Preneoplastic Markers of Hepatitis B Virus-Associated Hepatocellular Carcinoma

Subtractive Cell-SELEX Selection of DNA Aptamers Binding Specifically and Selectively to Hepatocellular Carcinoma Cells with High Metastatic Potential

Relapse and metastasis are two key risk factors of hepatocellular carcinoma (HCC) prognosis; thus, it is emergent to develop an early and accurate detection method for prognostic evaluation of HCC after surgery. In this study, we sought to acquire oligonucleotide DNA aptamers that specifically bind to HCC cells with high metastatic potential. Two HCC cell lines derived from the same genetic background but with different metastatic potential were employed: MHCC97L (low metastatic properties) as subtractive targets and HCCLM9 (high metastatic properties) as screening targets. To mimic a fluid combining environment, initial DNA aptamers library was firstly labelled with magnetic nanoparticles using biotin-streptavidin system and then applied for aptamers selection. Through 10-round selection with subtractive Cell-SELEX, six aptamers, LY-1, LY-13, LY-46, LY-32, LY-27/45, and LY-7/43, display high affinity to HCCLM9 cells and do not bind to MHCC97L cells, as well as other tumor cell lines, including breast cancer, lung cancer, colon adenocarcinoma, gastric cancer, and cervical cancer, suggesting high specificity for HCCLM9 cells. Thus, the aptamers generated here will provide solid basis for identifying new diagnostic targets to detect HCC metastasis and also may provide valuable clues for developing new targeted therapeutics.

NK cells are the crucial antitumor mediators when STAT3-mediated immunosuppression is blocked in hepatocellular carcinoma

STAT3 is highly activated in a wide variety of cancers and functions to promote tumor survival. We previously reported that blocking STAT3 activation inhibited human hepatocellular carcinoma (HCC) growth in vitro, but whether this treatment also triggered antitumor immune responses in vivo remained unknown. In this study, we found that blocking the STAT3 pathway in HCC cells dramatically inhibited murine HCC growth in vivo and prolonged survival of tumor-bearing mice. Importantly, the presence of STAT3-blocked HCC augmented NK cell cytotoxicity against HCC and increased expression of molecules associated with NK cell activation and cytotoxicity. In T cell-deficient nude mice, a unique NK cell-mediated antitumor function against STAT3-blocked HCC was suggested. NK cells were shown to be necessary and sufficient in NK or T cell depletion experiments, or by adoptively transferring NK cells. Furthermore, regulatory T cells and immunosuppressive IL-10 and TGF-β cytokines were reduced in mice bearing STAT3-blocked HCC cells, suggesting that these factors may be involved in HCC-induced NK cell suppression. These findings indicate that blocking STAT3 in HCC cells can initiate innate immunity in vivo.

Diagnostic and mechanistic implications of serum free light chains, albumin and alpha-fetoprotein in hepatocellular carcinoma

BACKGROUND

Mass spectroscopy analysis suggested low serum albumin and high immunoglobulin free light chain (sFLC) levels may have diagnostic value in hepatocellular carcinoma (HCC). Our aims were to apply quantitative assays to confirm these observations, determine their diagnostic utility, and investigate the mechanisms involved.

METHODS

Albumin, sFLC, routine liver and renal function tests were measured in patients with chronic liver disease with (n=102) and without (n=113) HCC. The discriminant performance was compared with the current standard serological test alpha-fetoprotein (AFP) using receiver operating characteristic (ROC) and area under the curve (AUC) analyses.

RESULTS

sFLC and serum albumin were each confirmed to have discriminatory utility in HCC with AUC values of 0.7 and 0.8, respectively. sFLC were strongly correlated with gammaglobulin levels and both these were inversely related to serum albumin levels. The discriminatory utility of sFLC was retained after adjusting for renal and liver function.

CONCLUSIONS

Serum levels of sFLC and albumin were strongly associated with HCC as predicted by mass spectroscopy. Discrimination of HCC by AFP was improved by the addition of either albumin or sFLC. Larger prospective studies are required to determine how AFP, sFLC and albumin might be combined in a useful diagnostic approach for HCC.

