Primary liver cancer: worldwide incidence and trends

NORE1B, a candidate tumor suppressor, is epigenetically silenced in human hepatocellular carcinoma

BACKGROUND/AIMS

In human hepatocellular carcinoma (HCC) the ras-proto-oncogene is rarely mutated. We therefore studied the possible inactivation of the putative tumor-suppressors and ras-associating proteins, NORE1A, NORE1B, and RASSF1A in HCCs by mutation or epigenetic gene silencing through promoter-CpG hypermethylation.

METHODS

SSCP-analyses, sequencing, and methylation-specific PCR were performed in 28 fibrotic/cirrhotic livers and 40 HCCs.

RESULTS

The sequence of NORE1A/B exhibited no deviations and that of the RASSF1A gene a non-silent polymorphism ( approximately 10% of cases) and a missense mutation (one HCC). Both alterations may affect the growth-inhibiting capability of RASSF1A. Epigenetic inactivation of NORE1B was found in 62% of the HCCs and in hepatocarcinoma-cell lines due to considerable promoter-methylation of the gene. Methylation was detected also for RASSF1A in HCCs and hepatocarcinoma cell-lines. As a result, 97% of the HCCs revealed epigenetic silencing of NORE1B, RASSF1A, or both. In contrast every third fibrotic/cirrhotic liver only exhibited silencing of one or both genes.

CONCLUSIONS

The candidate tumor suppressor genes NORE1B and RASSF1A are epigenetically down-regulated alone in at least 62%, or in combination in 97% of the HCCs studied. This indicates a frequent and critical event in hepatocarcinogenesis, which may allow HCCs to subverse growth-control in the presence of an unaltered Ras.

Risk factors and mechanisms of hepatocarcinogenesis with special emphasis on alcohol and oxidative stress

Hepatocellular cancer is the fifth most frequent cancer in men and the eighth in women worldwide. Established risk factors are chronic hepatitis B and C infection, chronic heavy alcohol consumption, obesity and type 2 diabetes, tobacco use, use of oral contraceptives, and aflatoxin-contaminated food. Almost 90% of all hepatocellular carcinomas develop in cirrhotic livers. In Western countries, attributable risks are highest for cirrhosis due to chronic alcohol abuse and viral hepatitis B and C infection. Among those with alcoholic cirrhosis, the annual incidence of hepatocellular cancer is 1-2%. An important mechanism implicated in alcohol-related hepatocarcinogenesis is oxidative stress from alcohol metabolism, inflammation, and increased iron storage. Ethanol-induced cytochrome P-450 2E1 produces various reactive oxygen species, leading to the formation of lipid peroxides such as 4-hydroxy-nonenal. Furthermore, alcohol impairs the antioxidant defense system, resulting in mitochondrial damage and apoptosis. Chronic alcohol exposure elicits hepatocyte hyperregeneration due to the activation of survival factors and interference with retinoid metabolism. Direct DNA damage results from acetaldehyde, which can bind to DNA, inhibit DNA repair systems, and lead to the formation of carcinogenic exocyclic DNA etheno adducts. Finally, chronic alcohol abuse interferes with methyl group transfer and may thereby alter gene expression.

Cleavage of endoplasmic reticulum proteins in hepatocellular carcinoma: Detection of generated fragments in patient sera

BACKGROUND & AIMS

In the past decade, there has been a rising incidence of hepatocellular carcinoma (HCC) and a progressive increase in HCC-related mortality in the United States and Western Europe. The poor survival of patients with HCC is largely related to the lack of reliable tools for early diagnosis.

METHODS

We have applied proteomics tools to the comparative analysis of protein profiles between HCC and adjacent nontumor tissues as a means for discovering novel molecular markers.

RESULTS

Forty-seven protein spots that showed reproducible variation were identified by mass spectrometry, corresponding to 23 distinct genes. A positive correlation between transcript and protein level variations was observed for only 7 out of the 23 genes. Proteolytic cleavage accounted for the discrepancies between messenger RNA and protein level changes for 7 genes including calreticulin, PDIA3, PDI, and GRP78. We detected a fragment of each of these 4 endoplasmic reticulum proteins in the culture supernatant of the PLC-PRF5 hepatoma cell line, suggesting that their cleavage leads to release of selected cleaved products in the extracellular compartment. We also detected calreticulin and PDIA3 cleavage products in sera of patients with HCC. A statistically highly significant difference in calreticulin and PDIA3 fragment serum levels between patients with HCC and healthy individuals was observed. Amounts of calreticulin and PDIA3 fragments were also significantly different between patients with HCC and at-risk patients (patients with chronic hepatitis or cirrhosis).

