An oncovirus or oncogenic virus is a virus that can cause cancer.[4] This term originated from studies of acutely transforming retroviruses in the 1950–60s,[5] when the term oncornaviruses was used to denote their RNA virus origin.[6] With the letters RNA removed, it now refers to any virus with a DNA or RNA genome causing cancer and is synonymous with tumor virus or cancer virus. The vast majority of human and animal viruses do not cause cancer, probably because of longstanding co-evolution between the virus and its host. Oncoviruses have been important not only in epidemiology, but also in investigations of cell cycle control mechanisms such as the retinoblastoma protein.
The World Health Organization's International Agency for Research on Cancer estimated that in 2002, infection caused 17.8% of human cancers, with 11.9% caused by one of seven viruses.[7] A 2020 study of 2,658 samples from 38 different types of cancer found that 16% were associated with a virus.[8] These cancers might be easily prevented through vaccination (e.g., papillomavirus vaccines), diagnosed with simple blood tests, and treated with less-toxic antiviral compounds.
^Valladares Y (1960). "Studies on cancerous pathogenesis. Production of leukemia and polycythemia vera by means of cancerous nucleoproteins from tissue cultures". Medicina Experimentalis. 2: 309–316. doi:10.1159/000134890. PMID13779782.
^Herberman RB (2012). "12: Immunology of Oncornaviruses". In Nahmias AJ, O'Reilly RJ (eds.). Immunology of Human Infection: Part II: Viruses and Parasites; Immunodiagnosis and Prevention of Infectious Diseases. Comprehensive Immunology. Vol. 9 (reprint ed.). New York: Plenum Publishing Corporation. pp. 273, 275. ISBN9781468410129. Retrieved 20 October 2016. Viruses known as oncogenic RNA viruses or oncornaviruses have been described in a wide variety of vertebrate species [...] there have been very few, if any, completely convincing examples of isolation of human oncornaviruses.