This presentation discusses oncoviruses, which are viruses that can cause cancer. It provides examples of several known oncoviruses including hepatitis B and C viruses, human papillomavirus, Epstein-Barr virus, human T-lymphotropic virus type 1, Kaposi's sarcoma-associated herpesvirus, and Merkel cell polyomavirus. For each virus, it describes the specific cancer(s) caused, how the virus contributes to cancer development, populations at highest risk, and available treatment options.

1. Oncoviruses
A presentation by Cari Jennings
CHTN Vanderbilt

2. First of all…what is a virus?
• Infectious
• Non-living
• Composed of:
– Capsid
– Genome
– (sometimes) Envelope
– “Obligate intracellular parasite”

3. Examples of viruses…
• HIV
• Influenza
• Rhinoviruses

4. So what is an oncovirus?
• Virus that causes cancer
• Known oncoviruses are:
– Hepatitis C
– Hepatitis B
– HTLV-1
– HPV
– HHV-8 (KSHV)
– Merkel Cell Polyomavirus
– EBV

5. Hepatitis C
• Which cancer?
– Hepatocellular carcinoma
• How?
– HCV core protein interferes with p53
(tumor suppressor gene)
• Who?
– Anyone! (Particularly IV drug users,
transplants/transfusions before 1990, high
risk sex, body piercing/tattoos, babies
born to HepC + mothers)
– 1 in 30 baby boomers, 75% of those living
with it!

6. Hepatitis C
• Treatment?
– Treatment for virus = interferon + ribavirin,
other antivirals + ribavirin, liver
transplantation (treatment based on
genotype)
– Treatment for HCC = liver
resection/transplantation, TACE, adjuvant
chemo, XRT

7. Hepatitis B
• Which cancer?
– Hepatocellular carcinoma
• How?
– Virus binds to liver cells and
is taken inside
– Viral DNA is reproduced in
the liver cell nucleus, which
helps create new virus
particles which infect
surrounding cells

8. Hepatitis B
• Who?
-Anyone! Primarily childbirth, person-to-person in early childhood, body
piercings/tattoos, toiletries
-Also sexually transmitted
-Transmitted via infected blood, wet or dried
-Each subtype has a different genome, and each genome is endemic to a different
area
• Treatment?
-Vaccine available since 1982, 95% effective, 1st against major human cancer
-Treatment for virus: based on viral genotype, usually includes antivirals and
interferon
-Treatment for cancer: liver resection/transplantation, TACE, adjuvant chemo, XRT

9. Human T-lymphotropic virus
(HTLV-1)
•Which cancer?
-Adult T-cell leukemia and lymphoma (Non-
Hodgkin’s)
-Also causes HTLV-1 associated
myelopathy/tropical spastic paraparesis
(HAM/TSP) (demyelinating disease)
-Most patients die within a year of diagnosis
•How?
-Virus enters T-cell, where its 2 strands of RNA
are copied into double-stranded DNA that can
integrate into the host cell’s genes (much like
HIV!)
-Believed to be sexually transmitted or
transmitted via breastfeeding

10. Human T-lymphotropic virus
(HTLV-1)
•Treatment
-Treatment for virus: prosultiamine, azacytidine, TDF (reverse-transcriptase
inhibitor), PCOANs
-Treatment for cancer: zidovudine + CHOP, pralatrexate is experimental for
ATL; for HCL, treatment usually includes purine analog chemo and
immunotherapy, splenectomy, bone marrow transplant
•Who?
-Anyone! Rare in U.S., where highest prevalence is in southeastern African-
Americans
-Endemic to southern Japan, the Caribbean, South American, and Africa
-Transmitted via infected blood

11. Human Papillomavirus (HPV)
•Which cancer?
-Cervical cancer…also associated with
oropharyngeal cancers, as well as anal
and genital cancers
•Who?
-Anyone!
-Cervical cancer is the second most
common in women (can take 15-20 years)
-Risk factors for persistent HPV leading to
cancer include multiple sexual partners,
tobacco use, and immune suppression

