Decreasing incidence of hepatocellular carcinoma among children following universal hepatitis B immunization

Exploring the optimal vaccination strategy against hepatitis B virus in childhood (Review)

Vaccination against hepatitis B virus (HBV) remains the most effective strategy against HBV infection in humans. The present review summarized the optimal vaccination strategies against HBV in childhood. The following points are discussed: i) When and how the first HBV vaccines were developed; ii) the dosages, schedules and injection routes that are used for HBV vaccination; iii) the contraindications for HBV vaccination in the general paediatric population; iv) the challenges with the use of multivalent vaccines; v) the long-term immunogenicity and duration of protection against HBV; vi) the use of selective HBV vaccination and the hepatitis B immune globulin strategy in HBV-exposed infants; and vii) the effectiveness of the current HBV vaccination schemes. The present review is based on a Paediatric Virology Study Group (PVSG) webinar performed in the context of the 8th Workshop on Paediatric Virology.

A case report of a teenager with hepatitis B surface antigen‐positive multifocal hepatocellular carcinoma in a noncirrhotic liver

Hepatitis B virus is a known carcinogen for hepatocellular carcinoma, which is rare in the pediatric population. We report a 13‐year‐old patient with hepatitis B surface antigen‐positive multifocal hepatocellular carcinoma in a noncirrhotic liver. Her APRI score was 0.24. Her BCLC stage was C, and her caregiver opted for palliative care.

Roles and Regulation of Long Noncoding RNAs in Hepatocellular Carcinoma

Next-generation sequencing has uncovered thousands of long noncoding RNAs (lncRNA). Many are reported to be aberrantly expressed in various cancers, including hepatocellular carcinoma (HCC), and play key roles in tumorigenesis. This review provides an in-depth discussion of the oncogenic mechanisms reported to be associated with deregulated HCC-associated lncRNAs. Transcriptional expression of lncRNAs in HCC is modulated through transcription factors, or epigenetically by aberrant histone acetylation or DNA methylation, and posttranscriptionally by lncRNA transcript stability modulated by miRNAs and RNA-binding proteins. Seventy-four deregulated lncRNAs have been identified in HCC, of which, 52 are upregulated. This review maps the oncogenic roles of these deregulated lncRNAs by integrating diverse datasets including clinicopathologic features, affected cancer phenotypes, associated miRNA and/or protein-interacting partners as well as modulated gene/protein expression. Notably, 63 deregulated lncRNAs are significantly associated with clinicopathologic features of HCC. Twenty-three deregulated lncRNAs associated with both tumor and metastatic clinical features were also tumorigenic and prometastatic in experimental models of HCC, and eight of these mapped to known cancer pathways. Fifty-two upregulated lncRNAs exhibit oncogenic properties and are associated with prominent hallmarks of cancer, whereas 22 downregulated lncRNAs have tumor-suppressive properties. Aberrantly expressed lncRNAs in HCC exert pleiotropic effects on miRNAs, mRNAs, and proteins. They affect multiple cancer phenotypes by altering miRNA and mRNA expression and stability, as well as through effects on protein expression, degradation, structure, or interactions with transcriptional regulators. Hence, these insights reveal novel lncRNAs as potential biomarkers and may enable the design of precision therapy for HCC.

IGFBP2 plays an important role in heat shock protein 27-mediated cancer progression and metastasis

Heat shock protein 27 (Hsp27) is a key chaperone that interacts with over 200 client proteins. The expression of Hsp27 might be correlated with poor outcome in many types of cancer. Previous study indicated that Hsp27 might be an important biomarker in hepatocellular carcinoma (HCC). However, the detailed mechanism is less well understood. The shRNA-mediated silencing of Hsp27 decreased the proliferation, migration and invasion of HCC cells. In a xenograft model, the silencing of Hsp27 reduced tumor progression. We revealed that the silencing of Hsp27 led to a reduction in insulin-like growth factor binding protein 2 (IGFBP2), which might mediate proliferation and metastasis through vimentin, snail and beta-catenin. The overexpression of IGFBP2 reversed the reductions in cell growth, migration and invasion. The tissue array results showed that HCC patients with high Hsp27 expression exhibited poor prognosis and increased metastasis. The Hsp27 expression was highly correlated with IGFPB2 in CRC specimen. ChIP and luciferase assays showed that Hsp27 does not directly bind the IGFBP2 promoter region to regulate the transcription of IGFBP2. In conclusion, our study demonstrated that Hsp27 is a key mediator of HCC progression and metastasis and that Hsp27 might regulate proliferation and metastasis through IGFBP2. This pathway might provide a new direction for the development of a novel therapeutic strategy for HCC.

24 year outcomes of hepatitis B vaccination in Hangzhou, China

To evaluate the impact of the universal infant HepB vaccination program on hepatitis B virus infection in Hangzhou, China. Hepatitis B incidences and HepB vaccination rates of Hangzhou from 1990 to 2003 were acquired from the historical paper-documents, while which were derived from China Information System for Diseases Control and Prevention and Zhejiang Information System for Immunization Program respectively from 2004 to 2013. A serology survey among person aged 0-59 y was conducted in Hangzhou in 2006. Participants were selected by stratified, multi-stage random sampling. Serum specimens were tested for HBsAg, anti-HBs , anti-HBc , HBeAg and anti-HBe by ELISA. For the past 24 years, hepatitis B incidence and mortality of Hangzhou declined dramatically (χ(2) = 3.2 × 10(4); χ(2) = 172.443; both P for trend < 0.001). Both urban and rural incidence descended (χ(2)urban = 1.904 × 10(4); χ(2)rural = 1.633 × 10(4) ; both P for trend < 0.001).Hepatitis B patients mainly concentrated in 20-40 y old; workers and farmers were the main infection occupations, which was varies in different years (χ(2) = 1.619 × 10(3), P < 0.001). Significant association was found between incidence of hepatitis B and HepB vaccination rate (r = 0 .946, χ(2) = 11.813, Pfor trend = 0.001). A total of 5605 participants aged 0-59 y included in this serological survey. The prevalence of HBsAg, anti-HBs, anti-HBc, HBeAg and anti-HBe were 6.19%, 45.83%, 57.25%, 0.62%, and 4.37%, respectively. Hangzhou has successfully integrated the HepB into routine immunization programs and this has had a significant impact on decreasing the incidence of hepatitis B infection.

