Hepatitis viruses and hepatocellular carcinoma

High-dose hepatitis B immunoglobulin therapy in hepatocellular carcinoma with hepatitis B virus-DNA/hepatitis B e antigen-positive patients after living donor liver transplantation

AIM: To investigate the impact of high-dose hepatitis B immunoglobulin (HBIG) on hepatocellular carcinoma (HCC) and hepatitis B virus (HBV) recurrence and overall survival after living donor liver transplantation (LDLT).

METHODS: We investigated 168 patients who underwent LDLT due to HCC, and who were HBV-DNA/hepatitis B e antigen (HBeAg) -positive, from January 2008 to December 2013. After assessing whether the patients met the Milan criteria, they were assigned to the low-dose HBIG group and high-dose HBIG group. Using the propensity score 1:1 matching method, 38 and 18 pairs were defined as adhering to and not adhering to the Milan criteria. For each pair, HCC recurrence, HBV recurrence and overall survival were analyzed by the Kaplan-Meier method and the log rank test according to the HBIG dose.

RESULTS: Among those who met the Milan criteria, the 6-mo, 1-year, and 3-year HCC recurrence-free survival rates were 88.9%, 83.2%, and 83.2% in the low-dose HBIG group and 97.2%, 97.2%, and 97.2% in the high-dose HBIG group, respectively (P = 0.042). In contrast, among those who did not meet the Milan criteria, HCC recurrence did not differ according to the HBIG dose (P = 0.937). Moreover, HBV recurrence and overall survival did not differ according to the HBIG dose among those who met (P = 0.317 and 0.190, respectively) and did not meet (P = 0.350 and 0.987, respectively) the Milan criteria.

CONCLUSION: High-dose HBIG therapy can reduce HCC recurrence in HBV-DNA/HBeAg-positive patients after LDLT.

The Role of Antiviral Therapy for HBV-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly prevalent and lethal cancer worldwide; despite the curative treatment for HCC, the rate of tumor recurrence after hepatectomy remains high. Tumor recurrence can occur early (<2 years) or late (>2 years) as metastases or de novo tumors. Several tumor factors were associated with HCC recurrence; high hepatitis B virus (HBV) load is the major risk factor for late recurrence of HCC after resection. Preoperative antiviral therapy improves liver function, and postoperative reduce HCC recurrence. In this paper, we focus on antiviral treatment to improve the liver function, prevent recurrence, and lengthen the overall survival for HBV-related HCC.

The influence of hepatitis B DNA level and antiviral therapy on recurrence after initial curative treatment in patients with hepatocellular carcinoma

BACKGROUND

Prediction and prevention of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) recurrence is an important clinical issue. We investigated whether HBV DNA level and antiviral therapy are associated with HCC recurrence.

METHODS

This retrospective study involved 103 patients who underwent hepatic resection or radiofrequency ablation for initial HCC. Patients were divided into four groups. Thirty had high serum HBV DNA levels (>4 log(10) copies/mL) and had not received antiviral therapy (high virus group; HVG). Thirty-four had low HBV DNA levels (< or =4 log(10) copies/mL) and had not received antiviral therapy (low virus group; LVG). Twenty received antiviral therapy after HCC developed (therapeutic group A, TG-A). Nineteen received antiviral therapy before HCC developed (therapeutic group B, TG-B).

RESULTS

Cumulative HCC recurrence rates at 3 years in the HVG, LVG, TG-B, and TG-A were 71.1%, 42.2%, 42.3%, and 52.0%, respectively. Recurrence rates differed significantly between the HVG and LVG (P = 0.016) and between the HVG and TG-B (P = 0.008). Recurrence rate in the TG-A was marginally lower than in the HVG (P = 0.10). On multivariate analysis, high serum hepatitis B virus DNA levels (hazard ratio: HR 2.67; 95% CI 1.31-5.47; P = 0.007) and absence of antiviral therapy (HR 2.57; 95% CI 1.34-4.94; P = 0.005) were independent risk factors for hepatocellular carcinoma recurrence.

CONCLUSION

HBV DNA level and antiviral therapy are associated with HCC recurrence. For patients with high HBV DNA levels, antiviral therapy before the development of HCC is important for prevention of recurrence.

