The clinicopathological and prognostic relevance of cytokeratin 7 and 19 expression in hepatocellular carcinoma. A possible progenitor cell origin

Intermediate hepatobiliary cells predict an increased risk of hepatocarcinogenesis in patients with hepatitis C virus-related cirrhosis

BACKGROUND & AIMS

The expression of biliary lineage markers such as cytokeratin (K) 7 by hepatocytes is thought to reflect an altered regeneration pathway recruiting a stem cell compartment, more prone to carcinogenesis. We aimed to investigate the presence of these so-called intermediate hepatobiliary cells (IHC) in liver biopsies of patients with hepatitis C-related cirrhosis and their potential influence on the subsequent occurrence of hepatocellular carcinoma (HCC).

METHODS

From a cohort of patients with hepatitis C-related cirrhosis, prospectively screened for HCC, we retrospectively selected those with a liver biopsy performed for the initial diagnosis of cirrhosis. Presence of IHC was recorded when foci of K7-positive, intermediate-sized hepatocytes were detected.

RESULTS

A total of 150 patients were included (87 men; mean age, 57 y; range, 19-84 y; body mass index, 25 kg/m(2)). After a median follow-up period of 4.85 years, HCC was diagnosed in 36 patients (24%). Baseline liver biopsy showed intermediate hepatobiliary cell foci in 61 patients (41%). Intermediate cells co-expressed both hepatocytes markers and the progenitor cell markers Ep-CAM and K19. The presence of intermediate hepatobiliary cells was associated independently with HCC occurrence (Fine and Gray model; hazard ratio, 2.48; 95% confidence interval, 1.24-4.96; P = .01). Other predictors of HCC were diabetes and low platelet count. The HCC annual incidence rate was significantly higher in patients with IHC compared with patients without (8.14% vs 3.12%, Gray's test, P = .003).

CONCLUSIONS

The aberrant expression of biliary K by hepatocytes in patients with hepatitis C virus-related cirrhosis is related independently to HCC occurrence.

Biomarkers for prediction of metastasis and recurrence of hepatocellular carcinoma

The metastasis of hepatocellular carcinoma (HCC) has long been recognized as a multi-step process that involves multiple factors. Instead of diagnostic models based on single-molecule detection, the combination of multiple molecules will be the trend for early tumor diagnosis or prediction of tumor metastasis and recurrence. Many differentially expressed metastasis-associated genes and proteins have been reported in HCC. This article gives an overview of protein biomarkers for prediction of HCC metastasis and recurrence.

Identification of a cholangiocarcinoma-like gene expression trait in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) are the major adult liver cancers. The existence of combined hepatocellular-cholangiocarcinoma (CHC), a histopathologic intermediate form between HCC and CC, suggests phenotypic overlap between these tumors. Here, we applied an integrative oncogenomic approach to address the clinical and functional implications of the overlapping phenotype between these tumors. By performing gene expression profiling of human HCC, CHC, and CC, we identified a novel HCC subtype, i.e., cholangiocarcinoma-like HCC (CLHCC), which expressed cholangiocarcinoma-like traits (CC signature). Similar to CC and CHC, CLHCC showed an aggressive phenotype with shorter recurrence-free and overall survival. In addition, we found that CLHCC coexpressed embryonic stem cell-like expression traits (ES signature) suggesting its derivation from bipotent hepatic progenitor cells. By comparing the expression of CC signature with previous ES-like, hepatoblast-like, or proliferation-related traits, we observed that the prognostic value of the CC signatures was independent of the expression of those signatures. In conclusion, we suggest that the acquisition of cholangiocarcinoma-like expression traits plays a critical role in the heterogeneous progression of HCC.

The use of Cytokeratin 19 (CK19) immunohistochemistry in lesions of the pancreas, gastrointestinal tract, and liver

Cytokeratin immunostaining forms the bedrock of the immunohistochemical evaluation of tumors. Cytokeratin 19 (CK19) belongs to a family of keratins, which are normally expressed in the lining of the gastroenteropancreatic and hepatobiliary tracts. CK19 immunohistochemistry has been used successfully in thyroid tumors to recognize papillary carcinomas for some time. However, its use in the pancreas, liver, and gastrointestinal tract (GIT) has only recently come to the fore. The purpose of this review is to look at the use of CK19 immunohistochemistry in tumors occurring at these sites. CK19 has been shown to be an independent prognostic factor for pancreatic neuroendocrine tumors, especially the insulin-negative tumors. CK19 positive tumors are associated with poor outcome irrespective of the established pathologic parameters such as size, mitoses, lymphovascular invasion, and necrosis. It is recommended that CK19 be part of the immunohistochemical panel in the work-up of pancreatic endocrine tumors. CK19 is positive in the most of neuroendocrine tumors occurring in the rest of the GIT, except rectal tumors, which are negative. In the liver, CK19 is of prognostic value in hepatocellular carcinomas and is of use in distinguishing cholangiocarcinoma from hepatocellular carcinomas. It can also be used to highlight native ductules in the liver and helps separate conditions such as focal nodular hyperplasia from hepatic adenoma. The vast majority of adenocarcinomas in the GIT and pancreas are CK19 positive.