Children with Chronic Hepatitis B in the United States and Canada

OBJECTIVES

To test the hypothesis that children with chronic hepatitis B living in the US and Canada would have international origins and characteristic hepatitis B virus (HBV) genotypes and laboratory profiles.

STUDY DESIGN

Clinical characteristics of children enrolled in the Hepatitis B Research Network were collected from 7 US and Canadian centers.

RESULTS

Children (n = 343) with an age range of 1.0-17.8 years were enrolled; 78% of the children were Asian, 55% were adopted, and 97% had international origins with either the child or a parent born in 1 of 31 countries. The majority had HBV genotype B (43%) or C (32%), and the remainder had genotype A (5%), D (16%), E (4%), or multiple (<1%). Children with genotype B or C were more likely to be Asian (98% and 96%), more consistently hepatitis B envelope antigen positive (95% and 82%), had higher median HBV DNA levels (8.2 and 8.3 log10 IU/mL), and less frequently had elevated alanine aminotransferase values (43% and 57%) compared with children with other genotypes. The percentage of hepatitis B envelope antigen positivity and of those with HBV DNA ≥6 log₁₀ IU/mL declined with age.

CONCLUSIONS

The majority of children in the Hepatitis B Research Network have HBV genotypes that reflect their international origins. Clinical and laboratory data differ substantially by patient age and HBV genotype. Use of these data can help drive the development of optimal strategies to manage and treat children with chronic hepatitis B.

Causes of death in people with chronic HBV infection: A population-based cohort study

BACKGROUND & AIMS

Mortality related to hepatitis B virus (HBV) is not well known in developed countries. The aim of this study was to investigate in a population-based cohort the excess risk of death in HBV patients compared with mortality in the general population and to identify risk factors related to all-cause mortality and HBV-related mortality.

METHODS

A specialized population-based registry has recorded data from patients with chronic HBV infection in a population of one million inhabitants in France since 1994. Standardized mortality rates for all-cause death and HBV-related death were calculated. Cumulative mortality rates were calculated using the Kaplan-Meier method. Multivariate analysis was performed using a Cox model.

RESULTS

Between 1994 and 2009, 1117 people were diagnosed with chronic HBV infection. Of these 136 (12.2%) died. All-cause mortality was significantly higher in HBV-infected people (standardized mortality ratio (SMR) 1.7 [1.4-2.0]). There was substantial excess mortality due to hepatocellular carcinoma (SMR 15.9 [10-24.1]), non-Hodgkin lymphoma (SMR 8.6 [3.1-18.6]) and liver disease (SMR 10.2 [5.8-16.6]). The cumulative rates for all-cause mortality were 8.6% at 5 years, 12.6% at 10 years and 18.5% at 15 years. The corresponding values for HBV-related mortality were 3.5%, 4.2%, and 5.8%. The multivariate analysis for all-cause mortality and for HBV-related mortality showed that male sex, age over 45 at diagnosis, current alcoholism and nosocomial risk factors were predictors of increased mortality.

CONCLUSION

This study shows increased all-cause mortality in HBsAg-positive patients, with considerable excess mortality due to chronic liver disease, hepatocellular carcinoma and non-Hodgkin lymphoma.

Prevention of hepatocellular carcinoma: beyond hepatitis B vaccination

Chronic hepatitis B (CHB) infection is the major cause of hepatocellular carcinoma (HCC), accounting for approximately 50% of the underlying etiologies. We reviewed the primary, secondary, and tertiary measures for the prevention of hepatitis B virus (HBV)-related HCC. The most effective method for preventing HBV-related HCC is vaccination. Universal hepatitis B vaccination has been shown to reduce the rates of HBV infection and HCC significantly. Once chronic HBV infection is established, antiviral treatment using interferon or nucleos(t)ide analogs is used to prevent disease progression to cirrhosis, HCC, or both. Studies have found viral replication indicated by HBV DNA level to be a strong risk factor for development of HCC. Additionally, periodic surveillance using ultrasonography and serum α-fetoprotein for earlier detection of HCC is also important so that curative treatments with survival benefit can be possible. Finally, adjuvant antiviral treatment using interferon or nucleos(t)ide analogs is used to prevent tumor recurrence after curative resection. Adjuvant interferon treatment prevented early recurrence, not late recurrence, probably due to its antiangiogenetic and antiproliferative effects. Adjuvant nucleos(t)ide analogs demonstrated promising results for preventing late recurrence, probably due to effective suppression of viral replication. Further investigations are required to establish the optimal preventive plans for HBV-related HCC.

Coinfection of hepatitis B and hepatitis delta virus in Belgium: a multicenter BASL study. Prospective epidemiology and comparison with HBV mono-infection

Epidemiological data on hepatitis delta virus (HDV) infection in Belgium are lacking. A multicenter questionnaire-based registry on HDV infection was collated between March 1, 2008 and February 28, 2009. It consisted of patients coinfected with hepatitis B virus (HBV) and HDV. The data samples were compared to those of a concurrent registry on HBV infection. Prospective data of patients with HBV-HDV coinfection were collected. Active HBV replication is defined as HBeAg positivity or HBV DNA > 2,000 IU/ml. Forty-four patients from 15 centers were registered. A comparison of 29 patients infected with HDV (registered in the concurrent HBV registry) was made against 785 HBV mono-infected patients. The seroprevalence of patients coinfected with HBV and HDV in Belgium is reported to be 3.7% (29/785), consisting solely of the HBV-HDV coinfected patients in the HBV registry. This rises to 5.5% (44/800) if all patients infected with HDV from the two registries combined are included. The patients coinfected with HBV and HDV had higher (P < 0.05) ALT values and more advanced liver disease (Metavir score ≥F2), but had less active HBV replication and lower HBV DNA titers when compared with the patients infected only with HBV. Additionally, the majority of HBV-HDV coinfected patient was male, and 13.6% (6/44) of the patients that were coinfected HBV and HDV were also infected with HCV. In conclusion, this study provided much needed epidemiological data on the current state of HDV infection in Belgium.

Epidemiological characteristics of hepatocellular carcinoma in Egypt: a retrospective analysis of 1313 cases

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours worldwide. Egypt has the highest prevalence of HCV in the world and the prevalence of HCC is increasing in the last years. The aim was to study epidemiological characteristics of HCC in Egypt.

METHODS

Retrospective chart review of 1456 Egyptian patients with HCC was done. Records of 1313 patients (1035 males, 278 females; median age 56 years) fulfilling diagnostic criteria for HCC were analysed for clinical, aetiological, radiological and tumour characteristics.