Persistent hepatitis B viral replication affects recurrence of hepatocellular carcinoma after curative resection

BACKGROUND

Elevated serum hepatitis B virus (HBV) DNA increases the development of hepatocellular carcinoma (HCC). Rather than instantaneous DNA level, the duration of persistent HBV replication is more important in carcinogenesis. Nevertheless, most investigators evaluated the DNA level at study entry. We assessed the effects of persistently detectable serum HBV DNA on HCC recurrence.

PATIENTS AND METHODS

We included 230 consecutive patients undergoing curative resection between 2000 and 2006. Patients who had antiviral therapy (at diagnosis or during follow-up), fluctuating DNA (cut-off value: 100,000 copies/ml) or recurrence within 12 months of resection were excluded. Ultimately, 157 were enrolled: 89 (non-viraemia group) had consistently negative DNA (<100,000 copies/ml), while 68 (viraemia group) had consistently positive DNA (>100 000copies/ml). Serum DNA level, biochemical tests, alpha-foetoprotein (AFP) and liver dynamic computed tomography were obtained every 3 months after surgery.

RESULTS

There were no significant differences in age, gender, liver function, histology, AFP, tumour stages or follow-up duration between the two groups. During follow-up (median: 35 months), patients in the non-viraemia group had a lower 5-year cumulative recurrence rate (54.7%) than those in the viraemia group (72.9%; P=0.043). In multivariate analysis, sustained viraemia (P=0.041) increased recurrence independently.

CONCLUSIONS

Persistent viraemia increased recurrence independently after surgery. To prevent long-term recurrences, antiviral therapy should be initiated in those with detectable serum HBV DNA.

Viral hepatitis and hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. The incidence of HCC varies considerably with the geographic area because of differences in the major causative factors. Chronic hepatitis B and C, mostly in the cirrhotic stage, are responsible for the great majority of cases of HCC worldwide. The geographic areas at the highest risk are South-East Asia and sub-Saharan Africa, here hepatitis B is highly endemic and is the main cause of HCC. In areas with an intermediate rate of HCC such as Southern Europe and Japan, hepatitis C is the predominant cause, whereas in low rate areas such as Northern Europe and the USA, HCC is often related to other factors as alcoholic liver disease. There is a rising incidence in HCC in developed countries during the last two decades, due to the increasing rate of hepatitis C infection and improvement of the clinical management of cirrhosis.

METHODS

This article reviews the literature on hepatitis and hepatocellular carcinoma. The Medline search was carried out using these key words and articles were selected on epidemiology, risk factors, screening, and prevention of hepatocellular carcinoma.

RESULTS

Screening of patients with advanced chronic hepatitis B and C with hepatic ultrasound and determination of serum alfa-fetoprotein may improve the detection of HCC, but further studies are needed whether screening improves clinical outcome. Hepatitis B and C viruses (HBV/HCV) can be implicated in the development of HCC in an indirect way, through induction of chronic inflammation, or directly by means of viral proteins or, in the case of HBV, by creation of mutations by integration into the genome of the hepatocyte.

CONCLUSION

The most effective tool to prevent HCC is avoidance of the risk factors such as viral infection. For HBV, a very effective vaccine is available. Preliminary data from Taiwan indicate a protective effect of universal vaccination on the development of HCC. Vaccination against HBV should therefore be a health priority. In patients with chronic hepatitis B or C, interferon-alfa treatment in a noncirrhotic stage is protective for HCC development in responders, probably by prevention of cirrhosis development. When cirrhosis is already present, the protective effect is less clear. For cirrhosis due to hepatitis B, a protective effect was demonstrated in Oriental, but not in European patients. For cirrhosis due to hepatitis C, interferon-alfa treatment showed to be protective in some studies, especially in Japan with a high incidence of HCC in untreated patients. Virological, but also merely biochemical response, seems to be associated with a lower risk of development of HCC. As most studies are not randomized controlled trials, no definitive conclusions on the long-term effects of interferon-alfa in HBV or HCV cirrhosis can be established. Especially in hepatitis C, prospective studies should be performed using the more potent reference treatments for cirrhotics, namely the combination of peginterferon and ribavirin.

