en Cancer Cancer Original Article Original Article <span style="font-family:Tahoma;"><span style="font-size:12px;"><span style="unicode-bidi:embed"><span style="line-height:107%">Epstein-Barr virus (EBV) represents one of the most important viral carcinogens. EBV nuclear antigen-1 (EBNA1) can induce the expression of different cellular and viral genes. In this study, we evaluated the EBNA1 effects on the expression patterns of human papillomavirus type 18 (HPV-18) E6 and E7 oncogenes and three cellular genes, including BIRC5, c-MYC, and STMN1, in a cervical adenocarcinoma cell line. HeLa cells were divided into three groups: one transfected with a plasmid containing the EBNA1 gene, one transfected with a control plasmid, and one without transfection. In all three groups, the expression levels of E6, E7, BIRC5, c-MYC, and STMN1 genes were checked using real-time PCR. Pathological staining was used to examine changes in cell morphology. Real-time PCR results showed that the expression level of HPV-18 E6 (P=0.02) and E7 (P=0.02) oncogenes significantly increased in HeLa cells transfected with the EBNA1 plasmid compared to cells transfected with control plasmid. Also, the presence of EBNA1 induced the expression of BIRC5 and c-MYC, which increased tenfold (P=0.03) and threefold (P=0.02), respectively. Regarding the STMN1 cellular gene, although the expression level in HeLa cells transfected with EBNA1 plasmid showed a twofold increase, this change was insignificant (P=0.11). Also, EBNA1 expression caused the creation of large HeLa cells with abundant cytoplasm and numerous nuclei. The EBV-EBNA1 could increase the expression levels of HPV-18 E6 and E7 viral oncogenes as well as c-MYC and BIRC5 cellular genes in the HeLa cell line. These findings indicate that the simultaneous infection of cervical cells with HPV-18 and EBV might accelerate the progression of cervical cancer.</span></span></span></span> Cervical carcinoma, human Papillomavirus, Epstein–Barr Virus, EBNA1 346 356 http://ijmcmed.org/browse.php?a_code=A-10-6758-1&slc_lang=en&sid=1 Amir Hossein Alipour amiralip26@gmail.com 100319475328460032665 100319475328460032665 No Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. Seyed Mohammad Ali Hashemi hashemit71@gmail.com 100319475328460032666 100319475328460032666 No Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. Afagh Moattari moattaria@sums.ac.ir 100319475328460032667 100319475328460032667 No Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. Ali Farhadi farhadi_a@sums.ac.ir 100319475328460032668 100319475328460032668 No Diagnostic Laboratory Sciences and Technology Research Center, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran. Jamal Sarvari sarvarijamal@gmail.com 100319475328460032669 100319475328460032669 Yes Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.