036 Viral aetiology of cancer

Question 1

What is abortive infection?

Answer 1

When the infection no longer productive but causes neoplasia instead.

Question 2

How does onco-viruses defy Koch’s postulate?

Answer 2

agent not present in every case of disease
cannot be replicated
may be present in other disease as non pathogenic

Question 3

Which HPV causes benign verrucas?

Answer 3

HPV1

Question 4

What does HPV2 result in?

Answer 4

Common warts

Question 5

Which gene is involved in immune system with associating beta virus with cancer?

Answer 5

EVA1 gene

Question 6

Which genes are responsible for replication in HPV

Answer 6

L1, L2

Question 7

Which genes are resopnsible for packaging in HPV?

Answer 7

E1, E2

Question 8

Which are the oncogenes in HPV?

Answer 8

E6, E7

Question 9

Describe the molecular mechanisms underlying cell cycle of epithelial cells

Answer 9

1. Growth factor release by underlying dermis
2. activates cyclin D
3. Phosphorylates Rb
4. Releases transcription factor
   p16 ensures negative feedback on cyclin D

Question 10

Describe molecular mechanisms of P53

Answer 10

P53 is apoptosis and cell grwoth stimulator
Normally degraded by ubiquitin ligase mdm2
P14 binds with mdm2 to prevent degredation of p53

Question 11

Describe the mechanism of E7

Answer 11

E7 causes cell proliferation

1. phosphorylates Rb directly to release transcription factor.
2. No negative feedback occuring by p16 because cyclin does not control the entry.
3. large overexpression of proteins –> neoplasia

Question 12

Describe the mechanisms of E6

Answer 12

1. Binds to P53 and recruits ubiquitin ligase Mdm2

Question 13

Which genes are responsible for cancer in adenoviruses?

Answer 13

E1A (inhibit repair) and E1B (cell proliferation)

Question 14

How do you define Burkitts lymphoma?

Answer 14

Myc translocation