What are Carcinogens
Cancer causing agents
Mutagens
Carcinogens Induce mutations so they are called mutagens
Mutagenicity can cause
Genetic defects
RNA viruses that are microbial carcinogens
Human T-cell Leukemia Virus type 1 (HTLV-1)
Hepatisis C virus
HTLV1 causes
Adult T-cell leukemia/ lymphomas
ATLL
hepatisis C virus causes
Hepatocellular cancer
What are examples of DNA virus carcinogens
EBV (epstein barr virus)
Hepatisis B virus
HHV8 (human herpes virus 8)
HPV (human papilloma virus)
EBV causes
Burkitt lymphoma
Nasopharyngeal carcinoma
B cell lymphoma
Hepatisis B causes
Hepatocellular Carcinoma
HHV8 human herpes virus 8 causes
Kaposi sarcoma
HPV human papilloma virus causes
Cervical cancer
Oropharyngeal cancer
Squamous cell carcinoma of vulva, vagina, anus, larynx, oropharynx
HPV mechanism
Synthesis & upregulation of viral oncogenes— E6 & E7.
E6– (type16. 50%) inhibits p53 gene.
E7– (type 17. 10%) inhibits Rb suppressor genes.
Leads to host cell immortalisation & malignant transformation.
Microbial carcinogens
Bacterial— Helicobacter Pylori
Parasitic— schistosoma hematobium
H.pylori causes
Gastric adenocarcinoma
MALT lymphoma of stomach(monoclonal b-cell tumour)
Schistosoma hematobium causes
Bladder cancer
