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Introduction: Single nucleotide polymorphisms (SNPs) in DNA repair genes are mainly correlated with the response to radiotherapy in nasopharyngeal cancer (NPC). In NPC patients, previous research has studied the association between X-ray repair cross-complementing group 1 and 3 (XRCC1 and XRCC3) polymorphisms and radio-therapeutic response. The objective of our study was to test the association between XRCC1 Arg399Gln and XRCC3 Thr241Met polymorphisms and the response to radiotherapy in the NPC Moroccan population., Material and Methods: A total of 100 patients with NPC were genotyped for polymorphisms in XRCC1 and XRCC3 genes., Results: The results revealed that the genotypes and alleles of both SNPs did not show any significant association with clinical stages (for XRCC1 Arg399Gln: p [genotype] = 0.559; p [allele] = 0.440) and (for XRCC3 Thr241Met: p [genotype] = 0.638; p [allele] = 0.567). Moreover, in the study of the association between the polymorphisms and radiotherapy, the response to radiation therapy between genotypes and alleles was not statistically significant (for XRCC1 Arg399Gln p [genotype] = 0.583; p [allele] = 0.459) and (for XRCC3 Thr241Met p [genotype] = 0.660; p [allele] = 0.590)., Conclusions: The present study suggests that XRCC1 Arg399Gln polymorphism does not have any impact on the radio-therapeutic response in Moroccan NPC patients whereas XRCC3 Thr241Met polymorphism may act as a prognostic indicator for NPC patients treated with radiotherapy. However, studies with a larger sample are needed to confirm our results., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 Termedia.)

Objective: Nasopharyngeal carcinoma (NPC) is a severe malignant disease. Despite its low frequency, NPC is very common in North African population. Radiotherapy is the standard therapeutic treatment of NPC. However, radioresistance hampers the success of treatment. At the molecular scale, radioresistance is due to genetic variations involved in DNA repair pathways in NPC patients. Several studies reported that single nucleotide polymorphisms (SNPs) in excision repair cross complementing group 1 (ERCC1) could be associated with radioresistance. In this optic, the present study aimed to evaluate the association between DNA repair gene polymorphisms ERCC1 C8092A and ERCC1 C118T and radiotherapy response of patients with NPC., Methods: A total of 95 patients with confirmed NPC were recruited at the Mohammed VI Center for Cancer Treatment, Casablanca - Morocco between 2016 and 2018. Two single nucleotide polymorphisms in ERCC1 gene were genotyped. Multiple analysis software was used to assess the correlation between these SNPs and radio-therapeutic response., Results: Sequencing of ERCC1 C8092A polymorphism revealed that CC and CA genotypes were found in 51.6% and 45.3% of cases, respectively, whereas the homozygote AA genotype was reported in only 3.1% of cases. For ERCC1 C118T polymorphism, the heterozygote CT genotype was identified in 49.5% of cases. Homozygotes genotypes CC and TT were detected in 17.9% and 32.6% respectively of NPC cases. Of note, no significant association was found between the ERCC1 C8092A polymorphism and response to radiation therapy (p=0.81). Similarly, there was no significant association between the response to radiotherapy and allelic distribution (p=0.56). Likewise, no correlation was observed neither with genotypes (p=0.07) nor with alleles (p=0.09) of ERCC1 C118T polymorphism and response to radiation therapy., Conclusion: Our results clearly showed that ERCC1 C8092A and ERCC1 C118T polymorphisms were not associated with response to radiotherapy in Moroccan NPC patients. Large studies are warranted to confirm the role of these SNPs in therapeutic response of NPC patients.

The current study was designed to investigate the changes in the circulating Epstein−Barr virus DNA load (EBV DNA) at various time points before and after treatment and its clinical significance in nasopharyngeal carcinoma (NPC). A total of 142 patients with NPC were prospectively enrolled in this study. The plasma EBV DNA concentration was measured before and after treatment using qPCR. The prognostic values of the EBV DNA load were analyzed using the Kaplan−Meier and Cox regression tests. Following multivariate analysis, our data showed that high pre-EBV DNA loads were associated with significantly poorer distant metastasis free survival (DMFS) and progression free survival (PFS); detectable end-EBV DNA loads were associated with significantly worse loco-regional recurrence free survival (LRRFS) and PFS, and the detecTable 6 months-post-EBV DNA loads were associated with significantly poorer overall survival (OS), DMFS and PFS (p < 0.05). Additionally, combining the pre-EBV DNA load and the stage of the disease, our results showed that patients at stage III-IVA with a low pre-EBV DNA load had similar survival rates as patients at stage II with a low or high pre-EBV DNA load, but had better survival rates than those at stage III-IVA with a high pre-EBV DNA load. Taken together, we showed that the change of the EBV DNA load measured at several time points was more valuable than at any single time point for predicting patients’ survival for NPC. Furthermore, combining the pre-EBV DNA load and the TNM classification could help to formulate an improved prognostic model for this cancer.

Background: The identification of effective prognosis biomarkers for nasopharyngeal carcinoma (NPC) is crucial to improve treatment and patient outcomes. In the present study, we have attempted to evaluate the correlation between pre-treatment plasmatic Epstein-Barr virus (EBV) DNA load and the conventional prognostic factors in Moroccan patients with NPC., Methods: The present study was conducted on 121 histologically confirmed NPC patients, recruited from January 2017 to December 2018. Circulating levels of EBV DNA were measured before therapy initiation using real-time quantitative PCR., Results: Overall, undifferentiated non-keratinizingcarcinoma type was the most common histological type (90.1 %), and 61.8 % of patients were diagnosed at an advanced disease stage (IV). Results of pre-treatment plasma EBV load showed that 90.9 % of patients had detectable EBV DNA, with a median plasmatic viral load of 7710 IU/ml. The correlation between pre-treatment EBV DNA load and the conventional prognostic factors showed a significant association with patients' age (p = 0.01), tumor classification (p = 0.01), lymph node status (p = 0.003), metastasis status (p = 0.00) and overall cancer stage (p = 0.01). Unexpectedly, a significant higher level of pre-treatment EBV DNA was also found in plasma of NPC patients with a family history of cancer (p = 0.04). The risk of NPC mortality in patients with high pretreatment EBVDNA levels was significantly higher than that of those with low pre-treatment plasma EBV-DNA levels (p < 0.05). Furthermore, patients with high pre-treatment EBV-DNA levels (≥ 2000, ≥ 4000) had a significant low overall survival (OS) rates (p < 0.05). Interestingly, lymph node involvement, metastasis status and OS were found to be the most important factors influencing the EBV DNA load in NPC patients., Conclusions: The results of the present study clearly showed a high association between pre-treatment EBV DNA load, the crucial classical prognostic factors (T, N, M and disease stage) of NPC and OS, suggesting that pre-treatment EBV DNA can be a useful prognostic biomarker in clinical decision-making and improving NPC treatment in Morocco.