RESULTS

The majority of cases (75%) were from rural areas. The most frequent age category affected by HCC was between 51 and 60 years (45.7%); 50% of the patients reported accidental discovery of their hepatic focal lesions. The major presenting symptom was newly developed right hypochondrial pain (66.3%). HCV Ab was detected in 91.32% of the studied patients while HVB infection was reported in 2.51%. 59.3% of patients had AFP levels below 200 ng/ml (the diagnostic level). On studying tumour characteristics, the right lobe of the liver was more frequently occupied by the focal lesions (75.4%) than the left lobe (15.7%) and 12.5% of patients had bilobar affection. Five hundred and six patients (38.6%) had more than one hepatic focal lesion and 228 patients (17.4%) had tumours occupying >50% of the liver.

CONCLUSION

HCC is a major health problem in Egypt and its incidence is increasing. The high prevalence of HCV infection makes screening programmes and surveillance of those patients a very important tool to early detect cases of small HCCs.

Helicobacter pylori CagA: From Pathogenic Mechanisms to Its Use as an Anti-Cancer Vaccine

Helicobacter pylori colonizes the gastric mucosa of more than 50% of the human population, causing chronic inflammation, which however is largely asymptomatic. Nevertheless, H. pylori-infected subjects can develop chronic gastritis, peptic ulcer, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Chronic exposure to the pathogen and its ability to induce epithelial to mesenchymal transition (EMT) through the injection of cytotoxin-associated gene A into gastric epithelial cells may be key triggers of carcinogenesis. By deregulating cell-cell and cell-matrix interactions as well as DNA methylation, histone modifications, expression of micro RNAs, and resistance to apoptosis, EMT can actively contribute to early stages of the cancer formation. Host response to the infection significantly contributes to disease development and the concomitance of particular genotypes of both pathogen and host may turn into the most severe outcomes. T regulatory cells (Treg) have been recently demonstrated to play an important role in H. pylori-related disease development and at the same time the Treg-induced tolerance has been proposed as a possible mechanism that leads to less severe disease. Efficacy of antibiotic therapies of H. pylori infection has significantly dropped. Unfortunately, no vaccine against H. pylori is currently licensed, and protective immunity mechanisms against H. pylori are only partially understood. In spite of promising results obtained in animal models of infection with a number of vaccine candidates, few clinical trials have been conducted so far and with no satisfactory outcomes. However, prophylactic vaccination may be the only means to efficiently prevent H. pylori-associated cancers.

Clinical characteristics and outcome of hepatocellular carcinoma in children and adolescents

PURPOSE

Hepatocellular carcinoma (HCC) rarely occurs in children and adolescents and has been reported to be highly hepatitis B related more than 10 years ago. However, after global vaccination for hepatitis B virus (HBV), the characteristics and outcome of pediatric HCC remain undefined.

METHODS

Patients with HCC admitted from 2004 to 2010 were retrospectively reviewed in a large tertiary hospital.

RESULTS

45 (1.97 %) pediatric HCC were diagnosed (age ≤18 years), with predominantly male patients (93.3 %). 32 (71.1 %) children were HBV positive, 30 of whom had vertical transmission from their mothers. HBV positivity was associated with liver cirrhosis and portal vein invasion, and thus compromised survival. Advanced disease prevented surgical resection due to large tumor size (>10 cm, 66.7 %), early metastasis (24.4 %), bilateral involvement (57.8 %) and portal vein invasion (46.7 %). The median survival for resectable, transarterial chemotherapy and embolization and untreated patients was 28.6, 4 and 5 months, respectively (p < 0.001). Patients with distal metastasis had significantly poorer survival rate than those without metastasis (p < 0.001).

CONCLUSION

Screening of children whose mothers are HBV carriers is important in early detection of pediatric HCC. HBV-associated HCC in pediatric patients, especially in endemic areas, should be detected earlier for more resectability and improvement of surgical prognosis.

Meeting the global demands of epidemiologic transition - the indispensable role of cancer prevention

The number of new cancer cases each year is projected to rise worldwide by about 70% by 2030 due to demographic changes alone, with the largest increases in the lower-income countries. Wider adoption of specific aspects of westernized lifestyles would translate to still greater increases in certain cancer types. In many countries the burden of cancer and other non-communicable diseases will add to communicable diseases and malnutrition to impose a "double burden" on the poorest. These trends represent major challenges to health, poverty, sustainable development and equality. Prevention is, however, possible based on implementing existing knowledge about risk factors and the natural history of the disease. Both primary and secondary cancer prevention offer therefore many opportunities to combat the projected increases. Tobacco control, reductions in obesity and physical inactivity, reduced consumption of alcohol, vaccination against hepatitis B and human papilloma viruses, safe sex, avoidance of environmental and occupational carcinogens and excessive sun exposure as well as the early detection and screening for breast, cervix and colorectal cancers would all make significant contributions. At the same time, for a number of major cancers (e.g., colon, prostate, kidney, pancreas, brain, lympho-haematological malignancies) research is needed to identify as yet unknown risk factors whilst for existing prevention strategies additional work is needed on their implementation into health services. Finally, there is a remarkable opportunity for advances in understanding the molecular basis of carcinogenesis to provide new tools and insights into aetiology and prevention. It is only by complementing efforts to improve treatment with those aimed at prevention that the impending epidemic of this disease can be addressed.

Deep sequencing of the hepatitis B virus in hepatocellular carcinoma patients reveals enriched integration events, structural alterations and sequence variations

Chronic hepatitis B virus (HBV) infection is epidemiologically associated with hepatocellular carcinoma (HCC), but its role in HCC remains poorly understood due to technological limitations. In this study, we systematically characterize HBV in HCC patients. HBV sequences were enriched from 48 HCC patients using an oligo-bead-based strategy, pooled together and sequenced using the FLX-Genome-Sequencer. In the tumors, preferential integration of HBV into promoters of genes (P < 0.001) and significant enrichment of integration into chromosome 10 (P < 0.01) were observed. Integration into chromosome 10 was significantly associated with poorly differentiated tumors (P < 0.05). Notably, in the tumors, recurrent integration into the promoter of the human telomerase reverse transcriptase (TERT) gene was found to correlate with increased TERT expression. The preferred region within the HBV genome involved in integration and viral structural alteration is at the 3'-end of hepatitis B virus X protein (HBx), where viral replication/transcription initiates. Upon integration, the 3'-end of the HBx is often deleted. HBx-human chimeric transcripts, the most common type of chimeric transcripts, can be expressed as chimeric proteins. Sequence variation resulting in non-conservative amino acid substitutions are commonly observed in HBV genome. This study highlights HBV as highly mutable in HCC patients with preferential regions within the host and virus genome for HBV integration/structural alterations.

