Is histological diagnosis of primary liver carcinomas with fibrous stroma reproducible among experts?

AIMS: In the era of targeted therapeutics, histological typing of hepatobiliary carcinomas has major clinical implications. Little is known about the reproducibility of the pathological diagnosis of primary liver carcinomas. Therefore, this study aimed to evaluate the worldwide variation in the pathological expert diagnoses of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis. METHODS: A single set of slides was selected from 25 tumours, and this set was reviewed independently by 12 pathologists who have worldwide expertise in liver tumours. Reproducibility of the diagnoses was evaluated by Light's kappa, and diagnoses were clustered by multidimensional scaling. Immunohistochemistry was performed after histological review. RESULTS: The interobserver reproducibility for diagnosis of hepatocellular carcinoma subtypes and cholangiocarcinomas was poor (kappa 0.23-0.52), even when the experts considered that the diagnosis required no additional stains or clinical information. Interestingly, multidimensional scaling revealed three main clusters of tumours: hepatocellular carcinoma with no other specifications (n = 13), fibrolamellar hepatocellular carcinoma (n = 3) and cholangiocarcinoma (n = 9). Using immunohistochemistry, these histological clusters correlated with expression of anti-hepatocyte and anti-cytokeratin 19 (p<0.001). CONCLUSIONS: The results demonstrate the poor reproducibility among experts of the pathological diagnosis of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis, and highlight that the systematic use of immunohistochemistry may improve the diagnostic accuracy.

Expression of matrix metalloproteinase-2 and -9 and of tissue inhibitor of matrix metalloproteinase-1 in liver regeneration from oval cells in rat.

Oval cells participate in liver regeneration when hepatocyte replication is impaired. These precursor cells proliferate in periportal regions and organize in ductules. They are surrounded by a basement membrane, the degradation of which by matrix metalloproteinases (MMP) might trigger their terminal differentiation into hepatocytes. We studied the expression of MMP-2 and MMP-9 and that of one of their tissue inhibitors (TIMP-1) in a model of hepatic regeneration from precursor cells. Regeneration was induced by treating rats with 2-acetylaminofluorene followed by partial hepatectomy. MMP-2 and MMP-9 hepatic expression paralleled oval cell number with a peak at day 9-14 after hepatectomy. They were mainly detected in oval cells. TIMP-1 mRNA and oncostatin M receptor mRNA, a major regulator of TIMP-1 synthesis, markedly increased from day 1 after surgery until day 9 and then declined; they were mainly detected in interlobular bile duct cells and oval cells until day 14. In agreement with the in vivo data, the WB-F344 liver precursor cell line expressed MMP-2 and MMP-9, as well as TIMP-1 and oncostatin M receptor. These data suggest that (a) early increased TIMP-1 synthesis by biliary and oval cells favors basement membrane deposition around proliferating ductular structures through MMP inhibition, (b) delayed increased MMP expression, concomitant to decreased TIMP-1 synthesis, leads to basement membrane degradation, preceding oval cell differentiation, (c) the oncostatin M pathway might play a major role in increased TIMP-1 synthesis.

Different mechanisms of steatosis in hepatitis C virus genotypes 1 and 3 infections.

This study reports evidence that hepatocellular steatosis, a frequent histological feature of chronic hepatitis C, is principally metabolic in hepatitis C virus (HCV) genotype 1-infected patients, whereas it is principally virus-induced in HCV genotype 3-infected patients. Multivariate analysis of data on 176 patients with chronic hepatitis C revealed that the severity of steatosis was independently related to HCV RNA load alone in patients infected by HCV genotype 3, whereas it was independently related to the body mass index, daily alcohol intake and histological activity grade (but not viral load) in patients infected by HCV genotype 1. These findings suggest that steatosis is a cytopathic lesion induced by HCV genotype 3, whereas HCV genotype 1 is not steatogenic per se or at the usual in vivo expression levels.

Effect of antiviral treatment on evolution of liver steatosis in patients with chronic hepatitis C: indirect evidence of a role of hepatitis C virus genotype 3 in steatosis.

BACKGROUND AND AIM: Recent studies suggest that liver steatosis in chronic hepatitis C may be the expression of a direct cytopathic effect of hepatitis C virus (HCV), particularly in patients infected with genotype 3. To investigate this hypothesis, we studied the relationship between steatosis evolution and HCV clearance after antiviral treatment in patients with chronic hepatitis C and paired liver biopsies. METHODS: A total of 151 patients (37 with HCV genotype 3; 114 with HCV non-3 genotypes) were selected according to the following criteria: presence of steatosis at initial biopsy; no antiviral treatment prior to the first biopsy; antiviral treatment received between the two biopsies; body mass index (BMI) <28 kg/m(2); absence of excessive alcohol intake; no serum hepatitis B surface antigen or human immunodeficiency virus antibodies; and absence of diabetes mellitus. Evolution of steatosis was examined by comparing steatosis grades between the two biopsies. RESULTS: Twenty five patients (16.5%) were sustained virological responders (SVR) to antiviral treatment. Steatosis evolution after antiviral treatment was as follows: improvement in 36% of cases; stability in 51%; and worsening in 13%. Steatosis improvement was significantly more frequent in SVR than in non-responders (NR) (64% v 31%; p<0.004). This significant difference occurred in patients infected with genotype 3 (91% v 19%; p<0.0001) but not in those infected with non-3 genotypes (43% v 34%; NS). Among the 25 SVR, improvement in steatosis was significantly more frequent in patients infected with genotype 3 than in those infected with non-3 genotypes (91% v 43%; p<0.04) whereas in NR, improvement in steatosis did not differ between those infected with genotype 3 and non-3 genotypes (19% v 34%; NS). In multivariate analysis, four factors were independently associated with steatosis improvement: sustained virological response to antiviral therapy (odds ratio (OR) 6.06 (95% confidence interval (CI) 1.61-22.9); p = 0.01), severe steatosis (OR 5.50 (95% CI 1.54-19.6); p = 0.01), HCV genotype 3 (OR 2.90 (95% CI 0.85-10.0); p = 0.07), and BMI >25 kg/m(2) (OR 0.24 (95% CI 0.08-0.73); p = 0.02). CONCLUSIONS: Our results showed significant improvement in steatosis in patients infected with HCV genotype 3, who achieved sustained viral clearance. This provides further evidence for direct involvement of HCV genotype 3 in the pathogenesis of hepatic steatosis.

Impact of moderate alcohol consumption on histological activity and fibrosis in patients with chronic hepatitis C, and specific influence of steatosis: a prospective study.

AIM: To evaluate the effects of minimal to moderate alcohol consumption on the severity of histological lesions in patients with chronic hepatitis C. METHODS: Daily alcohol intake (none, 1-20, 21-30, 31-50 g/day) and histological activity and fibrosis were recorded in 260 patients with chronic hepatitis C. RESULTS: The proportion of patients with moderate (A2) or marked (A3) activity increased gradually from 53.8% in abstinent patients to 86.5% for an intake between 31 and 50 g/day (P = 0.003). In multivariate analysis, age > 40 years, alcohol intake between 31 and 50 g/day and moderate or severe steatosis were independently related to histological activity. The proportion of patients with moderate (F2) or marked (F3) fibrosis or cirrhosis (F4) gradually increased from 29.0% in abstinent patients to 67.6% for an intake between 31 and 50 g/day (P < 0.001). Multivariate analysis also showed that alcohol intake between 31 and 50 g/day, moderate or severe steatosis and histological activity were independently related to fibrosis. The deleterious effect of alcohol intake on histological lesions differed according to gender. CONCLUSIONS: This study demonstrates that both activity and fibrosis gradually increase according to the amount of alcohol ingested, and that even moderate alcohol consumption, as low as 31-50 g/day in men and 21-50 g/day in women, may aggravate histological lesions in patients with chronic hepatitis C.

Worsening of steatosis is an independent factor of fibrosis progression in untreated patients with chronic hepatitis C and paired liver biopsies.

BACKGROUND AND AIMS: Steatosis, a frequent histological finding in patients with chronic hepatitis C (CHC), has been suggested to influence liver fibrosis progression. The aim of the present study was to evaluate in patients with CHC and paired liver biopsies the relationship between the evolution of steatosis and that of fibrosis between the two biopsies. METHODS: Ninety six patients were selected according to the following criteria: absence of treatment; absence of cirrhosis at initial biopsy; and serum hepatitis B surface antigen and human immunodeficiency virus antibody negativity. Degrees of necroinflammatory activity, fibrosis, and steatosis grades were assessed in the two biopsies. In addition to histological lesions, parameters studied included the source of infection, duration of infection, body mass index, alcohol intake, alanine aminotransferase levels, hepatitis C virus genotype, and viral load. RESULTS: The mean interval between the two biopsies was 48 (32) months. Steatosis was found in 54% of patients at first biopsy, and was severe in 9%. Worsening of steatosis was observed in 34% of patients, stability in 50%, and improvement in 16%. Worsening of steatosis was significantly associated with hepatic fibrosis progression in patients with (p=0.03) or without (p<0.03) steatosis at diagnosis. Overall, fibrosis progression was observed in 31% of patients and stability in 69%. In a univariate analysis, fibrosis progression was associated with male sex (p=0.05), worsening of histological activity (p=0.04), and worsening of steatosis (p=0.0003). In a multivariate analysis, the only factor independently associated with fibrosis progression was worsening of steatosis (worsening v improvement/stability: odds ratio 4.7 (95% confidence interval 1.3-10.8); p=0.0001). CONCLUSIONS: Our results suggest that in untreated patients with CHC and serial liver biopsies, fibrosis progression is strongly associated with worsening of steatosis.

Impact of smoking on histological liver lesions in chronic hepatitis C.

AIMS AND METHODS: To examine the association between smoking and histological liver lesions in chronic hepatitis C, we studied 244 consecutive patients (152 men, 92 women; mean age 45.9 (12.6) years) with histologically proven chronic hepatitis C. Daily tobacco consumption during the six months preceding liver biopsy was recorded as the number of cigarettes smoked daily. Total lifetime tobacco consumption was recorded as the number of cigarette packs smoked per year (packs-years). Liver biopsy specimens were graded for histological activity and fibrosis according to the METAVIR scoring system. RESULTS: The proportion of patients with moderate (A2) or marked (A3) activity increased gradually from 62.0% in non-smokers to 81.7% in patients who smoked more than 15 cigarettes per day (p<0.009). A similar relationship was observed with total lifetime tobacco consumption: 59.0% of patients who had never smoked had grade A2 or A3 disease activity compared with 84.6% of patients who smoked more than 20 packs per year (p<0.002). Multivariate analysis showed that age over 50 years (odds ratio (OR) 5.4), alcohol intake exceeding 20 g/day (OR 2.75), and tobacco consumption of more than 15 cigarettes/day (OR 3.6) were independently related to the histological activity score. No relationship was found between the severity of fibrosis and either daily tobacco consumption or total lifetime tobacco consumption. Multivariate analysis showed that only age over 50 years (OR 8.8), daily alcohol intake exceeding 30 g/day (OR 3.4), and histological activity score (OR 7.9) were independently related to the fibrosis score. CONCLUSION: This study suggests that smoking, independent of alcohol, could aggravate the histological activity of chronic hepatitis C and that patients with chronic hepatitis C virus infection should be advised to reduce or stop smoking.

Focal nodular hyperplasia of the liver in men: is presentation the same in men and women?

BACKGROUND: Focal nodular hyperplasia (FNH) of the liver is a benign hepatic lesion relatively common in women. No studies specifically designed to describe the presentation and imaging findings in males have been published. AIMS: The aims of this study were: (a) to describe the clinical and imaging findings in 18 men with FNH, and (b) to compare these data with those observed in 216 women with FNH observed during the same nine year period. PATIENTS AND METHODS: According to a final diagnosis of FNH assessed either by pathological examination or by magnetic resonance (MR), the medical charts of 18 men with FNH observed at our institution were reviewed. In order to compare clinical and MR presentations, the files of 216 women with a total of 291 FNH lesions, investigated during the same nine year period, were reviewed. RESULTS: Eighteen FNH lesions, with a mean diameter of 37.5 mm, were demonstrated in the 18 male patients. A total of 291 lesions with a mean diameter of 63.4 mm were comparatively demonstrated in 216 female patients. Mean age at diagnosis was significantly higher in men (p<0.01) and mean FNH size was significantly smaller in men (p<0.001). Surgery was more frequently performed in men (72.2%) than in women (16.7%) (p<0.001). CONCLUSIONS: Our data indicate that FNH is rare in men and that the lesions are smaller and more often atypical than those in women.

p15(INK4b) in bladder carcinomas: decreased expression in superficial tumours.

The p15 gene which encodes a cyclin-dependent kinase inhibitor, is located in the 9p21 chromosomal region that is frequently deleted in human bladder transitional cell carcinomas (TCCs). The aim of the present paper is to study the potential involvement of the p15 gene in the evolution of TCCs. p15 mRNA expression was investigated by semi-quantitative RT-PCR in a series of 75 TCCs, 13 bladder cell lines and 6 normal bladder urothelia by semi-quantitative RT-PCR. p15 was expressed in the normal urothelium but p15 mRNA levels were significantly decreased in 66% of the superficial (Ta-T1) TCCs (P = 0.0015). In contrast, in muscle-invasive (T2-T4) TCCs, p15 expression differed widely between samples. p16 mRNA levels were also studied and there was no correlation between p15 and p16 mRNA levels, thus indicating that the two genes were regulated independently. Lower p15 expression in superficial tumours did not reflect a switch from quiescence to proliferative activity as normal proliferative urothelial controls did not present decreased p15 mRNA levels relative to quiescent normal urothelia. We further investigated the mechanisms underlying p15 down regulation. Homozygous deletions of the p15 gene, also involving the contiguous p16 gene, were observed in 42% of the TCCs with decreased p15 expression. No hypermethylation at multiple methylation-sensitive restriction sites in the 5;-CpG island of p15 was encountered in the remaining tumours. Our data suggest that decreased expression of p15 may be an important step in early neoplastic transformation of the urothelium and that a mechanism other than homozygous deletions or hypermethylation, may be involved in p15 down regulation.

Frequent FGFR3 mutations in papillary non-invasive bladder (pTa) tumors.

We recently identified activating mutations of fibroblast growth factor receptor 3 (FGFR3) in bladder carcinoma. In this study we assessed the incidence of FGFR3 mutations in a series of 132 bladder carcinomas: 20 carcinoma in situ (CIS), 50 pTa, 19 pT1, and 43 pT2-4. All 48 mutations identified were identical to the germinal activating mutations that cause thanatophoric dysplasia, a lethal form of dwarfism. The S249C mutation, found in 33 of the 48 mutated tumors, was the most common. The frequency of mutations was higher in pTa tumors (37 of 50, 74%) than in CIS (0 of 20, 0%; P < 0.0001), pT1 (4 of 19, 21%; P < 0.0001) and pT2-4 tumors (7 of 43, 16%; P < 0.0001). FGFR3 mutations were detected in 27 of 32 (84%) G1, 16 of 29 (55%) G2, and 5 of 71 (7%) G3 tumors. This association between FGFR3 mutations and low grade was highly significant (P < 0.0001). FGFR3 is the first gene found to be mutated at a high frequency in pTa tumors. The absence of FGFR3 mutations in CIS and the low frequency of FGFR3 mutations in pT1 and pT2-4 tumors are consistent with the model of bladder tumor progression in which the most common precursor of pT1 and pT2-4 tumors is CIS.

[Diagnosis and histologic surveillance of hepatitis C]. / Diagnostic et surveillance histologiques de l'hépatite C.

The role of liver biopsy in hepatitis C viral infection is diagnostic and prognostic. It states diagnoses of chronic hepatitis, cirrhosis and hepatocellular carcinoma. The association of portal lymphoid nodules, inflammatory bile duct lesions and steatosis suggests an hepatitis C viral etiology. Liver biopsy allows grading (extent of necro-inflammatory lesions) and staging (amount of fibrosis) of the disease using scoring systems proposed by Knodell et al. and (or) by METAVIR group. It can be helpful in confirming (or refuting) the presence of secondary diagnoses such as alcohol-induce liver disease or haemochromatosis and in assessing the efficacy of antiviral treatments.

Randomized trial of interferon-alpha plus ursodeoxycholic acid versus interferon plus placebo in patients with chronic hepatitis C resistant to interferon.

BACKGROUND: Ursodeoxycholic acid (UDCA) could potentiate the effect of interferon (IFN) in patients with chronic hepatitis C resistant to IFN. We compared the efficacy of IFN with that of a combination of IFN and UDCA. METHODS: Patients were randomized to receive UDCA (13-15 mg/kg/day) (n = 47) or placebo (n = 44) plus interferon (3 MU three times weekly) for 6 months and were then followed up for 6 additional months. RESULTS: At entry 30% of patients had cirrhosis, and 70% had HCV genotype 1. Five and four patients withdrew from the combination and the monotherapy groups, respectively. At 6 months alanine aminotransferase (ALAT) and gamma-glutamyl transferase (GGT) activities were significantly lower (P < 0.001) in the combination group than in the monotherapy group; the differences were no longer significant at 1 year. At 6 months ALAT activities normalized in 10 and 8 patients in the combination and the monotherapy groups, respectively (P = 0.67). In 10 of them (5 in each group) HCV RNA levels became undetectable. At 1 year four versus one patient had a sustained normalization of ALAT, and in one patient the HCV RNA became negative. There was no difference in the histologic progression. In this setting, in contrast to chronic cholestasis, UDCA administration induced an increase in total serum bile acids and did not change primary bile acids. CONCLUSIONS: An IFN plus UDCA combination is more effective than IFN alone in terms of ALAT but not in terms of the virologic response. These results favor the hypothesis that UDCA has an effect on the biochemical indices of cellular injury independent of a change in primary bile acids.

Declining autopsy rate in a French hospital: physician's attitudes to the autopsy and use of autopsy material in research publications.

CONTEXT: Autopsy rates have been declining throughout the world, although preservation of the autopsy is considered a fundamental principle of medical care. In France, the 1994 bioethics law requires physicians to inform relatives before performing an autopsy. OBJECTIVE: To analyze the following factors that potentially influence hospital autopsy rates: legal constraints, autopsy reporting times, opinions of physicians requesting autopsies and pathologists regarding the usefulness of autopsy in patient care, and use of autopsy material in research publications. DESIGN: Record of the annual numbers of deaths and autopsies during a 10-year period (1988-1997). Record of the delays for transmission of final autopsy report to the requesting physician. Questionnaire analyzing the possible factors influencing autopsy rate. Categorization of articles published by pathologists according to the use of autopsy material. SETTING: A 1000-bed, university teaching hospital in the Paris, France, area. PARTICIPANTS: Questionnaire addressed to physicians, head nurses, and mortuary staff. RESULTS: A total of 1454 autopsies were reviewed. The autopsy rate declined from 15.4% in 1988 to 3.7% in 1997. This decline was marked after 1994 and tended to be slower for neurologic indications than for other indications. The final report had not been communicated within 180 days in 620 (42.6%) of 1454 autopsies. Fifty-five of 105 respondents considered that the bioethics law was one cause of the recent decrease of autopsy rate. Considering the contribution of autopsy to medical research, 94 (81%) of 116 articles dealing with central nervous system but only 28 (6%) of 464 articles dealing with other organs used autopsy-derived material. CONCLUSIONS: The 1994 bioethics law seems to contribute to the decline of autopsy. Inadequate delays for communicating autopsy results are frequent. Except for neuropathologists, autopsy is a minor source of research material.

Oral contraceptive use and focal nodular hyperplasia of the liver.

BACKGROUND & AIMS: Because most patients with focal nodular hyperplasia (FNH) are young women, an important decision is whether to discontinue oral contraceptive (OC) use. The aims of this study were to evaluate (1) the number and size of FNH lesions in women with various patterns of OC use and in women without OC use and (2) the modifications in the number and size of FNH lesions during follow-up, according to OC use. METHODS: In a 9-year study in 216 women with FNH, the diameter and number of lesions documented by magnetic resonance (MR) imaging were evaluated (1) at diagnosis according to OC use as follows: group A, no OC use (n = 28); group B, high-dose OC use (n = 46); group C, low-dose OC use (n = 98); group D, successive use of high-dose and low-dose OCs (n = 33); and group E, use of progestogens only (n = 11); and (2) during follow-up in 136 women, 14 of whom were OC nonusers who stayed off OCs, 89 discontinued OC use, 26 took low-dose OCs, and 7 stayed on a progestogen only. Twelve women became pregnant. In 168 women, the diagnosis of FNH was made based on a combination of rigorously defined MR criteria. In the remaining 48 patients, diagnosis was by surgical biopsy (n = 36) or resection (n = 12). Mean diameter and number of lesion(s) per patient were assessed by MR imaging using the same protocol in all study patients. RESULTS: No significant differences in the number or size of lesions were found in the 5 patient groups. During follow-up, a change in lesion diameter occurred in only 4 women; this event was not influenced by OC use. In the 12 patients who became pregnant, lesion size was unchanged after delivery, pregnancy was uneventful, and delivery occurred spontaneously. CONCLUSIONS: These data suggest that (1) neither the size nor the number of FNH lesions are influenced by OC use; (2) size changes during follow-up are rare and do not seem to depend on OC use; and (3) pregnancy is not associated with FNH changes or complications.

[Auxiliary hepatic transplantation in iproniazid-induced subfulminant hepatitis. Should iproniazid still be sold in France?]. / Transplantation hépatique auxiliaire pour hépatite subfulminante à l'iproniazide. Doit-on maintenir la commercialisation de l'iproniazide en France?

We report a new case of subfulminant hepatitis due to iproniazid, a MAO-inhibitor antidepressant, in a 27-year-old man. An auxiliary liver transplantation was performed. Liver function returned to normal and the patient was discharged from the hospital. However, the patient's native liver did not regenerate, and immunosuppressive therapy had to be maintained. Iproniazid hepatotoxicity is characterized by jaundice in 1% of cases, with a fulminant or subfulminant course in 20% of icteric patients. Although iproniazid is no longer sold in most countries, it is still commercialized in France. Because of the frequency and severity of hepatic injury, commercialization of iproniazid in France should no longer be authorized.

Liver iron accumulation in patients with chronic active hepatitis C: prevalence and role of hemochromatosis gene mutations and relationship with hepatic histological lesions.

BACKGROUND/AIMS: Liver iron accumulation has been described in patients with chronic active hepatitis (CAH) C, and could play a role in the course of liver disease and negatively influence the response to interferon. The aim of this study was to determine the prevalence and severity of liver iron accumulation in CAH C, to assess its relationship with the HFE C282Y and H63D mutations, and to study its interactions with hepatic histological lesions. METHODS: Two hundred and nine patients (131 men, 78 women, mean age 44.3+/-12.0 years) with CAH C, including 19 patients with cirrhosis (9.1%) were studied. A semiquantitative grading system from 0 to 3 was used for histological assessment of liver iron accumulation on Perls' staining. The HFE C282Y and H63D mutations were screened for by restriction enzyme analysis performed on PCR-amplified products. Histological scores of activity and fibrosis were determined according to a previously validated METAVIR score system. RESULTS: Liver iron accumulation was found in 88/209 patients (42.1%), and was generally mild. The C282Y and H63D allele frequencies were in 23 (11.0%), and 50 (23.9%), respectively. No association was found between the presence of liver iron accumulation and the detection of the C282Y and H63D mutations. A significant relationship was found between the severity of histological activity and liver iron accumulation of macrophagic or mixed (i.e. both macrophagic and hepatocytic) type (p = 0.04). Although the number of cirrhotic patients was small, cirrhosis was more frequently observed in patients with than without liver iron accumulation (17.2% vs. 3.3%, p = 0.004). CONCLUSIONS: Overall, these data suggest that the liver iron accumulation in patients with CAH C is significantly associated with histological activity and cirrhosis, whereas the two missense hemochromatosis gene mutations are not major determinants.

Nuclear accumulation of mutated beta-catenin in hepatocellular carcinoma is associated with increased cell proliferation.

Inappropriate activation of the Wnt pathway resulting from beta-catenin gene alterations has recently been implicated in the development of hepatocellular carcinoma (HCC). To explore the in vivo effects of mutated beta-catenin, HCC specimens from 32 patients carrying one or several tumors were screened for somatic mutations in exon 3 of the beta-catenin gene, and the expression and subcellular localization of beta-catenin was studied by immunohistochemistry. Missense mutations or interstitial deletions in beta-catenin exon 3 were detected in 12 of 35 (34%) HCC samples. After immunostaining, most tumors exhibited increased membranous and/or cytoplasmic expression of beta-catenin compared with adjacent nontumoral liver. Strong nuclear accumulation of beta-catenin was observed either focally or uniformly in 15 of 35 (43%) tumor specimens, but not in cirrhotic nodules or dysplastic liver cells in adjacent liver. Aberrant nuclear expression of beta-catenin was significantly associated with the presence of mutations in the beta-catenin gene (P < 0.005). Moreover, nuclear beta-catenin staining correlated significantly with increased Ki-67 proliferative index in tumor (P < 0.001) and seemed to be associated with poor outcome in patients with HCC. In conclusion, our data indicate that activation of the Wnt/beta-catenin pathway in HCC results mainly from somatic mutations in the beta-catenin gene and may promote tumor progression by stimulating tumor cell proliferation.