Hepatitis viruses (other than hepatitis B and C viruses) as causes of hepatocellular carcinoma: an update

Abstract

Chronic hepatitis B and C virus infections are universally accepted as causes of hepatocellular carcinoma in humans. Hepatitis A and E viruses cause only acute self-limiting infections of the liver. Of the remaining hepatitis viruses - Delta hepatitis, hepatitis G (GB-C), TT and SEN - all have at some time been incriminated as causes of hepatocellular carcinoma. Delta hepatitis virus requires helper functions from hepatitis B virus to become invasive. Chronic Delta/hepatitis B viral co-infection runs a more severe course than that resulting from chronic hepatitis B virus infection alone, with progression to cirrhosis being more likely and more rapid. A substantial majority of the early studies did not find an increased incidence of hepatocellular carcinoma in co-infected individuals. But more recently, an increased incidence of the tumour has been recorded more often than no increase. Further studies are needed to draw a firm conclusion with regard to the hepatocarcinogenic effect of dual Delta/hepatitis B virus co-infection. With one exception, no published study (of 13) has incriminated chronic infection with hepatitis G virus as a cause of hepatocellular carcinoma. The dissenting study, published in 1999, was the only one performed in the United States. Fewer studies of the hepatocarcinogenic effect of TT virus have been performed. Apart from one study, published in 1999, no convincing evidence is available that supports a causal role for TT virus in hepatocarcinogenesis. The exception was in Japanese patients with high hepatitis C viral loads but independent of chronic hepatitis C virus infection. No evidence has been produced to indicate that SEN virus causes hepatocellular carcinoma.

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“…Chronic HDV infection frequently is associated with active chronic hepatitis that leads to cirrhosis in 70% patients in 5 to 10 years. 8,9 Patients with chronic HDV infections have more rapidly progressive liver damage than patients infected with HBV alone. 10 The incidence of cirrhosis is 3-fold higher in patients with HBV/HDV chronic coinfection than chronic HBV monoinfection, with a higher risk of early decompensation and development of hepatocellular carcinoma (HCC).…”

“…10 The incidence of cirrhosis is 3-fold higher in patients with HBV/HDV chronic coinfection than chronic HBV monoinfection, with a higher risk of early decompensation and development of hepatocellular carcinoma (HCC). 9,11 Therefore, HDV infection in the world is an important health burden. The only established treatment for chronic HDV is interferon at high doses, but interferon therapy is associated with therapeutic success in only 25% to 30% treatments.…”

Does SEN virus (SENV) infection affect the progression of chronic hepatitis C or B among Egyptian patients?

“…In concordance, Tangkijvanich et al (2003) also reported no differences between SENVinfected and non-infected patients regarding severity of chronic liver disease and HCC. Recently, no evidence has been produced to indicate that SEN virus causes HCC (Kew, 2013). On the contrary, another study documented that SENV co-infection may influence the histopathological features of the livers of patients with CHC but does not affect the outcome of patients with type C chronic liver disease.…”

Development of an Immunoassay for Detection of Torque Teno Virus (TTV) Antibodies Using the N22 Expression Product from TTV Genotype 2

“…It has also been detected in various types of carcinoma including leukemia and colorectal cancer. However, the pathogenicity of TTV at present is unclear [7,18,20,26,27]. Due to the lack of available tissue-culture methods, TTV infection is often diagnosed on the basis of TTV-DNA detection by PCR.…”

“…This needs further extensive investigation. TTV shows a high prevalence both in healthy and in diseased individuals globally [19][20][21]. The virus has been detected in nearly all tissues of the body [22].…”