Elham Hassen

Combined analysis of interferon-γ and interleukin-10 gene polymorphisms and chronic hepatitis C severity.

Today there is increasing evidence concerning the contribution of pro-/anti-inflammatory cytokine balance and genetic factors in hepatitis C pathogenesis and interindividual heterogeneity of disease outcome. In the current study, we investigated the influence of functionally described single nucleotide polymorphisms (SNPs) present in interferon-gamma (IFNgamma) and interleukin-10 (IL-10) genes, on chronic hepatitis C severity. IFNgamma (+874T/A) and IL-10 (-1082G/A) genotypes were determined in 100 hepatitis C patients with different disease severities (chronic hepatitis, n = 42, liver cirrhosis [LC], and hepatocellular carcinoma in liver cirrhosis [HCC], n = 58) and 103 healthy controls using allele-specific polymerase chain reaction. No statistical differences in allele or genotype distributions of IFNgamma and IL-10 genes were observed between patients and controls. However, some significant differences in IFNgamma genotype frequencies were observed between the two groups of patients. IFNgamma(high producer) genotypes TT and TA were significantly more common in patients with LC and HCC (odds ratio = 2.65; p = 0.019). Although IL-10 genotypic frequencies were comparable between the different clinical forms of the disease, the combination of IFNgamma(low producer) and IL-10(high producer) genotypes was significantly associated with a lower risk of LC and HCC (odds ratio = 0.21; p = 0.015). In conclusion, our findings suggest that the imbalance between the pro-inflammatory and anti-inflammatory responses mediated by polymorphisms in the IFNgamma and IL-10 genes may influence the outcome of chronic HCV infection.

Implication of Xenobiotic Metabolizing Enzyme gene (CYP2E1, CYP2C19, CYP2D6, mEH and NAT2) Polymorphisms in Breast Carcinoma

BackgroundXenobiotic Metabolizing Enzymes (XMEs) contribute to the detoxification of numerous cancer therapy-induced products. This study investigated the susceptibility and prognostic implications of the CYP2E1, CYP2C19, CYP2D6, mEH and NAT2 gene polymorphisms in breast carcinoma patients.MethodsThe authors used polymerase chain reaction and restriction enzyme digestion to characterize the variation of the CYP2E1, CYP2C19, CYP2D6, mEH and NAT2 gene in a total of 560 unrelated subjects (246 controls and 314 patients).ResultsThe mEH (C/C) mutant and the NAT2 slow acetylator genotypes were significantly associated with breast carcinoma risk (p = 0.02; p = 0.01, respectively). For NAT2 the association was more pronounced among postmenopausal patients (p = 0.006). A significant association was found between CYP2D6 (G/G) wild type and breast carcinoma risk only in postmenopausal patients (p = 0.04). Association studies of genetic markers with the rates of breast carcinoma specific overall survival (OVS) and the disease-free survival (DFS) revealed among all breast carcinoma patients no association to DFS but significant differences in OVS only with the mEH gene polymorphisms (p = 0.02). In addition, the mEH wild genotype showed a significant association with decreased OVS in patients with axillary lymph node-negative patients (p = 0.03) and with decreasesd DFS in patients with axillary lymph node-positive patients (p = 0.001). However, the NAT2 intermediate acetylator genotype was associated with decreased DFS in axillary lymph node-negative patients.ConclusionThe present study may prove that polymorphisms of some XME genes may predict the onset of breast carcinoma as well as survival after treatment.

Interleukin-10 and interferon-gamma gene polymorphisms in patients with nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a multifactorial disease. Cytokines driving the immune response seem to be disturbed in NPC patients. Since interleukin‐10 (IL‐10) is known to reduce the production of interferon‐gamma (IFN‐γ), we supposed that genetic differences in IL‐10 and IFN‐γ expression could be a mechanism by which NPC cells escape antitumour immune response. As the production of each cytokine is affected by the genetic background, we investigated the possible association between single nucleotide polymorphisms in genes of IL‐10 and IFN‐γ with NPC. Different IL‐10 –1082 G/A and IFN‐γ+874 Τ/Α genotypes were determined in 160 patients with nasopharyngeal carcinoma and 197 healthy controls. No association was found either for each SNP studied alone or for the combined analysis for both IL‐10 and IFN‐γ polymorphisms among NPC patients in comparison with controls. Compared with individuals from high incidence countries, we noted huge significant differences in genotype distribution between individuals from low and intermediate NPC incidence countries. Polymorphisms of the IL‐10 and IFN‐γ do not appear to be associated with NPC risk in the Tunisian population. Nevertheless, we strongly believe that the relationship between cytokines polymorphisms and NPC susceptibility deeply depends on the ethnicity.