Environmental and chemical carcinogenesis

People are continuously exposed exogenously to varying amounts of chemicals that have been shown to have carcinogenic or mutagenic properties in experimental systems. Exposure can occur exogenously when these agents are present in food, air or water, and also endogenously when they are products of metabolism or pathophysiologic states such as inflammation. It has been estimated that exposure to environmental chemical carcinogens may contribute significantly to the causation of a sizable fraction, perhaps a majority, of human cancers, when exposures are related to "life-style" factors such as diet, tobacco use, etc. This chapter summarizes several aspects of environmental chemical carcinogenesis that have been extensively studied and illustrates the power of mechanistic investigation combined with molecular epidemiologic approaches in establishing causative linkages between environmental exposures and increased cancer risks. A causative relationship between exposure to aflatoxin, a strongly carcinogenic mold-produced contaminant of dietary staples in Asia and Africa, and elevated risk for primary liver cancer has been demonstrated through the application of well-validated biomarkers in molecular epidemiology. These studies have also identified a striking synergistic interaction between aflatoxin and hepatitis B virus infection in elevating liver cancer risk. Use of tobacco products provides a clear example of cancer causation by a life-style factor involving carcinogen exposure. Tobacco carcinogens and their DNA adducts are central to cancer induction by tobacco products, and the contribution of specific tobacco carcinogens (e.g. PAH and NNK) to tobacco-induced lung cancer, can be evaluated by a weight of evidence approach. Factors considered include presence in tobacco products, carcinogenicity in laboratory animals, human uptake, metabolism and adduct formation, possible role in causing molecular changes in oncogenes or suppressor genes, and other relevant data. This approach can be applied to evaluation of other environmental carcinogens, and the evaluations would be markedly facilitated by prospective epidemiologic studies incorporating phenotypic carcinogen-specific biomarkers. Heterocyclic amines represent an important class of carcinogens in foods. They are mutagens and carcinogens at numerous organ sites in experimental animals, are produced when meats are heated above 180 degrees C for long periods. Four of these compounds can consistently be identified in well-done meat products from the North American diet, and although a causal linkage has not been established, a majority of epidemiology studies have linked consumption of well-done meat products to cancer of the colon, breast and stomach. Studies employing molecular biomarkers suggest that individuals may differ in their susceptibility to these carcinogens, and genetic polymorphisms may contribute to this variability. Heterocyclic amines, like most other chemical carcinogens, are not carcinogenic per se but must be metabolized by a family of cytochrome P450 enzymes to chemically reactive electrophiles prior to reacting with DNA to initiate a carcinogenic response. These same cytochrome P450 enzymes--as well as enzymes that act on the metabolic products of the cytochromes P450 (e.g. glucuronyl transferase, glutathione S-transferase and others)--also metabolize chemicals by inactivation pathways, and the relative amounts of activation and detoxification will determine whether a chemical is carcinogenic. Because both genetic and environmental factors influence the levels of enzymes that metabolically activate and detoxify chemicals, they can also influence carcinogenic risk. Many of the phenotypes of cancer cells can be the result of mutations, i.e., changes in the nucleotide sequence of DNA that accumulate as tumors progress. These can arise as a result of DNA damage or by the incorporation of non-complementary nucleotides during DNA synthetic processes. Based upon the disparity between the infrequency of spontaneous mutations and the large numbers of mutations reported in human tumors, it has been postulated that cancers must exhibit a mutator phenotype, which would represent an early event in cancer progression. A mutator phenotype could be generated by mutations in genes that normally function to guarantee genetic stability. These mutations presumably arise via DNA damage by environmental or endogenous agents, but it remains to be determined whether the acquisition of a mutator phenotype is a necessary event during tumor progression.

Detection of different viral transcripts in sera of patients with chronic hepatitis B virus infection

AIM: To establish an assay for detecting serum hepatitis B virus (HBV) transcripts including the full-length (fRNA) and truncated RNA molecules (trRNA) in chronic HBV carriers, and to investigate its clinical significance.

METHODS: The serum viral nucleic acids were analyzed using PCR and RT-PCR targeted to the HBV x protein-encoding region. Reaction specificity was confirmed by Southern blotting. Representative amplification products were cloned and sequenced.

