BC [p = 0.018, OR 2.25 95 % CI (1.14-4.42) and p = 0.022, OR 2.26 95 % CI (1.12-4.58), respectively]. Carriers of -460CT and CT + CC genotypes had also a reduced risk to develop BC [p = 0.045, OR 2.63 95 % CI (1.19-5.84) and p = 0.043, OR 2.12 95 % CI (1.01-4.43), respectively]. Moreover, the A-1154A-2578G-634C-460 haplotype seems to have a protective effect against BC risk [p = 0.007, OR 2.41 95 % CI (1.27-4.55)]. Stratification for BC patients according to clinico-pathological characteristics reveals no association with any of VEGF-A SNPs. In conclusion, the data indicated significant associations of VEGF -1154A/G, -2578C/A and -460T/C polymorphisms with BC susceptibility in Moroccan individuals. These VEGF-A polymorphisms can be useful as predisposing genetic markers for BC. Further larger-scale studies are necessary to confirm our finding.

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.

Relation between plasma homocysteine, gene polymorphisms of homocysteine metabolism-related enzymes, and angiographically proven coronary artery disease.

BACKGROUND: Hyperhomocyteinemia (HHcy) is a risk factor for coronary artery disease (CAD), and methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and methionine synthase reductase (MTRR) polymorphisms may contribute to plasma total homocysteine (tHcy) variation. We investigated the association of polymorphisms 1298A-->C in the MTHFR gene, 2756A-->G in the MTR gene, and 66A-->G in the MTRR gene with tHcy levels and with CAD in patients undergoing coronary angiography. METHODS: CAD patients (n=151) and control subjects (n=79) were compared regarding the prevalence of the polymorphisms, risk factors, and biochemical parameters. RESULTS: The mean tHcy concentration was significantly higher in CAD patients than in control subjects (P<0.001). HHcy (tHcy>/=15 mumol/l) conferred an OR of CAD of 4.1 (95% CI 2.2-7.5, P<0.001). In both cases and controls, smokers had a higher tHcy level than non-smokers and demonstrated a markedly increased risk for CAD (OR=2.5, 95% CI 1.7-3.3, P<0.001). The allele frequencies of the MTHFR 1298A-->C, MTR 2756A-->G, and MTRR 66A-->G mutations were 36.7%, 15.7%, and 36.6%, respectively. The 1298C allele frequency was significantly higher in the CAD group than in controls (P<0.05) and showed a significant association with CAD in heterozygote carriers. There was no statistically significant difference between cases and controls in the frequencies of the A2756G alleles/genotypes in the MTR gene and of the A66G alleles/genotypes in the MTRR gene. The contributions to tHcy levels of the three common mutations were statistically significant. The heterozygosity of the MTHFR 1298AC genotype, MTR 2756G allele, and MTRR 66G allele yielded an OR of 3.4, 2.0, and 2.1, respectively, for having HHcy. CONCLUSION: We suggest that HHcy confers a risk for CAD, and smokers with tHcy are at a greatly increased risk. Our finding supports an important role of the MTHFR gene in CAD and provides evidence of polygenic regulation of tHcy.

Thermolabile methylenetetrahydrofolate reductase C677T polymorphism and homocysteine are risk factors for coronary artery disease in Moroccan population.

Increased plasma total homocysteine (tHcy) levels have been shown to be a risk factor for coronary artery disease (CAD). The common methylenetetrahydrofolate reductase C677T (MTHFR C677T) polymorphism has been reported to be a strong predictor of mild hyperhomocysteinaemia (HHcy). We assessed whether this mutation was associated with increased risk of CAD and plasma levels of tHcy. We also evaluated interactions between this polymorphism, mild elevated tHcy levels and conventional risk factors of CAD. Method. Using PCR-RFLP analysis, we studied the frequency of the C677T genotypes and its effect on CAD and on tHcy concentrations in 400 subjects without and with CAD angiographically confirmed. There were 210 subjects with CAD and 190 subjects without CAD. Results. The frequencies of the C677T genotypes were 53% (59.5% in controls versus 48.1% in cases), 34.8% (32.1 in controls versus 37.1 in cases), and 11.8% (8.4% in controls versus 14.8% in cases), respectively, for 677CC, 677CT, and 677TT. The genotype frequencies were significantly different between case and control groups (P < .05). The 677T allele enhances the risk of CAD associated to HHcy (P < .01). In multivariate analysis models, MTHFR C677T polymorphism effect on CAD was masked by other risk factors. HHcy was only and independently influenced by MTHFR polymorphism and smoking habits, and it is a strong predictor of CAD independently of conventional risk factors. Conclusion. Our data suggest that HHcy is strongly and independently associated to CAD risk increase; and MTHFR C677T polymorphism and smoking habits were the main predictors of tHcy levels. The CAD risk increase is mainly associated with mild HHcy in 677TT, whereas in 677CT and 677CC it is mainly associated with the conventional risk factors.

Influence of methionine synthase (A2756G) and methionine synthase reductase (A66G) polymorphisms on plasma homocysteine levels and relation to risk of coronary artery disease.

BACKGROUND: Elevated plasma total homocysteine (tHcy) is increasingly being recognized as a risk factor for coronary artery disease (CAD) and other defects. Recent genetic studies have characterized molecular determinants contributing to altered homocysteine metabolism. Our objectives were therefore to confirm the relationship of tHcy with CAD and to examine the importance of genetic influence on tHcy in the coronary angiograms and conventional cardiovascular risk factors recorded in 230 subjects. We also determined the genotype frequencies distribution of the A2756G transition of the B12-dependent methionine synthase (MTR) gene and the A66G mutation of the methionine synthase reductase (MTRR) gene. RESULTS: Patients with CAD (n=151) had significantly higher tHcy concentrations than control subjects (15.49 +/- 2.75 micromol/l vs. 11.21 +/- 3.54 micromol/l, P < 0.001). Hyperhomocysteinaemia (tHcy > or =15 micromol/l) was a risk factor for CAD [RR = 4.07, 95% CI: 2.21 - 7.47, P < 0.001]. The homocysteine concentrations were significantly different between smokers and non-smokers, at 15.63 +/- 3.10 vs. 12.45 +/- 3.84 micromol/l, P < 0.05. In addition, smokers with hyperhomocysteinaemia demonstrated a markedly increased risk of CAD (OR = 2.50, 95% CI: 1.67 - 3.32, P < 0.05) compared with non-smokers with normal homocysteine.The 2756G and the 66G allele contribute to a moderate increase in homocysteine levels (P = 0.008 and P = 0.007, respectively), but not to CAD (P > 0.05). Combined MTR and MTRR polymorphisms, the 2756AG + 66AG and the 2756AG + 66GG were the combined genotypes that were a significant risk factor for having hyperhomocysteinaemia (14.4 +/- 2.8 micromol/l, OR = 2.75, IC 95% = 1.21 - 6.24, P=0.016 and 17.9 +/- 4.1 micromol/l, OR = 6.28, IC 95% = 1.46 - 12.1, P = 0.021, respectively). Statistic analysis using the UniANOVA test shows that these two polymorphisms have an interactive effect circulating homocysteine levels (P < 0.05). CONCLUSION: Our data suggest that moderately elevated tHcy levels are prevalent in our population and are associated with an increased risk for CAD. This study provides evidence that the MTR A2756G and MTRR A66G polymorphisms significantly influence the circulating homocysteine concentration. In addition, the MTR and MTRR genes may interact to increase the risk for having hyperhomocysteinaemia.