Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 10 4 2018 10 07 266 274 EN Samira Izi Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Masoud Youssefi Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran AND Antimicrobial Resistance Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Farzad Rahmani Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Nema Mohammadian Roshan Department of Pathology, Ghaem Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Atefeh Yari Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Farnaz Zahedi Avval Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran AND Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran 2018 03 18 2018 05 13 Background and Objectives: Factors contributing to development of gastric cancer are still under investigation. The JC Virus (JCV), as an oncogenic virus, has been indicated to play a possible role in gastric carcinogenesis. Theoretically, tumor antigen (T-Ag), the viral transforming protein, is capable of binding and inactivating tumor suppressor proteins p53 and pRb, there by promoting cancer development although such a role in gastric cancer is still controversial and additional data is needed to reach a definite conclusion. The prevalence of the virus varies in different geographic regions, therefore, we aimed to investigate JCV presence in cancerous gastric tissues of Iranian patients. Materials and Methods: Thirty-one paired samples were included in this study (total of 62 samples). T-Ag sequences were investigated using real-time PCR in formalin fixed paraffin embedded (FFPE) tissue samples from the tumor site and relevant adjacent non-cancerous tissues (ANCT). In positive samples, JCV copy number (viral load) was also measured using real-time PCR. To evaluate T-Ag protein expression, immunohistochemistry examination was performed using an anti-T-Ag specific antibody. Results: JCV sequences were detected in 17 out of 31 gastric cancer tissue samples (54.84%) and in 10 out of 31 of the non-cancerous adjacent gastric mucosa (32.25%) (Odds ratio of 2.4). Viral load in tumoral and adjacent tissue samples was not statistically different (p=0.88). Immunohistochemical study confirmed presence of JC T-Ag in the nuclear compartment. Conclusion: We showed the presence of the JC virus in gastric carcinoma tissue samples in our geographic region. This finding provides supportive data for a possible contribution of JCV in gastric cell transformation to malignancy. However, we highly recommend additional investigations to further explore JC virus and gastric cancer in order to reach a conclusion. https://ijm.tums.ac.ir/index.php/ijm/article/view/1688 https://ijm.tums.ac.ir/index.php/ijm/article/download/1688/1065