RESULTS: Different viral transcripts including fRNA and trRNA were identified in sera of HBV carriers. Presence of fRNA was closely correlated with seropositivity of hepatitis B e antigen and viral DNA. However, trRNA did not depend on serum e antigen, its association with circulating viral DNA was weak. Similarly, no remarkable correlation was observed between the levels of trRNA and the degrees of liver damage. Different age-dependent representations for fRNA and trRNA were recognized, fRNA was progressively decreased to undetectable levels and trRNA increased to high levels in the second decade of life and then remained in high level in the rest of life. The trRNA and RNA without polyadenylation at either of the two addition sites were detected even in the absence of any other conventional HBV markers such as viral DNA. They were also observed in sera from patients with cryptogenic cirrhosis or chronic hepatitis C.

CONCLUSION: The viral transcripts are potential serum markers for identifying replicative and non-replicative infection stages and diagnosis of occult HBV infection.

Hepatocellular carcinoma among atomic bomb survivors: significant interaction of radiation with hepatitis C virus infections

We conducted a nested case-control study within the cohort of Japanese survivors of the 1945 atomic bombings to study the joint effects of HBV and HCV with radiation on the risk of HCC. Among subjects who received autopsies during 1954-1988, we analyzed archival tissue samples for 238 pathologically confirmed HCC cases and 894 controls who died from diseases other than liver cancer. Using logistic regression and adjusting for potential confounders and other factors, we found a statistically significant, supermultiplicative interaction between A bomb radiation and HCV in the etiology of HCC. Compared to subjects who were negative for HCV and radiation, ORs of HCC for HCV-positive subjects showed a statistically significant, greater than multiplicative increase for liver irradiation exposures in the second (>0.018-0.186 Sv, p = 0.04) and third (>0.186 Sv, p = 0.05) tertiles of non-zero radiation exposure but not for first tertile exposure (>0-0.018 Sv, p = 0.86). Limiting analysis to subjects without cirrhosis, HCV-infected subjects were at 58.0-fold (95% CI 1.99- infinity ) increased risk of HCC per Sv of radiation exposure (p = 0.017), a supermultiplicative interaction between radiation and HCV that was not found among subjects with cirrhosis (p = 0.67). We found no evidence of interaction between HBV infection and radiation exposure in the etiology of HCC, regardless of cirrhosis status (p = 0.58). We conclude that among survivors of the nuclear bombings of Hiroshima and Nagasaki, subjects who were both HCV-positive and radiation-exposed were at a significantly, supermultiplicatively increased risk of HCC without concurrent cirrhosis.

Seroprevalence of Hepatitis B virus infection among an Afro-descendant community in Brazil

Furnas dos Dionísios is an Afro-Brazilian black community whose descendants were mainly fugitive slaves that established themselves in the State of Mato Grosso do Sul (MS), Brazil. The population is comprised mainly of low socioeconomic individuals who are engaged in agricultural activities. The objective of this study was to investigate the prevalence of hepatitis B (HB) and its correlation with epidemiological data obtained from the community. The studied population totaled 260 individuals with ages varying from 1 to 79 years (median 20). One hundred thirty-three (51.2%) were females and 127 (48.8%) were males. A high prevalence for anti-HBc was observed (42.7%), with present infection detected in 9.2% of the subjects who were also HB surface antigens (HBs Ag) positive; 27.3% were anti-HBc and anti-HBs reactive, and 6.2% had anti-HBc as only marker. The prevalence for anti-HBc was proportional to age, reaching its highest peak in age categories greater than 50. No serological marker was detected in children under the age of 2 years, however anti-HBc was present in 12 subjects with ages between 2 and 14 years, of these 8 (7.4%) were HBsAg positive. Among individuals over the age of 15 years, 99 were anti-HBc reactive, of these 16 (10.5%) were also HBsAg positive, thus suggesting an increased prevalence of HBV carriers among children and adolescents. The risk factors observed in this community that were significantly associated with anti-HBc positivity were age (over 20 years) and having an anti-HBc positive mother. Both HBeAg and anti-HBe were detected in 44.4% of the samples tested. HBsAg subtypes found in the studied population were adw2 (77.7%) and ayw2 (23.3%). While intrafamilial transmission was most likely responsible for HBV infection among children, other routes such as sexual contact might be considered for individuals with ages over 15 years.

