Clonal analysis of micronodules in virus C-induced liver cirrhosis using laser capture microdissection (LCM) and HUMARA assay

Risk of de novo HCC in patients with MASLD following direct-acting antiviral-induced cure of HCV infection

BACKGROUND & AIMS

Data are limited on the risk of de novo hepatocellular carcinoma (HCC) in patients with metabolic dysfunction-associated steatotic liver disease (MASLD) after achieving sustained virologic response (SVR12) using direct-acting antivirals (DAAs) for hepatitis C virus (HCV).

METHODS

1598 eligible patients received biannual alpha-fetoprotein (AFP) and liver imaging surveillance to detect de novo HCC beyond achieving SVR12. MASLD was defined as presence of controlled attenuation parameter (CAP) ≥ 248 dB/m and ≥ one cardiometabolic risk factor (CMRF). Cumulative HCC incidence was compared between patients with/without MASLD. We built univariable and multivariable Cox proportional hazards models to evaluate factors associated with HCC. Sensitivity analysis was performed using the Fine-Gray subdistribution hazards model. Additionally, we evaluated the mediation effect of MASLD on CMRFs and of CMRFs on MASLD for HCC using mediation analysis with bootstrapping.

RESULTS

The incidence rate of HCC was 1.44 per 100 person-years of follow-up (PYFU) [95% confidence interval (CI): 1.19-1.74]. Patients with MASLD had a higher cumulative HCC incidence than those without MASLD (log-rank test, p < 0.001). Multivariable Cox regression analysis revealed that in addition to age, sex, LSM, platelet count, and AFP, MASLD (adjusted hazard ratio (aHR): 2.07 [95% CI:1.36-3.16], p < 0.001) was independently associated with HCC. This finding was confirmed by the Fine-Gray model, which showed a subdistribution HR (sHR) of 2.07 (95% CI: 1.34-3.19, p < 0.001) for MASLD. MASLD significantly mediated CMRFs for HCC development.

CONCLUSION

After achieving SVR12, patients with MASLD exhibited an increased HCC risk compared to those without MASLD. Vigilant HCC surveillance and control of CMRFs to mitigate the effect MASLD on HCC remain crucial for this population.

IMPACT AND IMPLICATIONS

The risk of de novo HCC among patients with MASLD, a novel nomenclature of steatotic liver disease (SLD), after the attaining of SVR12 using DAAs remains to be confirmed. In this study recruiting 1598 patients in Taiwan, individuals with MASLD exhibited approximately a two-fold increased risk of de novo HCC, compared to those without MASLD after achieving SVR12. MASLD significantly mediated CMRFs for HCC development. Our findings underscore the critical importance of pharmacological interventions and proactive lifestyle modifications to control CMRFs in patients with MASLD, as well as the need for vigilant HCC surveillance to ensure favorable outcomes following HCV eradication.

Surveillance for Hepatocellular Carcinoma in Patients with Successfully Treated Viral Disease of the Liver: A Systematic Review

Background

Surveillance for hepatocellular carcinoma (HCC) has been proven to increase the proportion of tumors detected at early stages and the chance of receiving curative therapies, reducing mortality by about 30%.

Summary

Current recommendations consist of a semi-annual abdominal ultrasound with or without serum alpha-fetoprotein measurement in patients with cirrhosis and specific subgroups of populations with chronic viral hepatitis. Antiviral therapies, such as nucleot(s)ide analogs that efficiently suppress the replication of hepatitis B virus (HBV) and direct-acting antiviral drugs able to eliminate the hepatitis C virus (HCV) in >90% of patients, have radically changed the outcomes of viral liver disease and decreased, but not eliminated, the risk of HCC in both cirrhotic and non-cirrhotic patients. HCC risk is a key starting point for implementing a cost-effective surveillance and should also guide the decision-making process concerning its modality. As the global number of effectively treated viral patients continues to rise, there is a pressing need to identify those for whom the benefit-to-harm ratio of surveillance is favorable and to determine how to conduct cost-effective screening on such patients.

Key Messages

This article addresses this topic and attempts to determine which patients should continue HCC surveillance after HBV suppression or HCV eradication, based on cost-effectiveness principles and the fact that HCC risk declines over time. We also formulate a proposal for a surveillance algorithm that switches the use of surveillance for HCC from the "one-size-fits-all" approach to individualized programs based on oncologic risk (precision surveillance).

