A Preliminary Sequence Analysis of the Epstein-Barr Virus Nuclear Antigen ۱ (EBNA۱) Carboxy-Terminal Region in Cervical and Ovarian Cancers

Background & Objective: Epstein-Barr virus nuclear antigen-۱ (EBNA۱) is one of the most important proteins of Epstein-Barr virus (EBV) that might be mutated in various related cancers. The purpose of this study was to compare EBNA۱ mutations in the C-terminal region between patients with cervical and ovarian cancer and healthy individuals.Methods: As test and control groups, ۱۸ EBV-positive paraffin-embedded samples of cervical and ovarian cancer and ۱۰ age- and gender-matched healthy volunteers who did not have cancer but were EBV-positive were both used. Utilizing a commercial DNA extraction kit, total DNA was extracted following deparaffinization. The entire C-terminal region of the EBNA۱ sequence was amplified using an in-house nested PCR. Phylogenetic analysis and Sanger sequencing were used to analyze the sequences using MEGA ۷ software and through NJ method.Results: Sequence analysis revealed that the P-Ala subtype of EBNA۱ was present in all samples. In two and one samples, respectively, of cervical cancer patients, the mutations A۱۸۸۷G and G۱۸۹۱A were found. The G۱۵۹۵T mutation was also detected in four sequences taken from ovarian cancer patients. No statistically significant difference could be found between the frequency of mutations in patients and controls (P>۰.۰۵). No known amino acid substitutions were found in the USP۷-binding region and the DBD/DD domain.Conclusion: The findings showed that P-Ala is the predominant EBV subtype across all samples. Additionally, as the sequence of EBNA۱'s C-terminal region is so stable, it's possible that it had little impact on the pathogenesis of ovarian and cervical malignancies. It is advised to conduct additional research to verify these findings.