Assessment of JC polyomavirus in normal colorectal mucosa, hyperplastic polyps and sporadic adenomas and adenocarcinomas in a Portuguese population and its association with cancer development

Abstract

CRC is the third most common tumour in women and the fourth in man; representing annually one million new cases worldwide and more than 500.000 deaths are caused by this malignant disease. It comprises 9% of the global cancer burden and is the most frequent in North America, Australia, New Zealand and parts of Europe, being considered as a disease of the Western lifestyle. In Portugal, CRC is highly prevalent, with over six thousand new cases per year, with a mortality rate approaching 50% and being the second leading cause of death by cancer, in both sexes[29]. Despite these high incidence and mortality rates no studies have been reported, so far, stating the JCV oncogenicity or even its occurrence among the Portuguese population. Considering the lack of reports on this matter, with this experimental we have studied: a) the prevalence rates of JCV (JC virus) infection in the colorectal mucosa, either normal or with hyperplastic, pre-malignant (adenomas) or malignant (adenocarcinomas) colonic lesions, and the viral shedding through urine, in an adult Portuguese population; and b) the potential association between the presence of the virus in the colon and the lesions development, severity and grade, using a panel of lesions with different grades of hyperplasia/dysplasia/neoplasia. It is concluded that JCV facilitates the progression of tumour lesions since it is always at higher levels in tumoral tissue with respect to normal surrounding mucosa or normal colon.