Polo-like kinase-1 mediates hepatitis C virus-induced cell migration, a drug target for liver cancer

Polo-like kinase 1 (PLK1) is a regulator of cell mitosis and cytoskeletal dynamics. PLK1 overexpression in liver cancer is associated with tumour progression, metastasis, and vascular invasion. Hepatitis C virus (HCV) NS5A protein stimulates PLK1-mediated phosphorylation of host proteins, so we hypothesised that HCV-PLK1 interactions might be a mechanism for HCV-induced liver cancer. We used a HCV cell-culture model (Jc1) to investigate the effects of virus infection on the cytoskeleton. In HCV-infected cells, a novel posttranslational modification in β-actin was observed with phosphorylation at Ser239. Using in silico and in vitro approaches, we identified PLK1 as the mediating kinase. In functional experiments with a phosphomimetic mutant form of β-actin, Ser239 phosphorylation influences β-actin polymerization and distribution, resulting in increased cell motility. The changes were prevented by treating cells with the PLK1 inhibitor volasertib. In HCV-infected hepatocytes, increased cell motility contributes to cancer cell migration, invasion, and metastasis. PLK1 is an important mediator of these effects and early treatment with PLK1 inhibitors may prevent or reduce HCC progression, particularly in people with HCV-induced HCC.

The care cascade for hepatitis C virus and prognosis of chronic hepatitis C patients treated with antiviral agents in a tertiary hospital

BACKGROUND

Some studies have analyzed the frequency of HCV RNA testing and actual treatment among anti-HCV positive patients in Korea, which has a low prevalence of HCV infection. This study aimed to analyze the diagnosis process, treatment results, and prognosis according to care cascade in patients who are anti-HCV positive.

METHODS

Three thousand two hundred fifty-three anti-HCV positive patients presented to a tertiary hospital between January 2005 and December 2020. The number of patients who underwent HCV RNA testing, treatment, and proportion of sustained virologic response (SVR) according to the type of antivirals was investigated. We investigated the cumulative incidence of hepatocellular carcinoma (HCC) and liver cirrhosis.

RESULTS

Of a total of 3,253 people, 1,177 (36.2%) underwent HCV RNA testing and 858 (72.9%) were positive for HCV RNA. 494 (57.6%) of HCV RNA positive patients received antiviral treatment, and 443 (89.7%) of initiated hepatitis C treatment experienced SVR. Of the 421 treated patients, 16 (14.2%) developed HCC. The cumulative incidence of HCC at 15 years was significantly different according to the presence of liver cirrhosis (10/83, 29.5% vs. 6/338, 10.8%, p < 0.001). The cumulative incidences of HCC or liver cirrhosis did not show significant differences according to the presence of SVR₁₂ (14/388, 13.2% vs. 2/33, 52.5%, p = 0.084, 21/319, 15.0%, vs. 3/22, 28.7%, p = 0.051).

CONCLUSIONS

Owing to the introduction of direct-acting antivirals, high SVR₁₂ was achieved, but the proportion of anti-HCV positive patients who received HCV RNA testing and treatment was not high. HCC surveillance after SVR₁₂ is recommended for chronic hepatitis C patients with cirrhosis.

Biology of cancer; from cellular and molecular mechanisms to developmental processes and adaptation

Cancer research has been largely focused on the cellular and molecular levels of investigation. Recent data show that not only the cell but also the extracellular matrix plays a major role in the progression of malignancy. In this way, the cells and the extracellular matrix create a specific local microenvironment that supports malignant development. At the same time, cancer implies a systemic evolution which is closely related to developmental processes and adaptation. Consequently, there is currently a real gap between the local investigation of cancer at the microenvironmental level, and the pathophysiological approach to cancer as a systemic disease. In fact, the cells and the matrix are not only complementary structures but also interdependent components that act synergistically. Such relationships lead to cell-matrix integration, a supracellular form of biological organization that supports tissue development. The emergence of this supracellular level of organization, as a structure, leads to the emergence of the supracellular control of proliferation, as a supracellular function. In humans, proliferation is generally involved in developmental processes and adaptation. These processes suppose a specific configuration at the systemic level, which generates high-order guidance for local supracellular control of proliferation. In conclusion, the supracellular control of proliferation act as an interface between the downstream level of cell division and differentiation, and upstream level of developmental processes and adaptation. Understanding these processes and their disorders is useful not only to complete the big picture of malignancy as a systemic disease, but also to open new treatment perspectives in the form of etiopathogenic (supracellular or informational) therapies.

