7. Which were the first viruses shown to cause cancer?
Answers
Explanation:
An oncovirus is a virus that can cause cancer. This term originated from studies of acutely transforming retroviruses in the 1950–60s,[1] when the term "oncornaviruses" was used to denote their RNA virus origin.[2] 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.[3] These cancers might be easily prevented through vaccination (e.g., papillomavirus vaccines), diagnosed with simple blood tests, and treated with less-toxic antiviral compounds.
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