Large liver cell dysplasia: a controversial entity

Cellular senescence and its pathogenic and therapeutic implications in autoimmune hepatitis

INTRODUCTION

Senescent cells are characterized by replicative arrest and phenotypes that produce diverse pro-inflammatory and pro-oxidant mediators. The senescence of diverse hepatic cell types could constitute an unrecognized pathogenic mechanism and prognostic determinant in autoimmune hepatitis. The impact of cellular senescence in autoimmune hepatitis is unknown, and it may suggest adjunctive management strategies.

AREAS COVERED

This review describes the molecular mechanisms of cellular senescence, indicates its diagnostic features, suggests its consequences, presents possible therapeutic interventions, and encourages investigations of its pathogenic role and management in autoimmune hepatitis. Treatment prospects include elimination or reversal of senescent cells, generation of ectopic telomerase, reactivation of dormant telomerase, neutralization of specific pro-inflammatory secretory products, and mitigation of the effects of mitochondrial dysfunction.

EXPERT OPINION

The occurrence, nature, and consequences of cellular senescence in autoimmune hepatitis must be determined. The senescence of diverse hepatic cell types could affect the outcome of autoimmune hepatitis by impairing hepatic regeneration, intensifying liver inflammation, and worsening hepatic fibrosis. Cellular senescence could contribute to suboptimal responses during conventional glucocorticoid-based therapy. Interventions that target specific pro-inflammatory products of the senescent phenotype or selectively promote apoptosis of senescent cells may be preferred adjunctive treatments for autoimmune hepatitis depending on the cancer risk.

Pathological predictive factors for late recurrence of hepatocellular carcinoma in chronic liver disease

BACKGROUND & AIMS

Late recurrence of hepatocellular carcinoma (HCC) is regarded as de novo HCC from chronic hepatitis. This study investigated clinicopathological and molecular factors to develop a nomogram for predicting late HCC recurrence (>2 years after curative resection).

METHODS

The training and validation cohorts included HCC patients with a major aetiology of hepatitis B who underwent curative resection. Clinicopathological features including lobular and porto-periportal inflammatory activity, fibrosis and liver cell change were evaluated. Proteins encoded by genes related to late recurrence were identified using a reverse phase protein array of 95 non-tumourous liver tissues. Immunoexpression of phosphorylated signal transducer and activator of transcription 3 (pSTAT3), plasminogen activator inhibitor-1, phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) and spleen tyrosine kinase (SYK) was measured.

RESULTS

Late recurrence occurred in 74/402 (18%) and 47/243 (19%) in the training and validation cohorts respectively. Cirrhosis, moderate/severe lobular inflammatory activity, and expression of pSTAT3, pERK1/2, and SYK proteins correlated to the gene signature of hepatocyte injury and regeneration were independently associated with late recurrence, with odds ratios (95% confidence intervals) of 2.0 (1.2-3.3), 21.1 (4.3-102.7) and 6.0 (2.1-17.7) respectively (P < .05 for all). A nomogram based on these variables (histological parameters and immunohistochemical marker combinations) showed high reliability in both the training and validation cohorts (Harrell's C index: 0.701 and 0.716; 95% confidence intervals: 0.64-0.76 and 0.64-0.79 respectively).

CONCLUSIONS

The combination of pSTAT3, pERK1/2 and SYK immunoexpression with high lobular inflammatory activity and cirrhosis (fibrosis) predicts late HCC recurrence.

Integration of VEGF and α-SMA Expression Improves the Prediction Accuracy of Fibrosis in Chronic Hepatitis C Liver Biopsy

INTRODUCTION

The progression of fibrosis in chronic hepatitis C (CHC) is a multifactorial process. The high adverse effects and the cost of standard health care increase the demand to discover new predictors for the progression of fibrosis in CHC patients. Our study aims to establish the relation between the angiogenic marker [vascular endothelial growth factor (VEGF)] and activated hepatic stellate cells (HSCs) represented by the expression of α-smooth muscle actin (α-SMA) and whether these 2 markers can be used as predictors for the progression of fibrosis in patients with CHC.

MATERIALS AND METHODS

Histopathologic and immunohistochemical analyses were used for examining the morphology and the expression of VEGF and α-SMA in 60 CHC biopsies procured from CHC patients. Multivariate analysis was used to correlate the protein expression with staging and grading of liver fibrosis. Cutoff values of α-SMA and VEGF were determined by the receiver operating characteristics curve.