HCC surveillance after SVR in patients with F3/F4 fibrosis

HCV eradication by antiviral treatment reduces but does not eliminate HCC risk. Patients with established cirrhosis require HCC surveillance "indefinitely" after sustained virologic response (SVR) because they appear to have a high risk of HCC even many years after SVR. Patients without established or known cirrhosis may still require surveillance after SVR if they have a sufficiently high HCC risk. In all patients who achieve SVR, the key question is how we can reliably estimate HCC risk, and the change in HCC risk over time, to determine whether the patient might benefit from HCC surveillance. HCC risk is one of the most important factors that should inform decisions of whether and how to screen for HCC. Promising strategies for estimating HCC risk include simplified scoring systems (such as fibrosis-4), liver elastography and multivariable HCC risk calculators. Such tools may enable risk stratification and individualised, risk-based surveillance strategies ("precision HCC screening") in the future.

Differential Roles for Diploid and Polyploid Hepatocytes in Acute and Chronic Liver Injury

Hepatocytes are the primary functional cells of the liver that perform essential roles in homeostasis, regeneration, and injury. Most mammalian somatic cells are diploid and contain pairs of each chromosome, but there are also polyploid cells containing additional sets of chromosomes. Hepatocytes are among the best described polyploid cells, with polyploids comprising more than 25 and 90% of the hepatocyte population in humans and mice, respectively. Cellular and molecular mechanisms that regulate hepatic polyploidy have been uncovered, and in recent years, diploid and polyploid hepatocytes have been shown to perform specialized functions. Diploid hepatocytes accelerate liver regeneration induced by resection and may accelerate compensatory regeneration after acute injury. Polyploid hepatocytes protect the liver from tumor initiation in hepatocellular carcinoma and promote adaptation to tyrosinemia-induced chronic injury. This review describes how ploidy variations influence cellular activity and presents a model for context-specific functions for diploid and polyploid hepatocytes.

Increased Risk for Hepatocellular Carcinoma Persists Up to 10 Years After HCV Eradication in Patients With Baseline Cirrhosis or High FIB-4 Scores

BACKGROUND & AIMS

It is unclear if hepatocellular carcinoma (HCC) risk declines over time after hepatitis C virus (HCV) eradication. We analyzed changes in HCC annual incidence over time following HCV eradication and identified dynamic markers of HCC risk.

METHODS

We identified 48,135 patients who initiated HCV antiviral treatment from 2000 through 2015 and achieved a sustained virologic response (SVR) in the Veterans Health Administration (29,033 treated with direct-acting antiviral [DAA] agents and 19,102 treated with interferon-based regimens). Patients were followed after treatment until February 14, 2019 (average 5.4 years), during which 1509 incident HCCs were identified.

RESULTS

Among patients with cirrhosis before treatment with DAAs (n = 9784), those with pre-SVR fibrosis-4 (FIB-4) scores ≥3.25 had a higher annual incidence of HCC (3.66%/year) than those with FIB-4 scores <3.25 (1.16%/year) (adjusted hazard ratio 2.14; 95% confidence interval 1.66-2.75). In DAA-treated patients with cirrhosis and FIB-4 scores ≥3.25, annual HCC risk decreased from 3.8%/year in the first year after SVR to 2.4%/year by the fourth year (P=.01). In interferon-treated patients with FIB-4 scores ≥3.25, annual HCC risk remained above 2%/year, even 10 years after SVR. A decrease in FIB-4 scores from ≥3.25 pre-SVR to <3.25 post-SVR was associated with an approximately 50% lower risk of HCC, but the absolute annual risk remained above 2%/year. Patients without cirrhosis before treatment (n = 38,351) had a low risk of HCC, except for those with pre-SVR FIB-4 scores ≥3.25 (HCC risk 1.22%/year) and post-SVR FIB-4 scores ≥3.25 (HCC risk 2.39%/year); risk remained high for many years after SVR.