CONCLUSIONS

Specific isoforms in general and cleavage products in particular should therefore be further evaluated as new markers for HCC.

Surveillance of hepatocellular carcinoma in patients with hepatitis C virus infection may improve patient survival

BACKGROUND

The benefit of surveillance of hepatocellular carcinoma (HCC) for patients with hepatitis C virus (HCV) infection, in terms of long-term survival, has not yet been established.

METHODS

A total of 384 consecutive anti-HCV-positive HCC patients admitted to our hospital between January 1991 and October 2003 were enrolled. Patients were categorized into two groups, a surveillance group (182 patients) and a non-surveillance group (202 patients), according to tumor detection in a surveillance program based on periodical examination via ultrasound sonography and alpha fetoprotein determination at 6-month intervals, and their survival rates were compared.

RESULTS

Although there were no significant differences in age and Child-Pugh classes between the two groups, the surveillance group exhibited a smaller tumor size (19 vs. 35 mm) and a higher incidence of single HCC (67% vs. 46%), compared with the non-surveillance group (each, P < 0.001). The cumulative survival rate in the surveillance group was higher than that in the non-surveillance group (5 years survival, 46% vs. 32%, P < 0.001). When the survival after correction of the lead-time bias in the surveillance group was analyzed according to the Child-Pugh classification, the surveillance program was found to have had a favorable outcome in Child-Pugh class A patients, but not in Child-Pugh class B/C patients.

CONCLUSIONS

HCC surveillance for patients with HCV infection can lead to discovery of tumors at an early stage, especially in Child-Pugh class A, resulting in a favorable outcome.

Impact of age on screening and surveillance for primary liver cancer

OBJECTIVES

Although screening and surveillance for liver cancers have become established practices, the impact of age on these practices is unknown. The age at which these could be stopped, if any, is unclear. Our aims were to assess the impact of age on developing or dying from liver cancer, and to define the relative impact of prematurely stopping screening.

METHODS

Actuarial life-table analyses were performed using age-stratified mortality rates for primary liver cancers, and for all other causes combined, obtained from population-based databases from the United States. The impact of prematurely stopping screening at a given age was expressed as days of life lost compared to the maximal benefit expected from lifelong screening.

RESULTS

Mortality from primary liver cancers increases with age and peaks at 37 per 100,000 persons at ages 85-90 yr. However, mortality from other causes increases even more with age. Consequently, the relative proportion of deaths from primary liver cancer is maximal at 1.34% of all deaths at age 50 yr, and gradually decreases thereafter. Eighty percent of the maximal potential benefit of lifetime screening from age 45 yr is achieved by age 77 yr, and 90% by age 82 yr.

CONCLUSIONS

The relative benefits from screening for primary liver cancer are reduced in the elderly due to competing risks for death despite an increasing incidence of primary liver cancer with age. The majority of societal benefit is gained from screening at younger ages, when the relative proportions of death attributable to liver cancer are the greatest.

Ellipticine induces apoptosis through p53-dependent pathway in human hepatocellular carcinoma HepG2 cells

Ellipticine (5,11-dimethyl-6H-pyrido[4,3-b]carbazole), one of the simplest naturally occurring alkaloids, was isolated from the leaves of the evergreen tree Ochrosia elliptica Labill (Apocynaceae). Here, we reported that ellipticine inhibited the cell growth of human hepatocellular carcinoma cell line HepG2 and provided molecular understanding of this effect. The XTT assay results showed that ellipticine decreased the cell viability of HepG2 cells in a dose- and time-dependent manner, and the IC50 value was 4.1 microM. Furthermore, apoptosis induction by ellipticine in HepG2 cells was verified by the appearance of DNA fragmentation and annexin V-FITC/propidium iodide (PI) staining assay. Ellipticine treatment was found to result in the upregulation of p53, Fas/APO-1 receptor and Fas ligand. Besides, ellipticine also initiated mitochondrial apoptotic pathway through regulation of Bcl-2 family proteins expression, alteration of mitochondrial membrane potential (DeltaPsim), and activation of caspase-9 and caspase-3. Taken together, ellipticine decreased the cell growth and induced apoptosis in HepG2 cell.