Progenitor-derived hepatocellular carcinoma model in the rat

Human hepatocellular carcinoma (HCC) is a heterogeneous disease of distinct clinical subgroups. A principal source of tumor heterogeneity may be cell type of origin, which in liver includes hepatocyte or adult stem/progenitor cells. To address this issue, we investigated the molecular mechanisms underlying the fate of the enzyme-altered preneoplastic lesions in the resistant hepatocyte (RH) model. Sixty samples classified as focal lesions, adenoma, and early and advanced HCCs were microdissected after morphological and immunohistochemical evaluation and subjected to global gene expression profiling. The analysis of progression of the persistent glutathione S-transferase (GSTP)(+) focal lesions to fully developed HCC showed that approximately 50% of persistent nodules and all HCCs expressed cytokeratin 19 (CK19), whereas 14% of remodeling nodules were CK19(+). Unsupervised hierarchical clustering of the expression profiles also grouped the samples according to CK19 expression. Furthermore, supervised analysis using the differentially expressed genes in each cluster combined with gene connectivity tools identified 1308 unique genes and a predominance of the AP-1/JUN network in the CK19(+) lesions. In contrast, the CK19-negative cluster exhibited only limited molecular changes (156 differentially expressed genes versus normal liver) consistent with remodeling toward differentiated phenotype. Finally, comparative functional genomics showed a stringent clustering of CK19(+) early lesions and advanced HCCs with human HCCs characterized by poor prognosis. Furthermore, the CK19-associated gene expression signature accurately predicted patient survival (P < 0.009) and tumor recurrence (P < 0.006).

CONCLUSION

Our data establish CK19 as a prognostic marker of early neoplastic lesions and strongly suggest the progenitor derivation of HCC in the rat RH model. The capacity of CK19-associated gene signatures to stratify HCC patients according to clinical prognosis indicates the usefulness of the RH model for studies of stem/progenitor-derived HCC.

Hepatic cancer stem cells and drug resistance: Relevance in targeted therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of most common malignancies in the world. Systemic treatments for HCC, particularly for advanced stages, are limited by the drug resistance phenomenon which ultimately leads to therapy failure. Recent studies have indicated an association between drug resistance and the existence of the cancer stem cells (CSCs) as tumor initiating cells. The CSCs are resistant to conventional chemotherapies and might be related to the mechanisms of the ATP Binding Cassette (ABC) transporters and alterations in the CSCs signaling pathways. Therefore, to contribute to the development of new HCC treatments, further information on the characterization of CSCs, the modulation of the ABC transporters expression and function and the signaling pathway involved in the self renewal, initiation and maintenance of the cancer are required. The combination of transporters modulators/inhibitors with molecular targeted therapies may be a potent strategy to block the tumoral progression. This review summarizes the association of CSCs, drug resistance, ABC transporters activities and changes in signaling pathways as a guide for future molecular therapy for HCC.

Primary liver tumors: origin and target therapy

BACKGROUND

The liver is the largest gland and chief metabolic organ of the human body possessing a unique ability to regenerate. The general interest of primary liver tumors is noteworthy because of their increasing worldwide incidence and mortality. Recent studies have focused on the ancestors of mature hepatocytes, which are capable of proliferating, differentiating and self-renewing.

OBJECTIVE

To provide a brief and up-to-date review on the cellular origin of primary liver tumors and to examine the use of stem cells in potential future therapeutic attempts.

METHODS

A review of relevant literature.

RESULTS

It is clear that hepatic progenitor cells (HPCs) could be the basis of some hepatocellular carcinomas (HCC), cholangiocarcinomas (CHC), hepatocellular adenomas and hepatoblastomas. Cancer stem cell (CSC) theory emphasizes the role of hepatic stem cells in the development and progression of liver tumors.

CONCLUSION

The expression of HPCs markers may be used as new independent prognostic factors in HCC. Conventional treatments for HCC do not seem to be beneficial for the majority of patients and new therapeutic approaches such as gene therapy and targeted drug therapy are of great clinical interest.

