Viral infection and cancer.

Infection with specific viruses has a role in the pathogenesis of some cancers in human beings. However, the incidence of such cancers is much lower than the frequency of virus infection, suggesting either that infection alone does not result in cancer and that cellular events in addition to the presence of the virus must occur, or that cancer occurs only if viral proteins are expressed in an appropriate cell type or in an immunocompromised host. Molecular analysis of viruses found in association with cancer has revealed that they function, at least in part, by encoding proteins which can associate with and subvert the function of host cell-encoded tumour suppressor proteins which regulate pathways of growth arrest and apoptosis. Better understanding of the mechanisms underlying this association will have diagnostic, prognostic, and therapeutic implications in the near future.