The risk of hepatocellular carcinoma in cirrhotic patients with small liver nodules on MRI

BACKGROUND AND AIM

The presence of hepatocellular carcinoma (HCC) has important implications for patients with cirrhosis. Studies have not compared the risk of cancer in cirrhotic patients with small liver nodules to cirrhotic patients without nodules. Our aim was to determine the risk of HCC in cirrhotic patients with small liver nodules on MRI compared to those without nodules.

METHODS

We conducted a prospective study to determine the rate of HCC in cirrhotic patients with and without liver nodules. Cases were patients with liver nodule(s) less than 2 cm on MRI and controls were cirrhotic patients without nodules. Kaplan-Meier estimates and multivariate analysis were performed to estimate the risk of HCC in the two groups.

RESULTS

A total of 310 liver transplant candidates with a mean follow-up of 663 days were included in the study and 133 underwent liver transplant during follow-up. The 1-yr incidence of HCC in the liver nodule group and control group was 11% and 0.5%, respectively, p < 0.001. The adjusted risk for HCC in the liver nodule group was 25 times higher compared to the control group, HR = 25.1 [95% CI 8.0, 78.9]. In 133 candidates who underwent transplant with and without liver nodules the rate of HCC was 11 (50%) and 4 (3.6%), respectively, p < 0.001.

CONCLUSION

The incidence of HCC in patients with small liver nodules is significantly higher compared to patients with cirrhosis without liver nodules. The presence of small liver nodules warrants increased imaging surveillance for HCC.

Interaction between hepatitis B and C viruses in hepatocellular carcinogenesis

Although hepatitis B (HBV) and C viruses (HCV) are, individually, major causes of hepatocellular carcinoma, the interaction, if any, between the carcinogenic effects of the two viruses is uncertain. Equal numbers of published studies have reported no risk interaction or a synergistic risk interaction. These conflicting results are explained by the rarity of concurrent infection with HBV and HCV in individuals without clinically evident liver disease, which severely limits the ability to accurately estimate the hepatocarcinogenic risk of dual infection compared with that of either infection alone. In an attempt to circumvent this difficulty, two meta-analyses have been performed, one based on studies published from a number of countries and the other on studies confined to Chinese patients. Both analyses concluded that a synergistic carcinogenic interaction existed between the two viruses and that the increased risk was super-additive but not multiplicative. If confirmed, this risk interaction will occur against a background of negative confounding effects on viral replication between HBV and HCV, which may be reciprocal. The mechanisms responsible for the carcinogenic interaction between the viruses are unknown. One possibility is that the increased incidence of cirrhosis with concurrent HBV and HCV infections acts as an even more potent tumour promoter than occurs with either virus alone. Synergism between the direct hepatocarcinogenic effects of the two viruses is another possible mechanism, but proof will have to await a fuller understanding of the pathogenetic mechanisms involved with the individual viruses.

Molecular tracing of the global hepatitis C virus epidemic predicts regional patterns of hepatocellular carcinoma mortality

BACKGROUND & AIMS

Molecular evolutionary analysis based on coalescent theory can provide important insights into epidemiologic processes worldwide. This approach was combined with analyses of the hepatitis C virus (HCV) epidemiologic-historical background and HCV-related hepatocellular carcinoma (HCC) in different countries.

METHODS

The HCV gene sequences of 131 genotype 1b (HCV-1b) strains from Japan, 38 HCV-1a strains from the United States, 33 HCV-1b strains from Spain, 27 HCV-3a strains from the former Soviet Union (FSU), 47 HCV-4a strains from Egypt, 25 HCV-5a strains from South Africa, and 24 HCV-6a strains from Hong Kong isolated in this study and previous studies were analyzed.