Functional IL-18 promoter gene polymorphisms in Tunisian nasopharyngeal carcinoma patients

OBJECTIVES There is growing evidence suggesting that IL-18 levels may affect individual to virus-associated neoplasia and that single nucleotide polymorphisms (SNPs) within the gene may influence its production. In this study we wanted to know whether IL-18 polymorphisms at positions -607 C/A and -137 G/A are associated with susceptibility and/or are markers of nasopharyngeal carcinoma (NPC) prognosis. METHODS Using the restriction fragment length polymerase chain reaction (RFLP-PCR), 163 Tunisian patients and 164 healthy controls were genotyped. RESULTS No significant association was found between each studied polymorphism and NPC. However, we noted that the -607 A allele, which is associated with lower IL-18 production, increased the risk of advanced tumor stages (OR=3.59; P=0.017) and that this risk was more pronounced among the older patients age at onset (OR=3.85; P=0.012). Moreover, the significant difference in CA/GG haplotype frequency distribution between young and older patients supported the idea that NPC disease has biologically different features between age sub-groups. CONCLUSION Functional IL-18 gene polymorphisms do not influence the susceptibility to NPC in Tunisians but may contribute to disease onset and aggressiveness.

Association of HLA-G polymorphisms with nasopharyngeal carcinoma risk and clinical outcome

The expression of human leukocyte antigen-G (HLA-G) in tumor cells may facilitate the escape of the tumor from immunosurveillance; thus the aim of this study was to evaluate the influence of HLA-G polymorphisms occurrence on nasopharyngeal carcinoma (NPC) susceptibility, severity, and survival. Using the restriction fragment length polymorphism-polymerase chain reaction and the amplification refractory mutation system-polymerase chain reaction method, 186 Tunisian patients and 189 healthy controls were genotyped for nonsynonymous polymorphisms in HLA-G codon 31Thr/Ser, codon 110Leu/Ile and codon 130Leu/framshift. When allele, genotype and haplotype frequencies between patients and controls were compared for each single nucleotide polymorphisms (SNP), no statistical significant differences were observed. According to the lymph node status and the tumor stages, the Ile110 allele was shown to be significantly less frequent among patients with a positive lymph node status and more severe tumor stages (stage I-II vs III-IV), respectively. Moreover, the codon 130C deletion occurrence was significantly associated with a decreased NPC free disease and overall survival. Altogether our results suggest a possible role for HLA-G locus in NPC progression and aggressiveness.

The human leukocyte antigen class I genes in nasopharyngeal carcinoma risk.

Nasopharyngeal carcinoma (NPC) is a virally associated cancer which is highly prevalent in Southeast Asia and North Africa. Several linkage analysis studies suggested the association of susceptibility HLA (Human Leukocyte Antigen) alleles and haplotypes with NPC development. The HLA system is very polymorphic and according to the ethnic group studied, it has been found to have the capacity to confer susceptibility or resistance to NPC. Our aim was to review the most important described genetic associations of HLA class I in NPC and to comment on the inconsistent associations found in the different NPC incidence areas. We believe that the mechanisms of these associations may involve HLA genes through the differential capacity of each allele to present antigens. However, because HLA genes contain various linked candidate genes, HLA-NPC associations should be carefully interpreted.

NS5AISDR‐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 NS5AISDR‐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 NS5AISDR‐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. J. Med. Virol. 81:2021–2028, 2009.

