NS5A(ISDR-V3) region genetic variability of Tunisian HCV-1b strains: Correlation with the response to the combined interferon/ribavirin therapy.

In the non-structural protein 5A (NS5A) of hepatitis C virus (HCV), mutations within the interferon sensitivity-determining region (ISDR), the PKR-binding domain (PKR-BD), the variable region 3 (V3), and the interferon/ribavirin resistance-determining region (IRRDR) have been correlated with the IFN-based therapy response. In Tunisia, where a high prevalence of HCV-1b has been found, no data regarding the implication of NS5A in treatment response were available. The current study examined the relationship between the pre-treatment mutation number within ISDR, PKR-BD, V3, IRRDR, as well as in the entire ISDR-V3 region of NS5A (aa 2209-2379) and the response to the 48-week course of combined IFN plus ribavirin therapy in 15 HCV-1b-infected Tunisian patients. Referring to HCV-J sequence, a significant high genetic variability was observed within PKR-BD in the sustained virological responder patients compared to non-responders (P = 0.040). More importantly, when considering the entire region from ISDR to V3, referred to as NS5A(ISDR-V3), a clear difference in the mutation number was observed between sustained virological responders (19.6 +/- 3.16) and non-responders (15.0 +/- 1.41) (P = 0.002). Additionally, a more detailed analysis of NS5A(ISDR-V3) region revealed an elevated degree of mutation rate within the region located between amino acids 2282 and 2308 (P = 0.0006). Interestingly, an analysis of specific amino acid variations defined proline and serine at position 2300 as signature patterns for sensitive and resistant strains, respectively. The genetic variability within the NS5A region of HCV-1b strains was associated with the response to the combined IFN plus ribavirin therapy in our Tunisian cohort.

Comparative clinical and transcriptomal profiles of breast cancer between French and South Mediterranean patients show minor but significative biological differences.

BACKGROUND: In Western countries, breast cancer incidence and mortality are higher than in Mediterranean countries. These differences have been ascribed to environmental factors but also to late-stage diagnostic and biological specific characteristics. PATIENTS AND METHODS: Between September 2002 and September 2005, we collected clinical data by phone counselling 180 French and Mediterranean breast cancer patients and performed microarray experiments. RESULTS: Characteristics of breast cancer in patients from Lebanon, Tunisia and Morocco were more aggressive (more SBR grade III and positive node invasion) and patients were 10 years younger at diagnosis. Sixteen differentially expressed genes such as MMP9, VEGF, PHB1, BRCA1, TFAP2C, GJA1 and TFF1 were also found. Additionally, an up-regulation of cytokeratins KRT8 and KRT18 may indicate a luminal B subtype in "South" (Lebanon, Tunisia and Morocco) tumors while "North" (France) tumors may more frequently be luminal A type. CONCLUSION: This study allowed the identification of specific clinical and transcriptomic parameters in patients from South Mediterranean countries.

Immunolocalization of BRCA1 protein in tumor breast tissue: prescreening of BRCA1 mutation in Tunisian patients with hereditary breast cancer?

BRCA1 is a tumor suppressor gene which is inactivated by mutation in familial breast and ovarian cancers. Over 300 different disease causing germ-line mutations have been described; 60% are unique to an individual family. This diversity and the large size of the gene lead us to search for a prescreening method for BRCA1 mutations. Since BRCA1 is a nuclear protein in normal cells, but reported by some authors to be cytoplasmic in breast tumor cells of patients with BRCA1 mutation, we evaluated immunohistochemistry as a prescreening technique to identify BRCA1 mutations in patients with familial presentation of breast cancer. Using a monoclonal antibody against the carboxy-terminal region of BRCA1, we performed immunohistochemistry on 18 tumor samples from patients with hereditary breast cancer. Cytoplasmic staining of BRCA1 was observed in 10 cases. Of the 18 tumors, 12 (66%) showed either BRCA mutation or BRCA1 accumulation or both, indicating that BRCA1 function might be lost in breast tumor cells not only through mutation, but also via abnormal cytoplasmic location. The immunohistochemical test used in this study would not be efficient as a pre-screening method of deleterious mutations, but it appeared useful to investigate tumor physiology.

Human papillomavirus genotypes and HPV-16 variants distribution among Tunisian women with normal cytology and squamous intraepithelial lesions.