CONCLUSIONS

Patients with cirrhosis before an SVR to treatment for HCV infection continue to have a high risk for HCC (>2%/year) for many years, even if their FIB-4 score decreases, and should continue surveillance. Patients without cirrhosis but with FIB-4 scores ≥3.25 have a high enough risk to merit HCC surveillance, especially if FIB-4 remains ≥3.25 post-SVR.

Polyploid Hepatocytes Facilitate Adaptation and Regeneration to Chronic Liver Injury

The liver contains diploid and polyploid hepatocytes (tetraploid, octaploid, etc.), with polyploids comprising ≥90% of the hepatocyte population in adult mice. Polyploid hepatocytes form multipolar spindles in mitosis, which lead to chromosome gains/losses and random aneuploidy. The effect of aneuploidy on liver function is unclear, and the degree of liver aneuploidy is debated, with reports showing aneuploidy affects 5% to 60% of hepatocytes. To study relationships among liver polyploidy, aneuploidy, and adaptation, mice lacking E2f7 and E2f8 in the liver (LKO), which have a polyploidization defect, were used. Polyploids were reduced fourfold in LKO livers, and LKO hepatocytes remained predominantly diploid after extensive proliferation. Moreover, nearly all LKO hepatocytes were euploid compared with control hepatocytes, suggesting polyploid hepatocytes are required for production of aneuploid progeny. To determine whether reduced polyploidy impairs adaptation, LKO mice were bred onto a tyrosinemia background, a disease model whereby the liver can develop disease-resistant, regenerative nodules. Although tyrosinemic LKO mice were more susceptible to morbidities and death associated with tyrosinemia-induced liver failure, they developed regenerating nodules similar to control mice. Analyses revealed that nodules in the tyrosinemic livers were generated by aneuploidy and inactivating mutations. In summary, we identified new roles for polyploid hepatocytes and demonstrated that they are required for the formation of aneuploid progeny and can facilitate adaptation to chronic liver disease.

Hepatitis C virus-associated cancer

Hepatitis C virus (HCV) is one of the major etiologic agents of liver cancer. HCV is an RNA virus that, unlike hepatitis B virus, is unable to integrate into the host genome. Through complex interactions between viral and host proteins that induce host responses and promote inflammation, fibrosis, and ultimately cirrhosis, HCV infection can result in the development of hepatocellular carcinoma (HCC). The HCV oncogenic process involves genetic and epigenetic alterations and oncogenic effects mediated by viral proteins in the activation of cellular oncogenes, inactivation of tumor-suppressor genes, and dysregulation of multiple signal-transduction pathways. Advances in genetics and gene expression profiling have enhanced our current understanding of the pathways involved in HCV-associated liver cancer development. In this review, we summarize the current understanding of mechanisms of hepatocarcinogenesis induced by HCV infection.

Molecular and metabolic changes in human liver clear cell foci resemble the alterations occurring in rat hepatocarcinogenesis

BACKGROUND & AIMS

Activation of the AKT/mTOR and Ras/MAPK pathways and the lipogenic phenotype occurs in both a rat model of insulin-induced hepatocarcinogenesis and in human hepatocellular carcinoma (HCC). In the rat model, activation of these pathways is evident within the earliest morphologic detectable alterations, i.e., clear cell foci (CCF) of altered hepatocytes. CCF have also been described in the human liver, but molecular and metabolic alterations within these foci remain to be determined.

METHODS

A collection of human liver specimens was examined using electron microscopy, histology, enzyme- and immunohistochemistry, and molecular analysis. Human data were compared to rat preneoplastic CCF and HCC induced by N-nitrosomorpholine administration.

RESULTS

CCF occurred in ∼33% of extrafocal tissues of human non-cirrhotic livers. Electron microscopy showed massive glycogen storage within CCF, largely due to the reduced activity of the glycogenolytic enzyme glucose-6-phosphatase. Hepatocytes in CCF overexpressed the insulin receptor and glucose transporter proteins. AKT/mTOR and Ras/MAPK pathways as well as enzymes of glycolysis, de novo lipogenesis, beta-oxidation, and cholesterol synthesis were upregulated, both in human CCF, and in CCF and HCC of N-nitrosomorpholine-treated rats. The Ki-67 proliferation index was 2-fold higher in human CCF than in extrafocal tissue.