RESULTS

The coalescent analysis indicated that a transition from constant size to rapid exponential growth (spread time) occurred in Japan in the 1920s (HCV-1b), but not until the 1940s for the same genotype in Spain and other European countries. The spread time of HCV-1a in the United States was estimated to be in the 1960s; HCV-3a in the FSU, HCV-5a in South Africa, and HCV-6a in Hong Kong in the 1960s, mid-1950s, and late 1970s, respectively. Three different linear progression curves were determined by analysis of the relationship between HCV seroprevalence and HCC mortality in different geographic regions; a steep ascent indicated the greatest progression to HCC in Japan, a near horizontal line indicated the least progression in the United States and the FSU, and an intermediate slope was observed in Europe.

CONCLUSIONS

These findings strongly suggest that the initial spread time of HCV is associated with the progression dynamics of HCC in each area, irrespective of genotype.

HCV-hepatocellular carcinoma: new findings and hope for effective treatment

We present here a comprehensive review of the current literature plus our own findings about in vivo and in vitro analysis of hepatitis C virus (HCV) infection, viral pathogenesis, mechanisms of interferon action, interferon resistance, and development of new therapeutics. Chronic HCV infection is a major risk factor for the development of human hepatocellular carcinoma. Standard therapy for chronic HCV infection is the combination of interferon alpha and ribavirin. A significant number of chronic HCV patients who cannot get rid of the virus infection by interferon therapy experience long-term inflammation of the liver and scarring of liver tissue. Patients who develop cirrhosis usually have increased risk of developing liver cancer. The molecular details of why some patients do not respond to standard interferon therapy are not known. Availability of HCV cell culture model has increased our understanding on the antiviral action of interferon alpha and mechanisms of interferon resistance. Interferons alpha, beta, and gamma each inhibit replication of HCV, and the antiviral action of interferon is targeted to the highly conserved 5'UTR used by the virus to translate protein by internal ribosome entry site mechanism. Studies from different laboratories including ours suggest that HCV replication in selected clones of cells can escape interferon action. Both viral and host factors appear to be involved in the mechanisms of interferon resistance against HCV. Since interferon therapy is not effective in all chronic hepatitis C patients, alternative therapeutic strategies are needed to treat chronic hepatitis C patients not responding to interferon therapy. We also reviewed the recent development of new alternative therapeutic strategies for chronic hepatitis C, which may be available in clinical use within the next decade. There is hope that these new agents along with interferon will prevent the occurrence of hepatocellular carcinoma due to chronic persistent hepatitis C virus infection. This review is not inclusive of all important scientific publications due to space limitation.

Liver disease in patients with diabetes mellitus

Diabetes mellitus is a growing health concern in our society. In addition to the well-known cardiovascular, renal, and ophthalmologic complications of diabetes, liver-related complications occur commonly and are often underrecognized. The ensuing article will review the relationship between diabetes mellitus and two common liver diseases: chronic hepatitis C and nonalcoholic fatty liver disease. The association with diabetes and cirrhosis, acute liver failure, hepatocellular carcinoma, and outcomes following orthotopic liver transplantation will also be discussed.

Occupational exposures and risks of liver cancer among Shanghai female textile workers--a case-cohort study

BACKGROUND

Liver cancer is the fifth most frequent malignancy worldwide. Viral hepatitis B and C, alcohol, and aflatoxin are the major established risk factors. Little is known about the aetiological contributions of occupational exposures, as previous occupational epidemiological studies of liver cancer suggest few agent-specific associations. We investigated associations of occupational exposures to dusts and chemicals in a cohort of female textile workers.

METHODS

Cancer incidence was determined among 267,400 female textile workers in Shanghai, China, who had been enrolled in an intervention trial of breast self-exam efficacy during 1989-98. Subjects were interviewed at baseline regarding basic demographics, smoking habits, alcohol consumption, and contraceptive practices. A case-cohort study of 360 liver cancer cases and 3,186 age-stratified randomly chosen subcohort subjects was conducted within this cohort. Exposures to workplace dusts and chemicals were reconstructed from complete work history data, historical exposure monitoring data for selected agents, and a specially designed job-exposure matrix for the textile industry. Relative risks and dose-response trends were estimated by Cox proportional hazards modelling, adapted for the case-cohort design. Latency analyses with different lag years were also applied.

