Jeanne Tran Van Nhieu

Genotype–phenotype correlation in hepatocellular adenoma: New classification and relationship with HCC

Hepatocellular adenomas are benign tumors that can be difficult to diagnose. To refine their classification, we performed a comprehensive analysis of their genetic, pathological, and clinical features. A multicentric series of 96 liver tumors with a firm or possible diagnosis of hepatocellular adenoma was reviewed by liver pathologists. In all cases, the genes coding for hepatocyte nuclear factor 1α (HNF1α) and β‐catenin were sequenced. No tumors were mutated in both HNF1α and β‐catenin enabling tumors to be classified into 3 groups, according to genotype. Tumors with HNF1α mutations formed the most important group of adenomas (44 cases). They were phenotypically characterized by marked steatosis (P < 10−4), lack of cytological abnormalities (P < 10−6), and no inflammatory infiltrates (P < 10−4). In contrast, the group of tumors defined by β‐catenin activation included 13 lesions with frequent cytological abnormalities and pseudo‐glandular formation (P < 10−5). The third group of tumors without mutation was divided into two subgroups based on the presence of inflammatory infiltrates. The subgroup of tumors consisting of 17 inflammatory lesions, resembled telangiectatic focal nodular hyperplasias, with frequent cytological abnormalities (P = 10−3), ductular reaction (P < 10−2), and dystrophic vessels (P = .02). In this classification, hepatocellular carcinoma associated with adenoma or borderline lesions between carcinoma and adenoma is found in 46% of the β‐catenin–mutated tumors whereas they are never observed in inflammatory lesions and are rarely found in HNF1α mutated tumors (P = .004). In conclusion, the molecular and pathological classification of hepatocellular adenomas permits the identification of strong genotype–phenotype correlations and suggests that adenomas with β‐catenin activation have a higher risk of malignant transformation. (HEPATOLOGY 2006;43:515–524.)

Liver Cirrhosis: Intravoxel Incoherent Motion MR Imaging—Pilot Study

PURPOSE To retrospectively evaluate a respiratory-triggered diffusion-weighted (DW) magnetic resonance (MR) imaging sequence combined with parallel acquisition to allow the calculation of pure molecular-based (D) and perfusion-related (D*, f) diffusion parameters, on the basis of the intravoxel incoherent motion (IVIM) theory, to determine if these parameters differ between patients with cirrhosis and patients without liver fibrosis. MATERIALS AND METHODS The institutional review board approved this retrospective study; informed consent was waived. IVIM DW imaging was tested on three alkane phantoms, on which the signal-intensity decay curves according to b factors were logarithmically plotted. Ten b factors (0, 10, 20, 30, 50, 80, 100, 200, 400, 800 sec/mm(2)) were used in patients. Patients with documented liver cirrhosis (cirrhotic liver group, n = 12) and patients without chronic liver disease (healthy liver group, n = 25) were included. The mean liver D, D*, and f values were measured and compared with the apparent diffusion coefficient (ADC) computed by using four b values (0, 200, 400, 800 sec/mm(2)). Liver ADC and D, f, and D* parameters were compared between the cirrhotic liver group and healthy liver group. Means were compared by using the Student t test. RESULTS Signal-intensity decay curves were monoexponential on phantoms and biexponential in patients. In vivo, mean ADC values were significantly higher than D in the healthy liver group (ADC = 1.39 x 10(-3) mm(2)/sec +/- 0.2 [standard deviation] vs D = 1.10 x 10(-3) mm(2)/sec +/- 0.7) and in the cirrhotic liver group (ADC = 1.23 x 10(-3) mm(2)/sec +/- 0.4 vs D = 1.19 x 10(-3) mm(2)/sec +/- 0.5) (P = .03). ADC and D* were significantly reduced in the cirrhotic liver group compared with those in the healthy liver group (respective P values of .03 and .008). CONCLUSION Restricted diffusion observed in patients with cirrhosis may be related to D* variations, which reflect decreased perfusion, as well as alterations in pure molecular water diffusion in cirrhotic livers.

CB1 cannabinoid receptor antagonism: a new strategy for the treatment of liver fibrosis.

Hepatic fibrosis, the common response associated with chronic liver diseases, ultimately leads to cirrhosis, a major public health problem worldwide. We recently showed that activation of hepatic cannabinoid CB2 receptors limits progression of experimental liver fibrosis. We also found that during the course of chronic hepatitis C, daily cannabis use is an independent predictor of fibrosis progression. Overall, these results suggest that endocannabinoids may drive both CB2-mediated antifibrogenic effects and CB2-independent profibrogenic effects. Here we investigated whether activation of cannabinoid CB1 receptors (encoded by Cnr1) promotes progression of fibrosis. CB1 receptors were highly induced in human cirrhotic samples and in liver fibrogenic cells. Treatment with the CB1 receptor antagonist SR141716A decreased the wound-healing response to acute liver injury and inhibited progression of fibrosis in three models of chronic liver injury. We saw similar changes in Cnr1−/− mice as compared to wild-type mice. Genetic or pharmacological inactivation of CB1 receptors decreased fibrogenesis by lowering hepatic transforming growth factor (TGF)-β1 and reducing accumulation of fibrogenic cells in the liver after apoptosis and growth inhibition of hepatic myofibroblasts. In conclusion, our study shows that CB1 receptor antagonists hold promise for the treatment of liver fibrosis.