Viral hepatitis: global goals for vaccination

In countries where hepatitis A is highly endemic, exposure to hepatitis A virus (HAV) is almost universal before the age of 10 years, and large-scale immunization efforts are not required. In contrast, in areas of intermediate endemicity or in transition from high to intermediate endemicity, where transmission occurs primarily from person to person in the general community (often with periodic outbreaks), control of hepatitis A may be achieved through widespread vaccination programmes. Hepatitis B virus (HBV) is one of the world's most widespread infectious agents and the cause of millions of infections each year. Between 500,000 and 700,000 people die each year from chronic infection-related cirrhosis, hepatocellular carcinoma (HCC) or from acute hepatitis B. Hepatitis B vaccine provides protection against infection and its complications including liver cirrhosis and HCC. It is therefore, the first vaccine against a cancer, the first vaccine protecting from a sexually transmitted infection, and the first vaccine against a chronic disease ever licensed. Control and significant reduction in incidence of new HBV infections as well as hepatocellular carcinoma has repeatedly been reported in countries in East Asia (i.e. Taiwan) and Africa (i.e. The Gambia). Two experimental vaccines against hepatitis E have been developed; one of them has been recently licensed but is not yet widely available. Attempts to develop a hepatitis C vaccine were so far unsuccessful.

Revaccination of non- and low- responders after a standard three dose hepatitis B vaccine schedule

BACKGROUND

Guangdong province of China is HBV high endemicity and 1.6 million neonates are administrated 5 μg yeast recombinant anti-HBV vaccine each year. But few studies are performed to evaluate the immunogenicity and revaccination effect on non- and low- responders.

METHODS

2,199 children were administered intramuscularly with 5 μg vaccine at 0, 1 and 6 mo after birth. A 3 ml blood sample was drawn from each infant 1 mo after the third dose for determination of anti-HBs level. Three additional doses (10 μg each) were given to non- and low- responders.

RESULTS

Of 1,814 subjects, 3.1% were non-responders (anti-HBs titer < 10 mIUml (-1) ) and 28.9% were low-responders (anti-HBs ≥ 10 mIUml (-1) and < 100 mIUml (-1) ). Low birth weight (LBW) was a risk factor for non- and low- responders (RR = 1.6, 95%CI = 1.2-2.0). After revaccination, of the 34 non-responders, 14.7% became low-responders and 85.3% became responders. Of the 74 low-responders, 21.6% remained at the same level and 78.4% shifted into responder category.

CONCLUSIONS

Based on the lower responding rate after the primary immunization cycle and the higher responding rate after the additional cycle, measurement of anti-HBs level should be considered for people who had been immunized with three-dose 5 μg HB vaccine in Guangdong, especially for specific populations including LBW infants, healthcare workers, and patients with immunodeficiency disorders. An amount of 10 μg vaccine should be revaccinated to any non- and low- responders to provide adequate seroprotection.

Factors influencing administration of hepatitis B vaccine to community-dwelling teenagers aged 12-18 with an intellectual disability

The study aims to determine hepatitis B vaccination coverage rates among community-dwelling teenagers with an intellectual disability in Taiwan and to identify the possible influencing factors of their vaccination. The present paper was part of the results of the "2007 National Survey on Healthy Behaviors and Preventive Health Utilizations of People with Intellectual Disabilities in Taiwan," which was a cross-sectional survey of 1111 intellectually disabled (ID) teenagers ranging from 12 to 18 years of age. The results showed that the completed hepatitis B vaccination rate was 72.9%, a rate lower than that in the general population of Taiwan considering the same age group. There was no gender difference between each age group in the vaccination rate in this population. Multilevel logistic regression analyses revealed that those ID individuals whose primary caregivers were parents or siblings (OR = 2.45, 95% CI = 1.29-4.64), whose household monthly income was 20,000-59,999 NTD vs. less than 20,000 NTD (OR = 2.47, 95% CI = 1.00-6.12), and who had ever undergone an oral health exam (OR = 2.29, 95% CI = 1.24-4.01) were more likely to receive a complete hepatitis B vaccination than their counterparts. The study highlighted that most teenagers had received complete hepatitis B vaccination. Nonetheless, better public health strategies may be needed to deliver the hepatitis B vaccine to those who do not comply with the vaccination schedule in the community.

Targeting dendritic cells with nano-particulate PLGA cancer vaccine formulations

Development of safe and effective cancer vaccine formulation is a primary focus in the field of cancer immunotherapy. The recognition of the crucial role of dendritic cells (DCs) in initiating anti-tumor immunity has led to the development of several strategies that target vaccine antigens to DCs as an attempt for developing potent, specific and lasting anti-tumor T cell responses. The main objective of this review is to provide an overview on the application of poly (d,l-lactic-co-glycolic acid) nanoparticles (PLGA-NPs) as cancer vaccine delivery system and highlight their potential in the development of future therapeutic cancer vaccines. PLGA-NPs containing antigens along with immunostimulatory molecules (adjuvants) can not only target antigen actively to DCs, but also provide immune activation and rescue impaired DCs from tumor-induced immuosupression.

[Hepatitis B vaccination: a major player in the control of primary liver cancer]

In worst cases, chronic hepatitis B ultimately leads to primary liver cancer. Populations the more at risk to develop hepatocellular carcinoma (HCC), i.e. patients infected perinatally, reside essentially in Asia. A quarter of century after its introduction in medical practice, data coming from Eastern Asia demonstrate a strong impact of the vaccine on HCC incidence. Strikingly, universal immunization of Taiwanese newborns reduced fourfold pediatric HCC incidence. However, residual cases still appear though among children infected at birth by HBe antigen-carrying mothers. Epidemiologic models indicate that the continuation of universal vaccination policy will reduce chronic hepatitis B endemicity 50-fold in three generations. Recently, mutant forms of HBV potentially escaping to vaccine appeared as a potential consequence of large-scale vaccination. Finally, lack of early immunization of newborns in developing countries still represents a major limitation to the progresses against liver cancer.