RESULTS

2,095,904 person-years were contributed by this female cohort. The results of the case-cohort analysis revealed a protective effect of cotton fibre exposure years [adjusted hazards ratio (HR) = 0.64; 95% confidence interval (95% CI) 0.44-0.92] or endotoxin exposure (adjusted HR = 0.60; 95% CI 0.41-0.88) for the fourth quartile with significant trends for 20 year exposure lags.

CONCLUSIONS

This study suggests that chronic exposure to endotoxin or some other component of cotton dust exposure may have reduced liver cancer risk in this population.

Mitochondrial targeting of growth suppressor protein DLC2 through the START domain

Deleted in liver cancer 2 (DLC2) is a candidate tumor suppressor frequently found to be deleted in hepatocellular carcinoma. In this study, we determined the subcellular localization of DLC2. Co-localization and biochemical fractionation studies revealed that DLC2 localized to mitochondria. In addition, the DLC2-containing cytoplasmic speckles were in proximity to lipid droplets. A DLC2 mutant containing the steroidogenic acute regulatory protein-related lipid transfer (START) domain only showed a localization pattern identical to that of DLC2. Taken together, we have provided the first evidence for mitochondrial localization of DLC2 through the START domain. These findings might have implications in liver physiology and carcinogenesis.

Molecular genetic evidence supporting a novel human hepatocellular carcinoma tumor suppressor locus at 13q12.11

A novel 1-cM (1.8 Mb) homozygous deletion (HD) on 13q12.11 was identified in a human hepatocellular carcinoma (HCC) cell line, SK-Hep-1, after high-density genetic marker scan and Southern blotting analysis. A loss of heterozygosity (LOH) analysis indicated that LOH frequency of the HD region in 48 pairs of HCC tissues was 52%. Interestingly, the occurrence of LOH in the 13q12.11 HD region is significantly associated with early-onset HCC, inferred from Fisher's exact test (P = 0.0047) and Mann-Whitney test (P = 0.023). Since the novel 1-cM (1.8 Mb) HD region is gene-rich with more than 37 predicted transcripts, we used a candidate gene approach by examining down-regulation of known tumor suppressor genes (TSGs), including LATS2, TG737, CRYL1, and GJB2, in HCC tissues. We detected only 14% down-regulation of the LAST2 gene that flanks the outside of the HD, in HCC tissues, by quantitative RT-PCR assays. However, we observed significant down-regulation of the TG737, CRYL1, and GJB2 genes located within the HD in 59, 64, and 71% of HCC tissues, respectively. Together, our results indicated that the identified 13q12.11 HD region contained at least three significant down-regulated TSGs, and preferential LOH in early-onset HCC patients is a putative tumor suppressor locus in HCC.

Usefulness of serum des-gamma-carboxy prothrombin in detection of hepatocellular carcinoma

AIM

Des-gamma-carboxy prothrombin (DCP) has been reported to be more sensitive and specific in diagnosing hepatocellular carcinoma (HCC) when compared with alpha-fetoprotein (AFP). However, its ability to identify small HCC still remains unclear. Thus, we conducted a cross-sectional case control study to evaluate whether DCP is better than AFP for differentiating HCC from nonmalignant liver disease and further evaluate the usefulness of DCP in early diagnosis of small HCC.

METHODS

Serum DCP and AFP levels were determined in 127 patients. Among these patients, 32 were with non-cirrhotic chronic hepatitis, 34 were with compensated cirrhosis, and 61 were with HCC. The cut-off value for the DCP and AFP were set as 40 mAU/mL and 20 ng/mL, respectively. To compare the diagnostic value of DCP and AFP in distinguishing HCC from nonmalignant chronic liver disease, receiver operating characteristic (ROC) curves were constructed for each assay.

RESULTS

The accuracy, sensitivity and specificity of DCP were higher than AFP in detecting HCC (81.9%, 77% and 86.4% vs 68.5%, 59% and 77.3%, respectively). The area under the ROC (AUROC) curves revealed that DCP had a better accuracy than AFP in diagnosis of HCC (0.85 [95%CI, 0.78-0.91] vs 0.73 [95%CI, 0.65-0.81], P = 0.013). In 39 patients with solitary HCC, the positive rates of DCP were 100% in patients with tumor size larger than 3 cm, 66.7% in patients with tumor size 2-3 cm and 50% in patients with tumor size less than 2 cm. The positive rates of AFP in patients with tumor size larger than 3 cm, 2-3 cm and less than 2 cm were 55.6%, 50%, and 33.3%, respectively. The median level of DCP in HCC patients with tumor size larger than 3 cm was significantly higher than those with tumor size 2-3 cm and those with the size of less than 2 cm.