CONCLUSIONS

The high degree of similarity between human CCF and pre-neoplastic lesions from experimental models of hepatocarcinogenesis in terms of morphologic, molecular and metabolic features suggests a low-grade dysplastic nature of these lesions in human non-cirrhotic livers.

Liver repopulation and regeneration: new approaches to old questions

PURPOSE OF REVIEW

Significant recent developments have occurred in the field of liver regeneration. Although the regenerative response to partial hepatectomy has been studied extensively, in recent years the use of new experimental approaches has incorporated a fresh look that may lead to a better understanding of hepatocyte dysfunction and regeneration.

RECENT FINDINGS

Liver injury promotes the regenerative responses that are relatively rare in healthy livers. Current research efforts focus on the mechanisms of hepatocyte adaptation in response to liver injury. We will discuss how hepatic aneuploidy and polyploidy contributes to liver regeneration, as well as new modalities to study cellular interactions using the organ-specific microenvironment.

SUMMARY

High mortality is generally limited to patients who develop terminal liver failure, which occurs when regenerative responses are unable to compensate for liver injury. Cellular adaptations and organ microenvironment changes are present during disease processes. This review aims to provide insights into the innovative approaches taken to investigate regeneration in liver diseases.

Aneuploidy, polyploidy and ploidy reversal in the liver

Polyploidy has been described in the liver for over 100 years. The frequency of polyploid hepatocytes varies by age and species, but up to 90% of mouse hepatocytes and approximately 50% of human hepatocytes are polyploid. In addition to alterations in the entire complement of chromosomes, variations in chromosome copy number have been recently described. Aneuploidy in the liver is pervasive, affecting 60% of hepatocytes in mice and 30-90% of hepatocytes in humans. Polyploidy and aneuploidy in the liver are closely linked, and the ploidy conveyor model describes this relationship. Diploid hepatocytes undergo failed cytokinesis to generate polyploid cells. Proliferating polyploid hepatocytes, which form multipolar spindles during cell division, generate reduced ploidy progeny (e.g., diploid hepatocytes from tetraploids or octaploids) and/or aneuploid daughters. New evidence suggests that random hepatic aneuploidy can promote adaptation to liver injury. For instance, in response to chronic liver damage, subsets of aneuploid hepatocytes that are differentially resistant to the injury remain healthy, regenerate the liver and restore function. Future work is required to elucidate the mechanisms regulating dynamic chromosome changes in the liver and to understand how these processes impact normal and abnormal liver function.

Aneuploidy as a mechanism for stress-induced liver adaptation

Over half of the mature hepatocytes in mice and humans are aneuploid and yet retain full ability to undergo mitosis. This observation has raised the question of whether this unusual somatic genetic variation evolved as an adaptive mechanism in response to hepatic injury. According to this model, hepatotoxic insults select for hepatocytes with specific numerical chromosome abnormalities, rendering them differentially resistant to injury. To test this hypothesis, we utilized a strain of mice heterozygous for a mutation in the homogentisic acid dioxygenase (Hgd) gene located on chromosome 16. Loss of the remaining Hgd allele protects from fumarylacetoacetate hydrolase (Fah) deficiency, a genetic liver disease model. When adult mice heterozygous for Hgd and lacking Fah were exposed to chronic liver damage, injury-resistant nodules consisting of Hgd-null hepatocytes rapidly emerged. To determine whether aneuploidy played a role in this phenomenon, array comparative genomic hybridization (aCGH) and metaphase karyotyping were performed. Strikingly, loss of chromosome 16 was dramatically enriched in all mice that became completely resistant to tyrosinemia-induced hepatic injury. The frequency of chromosome 16-specific aneuploidy was approximately 50%. This result indicates that selection of a specific aneuploid karyotype can result in the adaptation of hepatocytes to chronic liver injury. The extent to which aneuploidy promotes hepatic adaptation in humans remains under investigation.