[Long-term clevudine therapy in nucleos(t)ide-naïve and lamivudine-experienced patients with hepatitis B virus-related chronic liver diseases]

BACKGROUNDS/AIMS

Clevudine is an effective antiviral nucleoside analogue, but there are few data regarding its long-term effects, resistance, and safety. The aim of this study was to evaluate the long-term clinical efficacy of clevudine over a 1-year treatment period in nucleos(t)ide-naive and lamivudine-experienced chronic hepatitis B patients.

METHODS

Nucleos(t)ide-naive (group A, n=196) and lamivudine-experienced (serum hepatitis B virus, HBV DNA >2,000 copies/mL without resistant mutants at the start of clevudine therapy, group B, n=75) patients were included in this study. Basic clinical characteristics including age, sex, the presence of cirrhosis, laboratory data, and hepatitis B surface antigen (HBeAg) positivity were similar between the two groups. Pretreatment serum levels of HBV DNA were 7.4 and 6.6 log(10) copies/mL (P<0.001). The mean treatment duration was 8 months for both groups (range for group A: 3-21 months; range for group B: 3-20 months). Genotypic analysis for resistant mutations in the reverse transcriptase of HBV was performed after viral breakthrough.

RESULTS

After 1 year of therapy, 75.0% and 51.9% of groups A and B, respectively, had HBV DNA levels of <2,000 copies/mL (P=0.032), and HBeAg seroconversion rates were 16.9% and 16.7%, respectively. The rates of viral breakthrough at 1 year were 10.0% (8/80) and 44.4% (12/27), respectively (P<0.001). Proven sites of mutation of HBV DNA polymerase in naive patients were, for example, L80I, L180M, A181V/T, M204I and V207I. Ten patients complained of prominent fatigue and revealed elevated serum levels of aspartate aminotransferase (AST) and creatine phosphokinase (CPK). Two of these patients presented with severe myopathy from which they recovered completely after quitting clevudine.

CONCLUSIONS

Clevudine is one of the recommended first-line medicines for the treatment of chronic hepatitis B, but it is not free from resistance, particularly in patients with a history of previous lamivudine treatment, but also in naive patients. Clevudine should be avoided in previously lamivudine-exposed patients. In addition, reelevation of serum AST and CPK levels is not a rare occurrence, and close observation and follow-up tests are essential.

Hepatitis B immunity in adolescents and necessity for boost vaccination: 23 years after nationwide hepatitis B virus vaccination program in Taiwan

The first universal hepatitis B vaccination program for newborns in the world was launched in Taiwan in July 1984. Most studies on the effectiveness of hepatitis B vaccination focused on the seroprevalence of HBs Ag among children under 14 years old. Only few studies focused on the seropositivity of anti-HBs among adolescents aged 15-18 years old. The present study aimed to evaluate the impact of the nationwide hepatitis B vaccination program on the immunity to HBV infection and the necessity of boost among adolescents. In this study including eight annual seroprevalence surveys from 2000 to 2007, 2342 college entrants (1589 15-year-olds in group I and 753 18-year-olds in group II) and 1851 university freshmen (18-year-olds in group III) participated. Subjects identified anti-HBs, HBs Ag and anti-HBc negative were given boost three doses of HBV vaccine. The HBs Ag seroprevalence was 11.6%, 3.5% and 1.0% for participants who were born before 1984, 1984-1986 and after 1986. The anti-HBs-seropositive rates were significantly higher in group II (83.1%) than in group I (53.0%) and group III (53.5%). All 572 participants who were seronegative for anti-HBs, HBs Ag and anti-HBc became anti-HBs-seropositive after catch-up vaccination. It is concluded that the anti-HBs-seropositive rate decreased to 50% in 15 years after vaccination, and boost vaccination was 100% effective. The necessity and age for boost among anti-HBs negative adolescents and the timing of the first immunization should be further evaluated.

Chronic hepatitis B in Asian women of childbearing age

Hepatitis B virus (HBV) infection is a serious clinical problem affecting approximately 2 billion people worldwide. An estimated 350 million live with chronic hepatitis B (CHB) infection and are at an increased risk for serious liver sequelae and death from acute or chronic consequences of CHB infection. Individuals with CHB have a 20-30% risk of early death from complications, including liver cirrhosis and hepatocellular carcinoma. In the Asia-Pacific region, half of the CHB burden results from vertical or mother-to-child transmission, with early childhood horizontal transmission accounting for the remaining half. Screening and vaccination are key factors in the successful prevention and control of HBV infection. Over the last 20 years, the implementation of screening programs and universal HBV vaccination for all individuals born in endemic areas have reduced the prevalence of HBV infection and HBV-related liver diseases among individuals younger than 30 years. Women of childbearing age are key stakeholders in preventing HBV infection and, as such, play a critical role in reducing the vertical and horizontal transmission of HBV. Further efforts are needed to implement screening and educational programs for women of childbearing age, particularly those with CHB, to prevent the transmission of HBV to newborns, spouses, other household members, and sexual partners. In addition, healthcare workers need to learn how to avoid iatrogenic transmission in the healthcare setting. This article reviews these issues and highlights areas in which their engagement with public health efforts serves to improve quality of life and society as a whole.

Preoperative vaccination for HBV at Polish hospitals as a possible public health tool to limit the spread of the epidemic: a cross-sectional study

To determine the immunisation coverage for HBV and the prevalence of HBsAg an anonymous serosurvey of consecutive adult surgical/gynaecologic patients presenting to 16 randomly selected hospitals in West Pomerania, Poland, was conducted. Immunisation rate was 60.4%, of these 69.7% had received the complete course of three doses; 65.2% were immunised at the request of referring surgeons. The multivariable regression model revealed that age <40 years, low educational status, not having a surgery in the past, tattoo application, and emergency procedure were each associated with a greater odds of not being vaccinated. HBsAg prevalence was 0.6%. Authors conclude that the preoperative vaccination policy might be an effective public health tool to limit the spread of the epidemic.

