Catherine Guettier

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.)

Complete Pathologic Response After Preoperative Chemotherapy for Colorectal Liver Metastases: Myth or Reality?

PURPOSE Complete clinical response (CCR) of colorectal liver metastases (CLM) following chemotherapy is of limited predictive value for complete pathologic response (CPR) and cure of the disease. The objective of this study was to determine predictive factors of CPR as well as its impact on survival. PATIENTS AND METHODS From January 1985 to July 2006, 767 consecutive patients with CLM underwent liver resection after systemic chemotherapy. Patients with CPR were compared with patients without CPR. RESULTS Twenty-nine of 767 (4%) patients had CPR, and none of these 29 patients had CCR. Patients with CPR (mean age, 54 years) had a mean number of 3.3 metastases at diagnosis (mean size, 29.3 mm). Objective response and stable disease were observed in 79% and 21% of cases, respectively. Postoperative mortality rate was 0%. After a median follow-up of 52.2 months (range, 1.1 to 193.0 months), overall 5-year survival was 76% for patients with CPR compared with 45% for patients without CPR (P = .004). Independent predictive factors for CPR were: age <or= 60 years, size of metastases <or= 3 cm at diagnosis, carcinoembryonic antigen (CEA) level at diagnosis <or= 30 ng/mL, and objective response following chemotherapy. The probability of CPR ranged from 0.2% when all factors were absent to 30.9% when all were present. CONCLUSION CPR was observed in 4% of patients with CLM treated with preoperative chemotherapy. However, CPR may occur in almost one-third of objective responders age <or= 60 years with metastases <or= 3 cm and low CEA values. CPR is associated with uncommon high survival rates.

Endogenous Retrotransposition Activates Oncogenic Pathways in Hepatocellular Carcinoma

Summary LINE-1 (L1) retrotransposons are mobile genetic elements comprising ∼17% of the human genome. New L1 insertions can profoundly alter gene function and cause disease, though their significance in cancer remains unclear. Here, we applied enhanced retrotransposon capture sequencing (RC-seq) to 19 hepatocellular carcinoma (HCC) genomes and elucidated two archetypal L1-mediated mechanisms enabling tumorigenesis. In the first example, 4/19 (21.1%) donors presented germline retrotransposition events in the tumor suppressor mutated in colorectal cancers (MCC). MCC expression was ablated in each case, enabling oncogenic β-catenin/Wnt signaling. In the second example, suppression of tumorigenicity 18 (ST18) was activated by a tumor-specific L1 insertion. Experimental assays confirmed that the L1 interrupted a negative feedback loop by blocking ST18 repression of its enhancer. ST18 was also frequently amplified in HCC nodules from Mdr2−/− mice, supporting its assignment as a candidate liver oncogene. These proof-of-principle results substantiate L1-mediated retrotransposition as an important etiological factor in HCC.

Usefulness of corticosteroids for the treatment of severe and fulminant forms of autoimmune hepatitis

Immunosuppressive therapy, and particularly corticosteroids with or without azathioprine, can achieve a remission in more than 80% of patients with autoimmune hepatitis (AIH). By contrast, the usefulness of corticosteroid therapy in severe forms of AIH remains a subject of debate. Between 1986 and 2005, 16 patients (14 females, 2 males; mean age: 36.6 ± 13.1 yr) presenting with acute, severe, or fulminant disease due to type 1 AIH (n = 13) or type 2 AIH (n = 3) were admitted to our liver intensive care unit. At admission, 10 of 16 (62.5%) patients presented with encephalopathy. Median international normalized ratio (INR), bilirubin, alanine aminotransferase (ALT), and creatinine values were 5.36 (range, 1.7‐12.2), 425 μmol/L (range, 278‐850), 678 IU/L (range, 60‐2867), and 72 μmol/L (range, 52‐133), respectively. A total of 12 patients received corticosteroid therapy: 8 had started in the referring center a median of 2.5 days (range, 1‐89) previously, and this therapy was initiated in 4 patients at their admission to our unit (median: 2 days; range: 0‐5). Four patients were not treated because of a rapid deterioration in their AIH. Before treatment, 4 of 12 patients had been suffering from encephalopathy. The median duration of corticosteroid therapy was 7 days (range: 2‐135). Of 16 patients, 13 underwent liver transplantation (LT) (81%), at which time all were encephalopathic. Median values for INR, total bilirubin, and ALT were 7.2 (range: 3.3‐15.9), 400 μmol/L (range: 301‐550), and 706 IU/L (range: 69‐1,932), respectively, at the time of transplantation. All patients treated with corticosteroids had experienced a clinical (encephalopathy) and biochemical (Model for End‐Stage Liver Disease [MELD] score) deterioration at the time of transplantation. Histological findings did not reveal any features of underlying chronic liver disease. Of the 13 patients undergoing transplantation, 10 had received prior corticosteroid therapy. Of the 2 nontransplanted patients treated with corticosteroids, a clinical improvement was observed in only 1 patient. Severe septic complications occurred in 3 patients under corticosteroid therapy (gram‐negative septicemia n = 2; disseminated aspergillus n = 1). Nine of the treated patients are still alive; 1 died after liver transplantation (LT) (recurrence of AIH, acute pancreatitis, sepsis), 1 survived without LT, and 1 died without LT. Among the untreated patients, 3 survived after LT and 1 died without LT. In conclusion, corticosteroid therapy is of little benefit in severe and fulminant forms of AIH; it may favor septic complications and should not delay LT. Liver Transpl, 2007.

