T&H6 Oncogenic and tumor viruses

Question 1

What are the 3 main retrovirus genes? Describe their functions.

Answer 1

1. env = encodes glycoprotein
   - helps entry into the cell
2. gag = encodes capsid
   - helps assemble virions
3. pol = encodes reverse transcriptase
   - responsible for synthesis of viral DNA & integration into host DNA

Question 2

Polyomavirus is a ___ virus and causes what cancer? What accounts for its oncogenic properties?

Answer 2

• DNA
• Merkel cell carcinoma
• has 3 T antigens that interact with cell components

Question 3

Human adenovirus is a _____ virus. What genes integrate into host DNA to inhibit p53 and Rb?

Answer 3

• DNA
• E1B55K inhibits p53
• E1a inhibits Rb

Question 4

What is the Onyx-015 virus?

Answer 4

reengineered adenovirus that cannot express E1BBK. therefore, replicates in tumor cells and does not block p53

Question 5

Human papillomavirus is a ____ virus. What human cancers are associated with this virus?

Answer 5

cervical carcinoma, vulva, anus, penis, oropharyngeal carcinoma

Question 6

60-70% % of oropharyngeal SCC diagnosed in North America are from what virus?

Answer 6

HPV

Question 7

What is the preferential target for Epstein Barr Virus?

Answer 7

B lymphocyte

Question 8

What human cancers are associated with EBV?

Answer 8

• Burkitt LSA
• Hodgkin LSA
• LSA of immunocompromised host
• Gastric carcinoma
• Nasopharyngeal carcinoma
• T-cell LSA

Question 9

Deregulation of which oncogene contributes to Burkitt LSA?

Answer 9

c-myc

Question 10

Hepatitis B is a ___ virus that causes what cancer in people? In what animal can tumor formation be induced by this virus? What gene is often affected?

Answer 10

• DNA
• HCC
• Woodchuck
• DNA-binding protein 1 (DDB1)

Question 11

What additive factor acts with HIV to cause Kaposi’s Sarcoma?

Answer 11

development of AIDs

Question 12

Name a veterinary example of acute and chronic transforming retroviruses.

Answer 12

Acute: Rous sarcoma virus, feline sarcoma virus
Chronic: FeLV, avian leukemia virus

Question 13

What is the difference between acute and chronic transforming retroviruses?

Answer 13

• acute contains a viral oncogene so they are replicative defective and need helper virus to replicate
• chronic does not contain viral oncogene so can transform infected cells through insertional mutagenesis

Question 14

Which virus (and one additional carcinogen) plays a role in bovine bladder carcinoma?

Answer 14

• BPV-2
• Bracken fern ingestion

Question 15

Upper alimentary SCC in bovine is associated with what virus?

Answer 15

BPV-4

Question 16

Which form of bovine LSA is associated with BLV infection?

Answer 16

bovine leukosis, polyclonal expansion of B cells

Question 17

What cancer is caused by Jaagsiekte sheep retrovirus? What similar virus also causes cancers in sheep and goats?

Answer 17

• ovine pulmonary adenocarcinoma (OPA); aka contagious lung cancer
• ONAV/CNAV: Ovine/caprine nasal adenocarcinoma virus

Question 18

Kaposi sarcoma is associated with what virus? Is it DNA or RNA? What other human cancers are seen with this virus?

Answer 18

• Herpes virus 8
• DNA
• Multicentric Castleman’s disease and primary effusion lymphoma

Question 19

Human T-lymphotrophic virus is a ____ virus that causes what type of cancer, which is seen in ____-___% of infected people.

Answer 19

RNA
Adult lymphoma/leukemia
1-5%

Question 20

_______ are the only retroviruses known to lead directly to cancer in humans.

Answer 20

HTLV-1/2 (Human T-cell leukemia virus 1 and 2)

Question 21

Hepatitis C is a _____ virus that causes what type of cancer in people?

Answer 21

RNA
HCC

Question 22

HIV is a _____ virus.

Answer 22

RNA

Question 23

______ and _____ are cell receptors for EBC.

Answer 23

CD21 and MHCII

Question 24

Are retroviruses enveloped or non-enveloped?

Answer 24

enveloped

Question 25

______ is the cellular receptor for human T-cell leukemia virus (HTLV).

Answer 25

GLUT-1

Question 26

What are AIDs-related lymphomas?

Answer 26

Burkitt, Non-Hodgkin LSA, and CNS LSA

Question 27

________ does not cause cancer directly but can lead to cancer in late-stage infections by reactivation of other viruses, such as HPV, EBV, and human herpes virus 8.

Answer 27

HIV

Question 28

_____ virus is in the same family as yellow and dengue fever. _____ are the only primates besides humans that support its replication. It is a blood-borne pathogen that causes persistent infections in ___-___% of patients, leading to ______ and _______. It causes damage to ______ via the action of Fas ligand and perforin. It induces anergy in ______ and _____, which prevents clearance of the virus. What can accelerate its progression?

Answer 28

- Hepatitis C - Chimpanzees - 60-80% - cirrhosis and HCC - cytotoxic T cells - CD4 and CD8 T cells - alcohol abuse

Question 29

Woodchuck hepatitis virus infects the liver and can cause acute or chronic hepatitis. The _____ form leads to development of HCC within ____-____.

Answer 29

chronic 2-4 years

Question 30

In human papillomaviruses, which genes integrate into the host DNA to inhibit p53 and Rb?

Answer 30

- E6 targets p53 for degradation in the ubiquitin pathway - E7 binds to Rb and favors its degradation