Liver tumors: pediatric population

Liver tumors in childhood are rare and are typically not detected clinically until they reach a large size and often spread within the organ or metastasize. This can make surgical resection problematic, and almost all of them require extirpation for cure. With very effective chemotherapy for hepatoblastoma and to some extent for sarcomas, many cancers can be shrunk to permit partial hepatectomy, but for most hepatocarcinomas, some of the other malignancies, and even some benign proliferations, their location at the hilum and multiplicity of masses in multiple lobes make transplantation the treatment of choice. Major advances in diagnostic imaging, especially enhanced computed tomography and magnetic resonance imaging, permit a preoperative choice of resection versus transplantation to be achieved in almost all instances, and for the remainder, intraoperative ultrasonography can further help to determine the most desirable approach. The outcome is very much better in the case of hepatoblastoma when transplantation is a primary modality rather than following unsuccessful attempts at resection. In this review, transplantation for liver tumors in children is considered from all aspects, including the importance of screening for tumors whenever possible to avoid the need for transplantation.

Vaccination greatly reduces disease, disability, death and inequity worldwide

In low-income countries, infectious diseases still account for a large proportion of deaths, highlighting health inequities largely caused by economic differences. Vaccination can cut health-care costs and reduce these inequities. Disease control, elimination or eradication can save billions of US dollars for communities and countries. Vaccines have lowered the incidence of hepatocellular carcinoma and will control cervical cancer. Travellers can be protected against "exotic" diseases by appropriate vaccination. Vaccines are considered indispensable against bioterrorism. They can combat resistance to antibiotics in some pathogens. Noncommunicable diseases, such as ischaemic heart disease, could also be reduced by influenza vaccination. Immunization programmes have improved the primary care infrastructure in developing countries, lowered mortality in childhood and empowered women to better plan their families, with consequent health, social and economic benefits. Vaccination helps economic growth everywhere, because of lower morbidity and mortality. The annual return on investment in vaccination has been calculated to be between 12% and 18%. Vaccination leads to increased life expectancy. Long healthy lives are now recognized as a prerequisite for wealth, and wealth promotes health. Vaccines are thus efficient tools to reduce disparities in wealth and inequities in health.

Vaccination greatly reduces disease, disability, death and inequity worldwide

In low-income countries, infectious diseases still account for a large proportion of deaths, highlighting health inequities largely caused by economic differences. Vaccination can cut health-care costs and reduce these inequities. Disease control, elimination or eradication can save billions of US dollars for communities and countries. Vaccines have lowered the incidence of hepatocellular carcinoma and will control cervical cancer. Travellers can be protected against "exotic" diseases by appropriate vaccination. Vaccines are considered indispensable against bioterrorism. They can combat resistance to antibiotics in some pathogens. Noncommunicable diseases, such as ischaemic heart disease, could also be reduced by influenza vaccination. Immunization programmes have improved the primary care infrastructure in developing countries, lowered mortality in childhood and empowered women to better plan their families, with consequent health, social and economic benefits. Vaccination helps economic growth everywhere, because of lower morbidity and mortality. The annual return on investment in vaccination has been calculated to be between 12% and 18%. Vaccination leads to increased life expectancy. Long healthy lives are now recognized as a prerequisite for wealth, and wealth promotes health. Vaccines are thus efficient tools to reduce disparities in wealth and inequities in health.

Economic evaluation of hepatitis B vaccination in low-income countries: using cost-effectiveness affordability curves

OBJECTIVE

We sought to describe a method that explicitly considers both a health-care programmes cost-effectiveness and its affordability. For illustration, we apply the method to the programme to vaccinate infants against hepatitis B in the Gambia.

METHODS

We synthesized selected data and developed a computer-based model from the societal and payer perspectives to evaluate the cost-effectiveness of routine infant vaccination against hepatitis B in the Gambia compared with no vaccination. The primary outcome measure was cost per averted disability-adjusted life year (DALY), which was expressed in 2002 US dollars. We used Monte Carlo methods for uncertainty analysis to examine the affordability of the programme from the payers perspective, and we derived an affordability curve and cost-effectiveness affordability curves for the programme.

FINDINGS

In the Gambia, vaccinating infants against hepatitis B is highly cost-effective. Compared with offering no intervention, the vaccination programme would cost US$ 28 per DALY averted from the societal perspective or US$ 47 per DALY averted from the payers perspective. The programme also has the potential to be affordable, starting at a relatively low budget of US$ 160,000 per year. Combining the two dimensions of the outcome measure, the probability that vaccinating infants would be both cost-effective and affordable is 40% at an annual programme budget of US$ 182,000 (the estimated total programme cost from the payers perspective), given a threshold cost-effectiveness value of US$ 47 per DALY averted.

CONCLUSION

In the face of uncertainties about both the health and economic consequences of a vaccine programme, as well as the availability and magnitude of resources needed to fund the programme, cost-effectiveness affordability curves can provide information to decision-makers about the probability that a programme will be both cost-effective and affordable: these are distinct but equally relevant considerations in resource-poor settings.

Pediatric liver tumors: initial presentation, image finding and outcome

BACKGROUND

Few reports have been carried out on the characteristics of pediatric liver tumors.

METHODS

A retrospective study of 57 patients diagnosed with liver tumors from 1989 through 2004 was conducted. They were classified into groups; 10 benign, 33 primary malignant and 14 metastatic liver tumors. Their demographics, initial presentations, laboratory data, image findings and outcomes were investigated and compared.

RESULTS

Hepatocellular carcinoma (HCC) with 91% hepatitis B virus-related, constituted 23 of 33 primary malignant liver tumors and had the poorest survival rate. Initially, 70% of patients with primary malignant liver tumors were at disseminated stages. All of HCC and 88% of hepatoblastoma had elevated serum levels of aphal-fetoprotein. However, abnormal liver function tests as alanine aminotransferase, total bilirubin, albumin and alkaline phosphatase were uncommon in patients with pediatric liver tumors. Metastatic liver tumors compared with primary malignant liver tumors showed hypo-echogenicity in abdominal ultrasound (US) exam and a lesser presence of vessel invasion and contrast enhancement in computed tomography studies (P < 0.01).

CONCLUSIONS

It is important to diagnose primary malignant liver tumors before their clinical symptoms and signs develop. Children with chronic hepatitis B virus infection must be followed every 6 months by serum aphal-fetoprotein and abdominal US even when their liver function tests are normal. Image studies with abdominal US and computed tomography scan can differentiate between primary and metastatic liver tumors.

Antibody titer in Iranian children 6 years after hepatitis B vaccine administration

OBJECTIVE

The purpose of study was to evaluate the immune response in a sample of vaccinated children aged 6 years.

BACKGROUND

Although immunization of infants against hepatitis B virus (HBV) is the most effective way to prevent infection, duration of the afforded immunization is unknown.

