T-Ag Gene Of Polyomavirus JC In Colorectal Cancerous And Non-Cancerous Specimens, The First Report From Iran

Colorectal carcinogenesis is regarded as a multistep and multifactorial process. Among theexogenous agents are some infectious agents as important pathogenic elements in human cancer,since almost one fifth of human cancers are associated with infectious agent, including viruses andbacteria. More recently, it has been suggested a possible association between JC virus infection andcolorectal cancer. The oncogenic potential of JCV is mediated by a transforming protein, the Tantigen(T-Ag) might contribute to the cancer phenotype and cellular function by severalmechanisms. (T-Ag) is a multifunctional protein capable of promoting neoplastic transformation ofcells. JCV T-Ag has the ability to bind and inactivate tumor suppressor proteins including p53 andthe cell cycle regulator retinoblastoma gene product pRb, leading to their destruction, and allowingreplication of cancer cells with damaged chromosomes. The objective of this study was toinvestigate whether JCV DNA sequences is present in human colorectal cancer tissues and noncanceroustumor-adjacent tissues in our sociogeographical region. In this study, samples obtainedfrom tumor paraffin embedded tissues and matched normal tissues from 50 CRC patients. GenomicDNA was extracted from the tissue specimens. Real-time PCR method was used to detect the JCV TAgsequences. We found that JCV DNA sequences were present in 60% (30/50) of CRC tissues and 38%(19/50) in non-cancerous colorectal mucosa. These data indicate, for the first time, presence of JCvirus in colorectal carcinoma samples in Iran. These findings suggest a possible role forinvolvement of JCV T-Ag in carcinogenesis of colorectal malignancy in Iranian patients. Though, JCVmight not necessarily be the main cause of colorectal cancer, but it can contribute to some extent indevelopment of adenocarcinomas at one or several stages of tumor progression.