Viruses and Cancer

Viruses are ubiquitous and are also the pathogenic agents that are most commonly associated with neoplastic transformation of cells of several organs in human beings – thereby causing cancer of epithelial cells (carcinomas) or cancer of mesenchymal cells (leukemias, lymphomas and sarcomas) depending on the type and location of the infected host cell. This review highlights the six major groups of viruses that have established aetiological association with cancer in human populations. The epidemiology and the processes through which these pathogens cause malignant transformation of the infected host cells are discussed – with particular emphasis on the evolving and changing natures of the diseases as they parallel changes in human behaviours. Also discussed is a brief overview of the current understanding of molecular pathology as they emerge with the advent of new technological capabilities for studying these processes at subcellular (genomic) levels.