METHODS

The immunity derived from the HBV vaccine was assessed by measuring the antibody in 3752 children who were vaccinated in a routine vaccination program in three cities of Iran (Isfahan, Khoramabad, Shahrekord).

RESULTS

Seven hundred and twenty-three (19.3%) children had antibodies levels <10 MIU/mL and 1096 (29.2%) had antibodies levels >or=100 MIU/mL. The total GMT was 34.5+/-0.66, and GMT was statistically different in non-immune and immune children (3.1+/-0.36 versus 49.1+/-0.52). No correlation was found between HbsAb titers and growth pattern during the first and sixth years of life, number of vaccine, time of vaccination and drug use. The predictors were low birth weight and chronic disease.

CONCLUSION

It is recommended that high risk children should be monitored regularly for anti-HBS, and booster must be administrated, if necessary.

Excess mortality of hepatocellular carcinoma and morbidity of liver cirrhosis and hepatitis in HCV-endemic areas in an HBV-endemic country: geographic variations among 502 villages in southern Taiwan

AIMS

The aim of this study was to investigate excess mortality for hepatocellular carcinoma (HCC) and prevalence of hepatitis and liver cirrhosis (LC) in hepatitis C virus (HCV)-endemic areas in Taiwan, which is a hepatitis B virus (HBV)-endemic country.

METHODS

Tainan County, located in southern Taiwan, consists of 533 villages in 31 townships. A total of 56 702 subjects >or= 40 years old (mean age, 60.9 +/- 11.8 years) were enrolled from 502 of the 533 villages between April and November 2004 (n >or= 20/village). Serum blood HBV surface antigen (HBsAg), antibody to HCV (anti-HCV) and alanine transaminase (ALT) levels and platelet counts were measured. Township-specific mortality for liver cancer (ICD = 155) for both sexes between 1992 and 2001 were obtained from official publications.

RESULTS

The prevalence of anti-HCV in Tainan County was 10.2% (township range, 2.6-30.9%; village range, 0-90.5%). The prevalence of HBsAg was 10.9% (township range, 5.5-17.2%; village range, 0-30.8%). The prevalence of hypertransaminemia (serum ALT > 40 IU/L) was 12.8%. At township levels, prevalence of anti-HCV (r2 = 0.92, P < 0.001), HBsAg and anti-HCV (multiple r2 = 0.94) were correlated with hypertransaminemia prevalence by single and multiple linear analysis, respectively. At village levels, prevalence of anti-HCV (r2 = 0.52, P < 0.001), HBsAg and anti-HCV (multiple r2 = 0.53) were each correlated with prevalence of hypertransaminemia, respectively. The prevalence of thrombocytopenia (<150,000 platelets/microL) was 5.5%, and adopted as a surrogate prevalence for LC. At township levels, prevalence of anti-HCV (r2 = 0.58) was the only factor correlated by multivariate analysis with prevalence of thrombocytopenia. At village levels, prevalence of anti-HCV and female-to-male ratio (multiple r2 = 0.43) were each independently associated with prevalence of thrombocytopenia. At township levels, HBsAg prevalence (r2 = 0.42) was more correlated with HCC mortality than anti-HCV prevalence (r2 = 0.28) for male subjects, while anti-HCV prevalence (r2 = 0.45) was more correlated with HCC mortality than HBsAg prevalence (r2 = 0.14) for female subjects. Prevalence of HBV and HCV infection were associated by multivariate analysis with both male (multiple r2 = 0.62) and female (multiple r2 = 0.53) HCC mortality.

CONCLUSIONS

Prevalence of anti-HCV showed significant correlations with prevalence of hypertransaminemia, thrombocytopenia and liver cancer mortality. The findings indicate excessive mortality due to HCC, and LC and hepatitis prevalence in HCV-endemic areas in Taiwan, an HBV-endemic country.

Brain metastases from hepatocellular carcinoma in US patients

Hepatocellular carcinoma (HCC) is a disease on the rise in the United States, due to the epidemic of hepatitis C-induced liver disease. Better chemotherapy options, aggressive surgery, and liver transplantation have led to improved patient survival and an increase in late-appearing, distant metastases from HCC. Brain metastases, although formerly thought of as rare manifestations of HCC, may be more likely to come to clinical and pathological attention than extrahepatic metastases in other sites since they often produce clinical symptoms that necessitate neurosurgical intervention and metastasis removal. In addition, brain metastases from HCC are frequently associated with mass-producing hemorrhage, further requiring evacuation. Hence, pathologists are relatively more likely to encounter brain metastases from HCC as surgical specimens than metastases from HCC to some other common sites of spread, such as bone, lymph nodes, or adrenal. Brain metastases from HCC are being increasingly documented in areas of the world with high endemic rates such as Asia, but thus far have only very rarely been reported in patients native to the United States. We describe our institution's experience with three Caucasian US males, two with hepatitis C as risk factors, who developed metastatic HCC to the brain. We expect clinicians and pathologists will encounter more patients with HCC and extrahepatic metastases, particularly those to brain, in the near future.

Long-term immunogenicity of hepatitis B vaccination and policy for booster: an Italian multicentre study

BACKGROUND

Universal anti-hepatitis-B vaccination of infants and adolescents was implemented in Italy in 1991. We undertook a multicentre study in previously vaccinated individuals to assess the duration of immunity and need for booster, over 10 years after vaccination.

METHODS

In 1212 children and 446 Italian Air Force recruits vaccinated as infants and adolescents, respectively, we measured the concentrations of antibodies to hepatitis-B surface antigen (anti-HBs) and the presence of antibodies to hepatitis-B core antigen (anti-HBc) at enrollment; postimmunisation values were not available. Individuals positive for anti-HBc were tested for hepatitis B surface antigen (HBsAg) and hepatitis B viral DNA. Individuals with anti-HBs concentrations at 10 IU/L or more were regarded as protected; those with antibody less than 10 IU/L were given a booster dose and retested 2 weeks later. Individuals showing postbooster anti-HBs concentrations of less than 10 IU/L were offered two additional vaccine doses and retested 1 month after the third dose.