Frequent aneuploidy among normal human hepatocytes

Murine hepatocytes become polyploid and then undergo ploidy reversal and become aneuploid in a dynamic process called the ploidy conveyor. Although polyploidization occurs in some types of human cells, the degree of aneuploidy in human hepatocytes is not known. We isolated hepatocytes derived from healthy human liver samples and determined chromosome number and identity using traditional karyotyping and fluorescence in situ hybridization. Similar to murine hepatocytes, human hepatocytes are highly aneuploid. Moreover, imaging studies revealed multipolar spindles and chromosome segregation defects in dividing human hepatocytes. Aneuploidy therefore does not necessarily predispose liver cells to transformation but might promote genetic diversity among hepatocytes.

Clonality of nodular lesions in liver cirrhosis and chromosomal abnormalities in monoclonal nodules of altered hepatocytes

AIMS

To investigate the clonality and chromosome abnormalities of nodules of altered hepatocytes (NAH) in liver cirrhosis and determine whether there is a genetic link between monoclonal NAH and hepatocellular carcinoma (HCC).

METHODS AND RESULTS

First, 93 nodules from nine hepatitis B virus (HBV)-related liver cirrhosis patients were dissected by laser microdissection. Next, genomic DNA was extracted, pretreated with Hpa II or Hha I, and amplified via nested polymerase chain reaction for the phosphoglycerate kinase and androgen receptor genes. Finally, the chromosomal aberrations of 12 monoclonal NAH were studied using array-based comparative genomic hybridization (array-CGH). Loss of X chromosomal inactivation mosaicism was demonstrated in three large regenerative nodules and 12 NAH with small cell change (SCC), indicating their neoplastic nature. Among the 60 NAH without SCC, 29 (48.33%) were shown to be monoclonal, whereas four glycogen-storing foci and 14 regenerative nodules were found to be polyclonal. Array-CGH analysis revealed chromosomal abnormalities in one NAH with SCC. Moreover, a part of chromosomal abnormalities in the NAH with SCC coincided with those in HCC.

CONCLUSIONS

Some (48.33%) NAH in HBV-associated cirrhosis, particularly all those with SCC, are already neoplastic lesions. Occurrence of SCC is a late event during NAH progression, suggesting a premalignant phenotype.

Detection of clonally expanded hepatocytes in chimpanzees with chronic hepatitis B virus infection

During a hepadnavirus infection, viral DNA integrates at a low rate into random sites in the host DNA, producing unique virus-cell junctions detectable by inverse nested PCR (invPCR). These junctions serve as genetic markers of individual hepatocytes, providing a means to detect their subsequent proliferation into clones of two or more hepatocytes. A previous study suggested that the livers of 2.4-year-old woodchucks (Marmota monax) chronically infected with woodchuck hepatitis virus contained at least 100,000 clones of >1,000 hepatocytes (W. S. Mason, A. R. Jilbert, and J. Summers, Proc. Natl. Acad. Sci. USA 102:1139-1144, 2005). However, possible correlations between sites of viral-DNA integration and clonal expansion could not be explored because the woodchuck genome has not yet been sequenced. In order to further investigate this issue, we looked for similar clonal expansion of hepatocytes in the livers of chimpanzees chronically infected with hepatitis B virus (HBV). Liver samples for invPCR were collected from eight chimpanzees chronically infected with HBV for at least 20 years. Fifty clones ranging in size from approximately 35 to 10,000 hepatocytes were detected using invPCR in 32 liver biopsy fragments (approximately 1 mg) containing, in total, approximately 3 x 10(7) liver cells. Based on searching the analogous human genome, integration sites were found on all chromosomes except Y, approximately 30% in known or predicted genes. However, no obvious association between the extent of clonal expansion and the integration site was apparent. This suggests that the integration site per se is not responsible for the outgrowth of large clones of hepatocytes.