The hepatitis B x antigen anti-apoptotic effector URG7 is localized to the endoplasmic reticulum membrane

Hepatitis B x antigen up-regulates the liver expression of URG7 that contributes to sustain chronic virus infection and to increase the risk for hepatocellular carcinoma by its anti-apoptotic activity. We have investigated the subcellular localization of URG7 expressed in HepG2 cells and determined its membrane topology by glycosylation mapping in vitro. The results demonstrate that URG7 is N-glycosylated and located to the endoplasmic reticulum membrane with an Nlumen-Ccytosol orientation. The results imply that the anti-apoptotic effect of URG7 could arise from the C-terminal cytosolic tail binding a pro-apoptotic signaling factor and retaining it to the endoplasmic reticulum membrane.

Efficacy of early treatment on 52 patients with preneoplastic hepatitis B virus-associated hepatocellular carcinoma by compound Phyllanthus Urinaria L

OBJECTIVE

To observe the change in the number of antibodies of preneoplastic hepatocellular carcinoma (HCC) using early treatment by Compound Phyllanthus Urinaria L. (CPUL) on patients with preneoplastic hepatitis B virus (HBV)-associated HCC.

METHODS

A total of 102 cirrhosis patients with regenerative or dysplastic nodules whose sera were tested positive for at least one of these six proteins (five up-regulated genes URG4, URG7, URG11, URG12 and URG19, and one down-regulated gene DRG2) were assigned randomly to two groups using continual random codes by SPSS software. Fifty-two patients were in the treatment group and 50 patients were in the control group. CPUL was used in the treatment group for 3 years, while the control group did not receive any treatment. The changes in HBV-DNA level, number of antibodies, and hepatocarcinogenesis occurred were observed. Patients who did not develop HCC were followed up for another 2 years.

RESULTS

HBV-DNA levels decreased ⩾2log in 22.2% (10/45) of patients in the treatment group in contrast to only 5.0% (2/40) of patients in the control group (P=0.0228). The number of antibodies that were tested positive in the treatment group (1.08±1.01) was significantly lower compared with the control group (2.11±1.12) after 24 months of drug treatment (P<0.01). Both the positive rates of anti-URG11 (33/52) and anti-URG19 (31/52) were over 60% at baseline in the two groups, and were decreased to 48.1% (25/52) and 46.2% (24/52) respectively at 36 months of drug treatment, while the rates increased to 68.0% (34/50) and 66.0% (33/50) respectively (P=0.0417, P=0.0436) in the control group. The positive rate of anti-DRG2 was increased to 55.8% (29/52) at 36 months of drug treatment, while in the control group was decreased to 36.0% (18/50, P=0.0452). Among the 102 patients who developed HCC, 2 were in the treatment group and 9 were in the control group, meaning that a significant difference between the two groups (P=0.0212). In 11 patients who developed HCC, anti-URG11 and anti-URG19 were always positive, while anti-DRG2 was negative. Patients newly developing HCC were 6 (20.0%) in the control group, and only one (2.5%) in the treatment group (P=0.0441) during 2-year follow-up after the end of the treatment.

CONCLUSIONS

Anti-URG11, anti-URG19 and anti-DRG2 could be used as early markers in the prediction of the therapeutic efficacy of CPUL in treating preneoplastic HCC. CPUL is useful in preventing or delaying the development of HBV-associated cirrhosis to HCC.

Galectin-9 acts as a prognostic factor with antimetastatic potential in hepatocellular carcinoma

Considerable research has been conducted concerning galectin-9 and carcinomas, but little information is available about any relation with the hepatocellular carcinoma. In this study, we employed a small interfering RNA (siRNA) targeting galectin-9 to down-regulate the expression in HepG2 cells. As a result, after galectin-9 expression was reduced, cell aggregation was suppressed, while other behaviour such as the proliferation, adhesion and invasion to ECM, cell-endothelial adhesion and transendothelial invasion of the cells were markedly enhanced. When tumors of 200 patients with hepatocellular carcinoma were tested for galectin-9 expression by immunohistochemistry, binding levels demonstrated intimate correlations with the histopathologic grade, lymph node metastasis, vascular invasion and intrahepatic metastasis (P<0.05). Moreover, survival analysis indicated that patients with galectin-9 expression had much longer survival time than those with negative lesions, and the Log-rank test indicated that this difference was statistical significant (P<0.0001). The Cox proportional hazards model suggested that negative galectin-9 expression in hepatocellular carcinoma represented a significant risk factor for patient survival. We propose that galectin-9 might be a new prognostic factor with antimetastatic potential in patients with hepatocellular carcinoma.