CONCLUSION

Our study indicates that DCP has a better diagnostic value than AFP in differentiating HCC from nonmalignant chronic liver disease. DCP has not only a stronger correlation with HCC than AFP in tumor size but also more effectiveness than AFP in detecting small size of HCC.

The continuing challenge of hepatic cancer in Asia

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. The number of new cases is estimated to be 564,000 per year. About 80% of all cases are found in Asia. The goal of HCC management is "cancer control"--a reduction in its incidence and mortality as well as an improvement in the quality of life of patients with HCC and their family. Overall, 80% of HCC can be attributed to chronic hepatitis B and C infection. Prevention of infection with hepatitis B and C virus is the key strategy to reduce the incidence of HCC in Asia. Liver resection and liver transplantation remain the options that give the best chance of a cure. In the past two decades, operative mortality and surgical outcome of liver resection and liver transplantation for HCC have improved. Progress also has been made in multi-modality therapy which can increase the chance of survival and improve the quality of life for patients with advanced HCC. Many challenges are still present in Asia, such as the high prevalence of chronic hepatitis, the low resection rate of HCC, the high postoperative recurrence and the severe shortage of cadaveric organ donor. This article aims to discuss the development and challenges in the prevention and management of HCC in Asia.

Prognostic factors and longterm survival after hepatic resection for hepatocellular carcinoma originating from noncirrhotic liver

BACKGROUND

The incidence of hepatocellular carcinoma (HCC) in cirrhotic and noncirrhotic liver is increasing in the world, probably because of the high prevalence of infections by hepatitis B and C viruses. Despite numerous publications on hepatic resection, prognostic factors for intrahepatic recurrence and survival are not well known for patients with HCC without cirrhosis.

STUDY DESIGN

One hundred eight consecutive patients with HCC in noncirrhotic liver have been treated by hepatic resection in the past 18 years in our center. Clinical, biologic, and histopathologic parameters of these patients were collected. Risk factors for intrahepatic recurrence and prognostic factors for survival were evaluated by univariate and multivariate analyses.

RESULTS

Postoperative morbidity and mortality rates were 23% and 6.5%, respectively. The 3- and 5-year disease-free and overall survival rates were 55% and 43%, and 43% and 29%, respectively. Blood transfusion, absence of tumor capsule, and daughter nodules were independently associated with overall survival. But the only risk factors for recurrence were blood transfusion, absence of tumor capsule, daughter nodules, and margin resection < 10 mm.

CONCLUSIONS

In the treatment of HCC without cirrhosis, hepatectomy remains a safe and legitimate treatment, but longterm results are impaired by a high rate of early recurrence likely related to metastatic dissemination. Only histopathologic factors related to the tumor are predictive of recurrence and overall survival.

Glypican-3 and alphafetoprotein as diagnostic tests for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of malignant tumor. It is usually asymptomatic in the early stages and tends to be intravascularly and intrabiliary invasive. Therefore, most patients present with incurable disease at the time of detection and early diagnosis of HCC is critical for a good prognosis. The imaging-based diagnosis of small tumors is relatively inaccurate, as cirrhotic and dysplastic nodules mimic HCC radiologically. The availability of a suitable serological marker to distinguish between HCC and benign liver lesions would, therefore, be very useful for early diagnosis. The only serological marker currently widely used for the diagnosis of HCC is alphafetoprotein (AFP). However, the sensitivity of this marker is limited (41-65%). Given the high heterogeneity of HCC, it is currently thought that an optimal serological test for HCC will be based on the simultaneous measurement of two or three highly specific serological markers.Several laboratories have recently reported that glypican-3 (GPC3), a membrane-bound proteoglycan, is expressed by a large proportion of HCCs, but is undetectable in normal hepatocytes and non-malignant liver disease. Furthermore, various studies demonstrated that GPC3 could be used as a serological test for the diagnosis of patients with HCC. Although the specificity of the test was very high in the context of a population with chronic liver disease, the sensitivity was limited (within the same range as AFP). Interestingly, in most cases, elevated GPC3 values did not correlate with elevated AFP values. As a consequence, the serological level of at least one of the two markers was elevated in a large majority of HCC patients. These results suggest that the sensitivity of the diagnostic test can be significantly improved without compromising specificity with the simultaneous measurement of both GPC3 and AFP.