Evidence to support the role of HLA-G5 in allograft acceptance through induction of immunosuppressive/ regulatory T cells.

The soluble HLA-G5 isoform encoded by intron-4 retaining spliced transcript has been previously detected in vivo in sera and grafts from transplanted patients who had significantly better graft acceptance. These findings led us to investigate the role of HLA-G5 in tolerance induction in vitro and its biological relevance in allograft acceptance in vivo. We demonstrated that engagement of Ig-like transcript-2 and Ig-like transcript-4 receptors by HLA-G5 is involved in inhibition of T cell alloproliferative responses. Naive T cells sensitized in vitro with HLA-G5, for as little as 18 h, 1) lost their ability to respond to subsequent allogeneic stimulus, and 2) acquired regulatory properties because they inhibited the reactivity of other T cells. These HLA-G5-induced T cells act in an Ag-nonspecific fashion and through soluble factors. Biological relevance was provided by ex vivo analyzes of samples from liver-kidney cotransplanted patients who had high HLA-G5 serum levels and no graft rejection. We showed that addition of HLA-G5-containing sera from these patients inhibited T cell alloresponses and that serum HLA-G5 was responsible for this inhibition. Notably, PBMC from transplanted patients exposed to high levels of circulating HLA-G5 did not respond to allostimulation and inhibited alloreactivity of other T cells. These results demonstrate that HLA-G5-mediated tolerance involves the induction of immunosuppressive T cells. These findings provide evidence supporting the tolerogenic properties of HLA-G and emphasize its potential application as a relevant therapeutic candidate capable of limiting allograft rejection.

Cell-free arterial grafts: Morphologic characteristics of aortic isografts, allografts, and xenografts in rats

PURPOSE Chronic rejection of arterial allografts and xenografts results in arterial wall dilation and rupture, making them unsuitable for long-term arterial replacement in vascular surgery. In the arterial wall, as in other organs, the cells probably carry major antigenic determinants. Arterial wall cellular components can be removed by detergent treatment to produce a graftable matrix tube. METHODS We compared the patency and macroscopic and microscopic morphologic changes that occurred in sodium dodecyl sulfate (SDS)-treated and untreated arterial isografts, allografts, and xenografts 2 months after implantation in rats. We quantified elastin, collagen, and nuclear density in the three layers of the graft wall (intima, media, and adventitia) by morphometric methods. The SDS treatment removed endothelial and smooth muscle cells and cells in the adventitia but preserved elastin and collagen extracellular matrix. RESULTS All arterial xenografts, whether SDS treated or untreated, were aneurysmal 2 months after grafting, with loss of the medial cellular and extracellular components. In allografts, SDS treatment prevented dilation, reduced adventitial inflammatory infiltration, and preserved medial elastin. The SDS-treated allografts had an evenly distributed, noninflammatory intimal thickening that was richer in elastin fibers than that in untreated allografts. CONCLUSIONS These results suggest an interspecies, but not an intraspecies, graft antigenicity of arterial extracellular matrix. The SDS treatment prevented chronic rejection of the arterial allograft and led to the proliferation of an elastin-rich and adapted intima.

Human leukocyte antigen-G (HLA-G) expression in biliary epithelial cells is associated with allograft acceptance in liver-kidney transplantation

BACKGROUND/AIMS Liver allograft is known to protect simultaneously transplanted organs from acute rejection. We have reported that only 6% of combined liver-kidney recipients, versus 32.5% of kidney recipients, develop kidney graft acute rejection. Release of soluble human leukocyte antigen (HLA) molecules by the liver has been proposed as a possible tolerogenic mechanism involved in the better acceptance of double transplants. The HLA-G molecule is acknowledged to possess tolerogenic properties. METHODS We investigated the involvement of HLA-G in allogeneic transplant acceptance by analyzing its expression in kidney and liver biopsies of 40 combined transplanted patients. RESULTS We demonstrate the presence of HLA-G in 14 out of 40 liver and five out of nine kidney transplants biopsies. HLA-G is expressed de novo by cells that are otherwise frequently susceptible target cells of acute rejection, i.e. liver biliary and renal tubular epithelial cells. We show a significant association between HLA-G expression in liver biliary epithelial cells and the absence of liver graft rejection. No acute or chronic rejection of the kidney graft was observed in patients in whom HLA-G was expressed in the liver graft. CONCLUSIONS HLA-G expression in the liver allograft is associated with a lower frequency of hepatic and renal acute rejection and may be involved in the acceptance of simultaneously transplanted organs.