BACKGROUND: Little is known about the epidemiological characteristics of papillomavirus (HPV) infection among North African countries. Herein, we conducted a molecular epidemiological study to investigate prevalence of HPV type and HPV-16 variants among cervical-screened unvaccinated Tunisian women. METHODS: Cross-sectional study was performed on 494 Tunisian women visiting Women's Healthcare Centers. HPV-DNA detection was carried out on cervical samples using real-time polymerase chain reaction. HPV genotyping and HPV-16 variants were characterized by direct sequencing of L1 viral capsid gene. RESULTS: The overall HPV prevalence was 34% (95% CI: 30-38%) with significantly higher prevalence among women with squamous intraepithelial lesions (SIL) than those with no intraepithelial lesions (NIL) 84% (95% CI: 76-92%) and 24.5% (95% CI: 20-29%) respectively. The distribution of HPV prevalence according to women's age shows a U-shaped curve and the highest HPV prevalence rates were observed among the youngest (≤25 years; 51.2%, 95% CI: 37-67%) and the oldest women (>55 years; 41.7%, 95% The HPV-16 prevalence was 32.8% (95% CI: 22-45%) among women with SIL and 9.2% (95% CI: 6-12%) among women with NIL. Whereas, the HPV-18 prevalence was 1.3% (95% CI: 0-5%) among women with SIL and 0.3% (95% CI: 0-1%) among women with NIL. Among HPV-16 positive women, European lineage (E) was identified as the predominant HPV-16 variant (85.7%, 95% CI: 76-95%). The frequency of E variant was lower among SIL than among NIL women (81%, 95% CI: 64-99%, and 88%, 95% CI: 77-100%, respectively). Conversely, the African-2 variant frequency was higher among SIL than among NIL women (18%, 95% CI: 1-36% and 6%, 95% CI: 2-14%, respectively). In multivariate analysis, young age was the only risk factor that is independently associated with HPV infection. Moreover, HPV infection and menopause were both found to be independently associated with SIL and HSIL. CONCLUSION: HPV DNA testing should be proposed to young and menopausal Tunisian women. Considering HPV prevalence, only 13% of the Tunisian women could be protected by the bivalent HPV vaccine. These results may be helpful for designing an adapted HPV testing and vaccination program in Tunisia.

Complete mutation screening and haplotype characterization of BRCA1 gene in Tunisian patients with familial breast cancer.

Breast cancer, the most commonly diagnosed cancer in women, is the second leading cause of cancer death in women worldwide. To investigate the contribution of BRCA1 gene mutations to familial breast cancer in Tunisia, 32 unrelated patients who had at least one first degree relative affected with breast and/or ovarian cancer were analysed. BRCA1 mutation analysis was performed by DNA sequencing of all BRCA1 exons. We identified four different BRCA1 frameshift mutations: c.4041delAG, c.2551delG and c.5266dupC already been described and one novel mutation, c.211dupA, observed in two unrelated families. C.5266dupC has previously been found among Jewish Ashkenazi and Eastern European populations. Our study describes it in Arabic/Berber population. Five out of thirty two familial cases had deleterious BRCA1 mutations. Fifteen additional cases carried unclassified variants (UV) or single nucleotide polymorphisms (SNPs). Our study is the first molecular investigation on the role of BRCA1 in hereditary breast cancer in North Tunisia.

A polymorphism in FAS gene promoter correlated with circulating soluble FAS levels.

The -670FAS (A/G) polymorphism and elevated concentrations of the soluble form of FAS (sFAS) have been associated with neoplasic and autoimmune diseases. This polymorphism in the Fas promoter gene could modulate the transcription of Fas expression and therefore, contribute to these pathologies. The in vivo functional significance of the FAS polymorphism was investigated by assessing the correlation between FAS genotypes and the serum-circulating FAS (sFAS) levels. We determined the FAS polymorphism distributions by restriction fragment-length polymorphism-polymerase chain reaction in 170 normal subjects. We used enzyme-linked immunosorbent assay to evaluate the sFAS levels in 44 of these individuals. Assessment of the concentration of sFAS indicated that the level of sFAS in subjects carrying the FAS-A/A genotype was significantly higher than that of those carrying the G/G genotype (3.90 ng mL(-1) vs. 3.12 ng mL(-1), P = 0.035). Our results demonstrated that FAS promoter polymorphism was significantly associated with the level of soluble FAS production in normal subjects.

Contribution of the BRCA1 and BRCA2 mutations to breast cancer in Tunisia.

Hereditary breast cancer accounts for 3-8% of all breast cancers, with mutations in the BRCA1 and BRCA2 genes responsible for up to 30% of these. To investigate the prevalence of BRCA1 and BRCA2 gene mutations in breast cancer patients with affected relatives in Tunisia, we studied 36 patients who had at least one first degree relative with breast and/or ovarian cancer Thirty-four 34 patients were suggestive of the BRCA1 mutation and two were suggestive of the BRCA2 mutation, based on the presence of male breast cancer detected in their corresponding pedigrees. Four mutations in BRCA1 were detected, including a novel frame-shift mutation (c.211dupA) in two unrelated patients and three other frameshift mutations--c.4041delAG, c.2551delG and c.5266dupC. Our study is the first to describe the c.5266dupC mutation in a non-Jewish Ashkenazi population. Two frameshift mutations (c.1309del4 and c.5682insA) were observed in BRCA2. Nineteen percent (7/36) of the familial cases had deleterious mutations of the BRCA1 or BRCA2 genes. Almost all patients with deleterious mutations of BRCA1 reported a family history of breast and/or ovarian cancer in the index case or in their relatives. Our data are the first to contribute to information on the mutation spectrum of BRCA genes in Tunisia, and we give a recommendation for improving clinical genetic testing policy.