2. CANCER
Cancer is a complex group of diseases with
multiple eventual causes.
The impacts of cancer are multiple and far
reaching, affecting people of both gender,
and all ages.
3. Approximately 20% of all cancers are
associated with infectious agents , and
15% of all cancers are caused by
oncoviruses .
4.
5. "Infections are one of the biggest
and preventable causes of cancer
worldwide,”
6.
7. ETIOLOGY
The etiology of cancer is multifactorial, with
genetic, environmental, medical, and lifestyle
factors interacting to produce a given malignancy.
8. CARCINOGENESIS
The process is characterized by changes at
the cellular, genetics , epigenetic levels and
abnormal cell division.
9. INFECTIOUS AGENTS
Such as
Hepatitis B (HBV) and C viruses (HCV)
Epstein-Barr virus (EBV)
Human papillomavirus (HPV)
Human Immunodeficiency virus type 1 (HIV-1)
Helicobacter pylori (H. pylori)
Streptococcus bovis (S. bovis)
Schistosoma haematobium
contribute to the pathogenesis of different cancers
.
10. WHAT ARE COMMON FEATURES AMONG
ONCOGENIC VIRUSES
Most oncogenic viruses often contribute to cancer
development in similar ways
•These viruses have the ability to infect, but not kill their host
cells.
•They establish persistent and long-term infections.
•They have evolved strategies that enable them to evade
mechanisms of viral clearance by the host immune system.
11. Why not all virally infected
individuals develop cancer?
“There is no single mechanism by
which viruses cause tumors”
12.
13. VIRUSES ASSOCIATED WITH HUMAN CANCERS
Infectious Agent Associated Cancers
Epstein-Barr virus (EBV) Burkitt lymphoma- Hodgkin lymphoma
Nasopharyngeal carcinoma
Hepatitis B virus (HBV) Hepatocellular carcinoma
Hepatitis C virus (HCV) Hepatocellular carcinoma
Human papillomavirus types (HPV)16, 18 Genital tumors
Oropharyngeal cancer
Human immunodeficiency virus 1 (HIV 1) AID-related malignancies
Human T-cell lymphotropic virus 1 (HTLV1) Adult T-cell leukemia
Kaposi sarcoma herpesvirus/ human
herpesvirus 8 (KSHV/HHV 8)
Kaposi sarcoma
Markel cell virus Markel cell carcinoma
14. OTHER INFECTIOUS AGENTS ASSOCIATED WITH HUMAN
CANCERS
Infectious Agent Associated Cancers
Helicobacter pylori Gastric cancer
Streptococcus bovis Colorectal cancer
Liver flukes Cholangiocarcinoma
Schistosomes Bladder cancer
15. Multiple tools to fight infections, such as vaccination, safe
injection practices, screening of blood transfusion, safe sex
practices, antimicrobial treatments can have beneficial
effects on the future burden of cancer related-infections.
PREVENTION SOLUTION
16. SUMMARY
Viruses are causative agent of several type of
human cancer .
Tumor viruses established persistent infection in
hosts, with long latent period before tumor
appearance.
Viral infections tend to be more chronic than
bacterial infections, thus viruses have a more
prominent role in the development of cancer.
