VIROLOGY

DNA Oncogenic Viruses: 
                        Oncogenic viruses are found within several families of DNA containing
viruses. These groups include the Adenoviridae,
Herpesviridae, Poxviridae, Papovaviridae, and Hepadnaviridae.
Among the papovaviruses, papillomaviruses cause uterine (cervical)
cancer.
Virtually all cervical cancers are caused by human papilloma virus
 (HPV); HPV- 16 accounts for about half of all cervical
cancers. A vaccine against four HPVs, including HPV- 16, is recommended
for 11 - to 12 -year-old girls.
Epstein-Barr (EB) virus was isolated from Burkitt's lymphoma
cells in 1964 by Michael Epstein and Yvonne Barr. The proof that
EB virus can cause cancer was accidentally demonstrated in 1985
when a 12-year-old boy known only as David received a bone
marrow transplant. Several months after the transplant, he died of
cancer. An autopsy revealed that the virus had been unwittingly
introduced into the boy with the bone marrow transplant.   
        Another DNA virus that causes cancer is hepatitis B virus
(HBV). Many animal studies have been performed that have
clearly indicated the causal role of HBV in liver cancer. In one
human study, virtually all people with liver cancer had previous
HBV infections. 

 RNA Oncogenic Viruses:  
            Among the RNA viruses, only the onco viruses in the family
Retroviridae cause cancer. The human T-cell leukemia viruses
(HTLV- l and HTLV-2) are retroviruses that cause adult T-cell
leukemia and lymphoma in humans. (T cells are a type of white
blood cell involved in the immune response. )
Sarcoma viruses of cats, chickens, and rodents, and the mammary
tumor viruses of mice, are also retroviruses. Another retrovirus,
feline leukemia virus (FeLV), causes leukemia in cats and is
transmissible among cats. There is a test to detect the virus in cat
serum. 

                                                                                           


 Please visit these links: http://en.wikipedia.org/wiki/Oncovirus
http://www.life.umd.edu/classroom/bsci424/BSCI223WebSiteFiles/OncogenicViruses.htm
http://pathmicro.med.sc.edu/lecture/retro.htm 
http://www.nature.com/onc/journal/v20/n54/full/1204958a.html
https://www.boundless.com/microbiology/viruses-1/viruses-and-cancer/rna-oncogenic-viruses/

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