Hepatitis B e antigen and the risk of hepatocellular carcinoma

BACKGROUND

The presence of hepatitis B e antigen (HBeAg) in serum indicates active viral replication in hepatocytes. HBeAg is thus a surrogate marker for the presence of hepatitis B virus DNA. We conducted a prospective study to determine the relation between positivity for hepatitis B surface antigen (HBsAg) and HBeAg and the development of hepatocellular carcinoma.

METHODS

In 1991 and 1992, we enrolled 11,893 men without evidence of hepatocellular carcinoma (age range, 30 to 65 years) from seven townships in Taiwan. Serum samples obtained at the time of enrollment were tested for HBsAg and HBeAg by radioimmunoassay. The diagnosis of hepatocellular carcinoma was ascertained through data linkage with the computerized National Cancer Registry in Taiwan and with death certificates. We performed a multiple regression analysis to determine the relative risk of hepatocellular carcinoma among men who were positive for HBsAg alone or for HBsAg and HBeAg, as compared with those who were negative for both.

RESULTS

There were 111 cases of newly diagnosed hepatocellular carcinoma during 92,359 person-years of follow-up. The incidence rate of hepatocellular carcinoma was 1169 cases per 100,000 person-years among men who were positive for both HBsAg and HBeAg, 324 per 100,000 person-years for those who were positive for HBsAg only, and 39 per 100,000 person-years for those who were negative for both. After adjustment for age, sex, the presence or absence of antibodies against hepatitis C virus, cigarette-smoking status, and use or nonuse of alcohol, the relative risk of hepatocellular carcinoma was 9.6 (95 percent confidence interval, 6.0 to 15.2) among men who were positive for HBsAg alone and 60.2 (95 percent confidence interval, 35.5 to 102.1) among those who were positive for both HBsAg and HBeAg, as compared with men who were negative for both.

CONCLUSIONS

Positivity for HBeAg is associated with an increased risk of hepatocellular carcinoma.

Immunotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death, with over a million new cases annually. It is generally advanced upon detection due to underlying liver disease, which further complicates treatment. Most of the therapeutic strategies in current use (surgery, transplantation, irradiation or chemotherapy) are either palliative or only of benefit to a small percentage of patients. This article reviews the biology of HCC, including many of the molecular changes and mechanisms leading to HCC development. This article discusses the recent innovative strategies to interfere with the progression of HCC, including novel gene therapy strategies. The most recent data supporting the use of immunotherapy for hepatocellular cancer is reviewed in detail.

Inhibition of alcohol dehydrogenase blocks enhanced Gi-protein expression following ethanol treatment in experimental hepatocellular carcinoma in vitro

OBJECTIVE

Chronic alcohol abuse is one of the major contributors to the onset and progression of hepatocellular carcinoma (HCC). We have previously identified increased expression and function of inhibitory guanine nucleotide regulatory proteins (Gi-proteins) in primary human and animal models of HCC. Stimulation of Gi-proteins in HCC stimulates cell mitogenesis, an effect not observed in hepatocytes. The aim of this study was to determine the effect of ethanol and ethanol metabolism on Gi-protein expression in an experimental model of HCC.

DESIGN

Pharmacological agents that inhibit alcohol metabolism were used in conjunction with ethanol or ethanol metabolites. We were also able to assess the relative contribution of alcohol and acetaldehyde, the major metabolite of alcohol, on Gi-protein expression in HCC and hepatocytes.

METHODS

These studies used the rat hepatic tumorigenic H4IIE cell line in conjunction with isolated rat hepatocytes. Cells were cultured in vitro and exposed to ethanol, ethanol in the presence of an alcohol dehydrogenase (ADH) inhibitor, or acetaldehyde for varying lengths of time. Ethanol metabolism and changes in Gi-protein expression were subsequently determined by assay.