RESULTS

There was a positive correlation between VEGF and HSCs expressing α-SMA (ρ=0.287, P=0.026) and both factors were correlated with the stage of fibrosis (P<0.001). Using the receiver operating characteristics curve, both VEGF (area under the curve=0.71, P<0.006) and α-SMA (area under the curve=0.82, P<0.001) were positive predictors for moderate and severe fibrosis.

CONCLUSIONS

This study demonstrates the relation between VEGF expression and the activated HSCs denoted by the expression of α-SMA in CHC biopsies and together can be used as a predictor for the progression of fibrosis.

LATS-YAP/TAZ controls lineage specification by regulating TGFβ signaling and Hnf4α expression during liver development

The Hippo pathway regulates the self-renewal and differentiation of various adult stem cells, but its role in cell fate determination and differentiation during liver development remains unclear. Here we report that the Hippo pathway controls liver cell lineage specification and proliferation separately from Notch signalling, using mice and primary hepatoblasts with liver-specific knockout of Lats1 and Lats2 kinase, the direct upstream regulators of YAP and TAZ. During and after liver development, the activation of YAP/TAZ induced by loss of Lats1/2 forces hepatoblasts or hepatocytes to commit to the biliary epithelial cell (BEC) lineage. It increases BEC and fibroblast proliferation by up-regulating TGFβ signalling, but suppresses hepatoblast to hepatocyte differentiation by repressing Hnf4α expression. Notably, oncogenic YAP/TAZ activation in hepatocytes induces massive p53-dependent cell senescence/death. Together, our results reveal that YAP/TAZ activity levels govern liver cell differentiation and proliferation in a context-dependent manner.

The Hippo pathway regulates the differentiation of stem and progenitor cells, but it is unclear how it acts in liver development. Here, the authors knockout Hippo pathway components Lats1 and 2 in the liver, causing suppression of hepatocyte differentiation but promoting biliary cell differentiation.

Chronic replicative stress induced by CCl4 in TRF1 knockout mice recapitulates the origin of large liver cell changes

BACKGROUND & AIMS

Large liver cell changes (LLCC) are characterized by pleomorphic large nuclei frequently found in liver diseases as chronic viral hepatitis and liver cirrhosis. The origin of this lesion remains cryptic, but the presence of LLCC is correlated with an increased risk of hepatocellular carcinoma. Telomeric repeat binding factor 1 (TRF1) is part of the shelterin complex and is essential for telomere protection. Ablation of TRF1 induces telomere fragility and fusions and chromosomal instability.

METHODS

In this study, we addressed the role of TRF1 in liver regeneration generating a mouse model with conditional deletion of TRF1 in the liver.

RESULTS

TRF1 deletion has no deleterious effects in liver and leads to increased ploidy of hepatocytes after 2/3 hepatectomy. Mice lacking TRF1 in the liver can survive for over one year without any evidence for altered liver function. Importantly, applying chronic replicative stress by frequent carbon tetrachloride (CCl4) injections, TRF1 deleted mice undergo ploidy changes consistent with endoreduplication and develop LLCC like lesions in the liver positive for p21, Cyclin D1 and PCNA as observed in humans.

CONCLUSION

In summary, we provide mechanistic insight into the role of TRF1 in liver regeneration and provide a mouse model recapitulating the clinical features of LLCC.

Evidence for heightened hexokinase II immunoexpression in hepatocyte dysplasia and hepatocellular carcinoma

BACKGROUND

Normal hepatocytes exhibit low-affinity hexokinase (glucokinase [HKIV]), but during oncogenesis, there is a switch from HKIV to HKII expression. The aims of this study were to compare the immunoexpression of HKII in non-dysplastic cirrhosis (NDC), liver cell change/dysplasia in cirrhosis (LCD), HCC, and normal liver control tissues, and to correlate HKII expression with clinical and histopathological parameters.

DESIGN

Immunohistochemistry was performed on a liver cancer progression tissue array consisting of specimens from explants with cirrhosis, including 45 tissue samples with HCC, 108 without HCC, 143 with LCD, and 8 normal liver control tissues. HKII expression was quantified as positive pixel counts/square millimeter (ppc/mm(2)) by image analysis.

RESULTS

There was a stepwise increase in HKII level from normal liver tissue to NDC, to LCD, and to HCC (p = 0.001). HKII levels were significantly higher in areas of LCD versus NDC (p ≤ 0.001), and in LCD and HCC versus NDC (p = 0.007). HKII levels were similar in LCD and HCC (p = 0.124). HKII levels were higher in grade 2-4 versus grade 1 HCCs (p = 0.044), and in pleomorphic versus non-pleomorphic HCC variants (p = 0.041). Higher levels of HKII expression in LCD and HCC versus NDC and in higher tumor grade remained significant in multivariate analysis.

CONCLUSIONS

Higher levels of HKII immunoexpression in LDC and HCC compared with NDC suggest that upregulation of HKII occurs during the process of hepatocarcinogenesis in humans. In HCC, higher levels of HKII are associated with more aggressive histological features.

Expression of glypican 3 enriches hepatocellular carcinoma development-related genes and associates with carcinogenesis in cirrhotic livers

Glypican-3 (GPC3) protein expression was determined by immunohistochemical analysis from 29 normal livers, 80 cirrhotic livers sample taken near hepatocellular carcinoma (HCC), and 87 cirrhotic livers without HCC. The levels for miR-657 and HCC-related gene mRNAs were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Also, a published microarray dataset was used for gene set enrichment analysis (GSEA) to investigate the relationship between GPC3- and HCC-related gene signatures. Kaplan-Meier analysis was used to evaluate the relationship between GPC3 and HCC recurrence. GPC3 protein expression was not detected in any of the 29 (0%) normal livers, but was detected in 32 of 87 (37%) cirrhotic livers without HCC, and 51 of 80 (64%) cirrhotic liver samples taken near HCC sites (P < 0.001). The GPC3-positive rate in cirrhotic livers of viral origin was 68% (27/40), which was significantly higher than for non-viral cirrhotic livers (11%, 5/47) (P < 0.001). Also, GPC3 expression positively correlated with mRNA expression of HCC-related genes in the qRT-PCR and GSEA evaluations. Furthermore, HCC recurrence in cirrhotic liver samples taken near HCC sites was significantly higher in the GPC3-positive group than the GPC3-negative group (Log-rank P = 0.02, HR = 3.26; 95% CI = 1.20-10.29). This study demonstrated that highly expression of GPC3 could enrich HCC-related genes' mRNA expression and positive associate with dysplasia in cirrhotic livers. Therefore, GPC3 may serve as a precancerous biomarker in cirrhotic livers.

Pathological characteristics of patients who develop hepatocellular carcinoma with negative results of both serous hepatitis B surface antigen and hepatitis C virus antibody

AIM

We tried to characterize the pathological features of patients who developed hepatocellular carcinoma (HCC) with the negative results of both serous hepatitis B surface antigen and hepatitis C virus antibody (non-B, non-C).

METHODS

In a multicenter study in Kyushu, Japan, we studied the histopathological characteristics of non-cancerous liver tissues in 129 patients (103 men and 26 women) with non-B, non-C HCC. The histological liver damage was evaluated for fibrosis (stage) and inflammation (grade) according to the Ludwig classification of chronic hepatitis. In addition, we examined the hepatitis B virus (HBV) genome in serum samples and liver tissues of 20 patients with non-B, non-C HCC.

RESULTS

Positivity of serum hepatitis B core (HBc) antibody, alcohol abuse, diabetes and non-alcoholic steatohepatitis were present in 61 (47%), 76 (59%), 57 (44%) and eight (6%) patients, respectively. The degree of fibrosis was mild (stage 1.6 ± 1.2). The stage of patients with neither serum HBc antibody nor alcohol abuse was significantly lower than the stage of patients with HBc antibody and no alcohol abuse (P < 0.05). HBV genome was detected in 15 cancerous tissues (75%) and 16 non-cancerous liver tissues (80%) in 20 patients with non-B, non-C HCC. Only three of the 20 patients were positive for serum HBc antibody.

CONCLUSION

Non-B, non-C patients appear to develop HCC at a low stage of fibrosis. Occult hepatitis B virus infection is the major risk factor for HCC of non-B, non-C patients in Kyushu, Japan.

Dose-dependent induction of preneoplastic lesions by the tobacco-specific nitrosamine carcinogen NNK in the in ovo carcinogenicity assessment (IOCA) assay

The potential of the carcinogenic tobacco specific nitrosamine 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-1-butanone (NNK) to induce preneoplastic hepatocellular altered foci (HAF) was tested in the in ovo carcinogenicity assessment (IOCA) assay. Single doses of NNK over a dose range from 0.1 mg to 6 mg were injected into fertilized turkey eggs prior to incubation for 24 days. The livers were investigated by histological, histochemical and morphometric methods. Mortality was increased for eggs exposed to 6 mg. In this group, the whole livers were severely altered, showing pronounced changes of nucleus size and signs of cell death. At the dose of 2 mg various types of foci of altered hepatocytes (HAF) were observed. Basophilic cell foci of the solid or tubular type were most frequent. The NNK-induced HAF were very similar to the preneoplastic lesions that occur in the livers of mammals during hepatocarcinogenesis which are regarded as early indicators of carcinogenesis. The similarity to the HAF in rodents included histochemically detectable alterations like decreased activities of glucose-6-phosphatase, adenosine triphosphatase and glycogen phosphorylase. At doses of 1 mg or below, no HAF were detected. At all dose levels an increased occurrence of enlarged hepatocytes with enlarged nuclei and prominent nucleoli (karyomegalic hepatocytes) were observed. The increase in karyomegalic hepatocytes was also statistically significant at the low dose of 0.1 mg/kg NNK but the dose-effect curve for their induction was clearly non-linear. Induction of HAF and karyomegalic hepatocytes in ovo is a simple (one dose), rapid (24 days) and inexpensive (no animal purchase or housing) experimental approach for studies on chemically induced hepatocarcinogenesis.

Advanced precancerous lesions within the GI tract: the molecular background

The mainstream carcinogenic processes involved within the gastrointestinal tract are characterized by phenotypic multistep progression cascades that eventually result in full-blown cancers. In this scenario, the understanding of the molecular dysregulations underlying the precancerous lesions is increasing but still remains incomplete. However, in recent years, the enthusiastic rise of innovative technologies (i.e., next-generation sequencing, high-throughput microarray analysis, mass spectrometry based proteomics) and the unexpected discovery of new classes of biomarkers (i.e., miRNA, long-noncoding RNAs) prompted new strength in the exploration of the accurate and comprehensive molecular characterization of premalignant and malignant neoplastic lesions. The challenge ahead lies in the reliable identification of disease progression-specific targets to enable molecular testing in the clinical management of the secondary prevention of gastrointestinal cancers.

Comparative histomorphological review of rat and human hepatocellular proliferative lesions

In this comparative review, histomorphological features of common nonneoplastic and neoplastic hepatocyte lesions of rats and humans are examined using H&E-stained slides. The morphological similarities and differences of both neoplastic (hepatocellular carcinoma and hepatocellular adenoma) and presumptive preneoplastic lesions (large and small cell change in humans and foci of cellular alteration in rats) are presented and discussed. There are major similarities in the diagnostic features, growth patterns and behavior of both rat and human hepatocellular proliferative lesions and in the process of hepatocarcinogenesis. Further study of presumptive preneoplastic lesions in humans and rats should help to further define their role in progression to hepatocellular neoplasia in both species.

Transarterial chemoembolization plus sorafenib: a sequential therapeutic scheme for HCV-related intermediate-stage hepatocellular carcinoma: a randomized clinical trial

BACKGROUND

Recurrence of hepatocellular carcinoma (HCC) is a major problem after surgical or ablative treatments. The aim of this prospective, single-center, placebo-controlled, randomized, double-blind clinical study was to evaluate the effectiveness of transarterial chemoembolization (TACE) combined with sorafenib as a sequential treatment regimen in delaying time to progression (TTP) of intermediate-stage HCC in patients with chronic hepatitis C virus (HCV) infection.

MATERIAL AND METHODS

Between October, 2007 and January, 2011, 80 HCV-infected patients with Barcelona Clinic Liver Cancer stage B HCC underwent the TACE procedure. All had Child-Pugh class A disease. They were randomized 1:1 to receive sorafenib at a dose of 400 mg twice daily or placebo. Endpoints were the TTP and the rates of adverse events and toxicity.

RESULTS

Sixty-two of 80 patients (77%), 31 in the sorafenib group and 31 in the control group, completed the study. The median TTP was 9.2 months in the sorafenib group and 4.9 months in the placebo group (hazard ratio, 2.5; 95% confidence interval, 1.66-7.56; p < .001). Metachronous, multicentric HCC progression occurred less frequently in sorafenib-treated patients (p < .05). Adverse reactions to sorafenib caused withdrawal from the study of 9 (22%) patients.

CONCLUSION

A conventional TACE procedure followed by sorafenib treatment resulted in a significantly longer TTP in patients with intermediate-stage HCV-related HCC, with no unexpected side effects.

Hepatocarcinogenesis: imaging-pathologic correlation

Rapid advances in liver surgery, including liver transplantation, radiology, and pathology, have created a need for clinically relevant nomenclature for premalignant and early lesions of hepatocellular carcinoma (HCC). Precancerous lesions include dysplastic foci and dysplastic nodules (DNs) characterized by cytologic or structural atypia. Although imaging diagnosis is playing a crucial role in the evaluation of hepatocarcinogenesis and early diagnosis of HCC, it is still challenging to accurately characterize borderline nodules such as small arterially enhancing lesions or hypovascular nodules. This article discusses pathological and radiological features of these small nodular lesions and offers insights into the multistep process of hepatocarcinogenesis by describing the progression of pathologic change linking DNs to HCC.

Update on precursor and early lesions of hepatocellular carcinomas

CONTEXT

There is increasing evidence to support a multistep model of the process of human hepatocarcinogenesis. Precursor lesions are characterized by the appearance of dysplastic lesions in the form of microscopic dysplastic foci and macroscopic dysplastic nodules. There are 2 types of small hepatocellular carcinoma (HCC) (≤2 cm in diameter): (1) early HCC with an indistinct margin and (2) progressed HCC with a distinct margin. Pathologic diagnostic criteria for early HCC have recently been set up based on a consensus between Eastern and Western pathologists.

OBJECTIVE

To review the nomenclature, pathology, and biomarkers of precursor and early lesions of HCC.

DATA SOURCES

Literature review and illustrations from case materials were used.

CONCLUSIONS

Dysplastic foci are composed of large and small cell changes. Small cell change is considered to be a more advanced precursor lesion than large cell change, and large cell change is a rather heterogeneous lesion that may represent both reactive change and true dysplasia. Dysplastic nodules can be categorized as low or high grade according to the degree of atypia. High-grade dysplastic nodules have been reported to show molecular changes similar to HCC and have a high risk of malignant transformation. Early HCC, which may correspond to microinvasive carcinomas of other organs, is a well-differentiated HCC, and differential diagnosis between early HCC and high-grade dysplastic nodule is difficult. Identification of stromal invasion and application of a panel of markers (glypican-3, heat shock protein 70, and glutamine synthetase) is helpful for diagnosis of early HCC. Detection of precursor lesions of HCC is important in recognizing patients with higher risk of developing HCC, and diagnosis of early HCC can improve patient survival by allowing for early and adequate treatment.

Chronic viral hepatitis: the histology report

In chronic viral hepatitis, the role of liver biopsy as a diagnostic test has seen a decline, paralleled by its increasing importance for prognostic purposes. Nowadays, the main indication for liver biopsy in chronic viral hepatitis is to assess the severity of the disease, in terms of both necro-inflammation (grade) and fibrosis (stage), which is important for prognosis and therapeutic management. Several scoring systems have been proposed for grading and staging chronic viral hepatitis and there is no a general consensus on the best system to be used in the daily practice. All scoring systems have their drawbacks and all may be affected by sampling and observer variability. Whatever the system used, a histological score is a reductive approach since damage in chronic viral hepatitis is a complex biological process. Thus, scoring systems are not intended to replace the detailed, descriptive, pathology report. In fact, lesions other than those scored for grading and staging may have clinical relevance and should be assessed and reported. This paper aims to provide a systematic approach to the interpretation of liver biopsies obtained in cases of chronic viral hepatitis, with the hope of helping general pathologists in their diagnostic practice.

Mitosis is not the only distributor of mutated cells: non-mitotic endopolyploid cells produce reproductive genome-reduced cells

Giant endopolyploid nuclei (>16n) can spontaneously fragment by endomitosis (nuclear internal division) into near-diploid cells with reproductive capacity (depolyploidization), and endotetra/octopolyploidy can undergo chromosome-visible meiotic-like genome reductional divisions also to replicative subcells. These unconventional divisions are associated with production of aneuploidy, which led to the question in this study of whether endopolyploidy, in general, can contribute genetic variability to tumorigenic potential. For this purpose, non-proliferative endopolyploid cells (range: 4n-32n) in near-senescence of normal diploid cell strains were analysed for nuclear-morphogenic changes associated with the presence of diploid-sized nuclei in the cytoplasm. A one-by-one nuclear-cutoff process gave rise to reproducing genome-reduced cells. It was concluded that these unconventional cell divisions are, indeed, suspects of originating genetic variability. Details of these irregular mitoses were compared to 'mitotic-meiosis' in primitive organisms, which suggested activation of an ancestral trait in the mammalian cells.

Pathology of chronic hepatitis B and chronic hepatitis C

Histologic evaluation of the liver is a major component in the medical management and treatment algorithm of patients with chronic hepatitis B (HBV) and chronic hepatitis C (HCV). Liver biopsy in these patients remains the gold standard, and decisions on treatment are often predicated on the degree of damage and stage of fibrosis. This article outlines the clinical course and serologic diagnosis of HBV and HCV for the clinician and the pathologist, who together have a close working relationship in managing patients with acute and chronic liver disease. The salient histologic features are elucidated in an attempt to provide the clinician with an understanding of the basic histopathology underlying chronic HCV and HBV.

Large cell change of hepatocytes in chronic viral hepatitis represents a senescent-related lesion

Large cell change involves the clustering of hepatocytes with hyperchromatism and cellular enlargement without an increase in the nuclear/cytoplasmic ratio. This study investigated whether large cell change in chronic viral hepatitis reflects cellular senescence because of morphological similarities between the 2 conditions. The expression of markers of senescence such as senescence-associated beta-galactosidase, senescence-associated heterochromatic foci, and p21, as well as markers of cell kinetics such as Ki-67, was examined in 26 frozen and 82 formalin-fixed liver specimens. Large cell change was frequently detected in chronic hepatitis B cases with advanced histologic staging, particularly those with hepatocellular carcinoma. Senescence-associated beta-galactosidase activity, senescence-associated heterochromatic foci, and p21 were frequently detected in areas of large cell change. Hepatocytes with large cell change showed no proliferative or apoptotic activity. The frequent expression of senescent features and the absence of proliferative or apoptotic activity suggest that large cell change represents senescence. The parallel increase in large cell change and hepatocellular carcinoma in chronic hepatitis B raises the possibility that cellular senescence develops as a safeguard against malignant transformation rather than as a precursor of hepatocellular carcinoma.

Large liver cell change in hepatitis B virus-related liver cirrhosis

Large liver cell change (LLCC) refers to microscopic lesions often found in various chronic liver diseases; however, its nature is still controversial. Thirty-four formalin-fixed and 19 fresh frozen hepatitis B virus (HBV)-related cirrhosis samples were examined for the presence of LLCC, small liver cell change (SLCC), and hepatocellular carcinoma (HCC). The cell cycle checkpoint status (p21, p27, p16, Tp53), cell dynamics (proliferating cell nuclear antigen, Ki-67, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling, M30), DNA damage (gamma-H2AX [H2A histone family, member X]), telomere lengths, chromosomal instability (micronuclei index), and senescence-associated beta-galactosidase (SA-beta-Gal) activity were evaluated using an in situ approach and compared to those in normal liver (n = 5) and liver with chronic cholestasis (34 cases of hepatolithiasis and three cases of primary biliary cirrhosis). In HBV-related cirrhosis, the p21, p27, and p16 cell cycle checkpoint markers were activated in normal-looking cirrhotic hepatocytes (NLCH), but diminished gradually from LLCC, SLCC, to HCC, with an increase in Tp53 expression. There was a general decrease in telomere length from NLCH, LLCC, SLCC, to HCC. Micronuclei, gamma-H2AX foci, and net cellular gain were significantly increased from normal hepatocytes, NLCH, LLCC, SLCC, to HCC. The SA-beta-Gal activity was weaker in LLCC compared to NLCH and absent in SLCC and HCC. In contrast, cholestatic LLCC showed retained expression of cell cycle checkpoint markers and decreased net cellular gain compared to adjacent normal-looking hepatocytes. HBV-related LLCC showed significantly higher Tp53 labeling index, gamma-H2AX labeling index, and micronuclei index; shorter telomere length; decreased SA-beta-Gal activity; and increased net cellular gain compared to cholestatic LLCC.

CONCLUSION

The nature of LLCC is rather heterogeneous depending on the biological setting. The characteristics of HBV-related LLCC are more consistent with dysplastic rather than merely reactive hepatocytes, whereas cholestatic LLCC more likely represents reactive change with more stringent cell cycle checkpoint control.

Predictive value of liver cell dysplasia for development of hepatocellular carcinoma in patients with chronic hepatitis B

GOALS

We aimed to determine whether the presence of large liver cell dysplasia (LLCD) and/or small LCD (SLCD) in chronic hepatitis B is a risk factor for hepatocellular carcinoma (HCC) development.

BACKGROUND

A close relationship between LLCD/SLCD and hepatitis B virus has been observed and SLCD has been proposed to be a putative precursor of HCC, whereas the significance of LLCD is still controversial.

STUDY

One hundred eighty-one patients with chronic hepatitis B who underwent needle liver biopsy were evaluated for the presence of LLCD/SLCD. The predictive value of LLCD/SLCD for HCC development was assessed.

RESULTS

LLCD and SLCD were present at initial biopsy in 82 (45%) and 17 (9%) patients, respectively. During the mean follow-up of 115+/-48 months, 19 (10%) cases were diagnosed of HCC, of which 13 (76%) and 3 (17%) cases had demonstrated LLCD and SLCD, respectively, at initial evaluation. The patients with LLCD showed a significantly higher cumulative probability of HCC development than those without LLCD (P=0.016). The risk of HCC development in the presence of LLCD was approximately 3-fold, with positive and negative predictive values of 15.9% and 94.9%, respectively. The patients with SLCD showed no significant difference in cumulative probability of HCC development compared with those without (P>0.05).

CONCLUSIONS

LLCD in chronic hepatitis B is considered to be one of the risk factors for HCC development and its presence may help to identify a high-risk subgroup of patients requiring more intensive screening for HCC.

Elevated expression of PDCD5 and Fas in hepatocellular carcinoma and its adjacent tissues

AIM: To investigate expression of programmed cell death 5 (PDCD5) and Fas in hepatocellular carcinoma (HCC) tissues and its adjacent tissues and liver cirrhosis tissues and thereby to explore relationship between PDCD5 and HCC.

METHODS: Protein expression of PDCD5 and Fas from 40 HCC and its adjacent tissues (including 24 cases of liver cirrhosis, 16 cases of chronic liver hepatitis) were analyzed using immunohistochemistry. Positive protein expression rates and intensity of PDCD5 and Fas were investigated under microscopy. Statistics were analyzed using Kruskal-Wallis H test and Spearman's Rank correlation coefficient.

RESULTS: There was PDCD5 negative expression in HCC and raised expression rate in HCC adjacent tissues. There were significant difference in PDCD5 expression among HCC grpup, HCC adjacent tissue group and cirrhosis, chronic hepatitis group (χ² = 46.03, P = 0.000). The same significance between HCC and cirrhosis or chronic hepatitis was detected for Fas expression (χ² = 24.45, P = 0.000). Correlation analysis showed that PDCD5 was positively correlated with Fas (r = 0.839, P = 0.001).

CONCLUSION: PDCD5 is an important apoptosis-regulating factor in hepatocelluar carcinoma pathogenesis.

Liver repopulation and carcinogenesis: two sides of the same coin?

Liver repopulation by transplanted normal hepatocytes has been described in a number of experimental settings. Extensive repopulation can also occur from the selective proliferation of endogenous normal hepatocytes, both in experimental animals and in the human liver. This review highlights the intriguing association between clinical and experimental conditions related to liver repopulation and an increased risk for development of hepatocellular carcinoma. It is suggested that any microenvironment that is able to sustain the clonal growth of normal transplanted (or endogenous) hepatocytes is also geared to select for the emergence of rare resistant cells with an altered phenotype. Whereas the first pathway leads to liver repopulation with normal histology, the latter results in the growth of focal proliferative lesions and carries an increased risk of neoplastic disease. The implications of this association are discussed, both in terms of pathogenetic significance and possible therapeutic exploitation.

DNA of Helicobacter spp. and common gut bacteria in primary liver carcinoma

BACKGROUND AND AIM

Gastric and enteric Helicobacter species have been associated with the pathogenesis of some extragastric diseases.

METHODS

We retrospectively investigated the presence of DNA of Helicobacter species in samples of the cancer and the surrounding tumour-free liver tissues of patients with hepatocellular carcinoma (HCC, n=12) and cholangiocarcinoma (CC, n=13). The patients were from an area with low liver cancer incidence and with low hepatitis B and C prevalence. Patients with a benign liver disease (n=24) were included as controls. Paraffin-embedded liver samples were examined by a Helicobacter genus-specific PCR assay as well as group-specific PCR assays for Enterobacteriaceae, Bacteroides, Lactobacillus and Enterococcus. PCR products of positive samples were characterised by denaturing gradient gel electrophoresis (DGGE) and DNA sequencing.

RESULTS

PCR assay detected Helicobacter DNA in seven of 12 (58%) and eight of 13 (62%) normal liver tissue specimens from HCC and CC patients, respectively. Two cancer samples from HCC patients were Helicobacter-positive but none of the CC cancers. In the control group, three of 24 (12.5%) patients with a benign liver condition were positive for Helicobacter species (p<0.01 compared to results of tumour-free liver tissue from the cancer patients). DGGE and DNA sequence analysis showed that 90% of the detected PCR products were "H. pylori-like". DNA of some other enteric bacteria was detected in the liver of one cancer patient and one control (4% of all patients).

CONCLUSION

The presence of DNA of Helicobacter species in liver specimens, but not of other common gut bacteria, was associated with human hepatic carcinogenesis.

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.

Hepatobiliary pathology

PURPOSE OF REVIEW

Recent papers on disorders of the liver and biliary tract which clarify their pathogenesis and attendant morphologic changes are highlighted.

RECENT FINDINGS

The concept of 'bystander hepatitis' was cited in studies showing hepatic infiltration of CD8-positive T cells in the setting of extrahepatic infections such as influenza virus and severe acute respiratory syndrome. Diabetic liver lesions include glycogenic hepatopathy (in which poor diabetic control leads to swollen, glycogen-filled hepatocytes without fat, steatohepatitis or fibrosis) and diabetic hepatosclerosis in which there is diffuse perisinusoidal fibrosis (type IV collagen) without zonal predilection. Ground-glass hepatocellular inclusions (positive with periodic acid-Schiff stain for glycogen) were reported in three separate series of patients who were hepatitis B virus-negative, often transplant recipients, immunosuppressed and on multiple medications. A Banff consensus paper expertly compared and contrasted the histologic features which characterize the various causes of late liver allograft dysfunction.

SUMMARY

Informative papers emerged this past year concerning collateral damage to the liver in extrahepatic infections, diabetic lesions and causes of liver dysfunction after transplantation, among other topics.

Telomere shortening and inactivation of cell cycle checkpoints characterize human hepatocarcinogenesis

Telomere shortening and inactivation of cell cycle checkpoints characterize carcinogenesis. Whether these molecular features coincide at specific stages of human hepatocarcinogenesis is unknown. The preneoplasia-carcinoma sequence of human HCC is not well defined. Small cell changes (SCC) and large cell changes (LCC) are potential precursor lesions. We analyzed hepatocellular telomere length, the prevalence of DNA damage, and the expression of p21 and p16 in biopsy specimens of patients with chronic liver disease (n = 27) that showed different precursor lesions and/or HCC: liver cirrhosis (n = 25), LCC (n = 26), SCC (n = 13), and HCC (n = 13). The study shows a decrease in telomere length in nondysplastic cirrhotic liver compared with normal liver and a further significant shortening of telomeres in LCC, SCC, and HCC. HCC had the shortest telomeres, followed by SCC and LCC. Hepatocytes showed an increased p21 labeling index (p21-LI) at the cirrhosis stage, which remained elevated in most LCC. In contrast, most SCC and HCC showed a strongly reduced p21-LI. Similarly, p16 was strongly expressed in LCC but reduced in SCC and not detectable in HCC. gammaH2AX-DNA-damage-foci were not detected in LCC but were present in SCC and more frequently in HCC. These data indicate that LCC and SCC represent clonal expansions of hepatocytes with shortened telomeres.

CONCLUSION

The inactivation of cell cycle checkpoints coincides with further telomere shortening and an accumulation of DNA damage in SCC and HCC, suggesting that SCC represent more advanced precursor lesions compared with LCC.