Hepatic precancerous lesions and small hepatocellular carcinoma

Precancerous lesions that may be detected in chronically diseased, usually cirrhotic livers, include: clusters of hepatocytes with atypia and increased proliferative rate (dysplastic foci) that usually represent an incidental finding in biopsy or resection specimens; and grossly evident lesions (dysplastic nodules) that may be detected on radiologic examination. There are two types of small hepatocellular carcinoma (HCC) (defined as HCC that measures less than 2 cm): early HCC, which is well-differentiated and has indistinct margins; and distinctly nodular small HCC, which is well- or moderately differentiated, and is usually surrounded by a fibrous capsule. Precise diagnosis of precancerous and early cancerous lesions by imaging methods is often difficult or impossible. Detection of a dysplastic lesion in a biopsy specimen is a marker of increased risk for HCC development, and warrants increased surveillance. High-grade dysplastic nodules and small HCCs should be treated by local ablation, surgical resection, or liver transplantation.

Hepatitis C virus and malignancy

Hepatitis C virus (HCV) is a hepatotropic virus that causes chronic hepatitis, fibrosis and cirrhosis. HCV is associated with the development of primary liver tumors, namely hepatocellular carcinoma, cholangiocarcinoma and lymphoma. This article reviews HCV-related malignancies, and their prevalence and probable oncogenesis.

Nucleotide change of codon 38 in the X gene of hepatitis B virus genotype C is associated with an increased risk of hepatocellular carcinoma

BACKGROUND/AIMS

The hepatitis B virus (HBV) genotype C is associated with the development of hepatocellular carcinoma (HCC). In addition, the HBV X gene, which encodes the pleiotropic transactivator HBx, has also been associated with the development of HCC. In this study, we investigated whether nucleotide changes in the X gene of genotype C are associated with the development of HCC.

METHODS/RESULTS

We sequenced the X gene in age- and sex-matched 39 HBV-infected patients with HCC and 36 HBV-infected patients without HCC. A novel nucleotide change that resulted in a proline to serine substitution at codon 38 in HBx (codon-38 change) was preferentially found in patients with HCC. Then, sera were collected from a new group of age- and sex-matched 52 patients with HCC and 51 patients without HCC. In this cohort also, the codon-38 change was associated with HCC. Multiple logistic regression analysis showed the prevalence of the codon-38 change was significantly associated with HCC in all patients (P=0.001, odds ratio: 4.89).

CONCLUSION

The codon-38 change in genotype C is an independent risk factor for the development of HCC and may serve as a useful molecular marker for predicting the clinical outcomes in patients infected with HBV.

Global proteomic analysis of microdissected cirrhotic nodules reveals significant biomarkers associated with clonal expansion

Cirrhosis is a heterogeneous tissue composed of polyclonal regenerative and monoclonal neoplastic, potentially malignant nodules from which hepatocellular carcinoma (HCC) might develop. The aim of this study was to investigate proteomic profile changes associated with clonal expansion of cirrhotic nodules and malignant transformation of monoclonal nodules. Seventy-one cirrhotic nodules from 10 female patients with six HCC were dissected from liver surgical specimen by laser capture microdissection. Clonal status of each nodule was assessed by the study of X-chromosome inactivation pattern using the human androgen receptor. Protein profiles were determined by surface-enhanced laser desorption ionisation-time-of-flight technology using Q10 arrays (Cyphergen ProteinChip). Molecular weight of differentially expressed protein peaks was assessed. An average of 50 protein peaks was obtained for each nodule's profile. Comparison of protein profiles in polyclonal (n=45) and monoclonal cirrhotic nodules (n=26) identified three differentially expressed protein peaks (10,092, 54,025 and 62,133 Da). All were upregulated in monoclonal nodules. Twelve peaks were differentially expressed between monoclonal nodules and HCC with nine proteins upregulated in cancer samples. This study confirms that proteome analysis can be achieved from a limited number of microdissected cells, and provides further insight into the process of clonal expansion and malignant transformation of cirrhotic nodules.

