CancerQuest | Hepatitis Viruses and Cancer Development

Hepatitis B Virus (HBV)⁽¹⁾⁽²⁾

Associated Cancer: Human Hepatocellular Carcinoma (HCC)
Prevalence: HBV is prevalent on every continent, but is especially high in sub-Saharan Africa and Southeast Asia. It is estimated that over 400 million people worldwide are infected.
Transmission: HBV is transmitted via contact with contaminated blood, sweat, or tears. It can also be spread through sexual contact and from mother to child.
Infection: HBV Infection occurs mainly in the liver, but viral antigens can be detected in the blood throughout the body. Chronic Infection is indicated by the presence of viral antigens in the blood for longer than 6 months. Chronic Infection can lead to cirrhosis of the liver and development of HCC.
Carcinogenic Potential: Hepatitis viruses (B and C) are responsible for 70-85% of primary liver cancers. Viral integration into the host genome is regularly found in chronic liver infection and cancer. This suggests it plays an important role in carcinogenesis. HBV encodes a protein (HBX) that may promote cell proliferation and interfere with DNA repair. HBV mediated carcinogenesis is likely due to a number of factors; the oncogenic properties of HBX, chronic liver damage, chronic inflammation, and the continuous tissue regeneration needed to maintain the liver during an infection.

Hepatitis C Virus (HCV)⁽¹⁾⁽³⁾

Associated Cancer: Human Hepatocellular Carcinoma (HCC)
Prevalence: HCV is prevalent on every continent, but it is especially high in sub-Saharan Africa and Southeast Asia. It's estimated over 170 million people are infected with HCV worldwide.
Transmission: HCV is transmitted primarily through blood-blood contact.
Infection: HCV Infection occurs mainly in the liver and produces a more severe inflammation than HBV. Over 80% of those infected with HCV will develop cirrhosis of the liver or HCC.
Carcinogenic Potential: Hepatitis B and C are responsible for 70-85% of primary liver cancers. HCV is not known to integrate into the host genome. In vitro HCV has been shown to affect a wide range of cellular mechanisms that may promote carcinogenesis, but these have not been reproduced in vivo. The carcinogenic potential of HCV lies in its ability to cause chronic immune response-mediated hepatic damage, inflammation, and tissue regeneration.