Microbial dysbiosis in colorectal cancer (CRC) patients.

The composition of the human intestinal microbiota is linked to health status. The aim was to analyze the microbiota of normal and colon cancer patients in order to establish cancer-related dysbiosis. Patients and Methods Stool bacterial DNA was extracted prior to colonoscopy from 179 patients: 60 with colorectal cancer, and 119 with normal colonoscopy. Bacterial genes obtained by pyrosequencing of 12 stool samples (6 Normal and 6 Cancer) were subjected to a validated Principal Component Analysis (PCA) test. The dominant and subdominant bacterial population (C. leptum, C. coccoides, Bacteroides/Prevotella, Lactobacillus/Leuconostoc/Pediococcus groups, Bifidobacterium genus, and E. coli, and Faecalibacterium prausnitzii species) were quantified in all individuals using qPCR and specific IL17 producer cells in the intestinal mucosa were characterized using immunohistochemistry. Findings Pyrosequencing (Minimal sequence 200 nucleotide reads) revealed 80% of all sequences could be assigned to a total of 819 taxa based on default parameter of Classifier software. The phylogenetic core in Cancer individuals was different from that in Normal individuals according to the PCA analysis, with trends towards differences in the dominant and subdominant families of bacteria. Consequently, All-bacteria [log10 (bacteria/g of stool)] in Normal, and Cancer individuals were similar [11.88±0.35, and 11.80±0.56, respectively, (P = 0.16)], according to qPCR values whereas among all dominant and subdominant species only those of Bacteroides/Prevotella were higher (All bacteria-specific bacterium; P = 0.009) in Cancer (-1.04±0.55) than in Normal (-1.40±0.83) individuals. IL17 immunoreactive cells were significantly expressed more in the normal mucosa of cancer patients than in those with normal colonoscopy. Conclusion This is the first large series to demonstrate a composition change in the microbiota of colon cancer patients with possible impact on mucosal immune response. These data open new filed for mass screening and pathophysiology investigations.

Characteristics of patients with dual infection by hepatitis B and C viruses

BACKGROUND/AIMS The purpose of this study was to compare the epidemiological, biochemical, virological and histological characteristics of patients with chronic hepatitis B and C with those of patients suffering from chronic hepatitis C alone. METHODS Twenty-three patients with chronic hepatitis C, who were anti-HCV positive and HBs antigen positive, were studied and subdivided into two groups according to the presence or absence of HBV DNA replication. They were compared to 69 age- and sex-matched patients with chronic hepatitis who were anti-HCV positive and HBs antigen negative. All patients were HCV RNA positive by PCR, anti-HIV negative and anti-HDV negative. HBV DNA and HCV RNA were detected in serum by means of a branched DNA assay and PCR. The HCV serotypes were determined by the Chiron Riba HCV serotyping SIA technique. The histological characteristics included the Knodell score. RESULTS Epidemiological, biochemical and virological parameters were not different between the two groups. Only the prevalence of cirrhosis was greater in chronic hepatitis B and C patients than in patients with chronic hepatitis C alone (p = 0.01). Among chronic hepatitis B and C patients, HCV RNA level was significantly lower in HBV DNA positive than in HBV DNA negative patients (p = 0.01). Indeed, histological lesions were more severe in HBV DNA positive than in HBV DNA negative patients, including prevalence of cirrhosis (p = 0.01), Knodell score (p = 0.05) and, among the latter, piecemeal necrosis (p = 0.01) and fibrosis (p = 0.05). The characteristics of patients with dual infection did not differ according to the mode of contamination and duration of HBV disease, except for a shorter duration in patients contaminated by drug abuse than in other patients. CONCLUSIONS These results suggest that HBV DNA replication inhibits HCV RNA replication in patients with chronic active hepatitis B and C but increases the severity of histological lesions.