An electrochemical method to detect gamma glutamyl transpeptidase

Gamma glutamyl transpeptidase (GGT) is a transferase, which is of great importance in sustaining intracellular cysteine and glutathione levels. The abnormal expression of GGT is significantly associated with features of many metabolic syndromes (e.g., hepatocellular carcinoma). Therefore, it is essential to develop methods to detect GGT so as to monitor the physiological or pathological phenomena related to this species. In this work, by making use of a complex formed by Cu²⁺ and glutathione, which may exhibit excellent voltammetric response, we have proposed a novel potential electrochemical method for the detection of the enzyme. Results show that in the presence of GGT, the formation of Cu²⁺-glutathione complex on a working electrode will be disrupted, resulting in greatly depressed electrochemical signals. The primary method exhibits some advantages, such as it being fast, cost-efficient, and conveniently operated. It also has the potential to be further developed as an effective method in the quantitative detection of GGT in real samples.

Cooperation of tumor-derived HBx mutants and p53-249(ser) mutant in regulating cell proliferation, anchorage-independent growth and aneuploidy in a telomerase-immortalized normal human hepatocyte-derived cell line

Hepatocellular carcinoma (HCC) is a common cancer, and hepatitis B virus (HBV) is a major etiological agent. Convincing epidemiological and experimental evidence also links HCC to aflatoxin, a naturally occurring mycotoxin that produces a signature p53-249(ser) mutation. Recently, we have reported that tumor-derived HBx variants encoded by HBV exhibited attenuated transactivation and proapoptotic functions but retained their ability to block p53-mediated apoptosis. These results indicate that mutations in HBx may contribute to the development of HCC. In this study, we determined whether tumor-derived HBx mutants along, or in cooperation with p53-249(ser), could alter cell proliferation and chromosome stability of normal human hepatocytes. To test this hypothesis, we established a telomerase immortalized normal human hepatocycte line HHT4 that exhibited a near diploid karyotype and expressed many hepatocyte-specific genes. We found that overexpression one of the tumor-derived HBx mutants, CT, significantly increased colony forming efficiency (CFE) while its corresponding wild-type allele CNT significantly decreased CFE in HHT4 cells. p53-249(ser) rescued CNT-mediated inhibition of colony formation. Although HHT4 cells lacked an anchorage independent growth capability as they did not form any colonies in soft agar, the CT-expressing HHT4 cells could form colonies, which could be significantly enhanced by p53-249(ser). Induction of aneuploidy could be observed in HHT4 cells expressing CT, but additionally recurring chromosome abnormalities could only be detected in cells coexpressing CT and p53-249(ser). Our results are consistent with the hypothesis that certain mutations in HBx and p53 at codon 249 may cooperate in contributing to liver carcinogenesis.

Coronin-1C is a novel biomarker for hepatocellular carcinoma invasive progression identified by proteomics analysis and clinical validation

Background

To better search for potential markers for hepatocellular carcinoma (HCC) invasion and metastasis, proteomic approach was applied to identify potential metastasis biomarkers associated with HCC.

Methods

Membrane proteins were extracted from MHCC97L and HCCLM9 cells, with a similar genetic background and remarkably different metastasis potential, and compared by SDS-PAGE and identified by ESI-MS/MS. The results were further validated by western blot analysis, immunohistochemistry (IHC) of tumor tissues from HCCLM9- and MHCC97L-nude mice, and clinical specimens.

Results

Membrane proteins were extracted from MHCC97L and HCCLM9 cell and compared by SDS-PAGE analyses. A total of 14 differentially expressed proteins were identified by ESI-MS/MS. Coronin-1C, a promising candidate, was found to be overexpressed in HCCLM9 cells as compared with MHCC97L cells, and validated by western blot and IHC from both nude mice tumor tissues and clinical specimens. Coronin-1C level showed an abrupt upsurge when pulmonary metastasis occurred. Increasing coronin-1C expression was found in liver cancer tissues of HCCLM9-nude mice with spontaneous pulmonary metastasis. IHC study on human HCC specimens revealed that more patients in the higher coronin-1C group had overt larger tumor and more advanced stage.

Conclusions

Coronin-1C could be a candidate biomarker to predict HCC invasive behavior.

