Association of polyomavirus JC with colon cancer

JC virus (JCV) is a human polyomavirus that has recently been demonstrated to be associated with pediatric malignancies, ie, medulloblastomas. Recent controversial data suggests that JCV may play a role in the pathogenesis of colon cancer. Chromosomal instability, a hallmark of colon cancer, may also be induced by JCV. We further tested this hypothesis by employing polymerase chain reaction (PCR) technology to detect JCV in normal and colon cancer tissues. DNA was extracted using commercial kits from paraffin-embedded tissue specimens from eight colon cancer patients; one normal and one tumor tissue specimen from each patient. Extracted DNA was PCR amplified using primers specific for T antigen (TAg) and 610-bp JCV V-T region, cloned into the pCR2.1 vector, and the kanamycin resistant bacterial transformants were sequenced using the ABI Sequencer. The sequences were analyzed using the Lasergene Software. Our results showed 100% JCV infection of both the normal and tumor colon tissues, and 61% of the JCV transcriptional control region sequences were Mad1 type. Furthermore, genotyping based on the V-T intergenic region demonstrated that all eight patients were infected with JCV Type 1A. Presence of JCV in normal and colon cancer tissues suggests that JCV may act as a co-factor in colon cancer carcinogenesis.