FINDINGS

Protective anti-HBs concentrations were retained in 779 (64%, 95% CI 61.6-67) children and 398 (89%, 86.4-92.1) recruits. We recorded antibody amounts of less than 10 IU/L in 433 children (36%, 33-38.4) and 48 (11%, 7.9-13.6) recruits. One child and four recruits were positive for anti-HBc, but negative for HBsAg and hepatitis B viral DNA. Antibody concentrations were higher in recruits than in children (geometric mean titre 234.8 IU/L vs 32.1 IU/L, p=0.0001). 332 (97%) of 342 children and 46 (96%) of 48 recruits who received a booster showed an anamnestic response, whereas ten (3%) children and two (4%) recruits remained negative for anti-HBs or had antibody concentrations of less than 10 IU/L. Prebooster and postbooster antibody titres were strongly correlated with each other in both groups. All individuals given two additional vaccine doses (eight children and two recruits) showed anti-HBs amounts of more than 10 IU/L at 1 month after vaccination.

INTERPRETATION

Strong immunological memory persists more than 10 years after immunisation of infants and adolescents with a primary course of vaccination. Booster doses of vaccine do not seem necessary to ensure long-term protection.

Hepatocellular carcinoma in Egypt: A single center study over a decade

AIM: To identify the trend, possible risk factors and any pattern change of hepatocellular carcinoma (HCC) in Egypt over a decade.

METHODS: All HCC patients attending Cairo Liver Center between January 1993 and December 2002, were enrolled in the study. Diagnosis of HCC was based on histopathological examination and/or detection of hepatic focal lesions by two imaging techniques plus α-fetoprotein level above 200 ng/mL. The duration of the study was divided into two periods of 5 years each; period I (1993-1997) and period II (1998-2002). Trend, demographic features of patients (age, gender, and residence), risk factors (HBsAg, HCV-Ab, schistosomiasis and others) and pattern of the focal lesions were compared between the two periods. Logistic regression model was fitted to calculate the adjusted odds ratios for the potential risk factors. The population attributable risk percentage was calculated to estimate the proportion of HCC attributed to hepatitis B and C viral infections.

RESULTS: Over a decade, 1 328 HCC patients out of 22 450 chronic liver disease (CLD) patients were diagnosed with an overall proportion of 5.9%. The annual proportion of HCC showed a significant rising trend from 4.0% in 1993 to 7.2% in 2002 (P = 0.000). A significant increase in male proportion from 82.5% to 87.6% (P = 0.009); M/F from 5:1 to 7:1 and a slight increase of the predominant age group (40-59 years) from 62.6% to 66.8% (P = 0.387) in periods I and II respectively, reflecting a shift to younger age group. In the bivariate analysis, HCC was significantly higher in rural residents, patients with history of schistoso-miasis and/or blood transfusion. Yet, after adjustment, these variables did not have a significant risk for development of HCC. There was a significant decline of HBsAg from 38.6% to 20.5% (P = 0.000), and a slight increase of HCV-Ab from 85.6% to 87.9% in periods I and II respectively. HBV conferred a higher risk to develop HCC more than HCV in period I (OR 1.9 vs 1.6) and period II (OR 2.7 vs 2.0), but the relative contribution of HBV for development of HCC declined in period II compared to period I (PAR% 4.2%, 21.32%). At presentation, diagnostic α-fetoprotein level (≥200 ng/mL) was demonstrated in 15.6% vs 28.9% and small HCC (≤3 cm) represented 14.9% vs 22.7% (P = 0.0002) in periods I and II respectively.

CONCLUSION: Over a decade, there was nearly a twofold increase of the proportion of HCC among CLD patients in Egypt with a significant decline of HBV and slight increase of HCV as risk factors. α-Fetoprotein played a limited role in diagnosis of HCC, compared to imaging techniques. Increased detection of small lesions at presentation reflects increased awareness of the condition.

Transformation of hepatitis B serologic markers in babies born to hepatitis B surface antigen positive mothers

AIM: To better understand the clinical significance of hepatitis B serologic markers in babies born to hepatitis B surface antigen (HBsAg) positive mothers, the incidence of maternal serologic markers of hepatitis B via placenta and its transformation in these babies were investigated.

METHODS: Mothers with positive HBsAg were selected in the third trimester of pregnancy. Their babies received immunoprophylaxis with hepatitis B immunoglobulin and hepatitis B vaccine after birth, and were consecutively followed up for hepatitis B serologic markers and HBV DNA at birth, mo 1, 4, 7, 12, and 24.

RESULTS: Forty-two babies entered the study, including 16 born to hepatitis B e antigen (HBeAg)-positive HBsAg carrier mothers and 26 to HBeAg-negative HBsAg carrier mothers. Apart from four babies born to HBeAg-positive carrier mothers and demonstrated persistent positive HBeAg eventually became HBV carriers, all other babies developed anti-HBs before 12 mo of age. Among the other 12 babies born to HBeAg-positive carrier mothers, HBeAg was detected in 7 at birth, in 4 at mo 1, and in none of them thereafter. No antibody response to the transplacental HBeAg was detected. Among the babies born to HBeAg-negative carrier mothers, anti-HBe was detected 100% at birth and mo 1, in 88.5% at mo 4, in 46.2% at mo 7, in 4.2% at mo 12 and none in mo 24. Among all the immunoprophylaxis-protected babies born to either HBeAg-positive or HBeAg-negative carrier mothers, anti-HBc was detected in 100% at birth, mo 1 and mo 4, in 78.9% at mo 7, in 36.1% at mo 12 and in none at mo 24.

CONCLUSION: HBeAg can pass through human placenta from mother to fetus and become undetectable before 4 mo of age, but no antibodies response to the transplacental HBeAg can be detected till mo 24 in the immunoprophylaxis-protected babies. The sole existence of anti-HBe before 1 year of age or anti-HBc before 2 years of age in babies born to HBsAg carrier mothers may simply represent the transplacental maternal antibodies, instead of indicators of HBV infection status.

Hepatic tissue engineering for adjunct and temporary liver support: critical technologies

The severe donor liver shortage, high cost, and complexity of orthotopic liver transplantation have prompted the search for alternative treatment strategies for end-stage liver disease, which would require less donor material, be cheaper, and less invasive. Hepatic tissue engineering encompasses several approaches to develop adjunct internal liver support methods, such as hepatocyte transplantation and implantable hepatocyte-based devices, as well as temporary extracorporeal liver support techniques, such as bioartificial liver assist devices. Many tissue engineered liver support systems have passed the "proof of principle" test in preclinical and clinical studies; however, they have not yet been found sufficiently reliably effective for routine clinical use. In this review we describe, from an engineering perspective, the progress and remaining challenges that must be resolved in order to develop the next generation of implantable and extracorporeal devices for adjunct or temporary liver assist.