Oncogenic Viruses Flashcards
Describe p53’s mechanism of action
If DNA damage is too great, p53 to inhibits the cell cycle and causes apoptosis
Describe Rb normal mechnism of action.
E2F induces the cell cycle. Rb inhibits the action of E2F.
Why is SV40 know as the prototypical DNA tumor virus? What is SV40s mechanism of action?
It is a primate virus (not human), that produces a T protein that inhibitis the action of p53 and Rb resulting in cancer growth
What cancers do adenovirus cause in humans?
They don’t cause cancer in humans. They DO cause cancer in rodents.
What type of cancer is HPV typically responsible for in humans?
Cervical cancer
What two types of cancer is EBV responsible for in humans?
- Burkitt’s Lymphoma
- Naso-pharyngeal cancer
What type of cancer does HHV8 typically cause?
Kaposi’s Sarcoma
What are the high-risk strains of HPV?
16,18, 31, 33
What is the mechanism of oncogenesis of HPV?
- HPV produces E6 and E7 protein
- E6 binds to p53
- E7 binds Rb preventing inhibition of E2F
What is the difference between low risk and high risk HPV?
Both produce E6 and E7, but the E6 and E7 of low-risk HPV bind with much lower affinity
What is the significance of the E2 protein in HPV oncogenesis?
E2 (part of the HPV genome) typically suppresses E6 and E7 proteins. Loss of E2 upon HPV gene integration results in over-expression of E6 and E7
What is the geographical distribtution of Burkitt Lymphoma and Nasopharyngeal cancer?
- Burkitt - African Malarial Belt
- Nasopharyngeal - South china, Vietnam
Describe the chromosomal changes associated with EBV-relatedlymphomas
A 8-14 translocation causes the c-myc gene near an Ig promoter
What type of cancer is associated with HBV?
Liver cancer
What is another name for HHV8?
Kaposi Sarcoma Herpes Virus (KSHV)