Glypican-3 and alphafetoprotein as diagnostic tests for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of malignant tumor. It is usually asymptomatic in the early stages and tends to be intravascularly and intrabiliary invasive. Therefore, most patients present with incurable disease at the time of detection and early diagnosis of HCC is critical for a good prognosis. The imaging-based diagnosis of small tumors is relatively inaccurate, as cirrhotic and dysplastic nodules mimic HCC radiologically. The availability of a suitable serological marker to distinguish between HCC and benign liver lesions would, therefore, be very useful for early diagnosis. The only serological marker currently widely used for the diagnosis of HCC is alphafetoprotein (AFP). However, the sensitivity of this marker is limited (41-65%). Given the high heterogeneity of HCC, it is currently thought that an optimal serological test for HCC will be based on the simultaneous measurement of two or three highly specific serological markers.Several laboratories have recently reported that glypican-3 (GPC3), a membrane-bound proteoglycan, is expressed by a large proportion of HCCs, but is undetectable in normal hepatocytes and non-malignant liver disease. Furthermore, various studies demonstrated that GPC3 could be used as a serological test for the diagnosis of patients with HCC. Although the specificity of the test was very high in the context of a population with chronic liver disease, the sensitivity was limited (within the same range as AFP). Interestingly, in most cases, elevated GPC3 values did not correlate with elevated AFP values. As a consequence, the serological level of at least one of the two markers was elevated in a large majority of HCC patients. These results suggest that the sensitivity of the diagnostic test can be significantly improved without compromising specificity with the simultaneous measurement of both GPC3 and AFP.

IKKbeta couples hepatocyte death to cytokine-driven compensatory proliferation that promotes chemical hepatocarcinogenesis

IkappaB kinase beta (IKKbeta), required for NF-kappaB activation, links chronic inflammation with carcinogenesis. We investigated whether IKKbeta is involved in chemically induced liver cancer, a model not involving overt inflammation. Surprisingly, mice lacking IKKbeta only in hepatocytes (Ikkbeta(Deltahep) mice) exhibited a marked increase in hepatocarcinogenesis caused by diethylnitrosamine (DEN). This correlated with enhanced reactive oxygen species (ROS) production, increased JNK activation, and hepatocyte death, giving rise to augmented compensatory proliferation of surviving hepatocytes. Brief oral administration of an antioxidant around the time of DEN exposure blocked prolonged JNK activation and compensatory proliferation and prevented excessive DEN-induced carcinogenesis in Ikkbeta(Deltahep) mice. Decreased hepatocarcinogenesis was also found in mice lacking IKKbeta in both hepatocytes and hematopoietic-derived Kupffer cells. These mice exhibited reduced hepatocyte regeneration and diminished induction of hepatomitogens, which were unaltered in Ikkbeta(Deltahep) mice. IKKbeta, therefore, orchestrates inflammatory crosstalk between hepatocytes and hematopoietic-derived cells that promotes chemical hepatocarcinogenesis.

Non-parenchymal liver cells support the growth advantage in the first stages of hepatocarcinogenesis

