Tumor virus

Article By:

Voevodin, Alexander F. Vir&Gen, Toronto, Canada.

Last reviewed:September 2021

DOI:https://doi.org/10.1036/1097-8542.714400

A virus that causes tumors. Various tumor or oncogenic viruses (also called oncoviruses) are known, including both RNA and DNA viruses (see illustration). These viruses, especially under experimental conditions, are capable of causing cancer in animals, including humans. Most tumor viruses have been isolated from animals (Table 1). Animal tumor viruses are very useful as a research tool for unraveling mechanisms of tumor development (carcinogenesis) as well as normal processes controlling cell growth and differentiation. Tumor viruses are capable of inducing tumors reproducibly within a short period of time, as well as transforming normal cells into tumor cells in vitro. Importantly, just a few viral genes and proteins are responsible for the oncogenic activity, simplifying the analysis. The oncogenicity of animal viruses can be established by the inoculation of susceptible animals. In such experimental settings, various artificial conditions can be recreated to reveal oncogenic potential of the viruses and to decipher the mechanisms of carcinogenesis. However, this approach also has limitations. Many strains of animal tumor viruses are “artificial” due to the history of selection for enhanced oncogenicity in the laboratory. Relatively few animal viruses cause tumors in their natural hosts in nonexperimental conditions. In addition, the most extensively studied animal oncogenic viruses have no analogs in humans. See also: Animal virus; Cancer; Oncogene; Oncology; Virus

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