12. Human Papillomavirus (HPV)
•How?
-Transmitted via sexual contact, skin-to-skin
contact; can be transmitted (rarely) during
childbirth
-Many different subtypes- types 16 and 18 are
responsible for cancers and recurrent
respiratory papillomatosis (RRP)
-Types 6 and 11 are associated with genital
warts
-Nearly all cervical cancers and all cases of
genital warts are caused by HPV
•Treatment?
-Vaccine for virus (Gardasil and Cervarix)
-Cautery or cryotherapy for warts/cancer
-Condom, circumcision encouraged

13. Kaposi’s sarcoma-associated
herpesvirus (HHV-8)
•Which cancer?
-Kaposi’s sarcoma
-Rarely, primary effusion lymphoma
•Who?
-Can infect anyone
-Causes disease in immunosuppressed
patients; asymptomatic in healthy people
-HIV/AIDS patients, transplant patients, the
elderly, chemo patients
-While this virus is typically associated with
AIDS patients in the U.S., infection is
widespread in sub-Saharan Africa and there are
more cases of KS there

14. Kaposi’s sarcoma-associated
herpesvirus (HHV-8)
•How?
-Sexually transmitted
-Infects lymphocytes, establishes latency
-Inflammation or some other stimulus ignites
the lytic cycle
-Inhibits p53 tumor suppressor protein
-Cell lysis allows virus to escape and infect
surrounding cells
•Treatment?
-Prevention = safe sexual practices, condom
use
-Cancer treatment = surgery, radiation, and
chemotherapy (typically
anthracyclines/paclitaxel)
-Antiviral drug ganciclovir targets HHV-8, but
isn’t effective once tumor forms
-If the sarcoma is AIDS-related, best course of
action is anti-retroviral medication

15. Epstein-Barr Virus (EBV)
•Which cancer?
-Hodgkin’s lymphoma, Burkitt’s
lymphoma, nasopharyngeal carcinoma
-In HIV patients, infection associated with
CNS lymphomas and hairy leukoplakia
•Who?
-90-95% of people are infected in
childhood, with no symptoms
-Causes infectious mononucleosis in
adolescents
-Causes cancer in certain geographical
locations, and in immunocompromised
patients

16. Epstein-Barr Virus (EBV)
•How?
-Transmitted by transfer of saliva/genital
secretions
-Same genus as HHV-8
-Infects B cells and epithelial cells
-Can establish latency
•Treatment?
-Vaccine is currently in clinical trials
-For Burkitt’s lymphoma: chemotherapy,
immunotherapy, bone marrow transplant,
stem cell transplant, surgery, radiation
-For Hodgkin’s: early stage =
chemo/radiation, late stage = chemo only
-For NPC: chemo, radiation, and surgery

17. Merkel cell polyomavirus
•Which cancer?
-Merkel cell carcinoma (rare, aggressive
neuroendocrine skin cancer)
-Merkel cells help make up the barrier
between dermis/epidermis
-Can occur anywhere you have skin, most
commonly face
•Who?
-Chronically immunosuppressed
(HIV/AIDS, transplant, chronic lymphocytic
leukemia)
-More common in Caucasians, males
-Median age is 65 years old
-UV radiation may increase risk of cancer
formation
-rare---around 1500 new cases each year

18. Merkel cell polyomavirus
•How?
-The exact mechanism of cancer
formation is not known yet…the virus was
first described in 2008!
•Treatment?
-No vaccine or treatment for virus
-For MCC: surgery and adjuvant radiation
-Chemo can be used palliatively or to
shrink a tumor if needed

19. Sources
• http://www.virology.ws/2004/07/28/what-is-a-virus/
• http://www.webmd.com/hepatitis/hepc-guide/hepatitis-c-and-liver-cancer
• http://www.who.int/mediacentre/factsheets/fs204/en/
• http://www.webmd.com/hepatitis/hepb-guide/hepatitis-b-cause
• http://www.who.int/dsa/cat98/can8.htm#Human%20Immunodeficiency%20Vi
ruses,
• http://www.webmd.com/hiv-aids/htlv-type-i-and-type-ii
• www.webmd.com/cancer/tc/ncicdr0000062914-general-information-about-
kaposi-sarcoma
• www.who.int/vaccine_research/diseases/viral_cancers/en/index1.html
• http://www.who.int/vaccine_research/diseases/viral_cancers/en/index1.html
• http://www.webmd.com/cancer/tc/ncicdr0000062878-unusual-cancers-of-
the-head-and-neck
• http://www.tumorvirology.pitt.edu/mcvrsch.html