Laparoscopic Liver Resection for Peripheral Hepatocellular Carcinoma in Patients With Chronic Liver Disease: Midterm Results and Perspectives

Objective:Report the midterm results of laparoscopic resection for hepatocellular in chronic liver disease (CLD). Summary Background Data:Surgical resection for hepatocellular carcinoma (HCC) in chronic liver disease (CLD) remains controversial because of high morbidity and recurrence rates. Laparoscopic resection of liver tumors has recently been developed and could reduce morbidity. Methods:From 1998 to 2003, patients with HCC and CLD were considered for laparoscopic liver resection. Inclusion criteria were chronic hepatitis or Childs A cirrhosis, solitary tumor ≤5 cm in size, and location in peripheral segments of the liver. Mortality, morbidity, recurrence rates, and survival were analyzed. Results:A total of 27 patients were included. Liver resections included anatomic resection in 17 cases and non anatomic resection in 10. Seven conversions to laparotomy (26%) occurred for moderate hemorrhage in 5 cases and technical difficulties in 2 cases. Mortality and morbidity rates were 0% and 33%, respectively. Postoperative ascites and encephalopathy occurred in 2 patients (7%) who both had undergone conversion to laparotomy. Mean surgical margin was 11 mm (range, 1–47 mm). After a mean follow-up of 2 years (range, 1.1–4.7), 8 patients (30%) developed intrahepatic tumor recurrence of which one died. Treatment of recurrence was possible in 4 patients (50%), including orthotopic liver transplantation, right hepatectomy, radiofrequency ablation, and chemoembolization in 1 case each. There were no adhesions in the 2 reoperated patients. Overall and disease-free 3-year survival rates were 93% and 64%, respectively. Conclusion:Our study shows that laparoscopic liver resection for HCC in selected patients is a safe procedure with very good midterm results. This approach could have an impact on the therapeutic strategy of HCC complicating CLD as a treatment with curative intent or as a bridge to liver transplantation.

Nuclear Accumulation of Mutated β-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.

Potential of fecal microbiota for early-stage detection of colorectal cancer

Several bacterial species have been implicated in the development of colorectal carcinoma (CRC), but CRC‐associated changes of fecal microbiota and their potential for cancer screening remain to be explored. Here, we used metagenomic sequencing of fecal samples to identify taxonomic markers that distinguished CRC patients from tumor‐free controls in a study population of 156 participants. Accuracy of metagenomic CRC detection was similar to the standard fecal occult blood test (FOBT) and when both approaches were combined, sensitivity improved > 45% relative to the FOBT, while maintaining its specificity. Accuracy of metagenomic CRC detection did not differ significantly between early‐ and late‐stage cancer and could be validated in independent patient and control populations (N = 335) from different countries. CRC‐associated changes in the fecal microbiome at least partially reflected microbial community composition at the tumor itself, indicating that observed gene pool differences may reveal tumor‐related host–microbe interactions. Indeed, we deduced a metabolic shift from fiber degradation in controls to utilization of host carbohydrates and amino acids in CRC patients, accompanied by an increase of lipopolysaccharide metabolism.

Liver resection for transplantable hepatocellular carcinoma: long-term survival and role of secondary liver transplantation.

Background/Purpose:Liver transplantation (LT) is the best theoretical treatment of hepatocellular carcinoma (HCC) fulfilling the Milan criteria (TNM stages 1–2). However, LT is limited by organ availability and tumor progression on the waiting list. Liver resection (LR) may represent an alternative in these patients. The aim of this study is to report the results of LR in transplantable patients. Patients:From 1990 to 2007, 274 patients underwent liver resection for HCC. Sixty-seven (24%) met the Milan criteria on pathologic study of the specimen. Ten were TNM stage 1 and 57 stage 2 and all had chronic liver disease. There were 56 men and 11 women with a mean age of 63. LR included 12 major hepatectomies, 14 bisegmentectomies, 14 segmentectomies, and 27 nonanatomic resections. Thirty-seven resections were performed through a laparoscopic approach and there were only 8 open resections since 1998. Results:Three patients died postoperatively (4.5%), none after laparoscopic resection. Morbidity rate was 34%. After a mean follow-up of 4.8 years, 36 patients (54%) developed intrahepatic tumor recurrence. Twenty-eight (77%) were again transplantable of which 16 (44%) were transplanted. Two additional patients underwent pre-emptive LT (ie before recurrence). When considering 44 patients <65 years at the time of resection (ie upper age limit for LT), the rates of recurrence, transplantable recurrence, and intention to treat salvage transplantation (patients with transplantable recurrence actually transplanted) were 59%, 80%, and 61%, respectively. Overall and disease free 5-year survival rates were 72% and 44%, respectively. Survival was not influenced by TNM stage 1 or 2, AFP level, tumor differentiation, or the presence microscopic vascular invasion. Survival after salvage LT was 70% and 87% when calculated from the date of LT and LR, respectively. Conclusion:LR for small solitary HCC in compensated cirrhosis yields an overall survival rate comparable to upfront LT. Despite a significant recurrence rate, close imaging monitoring after resection allows salvage LT in 61% of patients with recurrence on intention to treat analysis.

Somatic mutations activating STAT3 in human inflammatory hepatocellular adenomas

Somatic STAT3 mutations present in a subset of inflammatory hepatocellular adenomas result in the generation of constitutively active STAT3 proteins that homodimerize independently of IL-6 stimulation.