Microorganisms causing cancer Flashcards
Parasite/virus causing cholangioma liver cancer
Opisthorchid trematodes
Parasite/virus causing bladder cancer
Trematodes
Parasite/virus causing Burrito’s lymphoma
EBV
Parasite/virus causing T cell leukaemia
T lymphotropic virus
Parasite/virus causing cervical camcer
HPV
Parasite/virus causing nasopharyngeal cancer
EBV
Parasite/virus causing liver cancer
Hep B and C
Parasite/virus causing Kaposi’s sarcoma
HHV
Parasite/virus causing stomach cancer
h.pylori
Parasite/virus causing oropharyngeal cancer
HPV
Avian leukosis
- Avian Leukosis virus (RNA virus)
- Integrates pro-viral DNA into host cell genome adjacent to cellular oncogene
- Cell has proliferative advantage = tumour development
- MYC oncogene - Burkitt’s lymphoma etc
How does HPV cause cancer?
Infects basal epithelium - CIN - cervical cancer
Viral DNA integrates into host genome and causes expression of E6 and E7 - expression of these genes causes carcinogenesis
RB pathway
- RB binds to E2F transcription factor
- This prevents E2F being available to activate cell cycle
- Phosphorylation of RB releases e2F so they can interact with genes in cell cycle progression
- When HPVE7 binds to RB it is targeted for degradation
- E2F available to activate genes involved in cellular proliferation
p53 pathway
DNA damage = phosphorylation of p53, turning it into stable protein -> up regulation of p21
Cell cycle stops and apoptosis
How does EBv attack B cells?
CD21
What is Burkitt’s lymphoma?
Neoplasm of B lymphocytes (8:14 translocation of myc)
LMP-1
Activates NF-kB and JAK/STAT signalling pathways - prevents apoptosis by activating BCL2
EBNA-2
activates host genes e.g. cyclin D and Src proto-oncogenes (B cell proliferation)
EBV indirect mechanism
Burkitt’s lymphoma = 8:14 translocation via malaria causing sustaining B cell proliferation. T cells eliminate most EBV infected B cells but some hide and persist and acquire additional mutations = translocation
What type of viruses are hep B and C
B is DNA and C is RNA