Keratin 19 marks poor differentiation and a more aggressive behaviour in canine and human hepatocellular tumours

Background

The expression of Keratin 19 (K19) was reported in a subset of hepatocellular carcinomas (HCCs). K19 positive HCCs are associated with an increased malignancy compared to K19 negative HCCs. No suitable mouse models exist for this subtype of HCC, nor is the incidence of K19 expression in hepatocellular neoplasia in model animals known. Therefore, we compared the occurrence and tumour behaviour of K19 positive hepatocellular neoplasias in dog and man.

Results

The expression of hepatocellular differentiation (HepPar-1), biliary/progenitor cell (K7, K19), and malignancy (glypican-3) markers was semi-quantitatively assessed by immunohistochemistry. The histological grade of tumour differentiation was determined according to a modified classification of Edmondson and Steiner; the staging included intrahepatic, lymph node or distant metastases. Four of the 34 canine hepatocellular neoplasias showed K19 positivity (12%), of which two co-expressed K7. K19 positive tumours did not express HepPar-1, despite the histological evidence of a hepatocellular origin. Like in human HCC, all K19 positive hepatocellular neoplasias were glypican-3 positive and histologically poorly differentiated and revealed intra- or extrahepatic metastases whereas K19 negative hepatocellular neoplasias did not.

Conclusions

K19 positive hepatocellular neoplasias are highly comparable to man and occur in 12% of canine hepatocellular tumours and are associated with a poorly differentiated histology and aggressive tumour behaviour.

Stem cells in hepatocarcinogenesis: evidence from genomic data

Increasing evidence suggests that many, perhaps all solid tumors contain a subset of cells that possess functional properties similar to the normal tissue stem cells, including self-renewal, unlimited proliferative capacity, and pluripotency. The hierarchical cancer model that places a cancer stem cell (CSC) population at the apex of tumor formation is based on this notion. The cancer stem cell hypothesis posits that CSCs are responsible not only for tumor initiation, but also generation of metastasis and local recurrence after therapy. Current definitions of the CSC are based only on functional properties regardless of potential cellular origin. Histopathology investigations of chronic liver diseases and experimental studies support the existence of CSCs in liver cancer. In particular, recent advances in microarray technologies utilizing integrative comparative genomic analysis of human hepatocellular carcinoma specimens, cancer cell lines, and transgenic models establish the molecular similarities between CSC and normal tissue stem cells and highlight the importance of CSC for the prognosis of liver cancer patients. The results have also uncovered the key "stemness" and oncogenic pathways frequently disrupted during hepatocarcinogenesis providing the basis for identifying novel therapeutic targets against CSC.

Bone marrow-derived stem cells in liver repair: 10 years down the line

Hematopoietic stem cells have potential in the field of regenerative medicine because of their capacity to form cells of different lineages. Bone marrow stem cells have been shown to contribute to parenchymal liver cell populations, and although this may not be functionally significant, it has sparked interest in the field of autologous stem cell infusion as a possible treatment for cirrhosis. In this review, we will examine the evidence for the contribution of bone marrow-derived cells to populations of liver cells and for the functional contribution of bone marrow-derived cells to both liver fibrosis and repair. The mechanisms by which cells are trafficked from the bone marrow to the liver are complex; the stromal derived factor-1/CXC receptor 4 axis is central to this process. There are limited data in liver injury, but we will examine findings from the bone marrow transplantation literature and discuss their relevance to liver disease. Stromal derived factor-1 also has a role in endogenous liver stem cell accumulation. Some groups have already started infusing autologous bone marrow cells into patients with cirrhosis. We will review these trials in the context of the basic science that we have discussed, and we will consider targets for investigation in the future.

Hepatic progenitor cells in liver cancers from Asian children

BACKGROUND/AIMS

Hepatoblastoma (HB) and hepatocellular carcinoma (HCC) are the two most common primary malignant liver tumours in children. Hepatic progenitor cells have been described and can be stained with K19, EpCAM and CD117. We investigated the morphology and staining patterns of primary liver tumours in Asian children.

METHODS

Four pathologists studied slides from 39 paediatric patients from Vietnam and Korea aged 8 months to 16 years. We performed immunohistochemical stains for K19, EpCAM and CD117, and polymerase chain reaction for tissue hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA.