Surveillance and diagnosis of hepatocellular carcinoma in patients with cirrhosis

Early identification of hepatocellular carcinoma (HCC) is more frequent because of surveillance programs for HCC worldwide. The optimal strategy of surveillance in cirrhosis is a current topical issue. In terms of diagnosis, recent advances in non-invasive imaging technology, including various techniques of harmonic ultrasound, new ultrasound contrast agents, multi-slice helical computed tomography and rapid high quality magnetic resonance, have all improved the accuracy of diagnosis. Consequently the role of liver biopsy in diagnosis of HCC has declined. The imaging diagnosis relies on the hallmark of arterial hypervascularity with portal venous washout. However, with recent advances in genomics and proteomics a great number of potential serum and tissue markers have been identified and are being developed as new candidate markers for both diagnosis and prognosis of hepatocellular carcinoma, and may increase the need for liver biopsy.

Anti-hepatitis B virus X protein in sera is one of the markers of development of liver cirrhosis and liver cancer mediated by HBV

Hepatitis B virus X protein (HBx) plays a crucial role in the development of hepatocellular carcinoma (HCC). However, the significance of circulating antibody to hepatitis B virus X antigen (anti-HBx) in sera remains unclear. In the present study, we examined the titers of anti-HBx (IgG) in the sera from 173 patients with chronic hepatitis B (CHB), 106 liver cirrhosis (LC), and 61 HCC by enzyme-linked immunosorbent assay (ELISA), respectively. Our data showed that the positive rates of anti-HBx were higher in sera of LC (40.6%) and HCC (34.4%) than those of CHB (10.4%), P < .05. In all 40 patients with anti-HBx+ out of 340 patients, 39 (97.5%) were HBsAg/HBeAg/anti-HBc+ and 1 (2.5%) was anti-HBs+ (P < .01), suggesting that anti-HBx in sera is a marker of HBV replication rather than a protective antibody. Thus, our findings reveal that circulating anti-HBx in sera is one of the markers of development of LC and HCC mediated by HBV.

Evidence-based diagnosis and locoregional therapy for hepatocellular carcinoma

Early identification of hepatocellular carcinoma (HCC) is crucial to improving the results of therapy and for patients to be eligible for liver transplantation. Recent advances in noninvasive imaging technology include various techniques of harmonic ultrasound, new ultrasound contrast agents, multislice helical computed tomography and rapid high-quality magnetic resonance. The imaging diagnosis relies on the hallmark of arterial hypervascularity with portal venous washout. Since the use of better radiological techniques has improved the accuracy of noninvasive diagnosis, the role of liver biopsy in the diagnosis of HCC has declined. With recent advances in genomics and proteomics, a great number of potential markers have been identified and developed as new candidate markers for HCC. Locoregional therapies currently constitute the best options for early nonsurgical treatment of HCC. Percutaneous ethanol injection shows similar results to resection surgery for single tumors less than 3 cm in diameter. Radiofrequency ablation is superior to percutaneous ethanol injection in terms of local recurrence. Transarterial chemoembolization is currently the most common approach for the management of HCC without curative options since it improves patient survival, but the optimal embolizing agent, length of interval between sessions and whether the chemotherapeutic agent has any effect have not yet been determined. Combining transarterial chemoembolization with antiangiogenic agents, as well as with other techniques, such as radiofrequency ablation, may improve the results. Injection of radioisotopes such as yttrium-90, via the hepatic artery, may be particularly useful in patients with portal vein thrombosis. Comparisons with other transarterial techniques are needed.

Pharmacotherapy of chronic viral hepatitis and hepatocellular carcinoma

BACKGROUND

Hepatitis B virus (HBV) is a major etiologic agent of chronic liver disease (CLD) and hepatocellular carcinoma. Drugs have been developed and shown to be effective against HBV replication. These treatments are often associated with the resolution of CLD. However, they are too expensive, not well tolerated, and result in the development of resistance when given as mono or salvage therapies. In addition, most of these drugs target only the virus polymerase.

OBJECTIVE

To revitalize the field, drugs with other targets and combination therapies need to be developed.

METHODS

Major advances in HBV and liver cancer drug development over the past decade, focusing on Phase III trials and FDA-approved compounds, are presented.

