en Microbiology Microbiology Original Article Original Article <span style="font-family:Times New Roman;"><span style="font-size:14px;"><span style="color:#0033ff;"><strong><em>Background</em></strong><em>:</em></span> Due to persistent infections of human central nervous system (CNS), polyomaviruses have been identified as one of the risk factors for brain tumor development. Human BK virus is of significant interest due to its experimental neuro-oncogenic potential and the possible association with CNS neoplasms. However, the results of different studies are discrepant. In the present study, we aimed to investigate the prevalence of BK virus genome and quantify BK viral load in Iranian patients with primary and metastatic brain malignancies.<br> <span style="color:#0033ff;"><strong><em>Methods</em></strong><em>:</em></span> To assess the prevalence of BK virus sequences, a total of 58 fresh brain tumors were examined by quantitative real-time PCR. The BK viral load was determined as viral copy number per cell.<br> <span style="color:#0033ff;"><strong><em>Results</em></strong><em>:</em></span> Of the 58 brain tumor samples BK tumor antigen (TAg) sequences were detected in 26 (44.8%) of cases. In primary brain tumors, BK virus sequences were recognized more frequently in schwannomas (15.5%) and meningiomas (12.1%)<span dir="RTL">.</span> The mean BK virus TAg copy number in positive cases was 0.20&times;10^-3&plusmn;0.27&times;10^-3 (range 0.01&times;10^-3- 0.8&times;10^-3) copies per cell.<br> <span style="color:#0033ff;"><strong><em>Conclusion</em></strong><em>:</em></span> Taken together, in the present study low copy numbers of BK virus TAg gene was detected in brain tumor cells, which can indicate that BK virus may contribute to tumor induction by indirect mechanisms or neuro-persistence of this virus without any pathological consequences.</span></span><span dir="RTL"></span> BK Human Polyomavirus, Brain tumors, Tumor Antigen 173 179 http://caspjim.com/browse.php?a_code=A-10-941-2&slc_lang=en&sid=1 Saghar Saber Amoli sagharsaberamoli2@gmail.com 100319475328460028167 100319475328460028167 No Department of Microbiology, School of Medicine, Babol University of Medical Sciences, Babol, Iran Arqavan Zebardast arqavan9372@gmail.com 100319475328460028168 100319475328460028168 No Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Hossein Keyvani keyvanlab@yahoo.com 100319475328460028169 100319475328460028169 No Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Yousef Yahyapour uyahyapoor@yahoo.com 100319475328460028170 100319475328460028170 No Infectious Diseases & Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Seyed Mohammad Ghodsi ghodsi1333@gmail.com 100319475328460028171 100319475328460028171 No Department of Neurosurgery, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran Mahmood Maniati manati@gmail.com 100319475328460028172 100319475328460028172 No School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Farzin Sadeghi sadeghifarzin6@gmail.com 100319475328460028173 100319475328460028173 Yes Cellular & Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran