RNA virus
HTLV1 (human t lymphotrophic virus 1)
DNA viruses
- HPV
- EBV
- HBV
- HCV
- HHV8
Ways of developing viral oncogenesis (3)
- integration into DNA
- Episomal
- Infection - cell death
Ways of viruses to cause oncogenesis by integrating into DNA (2)
- acting as oncogene
- regulating host genes : inactivation of tumor suppressor genes
How do viruses cause oncogenesis by episomal transformation? (2)
- either activate oncogene in the host DNA
- or inactivate tumor suppressor gene in host DNA
How do viruses cause oncogenesis by infection? (2)
- produces ROS which are genotoxic
- elimination by immune system causes increased regeneration of cells an can activate oncogene
how do EBV, HBV cause oncogenesis?
by integration to host DNA
Diseases caused by EBV? (3)
- mononucleosis
- burkitt lymphoma
- nasopharyngeal carcinoma
What are the 2 oncogenic sequences of EBV?
- LMP1 (oncogene)
- EBVA2 (transactivation)
What is the effect of EBV on the cell?
causes the cell to proliferate so much that mistakes happen like t(8;14)
What are the low risk types of HPV?
1, 2, 4, 7
What do the low risk types of HPV cause?
papilloma
What are the high risk types of HPV?
16, 18, 31
What do the high risk types of HPV cause?
- cervix carcinoma
- oropharyngeal carconoma
What are the oncogenic sequences in HPV?
E7, E6
What type of carcinoma is caused by HBV?
hepatocellular carnicoma
Ways HBC causes carcinogenesis? (4)
- initiate inflammatory reaction
- cause microdeletions
- increase cell proliferation
- HBX gene inactivates p53
Which bacteria can cause oncogenesis?
helicobacter pylori
Which neoplasms does helicobacter pylori cause?
- mucosal gastric cancer
- MALT lymphoma
How does helicobacter pylori cause gastric cancer?
chronic inflammation triggers mucous membrane atrophy, which causes dysplasia and cancer
How does helicobacter pylori cause MALT lymphoma?
chronic inflammation triggers t cell response and b cell proliferation
