This document summarizes information about oncogenic viruses. It begins with definitions of oncoviruses and tumor viruses. It then estimates that viruses cause approximately 18% of human cancers. Several important historical discoveries are outlined, such as the first demonstration that avian sarcoma leukosis virus could cause leukemia when transmitted between chickens. Mechanisms by which viruses can cause cancer are discussed, such as by inserting oncogenes into host cells. Several specific DNA and RNA viruses that are known to cause cancer are described, including their associated cancer types. Precautions to prevent viral infection during cancer treatment are provided. In conclusion, viruses can stimulate cell proliferation and cause cancer through various mechanisms such as modifying proto-oncogenes or stimulating growth.

1. ONCOGENIC VIRUS
1
A Concise Presentation
By
Mr. Deepak Sarangi M.Pharm

2.  Introduction
 Discovery of viruses
 History
 What is cancer
 How viruses cause cancer
 Growth of cancer cells
 Classification of oncogenic virus
 Mechanism of oncogenic virus
 Drugs used to treat oncogenic viruses
 Precautions to prevent infection during cancer treatment
 Conclusion
 References
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3.  An oncovirus is a virus that can cause cancer. This term
originated from studies of acutely transforming retroviruses in
the 1950–60s, often called oncornaviruses to denote their RNA
virus origin.
 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 long-standing coevolution between
the virus and its host.
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4.  Worldwide, the WHO International Agency for Research on
Cancer estimated that in 2002, 17.8% of human cancers were
caused by infection, with 11.9% being caused by one of seven
different viruses.
 The importance of this is that 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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5.  1908: Vilhelm Ellerman and Olaf Bang, University of
Copenhagen, first demonstrated that avian sarcoma leukosis
virus could be transmitted after cell-free filtration to new
chickens, causing leukemia.
 1933: Richard Edwin Shope discovered cottontail rabbit
papillomavirus or Shope papillomavirus, the first mammalian
tumor virus.
 1957: Sarah Stewart and Bernice Eddy discovered polyoma
virus.
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6.  1964: Anthony Epstein, Bert Achong and Yvonne Barr identify the
first human oncovirus from Burkitt lymphoma cells. A herpesvirus,
this virus is formally known as human herpesvirus 4 but more
commonly called Epstein-Barr Virus or EBV.
 1980: Human T-lymphotropic virus 1 (HTLV I), the first human
retrovirus was discovered by Bernard Poiesz and Robert Gallo at NIH
and Mistuaki Yoshida and coworkers in Japan.
 2008: Chang and Moore, now at the University of Pittsburgh Cancer
Institute, developed a new method to identify cancer viruses based on
computer subtraction of human sequences from a tumor
transcriptome, called digital transcriptome subtraction (DTS).
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7.  The theory that cancer could be caused by a virus began with
the experiments of Oluf Bang and Vilhelm Ellerman in 1908
who first show that avian erythroblastosis (a form of chicken
leukemia) could be transmitted by cell-free extracts. This was
subsequently confirmed for solid tumors in chickens in 1910-
1911 by Peyton Rous.
 By the early 1950s it was known that viruses could remove and
incorporate genes and genetic material in cells. It was suggested
that these new genes inserted into cells could make the cell
cancerous. Many of these viral oncogenes have been discovered
and identified to cause cancer.
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8. Cancer results from alterations in critical
regulatory genes that control cell proliferation,
differentiation, and survival. Studies of tumor
viruses revealed that specific genes (called
oncogenes) are capable of inducing cell
transformation, thereby providing the first
insights into the molecular basis of cancer.
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9.  The viral agents causing cancer in eukaryotic animals by
integrating in host genome.
 A virus associated with malignancies in natural host,
experimental animals or cell cultures.
 viruses which modified proto- oncogene, obligatory host
specific, with the ability immortalization, possess genes which
stimulate growth and cause cancer.
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10. 10

11. 11
Oncovirus
DNA oncogenic
viruses
RNA oncogenic
viruses

12.  Human papilloma virus (HPV), a DNA virus, causes
transformation in cells through interfering with tumor suppressor
proteins such as p53.
 Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8) is
associated with Kaposi’s sarcoma, a type of skin cancer.
 Epstein-Barr virus (EBV or HHV-4) is associated with four types
of cancers.
 Merkel cell polyomavirus – a polyoma virus – is associated with
the development of Merkel cell carcinoma.
 Human cytomegalovirus (CMV or HHV-5) is associated with
mucoepidermoid carcinoma and possibly other malignancies.
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13. Not all oncoviruses are DNA viruses. Some RNA viruses have
also been associated such as the hepatitis C virus as well as
certain retroviruses, e.g., human T-lymphotropic virus (HTLV-1)
and Rous sarcoma virus (RSV).
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14. Virus
Percent of
cancers
Associated cancer types
Hepatitis viruses, including hepatitis B
(HBV) and hepatitis C (HCV)
4.9
Hepatocellular carcinoma (liver
cancer).
Human T-lymphotropic virus (HTLV) 0.03 Adult T-cell leukemia
Human papillomaviruses (HPV) 5.2
Cancers of cervix, anus, penis,
vulva/vagina, and oropharyngeal
cancer.
Kaposi’s sarcoma-associated herpesvirus
(HHV-8)
0.9
Kaposi’s sarcoma, multicentric
Castleman's disease and primary
effusion lymphoma
Merkel cell polyomavirus Not available Merkel cell carcinoma
Epstein–Barr virus (EBV) Not available
Burkitt’s lymphoma, Hodgkin’s
lymphoma, Post-transplant
lymphoproliferative disease and
Nasopharyngeal carcinoma. 14

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17. 17

18.  Wash your hands after using the bathroom, blowing your nose,
coughing, or sneezing.
 Wash your hands after touching animals, collecting trash, or taking
out garbage.
 Use moist cleaning wipes to clean surfaces and things that you
touch, such as door handles, ATM or credit card keypads, and any
items that are used by other people.
 Stay away from anyone with a fever, the flu, or other infection.
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19.  Do not wade, play, or swim in ponds, lakes, rivers, or water
parks.
 Wear shoes all the time — in the hospital, outdoors, and at
home. This helps you avoid injury and keep germs off your
feet.
 Do not keep fresh flowers or live plants in your bedroom.
 Use hot water to clean your dishes.
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20. Globally, almost 20% of cancers are related to infection
agents. Several viruses with oncogenic potential stimulate cell
proliferation and cause tumors and cancer in animals and
humans. They act with different mechanisms depending on
different factors.
The tumor viruses with small genomes integrate into host
cell chromosomal DNA and cause mutations and chromosomal
rearrangements that predispose to cancer. The oncogenic DNA
and RNA viruses that are carrying oncogenes encode
transforming proteins to stimulate tumor formation.
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21. 1. Murat ŞEVİK, Laboratory of Molecular Microbiology,
Veterinary Control Institute, Konya – TURKEY, Oncogenic
viruses and mechanism of oncogenesis, 2012; 36(4): pg.
no.323-329.
2. Parkin, Donald Maxwell (2006). "The global health burden
of infection-associated cancers in the year 2002".
International Journal of Cancer, 118 (12): pg. no.3030–44.
3. Oncovirus, from wikipedia, the free encyclopedia.
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