Hepatocellular Carcinoma Is Associated With an Increased Risk of Hepatitis B Virus Recurrence After Liver Transplantation

BACKGROUND & AIMS Hepatitis B virus (HBV) recurrence after orthotopic liver transplantation (OLT) is significantly reduced by prophylaxis with hyperimmune antibody to hepatitis B surface antigen (anti-HBs) globulins (HBIG) and antiviral drugs. The role of hepatocellular carcinoma (HCC) in HBV recurrence remains unclear. We investigated the association between HCC pre-OLT and HBV recurrence post-OLT. METHODS We studied 99 hepatitis B surface antigen-positive patients who underwent OLT for cirrhosis. The median follow-up period was 43 months. All patients received HBIG, and 51 also received lamivudine and/or adefovir. Of these 99 patients, 31 had HCC before OLT. Total HBV DNA and covalently closed circular (ccc)-DNA were measured in tumor and nontumor tissues from the explanted livers of 16 of these 31 HCC patients and, also, in a context of tumor recurrence, in 3 patients who developed HBV/HCC recurrence. RESULTS Fourteen patients (14.1%) developed HBV recurrence within a median period of 15 months post-OLT. HCC at OLT, a pre-OLT HBV DNA viral load > or = 100,000 copies/mL, and HBIG monoprophylaxis were independently associated with HBV recurrence post-OLT. Eleven out of the 31 patients with HCC at OLT presented with HBV recurrence and 3 out of the 68 patients without HCC had HBV recurrence (P < .0001). HBV recurrence was more frequent in patients who developed HCC recurrence (7/8 patients, 87.5%) than in those who did not (4/23 patients, 17.4%) (P < .0001). In the 16 explanted livers, cccDNA was detectable in HCC cells in 11 and in nontumor cells in 12. cccDNA was detected in a context of HCC recurrence in 2 of the 3 patients tested who developed HBV/HCC recurrence. CONCLUSIONS The associations of HCC pre-OLT, and HCC recurrence with HBV recurrence post-OLT, and the detection of HBV DNA and cccDNA in HCC suggest that HBV replication in tumor cells may contribute to HBV recurrence post-OLT.

Genomic profiling of hepatocellular adenomas reveals recurrent FRK-activating mutations and the mechanisms of malignant transformation.

Hepatocellular adenomas (HCA) are benign liver tumors predominantly developed in women using oral contraceptives. Here, exome sequencing identified recurrent somatic FRK mutations that induce constitutive kinase activity, STAT3 activation, and cell proliferation sensitive to Src inhibitors. We also found uncommon recurrent mutations activating JAK1, gp130, or β-catenin. Chromosome copy number and methylation profiling revealed patterns that correlated with specific gene mutations and tumor phenotypes. Finally, integrative analysis of HCAs transformed to hepatocellular carcinoma revealed β-catenin mutation as an early alteration and TERT promoter mutations as associated with the last step of the adenoma-carcinoma transition. In conclusion, we identified the genomic diversity in benign hepatocyte proliferation, several therapeutic targets, and the key genomic determinants of the adenoma-carcinoma transformation sequence.

Clinical and biological relevance of hepatocyte apoptosis in alcoholic hepatitis.

BACKGROUND/AIMS Although human and experimental studies have shown that apoptosis plays a role in hepatocyte death in alcoholic liver disease, its clinical and biological significance has not been investigated in alcoholic hepatitis (AH). The aim of this study was to quantify hepatocyte apoptosis in AH and to attempt to relate it to the clinical and biological severity of the disease. METHODS The hepatocyte apoptotic index was determined using a double in situ transferase-mediated dUTP nick end (TUNEL) and CD15 (neutrophils) labelling on 35 liver biopsies from patients with AH lesions of different severities. The specificity of TUNEL labelling for apoptosis was monitored both by morphology and fractin (a caspase actin cleavage site) immunostaining. RESULTS The hepatocyte apoptotic index ranged from 0.3 to 28% and was related to the severity of alcoholic hepatitis as measured by the Maddrey score (P < 0.05; Mann-Whitney test) while ballooning (which reflects hepatocytes potentially undergoing necrosis) and neutrophil indexes were not. CONCLUSIONS This suggests that hepatocyte apoptosis could be a therapeutic target to treat or to prevent alcoholic hepatitis in cirrhotic patients. Co-localization of apoptotic hepatocytes with neutrophils and the strong quantitative correlation would suggest an apoptosis dependent transmigration of neutrophils.