RESULTS/DISCUSSION

A number of potent nucleoside/nucleotide analogs are now available for treatment, but for the long-term management of CLD, the development of combination therapies will probably be required. Development of compounds with new virus targets will enhance the utility of combination therapies. Development of compounds to host targets altered prior to or after the development of liver cancer, as demonstrated by sorafenib, need to be developed. The goal is to devise drug cocktails that will yield sustained virus responses and halt disease progression and tumor development.

Recent advances in tumor markers of human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most devastating malignancies in the world and is the third most common cause of cancer-related death in Korea. Because most HCC are accompanied by chronic liver disease that results from hepatitis B or C viruses, prognosis is still poor even after surgical resection of the tumor. Moreover, diagnosis of advanced HCC still leads to an extremely bleak prognosis. Earlier detection of HCC, therefore, could improve patient survival. Accordingly, the development of tumor markers that can detect HCC at even earlier stages is essential. The functions of tumor markers include prediction of prognosis or therapeutic response as well as diagnosis or screening of cancer. Possible candidate tumor markers may be quantitative alterations in DNA-, RNA- or protein-based molecules in tumorous conditions assessed by various technologies, e.g. serological assays, microarrays, mass spectrometry and proteomics. However, validation and clinical implementation is needed after the discovery of novel genes. An ideal tumor marker for HCC would be sensitive and specific enabling to differentiate it at an early stage from premalignant lesions like dysplastic nodules. In addition, the marker should be easily measurable, reproducible and minimally invasive. Although it is important to identify new biomarkers for HCC, the validation and cost-effectiveness of those markers as diagnostic or prognostic tools need confirmation in large-scale studies in clinical practice.

A concise review of serum markers for hepatocellular cancer

BACKGROUND

The rising incidence of hepatocellular cancer in the US and worldwide has sparked a renewed interest in HCC serum markers. HCC typically develops in patients with chronic liver disease and cirrhosis. It is in these target populations that serum markers are most urgently needed. Unfortunately, the currently available markers lack sensitivity and specificity. A number of novel candidate markers have recently been introduced.

METHODS

We performed a review of the literature (2001-2006) of traditional and novel serum markers for hepatocellular cancer.

RESULTS

Several promising new HCC markers have been identified over the past 5 years. They include single proteins, complex proteomics features, and tumor-specific autoantibodies. The excitement about the new markers is tempered by the realization that none of them have yet met the most stringent criteria defined by the Early Detection Research Network (EDRN).

CONCLUSION

A new generation of HCC serum markers awaits validation in properly controlled clinical studies.

Pathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) consists of a circular, partially double-stranded DNA molecule of 3.2 kb in length, which contains four overlapping reading frames that code for surface proteins (HBsAg), core proteins (HBcAg/HBeAg), the viral polymerase and the transcriptional transactivator X protein. HBV infection can lead to chronic carriage of the virus and progressive liver diseases, such as hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC). HBV and hepatitis C virus or HIV coinfections can increase the HCC risk. A great amount of evidence demonstrates that HBV plays an important role in the development of liver diseases. Chronic hepatitis appears to be due to a suboptimal cellular immune response that destroys some of the infected hepatocytes and does not purge the virus from the remaining infected hepatocytes, thereby permitting the persisting virus to trigger a chronic indolent necroinflammatory liver disease that sets the stage for the development of HCC. However, the pathogenesis of HBV-related HCC is incompletely clarified. Hepatitis B virus X protein (HBx), an important transforming inducer, plays a crucial role in HCC occurrence, invasion and metastasis. Monitoring of the HBV genotypes and antibody to hepatitis B x antigen (anti-HBx) are significant for predicting the outcome of antiviral therapy or early diagnosis of liver cirrhosis and HCC. Some molecular approaches, such as antisense, oligonucleotides, ribozymes, RNA interference targeting HBV mRNA, are available in antiviral therapies. The intracellular antibody technique and immune therapy by dendritic cells could potentially be used in future antiviral therapies.