Lack of Association Between Human Leukocyte Antigen-E Alleles and Nasopharyngeal Carcinoma in Tunisians

Nasopharyngeal carcinoma (NPC), a cancer with a remarkable geographical and worldwide ethnic distribution, has been strongly associated with human leukocyte antigen (HLA) class I genes. The presence of additional HLA risk factors has been suggested by several reports. In the present study, we analyzed the implication of HLA-E gene polymorphisms in NPC susceptibility in Tunisians, a population characterized by an intermediate incidence of NPC with specific clinical features. Peripheral blood DNA was obtained from 185 patients with NPC and 177 matched controls. Genotyping for three single-nucleotide polymorphisms, codon 83Gly/Arg, codon 157Arg/Gly, and codon 107Arg/Gly, was performed using the polymerase chain reaction method. The HLA-E*01:01 and HLA-E*01:03 were the only alleles found among Tunisians. The HLA-E*01:03 allele had a slight increase in patients with NPC (43%) compared with controls (37%), but the difference did not reach a statistical significance. Our results show the lack of association between HLA-E alleles and NPC in the Tunisian population. This is not in agreement with the previous studies, suggesting a potential implication of HLA-E gene polymorphisms in the susceptibility to NPC among populations with high-risk incidence. Our study further supports the dissimilarity of NPC between populations with different NPC incidence.

Molecular epidemiology and genotype distribution of Human Papillomavirus (HPV) among Arab women in the state of Qatar

BackgroundHuman Papilloma Virus (HPV) infection is the major cause of cervical cancer worldwide. With limited data available on HPV prevalence in the Arab countries, this study aimed to identify the prevalence and genotypic distribution of HPV in the State of Qatar.Methods3008 cervical samples, exclusively of women with Arabic origin residing in Qatar were collected from the Women’s Hospital and Primary Health Care Corporation in Doha, State of Qatar. HPV DNA detection was done using GP5+/6+ primers based real time-polymerase chain reaction (RT-PCR) assay followed by the usage of HPV type specific primers based RT- PCR reactions and Sanger sequencing for genotype identification.ResultsSimilar prevalence rates of HPV infection was identified in both Qatari and non-Qatari women at 6.2% and 5.9% respectively. HPV prevalence rate of 5.8% and 18.4% was identified in women with normal cytology and in women with abnormal cytology respectively. HPV 81, 11 and 16, in decreasing order were the most commonly identified genotypes. HPV 81 was the most frequent low-risk genotype among women with both normal (74.0%) and abnormal (33.3%) cytology. HPV 16 (4.6%) was identified as the predominant high-risk HPV genotype among women with normal cytology and HPV 16, HPV 18, and HPV 56 (22.2% each) were the most common identified high-risk genotypes in women with abnormal cytology.ConclusionsThe overall HPV prevalence in Arab women in Qatar was identified as 6.1% with an increased HPV prevalence seen in women with abnormal cytology results and no significant trends seen with age. In contrast to Western countries, we report a varied genotypic profile of HPV with a high prevalence of low-risk HPV genotype 81 among the Arab women residing in Qatar.

E-cadherin genetic variants predict survival outcome in breast cancer patients

BackgroundE-cadherin is a major component of adherens junctions that regulates cell shape and maintains tissue integrity. A complete loss or any decrease in cell surface expression of E-cadherin will interfere with the cell-to-cell junctions’ strength and leads to cell detachment and escape from the primary tumor site. In this prospective study, three functional single nucleotide polymorphisms (−347G/GA, rs5030625; −160C/A, rs16260; +54C/T, rs1801026), were found to modulate E-cadherin expression.Methods577 DNA samples from breast cancer (BC) cases were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP).ResultsWe detected no significant correlations between each polymorphism and the clinical parameters of the patients whereas the GACC haplotype was significantly associated with low SBR grading. Overall survival analysis showed that both −347G/G and +54C/C wild (wt) genotypes had a significantly worse effect compared to the other genotypes (non-wt). Moreover, carrying simultaneously both the −347 and +54 wt genotypes confers a significantly higher risk of death. However, with metastatic recurrence, the death-rate was null in patients carrying the non-wt genotypes, and attained 37% in those carrying the wt genotype. A multivariate analysis showed that these two polymorphisms are independent prognostic factors for overall survival in BC patients.ConclusionsOur results support the fact that E-cadherin genetic variants control disease severity and progression and could be a marker of disease outcome. These findings could be useful in selecting patients that should be monitored differently.