Quantitative RT-PCR in cirrhotic nodules reveals gene expression changes associated with liver carcinogenesis

Cirrhosis is considered to be the precursor of most hepatocellular carcinomas. To gain insight into the early molecular mechanisms of liver carcinogenesis, this study compared, using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), the expression levels of 31 selected genes in normal livers, cirrhotic nodules, and hepatocellular carcinomas. Since cirrhosis is composed of a mixture of polyclonal and monoclonal nodules, gene expression levels were also compared according to the clonal status of the cirrhotic nodules. The expression of eight of the 31 genes studied was significantly increased (NEGF2, ANGPT1, ARF, KRT19, SFN, CLDN4, MMP7, and ETV4) in cirrhotic nodules compared with normal liver, while only one was decreased (LYVE1). The same trend of variation was observed in cirrhosis and hepatocellular carcinomas for all of these genes except KRT19. When gene expression variation was compared according to the clonal status of cirrhotic nodules, only the LYVE1 expression level was significantly different. The LYVE1 gene expression level decreased progressively from polyclonal cirrhotic nodules to monoclonal cirrhotic nodules (polyclonal nodules 0.39 +/- 0.25; monoclonal nodules 0.20 +/- 0.14; p < 0.05) and to hepatocellular carcinoma (0.07 +/- 0.1). In conclusion, this study highlights the fact that among genes strongly dysregulated in hepatocellular carcinoma, some are already abnormally expressed in cirrhosis. The decrease in the expression level of one of these genes, LYVE1, was associated with monoclonality in cirrhotic nodules.

A novel, essential control for clonality analysis with human androgen receptor gene polymerase chain reaction

The most widely used technique for determining clonality based on X-chromosome inactivation is the human androgen receptor gene polymerase chain reaction (PCR). The reliability of this assay depends critically on the digestion of DNA before PCR with the methylation-sensitive restriction enzyme HpaII. We have developed a novel method for quantitatively monitoring the HpaII digestion in individual samples. Using real-time quantitative PCR we measured the efficiency of HpaII digestion by measuring the amplification of a gene that escapes X-chromosome inactivation (XE169) before and after digestion. This method was tested in blood samples from 30 individuals: 2 healthy donors and 28 patients with myelodysplastic syndrome. We found a lack of XE169 DNA reduction after digestion in the granulocytes of two myelodysplastic syndrome patients leading to a false polyclonal X-chromosome inactivation pattern. In all other samples a significant reduction of XE169 DNA was observed after HpaII digestion. The median reduction was 220-fold, ranging from a 9.0-fold to a 57,000-fold reduction. Also paraffin-embedded malignant tissue was investigated from two samples of patients with mantle cell lymphoma and two samples of patients with colon carcinoma. In three of these cases inefficient HpaII digestion led to inaccurate X-chromosome inactivation pattern ratios. We conclude that monitoring the efficiency of the HpaII digestion in a human androgen receptor gene PCR setting is both necessary and feasible.

Molecular pathogenesis of human hepatocellular carcinoma

Hepatocarcinogenesis is a slow process during which genomic changes progressively alter the hepatocellular phenotype to produce cellular intermediates that evolve into hepatocellular carcinoma. During the long preneoplastic stage, in which the liver is often the site of chronic hepatitis, cirrhosis, or both, hepatocyte cycling is accelerated by upregulation of mitogenic pathways, in part through epigenetic mechanisms. This leads to the production of monoclonal populations of aberrant and dysplastic hepatocytes that have telomere erosion and telomerase re-expression, sometimes microsatellite instability, and occasionally structural aberrations in genes and chromosomes. Development of dysplastic hepatocytes in foci and nodules and emergence of hepatocellular carcinoma are associated with the accumulation of irreversible structural alterations in genes and chromosomes, but the genomic basis of the malignant phenotype is heterogeneous. The malignant hepatocyte phenotype may be produced by the disruption of a number of genes that function in different regulatory pathways, producing several molecular variants of hepatocellular carcinoma. New strategies should enable these variants to be characterized.

Pathology of the liver

Traditional anatomic pathology studies and molecular investigations both contributed to the breadth of current information in the field of liver pathology this year. Techniques such as reverse transcription polymerase chain reaction can identify recurrence of hepatitis C virus infection in the liver as early as 5 days after transplantation. Chronic rejection after transplantation may be characterized not only by ductopenia but also by loss of portal tract hepatic artery branches. There are many diseases of small bile ducts in adults, and idiopathic adulthood ductopenia has been identified in extended family members. Adverse reactions to drugs may precipitate their removal from the pharmacopoeia, such as the many cases reported of severe bridging and submassive necrosis due to troglitazone (a thiazolidinedione antidiabetic agent). Several publications highlighted the association of hepatitis C virus infection with lymphoproliferative diseases and, newly, with cholangiocarcinoma.