Comprehensive regression analysis of hepatitis B virus X antigen level and anti-HBx antibody titer in the sera of patients with HBV infection

Although the pathogenetic significance of hepatitis B virus x protein (HBxAg) in chronic hepatitis, liver cirrhosis, and primary hepatocellular carcinoma has already been studied, the comparative analyses of both the actual serum HBxAg levels and antibody production against various HBx epitopes have been examined to lesser extent. We have simultaneously investigated the relationship between antibody production (IgG and IgM) against the HBxAg fragments and HBxAg level in the sera of patients with acute (14) or chronic hepatitis (80) and symptomless carriers (12). A recently developed sandwich-type ELISA was used for the quantitative measurements of HBxAg. Overlapping recombinant and synthetic antigens were used to map the fine epitope specificities of circulating anti-HBx antibodies. In acute hepatitis, we have found high and homogenous correlation in the IgM type immune responses against all the examined HBxAg regions. Moreover, strong correlation has been observed between IgG type immune responses to a characteristic C-terminal region (C1: 79-117) and the longest fragment (X: 10-143). Moderate correlation has been found between HBxAg concentration and the IgG type anti-HBx antibody levels against C-terminus of HBxAg in patients with chronic hepatitis. In the case of symptomless carriers, there were also demonstrable associations in the immune responses against the C-terminal sequences; however, significant correlations were found for antibody production against the N-terminal region as well. The examinations show that the C-terminal sequence, responsible for transactivation, promotes an efficient IgG antibody response in all three groups of patients, whereas the negative regulator N-terminal part of the HBxAg molecule for the most part does not trigger antibody production. This suggests that the immune responses against various - biologically active - epitopes of the HBxAg may have a different role in the pathogenesis of hepatitis and may be used as prognostic markers in human HBV infections.

Detecting AFP mRNA in peripheral blood of the patients with hepatocellular carcinoma, liver cirrhosis and hepatitis

BACKGROUND

The low frequency of disseminated carcinoma cells in the blood now makes immunomagnetic bead sorting and reverse transcriptase-polymerase chain reaction (RT-PCR) technique more popular.

METHODS

Three milliliters of peripheral blood were collected from 91 patients and 18 normal donors. The circulating carcinoma cells were enriched with CD45 and Ber-EP4 immunomagnetic beads. The alpha-fetoprotein (AFP) mRNA was amplified with nested RT-PCR.

RESULTS

The total positive detection rate was 72.1%, 43.8%, 25.0%, 100%, and 66.7% in patients with hepatocellular carcinoma (HCC) untreated, liver cirrhosis (LC), hepatitis, metastasis liver cancer, and postsurgery of hepatocellular carcinoma, respectively. There was a significant difference among the patients with HCC, LC and hepatitis (HCC vs. LC, P<0.05; HCC vs. hepatitis, P<0.01) and between Class A and B of the HCC patients (P<0.05). Meanwhile, AFP mRNA was markedly expressed in HCC patients compared to the patients with no HCC (LC and hepatitis). The levels of aspartate transaminase (AST) and gamma-glutamyltranspeptidase (GGT) were significantly different in AFP mRNA-positive patients with autoimmune chronic active hepatitis B (CAHB) or LC in contrast to the corresponding negative patients.

CONCLUSION

Combining negative and positive immunomagnetic bead sorting and RT-PCR technique can effectively detect circulating tumor cells. AFP mRNA is a more reliable marker of metastasis compared to serum AFP.

Sandwich type ELISA and a fluorescent cytometric microbead assay for quantitative determination of hepatitis B virus X antigen level in human sera

The hepatitis B virus X protein (HBxAg) is responsible for severe complications of HBV infections including primary hepatocellular carcinoma. A sandwich type ELISA and a flow cytometric microbead assay for quantitative determination of serum levels of Hbx-Ag are introduced. We have previously developed monoclonal antibody families against well-conserved epitopes on HbxAg, characterized by different immunohistochemical and immunoserological techniques. Special selection of the antibody pairs provided highly sensitive and highly specific tools for quantitative immunoassay development. The resulting assays were tested on human sera (208 samples) collected from patients suffering from different clinical forms of HBV infection. The sensitivity range of the sandwich type ELISA was between 4 and 2000 ng/ml as measured on both the recombinant antigen and the sera of chronic hepatitis patients. A further flow cytometric microbead assay was established and tested in parallel with the ELISA. The quantitative results of these two immunoserological techniques were in strong correlation and they were found to be highly specific and sensitive on clinical samples. The HBxAg ELISA technique is applicable for routine clinical laboratory measurements, and our HBxAg microbead technique is recommended for complex multiparametric measurements combined with other markers.

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.