Prevalence of JC polyomavirus large T antigen sequences among Iranian patients with central nervous system tumors

The human neurotropic JC virus (JCV) is of significant interest due to its experimental neuro- oncogenic potential. In clinical samples from human central nervous system (CNS) tumors, detection of JCV sequences suggests a possible association with CNS neoplasms, but the results are discrepant worldwide. To assess the prevalence of JCV sequences in Iranian patients with primary and metastatic CNS malignancies, a total of 58 fresh CNS tumors were examined by quantitative real-time PCR targeting the JCV large T antigen (LT-Ag) gene, and JCV DNA load was determined as viral copy number per cell. All patients were immunocompetent, and none of them had received immunosuppressive therapy before surgical operation. JC virus LT-Ag sequences were found in a total of 15 (25.9 %) out of the 58 tested samples. In primary CNS tumors, JCV sequences were identified more frequently in meningiomas (50.0 %) and schwannomas (35.7 %). In metastatic CNS tumors, JCV LT-Ag was identified in one case with brain adenocarcinoma originating from lung cancer. No statistically significant association between JCV positivity and various types of CNS malignancies was observed (P = 0.565). The mean JCV LT-Ag copy number in 15 positive cases was 1.8 x 10(-4) +/- A 4.5 x 10(-4) copies per cell (range 1.0 x 10(-5)-1.78 x 10(-3) copies per cell). An inverse correlation between white blood cell (WBC) count and JCV copy number was observed, but this correlation was not statistically significant (R = -0.198, P = 0.480). This study provides the first data on the prevalence of JCV in primary and metastatic CNS tumors from Iranian patients.