RESULTS

Exposure to ethanol alone led to significant dose and time dependent increases in Gialpha1/2 and Gialpha3 protein and mRNA expression in HCC cells. In contrast, ethanol failed to alter Gialpha1/2, and only moderately affected Gialpha3 protein expression in isolated cultured hepatocytes. Pretreatment of HCC cells and hepatocytes with 4-methyl pyrazole (4-MP, 10 microm) significantly inhibited alcohol metabolism. Treatment of HCC cells with 4-MP inhibited changes in Gi-protein expression following exposure to ethanol (25 mm, 24 h). In addition, the increased expression of Gi-proteins observed after exposure to ethanol in HCC were mimicked by direct exposure of HCC cells to acetaldehyde in a dose and time dependent manner.

CONCLUSIONS

These data suggest that alcohol metabolites, not alcohol, lead to increased Gi-protein expression in HCC in vitro. Ethanol and ethanol metabolites, in contrast, fail to significantly alter Gialpha1/2 protein expression in hepatocytes. These data may have significant implications in HCC progression in vivo.

Impacts of chemicals on liver cancer risk

Primary liver cancer (PLC) is of multifactorial etiology. Chronic infections by hepatitis B (HBV) and hepatitis C (HCV) viruses are major risk factors for most PLC cases worldwide, although mechanisms through which the infections cause PLC are still unknown. Epidemiologic and experimental evidence indicates that exposure to certain chemicals can also contribute significantly to PLC development, some of which have been designated as human liver carcinogens (Group 1) by the International Agency for Research on Cancer. These include aflatoxins and chronic consumption of alcoholic beverages. Many naturally occurring and synthetic chemicals have been shown to induce liver cancer in experimental animals. Humans are exposed to these carcinogens via accidental contamination of food or water; usually at levels far lower than those that are carcinogenic to experimental animals. Consequently, assessment of possible human PLC risk associated with such exposures is complex and uncertain. Evidence regarding aflatoxin as a human carcinogen has been extensively documented and is reviewed as an example of the usefulness of parallel experimental and epidemiological investigations in cancer risk assessment. Aflatoxins are toxic metabolites of certain spoilage molds that are potent liver carcinogens in experimental animals and frequently contaminate human diets. Collectively, epidemiologic data together with evidence from many types of experimental models defines the role of aflatoxin exposure in PLC causation. Molecular epidemiology involving the use of biomarkers of exposure has been particularly effective in linking aflatoxin exposure to PLC. Biomarkers of aflatoxin exposure have been validated with particular thoroughness. Dose-response relationships between biomarker levels and liver tumor incidence were first established in experimental animals. The biomarkers were then employed in pilot studies of limited scale in humans to define sensitivity, specificity, accuracy, and reliability parameters. Further validation in transitional epidemiological studies assessed intra- and interindividual variability, background levels, external dose-marker relationship, and feasibility for use in larger population-based studies. Finally, prospective epidemiological studies were conducted to evaluate biomarker effectiveness in identifying PLC risk.

The Fn14 immediate-early response gene is induced during liver regeneration and highly expressed in both human and murine hepatocellular carcinomas

Polypeptide growth factors stimulate mammalian cell proliferation by binding to specific cell surface receptors. This interaction triggers numerous biochemical responses including the activation of protein phosphorylation cascades and the enhanced expression of specific genes. We have identified several fibroblast growth factor (FGF)-inducible genes in murine NIH 3T3 cells and recently reported that one of them, the FGF-inducible 14 (Fn14) immediate-early response gene, is predicted to encode a novel, cell surface-localized type Ia transmembrane protein. Here, we report that the human Fn14 homolog is located on chromosome 16p13.3 and encodes a 129-amino acid protein with approximately 82% sequence identity to the murine protein. The human Fn14 gene, like the murine Fn14 gene, is expressed at elevated levels after FGF, calf serum or phorbol ester treatment of fibroblasts in vitro and is expressed at relatively high levels in heart and kidney in vivo. We also report that the human Fn14 gene is expressed at relatively low levels in normal liver tissue but at high levels in liver cancer cell lines and in hepatocellular carcinoma specimens. Furthermore, the murine Fn14 gene is rapidly induced during liver regeneration in vivo and is expressed at high levels in the hepatocellular carcinoma nodules that develop in the c-myc/transforming growth factor-alpha-driven and the hepatitis B virus X protein-driven transgenic mouse models of hepatocarcinogenesis. These results indicate that Fn14 may play a role in hepatocyte growth control and liver neoplasia.