Hepatocellular carcinoma almost always arises in chronically inflamed livers. We developed a culture model to study the role of non-parenchymal cells (NPCs) for inflammation-driven hepatocarcinogenesis. Rats were treated with the carcinogen N-nitrosomorpholine, which induced initiated hepatocytes expressing the marker placental glutathione-S-transferase (GSTp). After 21 days two preparations of hepatocytes were made: (i) conventional ones (Hep-conv) containing NPCs and (ii) hepatocytes purified of NPCs (Hep-pur). Initiated hepatocytes, being positive for GSTp (GSTp-pos) were present in both preparations and were cultured along with normal hepatocytes, being negative for GSTp (GSTp-neg). Under any culture condition DNA synthesis was approximately 4-fold higher in GSTp-pos than in GSTp-neg hepatocytes demonstrating the inherent growth advantage of the first stages of hepatocarcinogenesis. Hepatocytes showed approximately 3-fold lower rates of DNA synthesis in Hep-pur than in Hep-conv, which was elevated above Hep-conv levels by addition of NPC or NPC-supernatant. Pretreatment of NPCs with proinflammatory lipopolysaccharide (LPS) further increased DNA synthesis. Thus, NPCs release soluble growth stimulators. Next we investigated the effect of specific cytokines produced by NPCs. Tumour necrosis factor alpha and interleukin 6 barely altered DNA synthesis, whereas hepatocyte growth factor (HGF), keratinocyte growth factor (KGF) and the heparin-binding epidermal growth factor-like growth factor (HB-EGF) were potent inducers of DNA replication in both, GSTp-neg and GSTp-pos cells. In conclusion, DNA synthesis of hepatocytes is increased by factors released from NPCs, an effect augmented by LPS-stimulation. NPC-derived cytokines, such as KGF, HGF and HB-EGF, stimulate DNA synthesis preferentially in initiated hepatocytes, presumably resulting in tumour promotion. Similar mechanisms may contribute to carcinogenesis in human inflammatory liver diseases.

Survival rate in patients with hepatocellular carcinoma: a retrospective analysis of 389 patients

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. However, treatment options are limited and often inefficient. The aim of this study was to determine current survival rates for patients diagnosed with HCC and to identify prognostic factors, which will help in choosing optimal therapies for individual patients. A retrospective analysis of medical records was performed on 389 patients who were identified through the central tumour registry at our institution from 1998 to 2003. Clinical parameters, treatments received and survival curves from time of diagnosis were analysed. Overall median survival was 11 months. Liver cirrhosis was diagnosed in 80.5% of all patients. A total of 170 patients received transarterial chemoembolisation (TACE) and/or percutaneous ethanol injections (PEI) with a median survival rate of 16 months for patients receiving TACE, 11 months for patients receiving PEI and 24 months for patients receiving TACE followed by PEI. Independent negative prognostic parameters for survival were the presence of portal vein thrombosis, advanced liver cirrhosis (Child–Pugh score B or C) and a score of >2. This study will help to estimate survival rates for patients with HCC according to their clinical status at diagnosis and the treatments received.

Epidemiology of hepatocellular carcinoma

Year 2000 estimates of the incidence of cancer indicate that primary liver cancer remains the fifth most common malignancy in men and the eighth in women. The number of new cases has been predicted as 564,000, corresponding to 398,000 in men and 166,000 in women. The geographic areas at highest risk are located in Eastern Asia, Middle Africa, and some countries of Western Africa. Changes in incidence among migrant populations underline the predominant role of environmental factors in the etiology of primary liver cancer. In high-risk countries, the early cases of primary liver cancer occur already at ages 20 and above, underlying the impact of viral exposures early in life. In countries at low risk, primary liver cancer is rare before the 50s, translating the impact of late exposures with moderate risks and long latency intervals. Sex ratios are typically between 2 and 4. The incidence of primary liver cancer is increasing in several developed countries including the United States, and the increase will likely continue for several decades. The trend has a dominant cohort effect related to exposures to hepatitis B and C viruses. The variability of primary liver cancer incidence is largely explained by the distribution and the natural history of the hepatitis B and C viruses. The attributable risk estimates for the combined effects of these infections account for well over 80% of liver cancer cases worldwide. Primary liver cancer is the first human cancer largely amenable to prevention using hepatitis B virus vaccines and screening of blood and blood products for hepatitis B and C viruses.

Role of infectious diseases in human carcinogenesis

The burden of human infectious diseases remains a public health problem worldwide. At least 2 billion people are affected by viral infections, and a similar number by bacteria or helminths. The long-term effects of these maladies have raised particular concern since some infectious agents have been associated with chronic human diseases, especially cancer. It is estimated that 13-20% of the world cancer cases are associated with some virus, bacteria, or helminth, e.g., human papillomavirus, Helicobacter pylori, and Schistosoma haematobium that cause cervical, stomach, and urinary bladder cancer, respectively. Certain associations between infection and malignancy are strong and irrefutable; others are still speculative. This article reviews the infectious agents that have been associated with cancer and current knowledge about the mechanisms underlying these associations.