Genetic variations in CYP2A6, CYP2E1, GSTM1, GSTT1 genes and the risk of Nasopharyngeal carcinoma in North African population.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a multifactorial malignancy associated with both genetic and environmental factors. Polymorphic deletions of the phase I and phase II genes involved in the detoxification of potential carcinogens may be a risk factor for nasopharyngeal carcinoma. In this study, we investigated the relationship between CYP2E1 (rs3813867), CYP2A6, GSTM1(rs1183423000) and GSTT1(rs1601993659) gene variations and NPC risk in North African countries with the highest incidence of NPC (Morocco, Algeria and Tunisia). and the evaluation of the potential use of these variants as potential biomarkers for NPC management. METHODS: A total of 600 NPC cases and 545 controls frequency-matched on ethnicity, sex, age and childhood household type, were recruited from three North African countries (Morocco, Algeria and Tunisia) and analysed. Genotyping of CYP2A6 and CYP2E1(rs3813867) was performed by polymerase chain reaction restriction (PCR)-fragment length polymorphism (RFLP) analysis and the GSTM1 (rs1183423000) and GSTT1(rs1601993659) genetic variations were evaluated using the PCR technique. RESULTS: The genotype distributions of CYP2E1(rs3813867), CYP2A6, GSTM1(rs1183423000) and GSTT1(rs1601993659) genotypes did not differ significantly among NPC cases and controls (p > 0.05). Furthermore, our data did not reveal any association with smoking and the studied variants, even when the samples were stratified by the duration period of smoking. CONCLUSION: In this large studied North African population, our findings suggest that the functional CYP2E1, CYP2A6, GSTM1 and GSTT1 variations did not influence NPC susceptibility.

Prognostic value of Epstein-Barr virus DNA load in nasopharyngeal carcinoma: a meta-analysis.

The present meta-analysis was conducted to evaluate the prognostic value of pre and post-Epstein Barr Virus (EBV) DNA load testing and to assess the clinical benefit of using this molecular approach in the prognosis for a better nasopharyngeal carcinoma (NPC) management. Relevant studies were searched in different database until May 2020. Patient´s outcomes overall survival (OS), disease free survival (DFS), progression-free survival (PFS), distant-metastasis-free survival (DMFS), and local-regional-failure-free survival (LRFS), hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted from selected studies. The association of pre and post-EBV DNA load and survival outcomes was assessed using review manager and the pooled HRs with 95% CIs were calculated. Twenty-six eligible studies were included in this meta-analysis, with a total of 9966 patients. Pooled HRs showed that EBV DNA levels before and after treatment are significantly associated with survival outcomes, with HR (95% CI) of 2.09 [1.74, 2.51] for OS, 1.77 [1.19, 2.62] for DFS, 2.53 [2.18, 2.92] for DMFS, 1.78 [1.45, 2.19] for LRFS and 2.17 [1.91, 2.47] for PFS in pre-EBV DNA, and an HR (95%) of 4.52 [2.44, 8.36], 4.08 [2.38, 6.99], 5.59 [ 3.58, 8.71] and 8.88 [5.29, 14.90] for OS, DFS and PFS and DMFS in post-EBV DNA, respectively. High pre and post-EBV DNA levels were significantly associated with poor NPC patient´s survival outcomes; which clearly confirm the high interest to introduce viral EBV DNA load as a prognostic biomarker for NPC management.

Molecular characterization of mutations associated with resistance to second line drugs in Mycobacterium tuberculosis patients from Casablanca, Morocco.

The emergence and spread of extensively drug-resistant tuberculosis (XDR-TB) is a serious threat to global health. Therefore, its rapid diagnosis is crucial. The present study aimed to characterize mutations conferring resistance to second line drugs (SLDs) within multidrug Mycobacterium tuberculosis (MDR-MTB) isolates and to estimate the occurrence of XDR-TB in Casablanca, Morocco. A panel of 200 MDR-TB isolates was collected at the Pasteur Institute between 2015-2018. Samples were subjected to drug susceptibility testing to Ofloxacin (OFX), Kanamycin (KAN) and Amikacin (AMK). The mutational status of gyrA, gyrB, rrs, tlyA and eis was assessed by sequencing these target genes. Drug susceptibility testing for SLDs showed that among the 200 MDR strains, 20% were resistant to OFX, 2.5% to KAN and 1.5% to AMK. Overall, 14.5% of MDR strains harbored mutations in gyrA, gyrB, rrs and tlyA genes. From the 40 OFXR isolates, 67.5% had mutations in QRDR of gyrA and gyrB genes, the most frequent one being Ala90Val in gyrA gene. Of note, none of the isolates harbored simultaneously mutations in gyrA and gyrB genes. In eight out of the 200 MDR-TB isolates resistant either to KAN or AMK, only 25% had A1401G or Lys89Glu change in rrs and tlyA genes respectively. This study is very informative and provides data on the alarming rate of fluoroquinolone resistance which warrants the need to implement appropriate drug regimens to prevent the emergence and spread of more severe forms of Mycobacterium tuberculosis drug resistance.

Human papillomavirus detection in moroccan patients with nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a malignant tumor which arises in surface epithelium of the posterior wall of the nasopharynx. There's is evidence that Epstein Barr virus (EBV) is associated to NPC development. However, many epidemiologic studies point to a connection between viral infections by the human papillomavirus (HPV) and NPC. METHOD: Seventy Moroccan patients with NPC were screened for EBV and HPV. EBV detection was performed by PCR amplification of BZLF1 gene, encoding the ZEBRA (Z Epstein-Barr Virus Replication Activator) protein, and HPV infection was screened by PCR amplification with subsequent typing by hybridization with specific oligonucleotides for HPV types 16, 18, 31, 33, 35, 45 and 59. RESULTS: The age distribution of our patients revealed a bimodal pattern. Sixty two cases (88.9%) were classified as type 3 (undifferentiated carcinoma), 6 (8.6%) as type 2 (non keratinizing NPC) and only 2 (2.9%) cases were classified as type 1 (keratinizing NPC). EBV was detected in all NPC tumors, whereas HPV DNA was revealed in 34% of cases (24/70). Molecular analysis showed that 20.8% (5/24) were infected with HPV31, and the remaining were infected with other oncogenic types (i.e., HPV59, 16, 18, 33, 35 and 45). In addition, statistical analysis showed that there's no association between sex or age and HPV infection (P > 0.1). CONCLUSION: Our data indicated that EBV is commonly associated with NPC in Moroccan patients and show for the first time that NPC tumours from Moroccan patients harbour high risk HPV genotypes.