RESULTS

There was agreement on the diagnosis of 24 cases of HCC and 10 cases of HB (one recurrent case). The diagnosis was split for six cases (HCC/HB). All 20 cases of HCC tested were HBV DNA+ and HCV RNA-. All nine cases of HB tested were HBV DNA-, while one was HCV RNA+. Of four HCC/HB cases tested, three were HBV DNA+ and all were HCV RNA-. By immunohistochemistry, 8/24 (33%) cases of HCC were K19+ and 18/24 (75%) were EpCAM+, 5/10 (50%) cases of HB were K19+ and 7/10 (70%) were EpCAM+ and 3/6 (50%) cases of HCC/HB were K19+ and 5/6 (83%) were EpCAM+. CD117 was negative in all 38 cases tested. Paediatric HCC has a morphology different from adult HCC, sometimes resembling HB, and a larger proportion of paediatric tumours have progenitor cell features.

CONCLUSIONS

HB and HCC in children may represent malignant transformation at an early stage in the cellular lineage and often arise from hepatic progenitor cells.

Expression of contactin associated protein-like 2 in a subset of hepatic progenitor cell compartment identified by gene expression profiling in hepatitis B virus-positive cirrhosis

BACKGROUND

Hepatic progenitor cells (HPC), a cell compartment capable of differentiating into hepatocytic and biliary lineages, may give rise to the formation of intermediate hepatobiliary cells (IHBC) or ductular reactions (DR).

AIMS

The aim of this study was to analyse the gene expression profiles of DR in cirrhosis and further investigate novel proteins expressed by HPC and their intermediate progeny.

METHODS

DR in hepatitis B virus (HBV)-positive cirrhotic liver tissues adjacent to hepatocellular carcinoma and interlobular bile ducts (ILBDs) in normal liver tissues were isolated by laser capture microdissection and then subjected to microarray analysis. Differential gene expression patterns were verified by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry on serial sections. HPC and their intermediate progeny were recognized by immunostaining with hepatocytic and biliary markers [HepPar1, cytokeratin (CK)7, CK19, neural cell adhesion molecule (NCAM), epithelial cell adhesion molecule (EpCAM)].

RESULTS

A total of 88 genes showed upregulation in DR compared with ILBDs. Gene ontology analyses revealed that these upregulated genes were mostly associated with cell adhesion, immune response and the metabolic process. Contactin associated protein-like 2 (CNTNAP2) was first confirmed to be a novel protein expressed in a subpopulation of DR that was positive for CK7, NCAM or EpCAM. In addition, immunoreactivity for CNTNAP2 was also noted in a subset of isolated CK7-positive HPC as well as some ductular IHBC positive for CK19 and HepPar1 in DR.

CONCLUSION

CNTNAP2 is specifically associated with the emergence of ductular populations and may be identified as a novel protein for defining a subset of HPC and their intermediate progeny in cirrhosis.

Advances in research on liver cancer stem cells

Cancer stem cells have been identified in various human tumors. However, it remains controversial as to whether or not liver cancer stem cells (LCSCs) exist until now. There are two hypotheses to explain the origin of liver cancer stem cells: the dedifferentiation of mature hepatocytes and the maturation arrest of liver stem cells. Now, the latter is generally acknowledged to be the better one. To obtain direct evidence for the existence of LCSCs, many researchers focus their studies on the surface markers on LCSCs to identify ideal markers for isolation of LCSCs. Besides, the relationship between side population (SP) cells and LCSCs also attracts much attention. Therefore, the study of LCSCs is probably of great significance for the diagnosis and treatment of liver cancer.

Nuclear beta-catenin induces an early liver progenitor phenotype in hepatocellular carcinoma and promotes tumor recurrence

Transforming growth factor-beta cooperates with oncogenic Ras to activate nuclear beta-catenin during the epithelial to mesenchymal transition of hepatocytes, a process relevant in the progression of hepatocellular carcinoma (HCC). In this study we investigated the role of beta-catenin in the differentiation of murine, oncogene-targeted hepatocytes and in 133 human HCC patients scheduled for orthotopic liver transplantation. Transforming growth factor-beta caused dissociation of plasma membrane E-cadherin/beta-catenin complexes and accumulation of nuclear beta-catenin in Ras-transformed, but otherwise normal hepatocytes in p19(ARF)-/- mice. Both processes were inhibited by Smad7-mediated disruption of transforming growth factor-beta signaling. Overexpression of constitutively active beta-catenin resulted in high levels of CK19 and M2-PK, whereas ablation of beta-catenin by axin overexpression caused strong expression of CK8 and CK18. Therefore, nuclear beta-catenin resulted in dedifferentiation of neoplastic hepatocytes to immature progenitor cells, whereas loss of nuclear beta-catenin led to a differentiated HCC phenotype. Poorly differentiated human HCC showed cytoplasmic redistribution or even loss of E-cadherin, suggesting epithelial to mesenchymal transition. Analysis of 133 HCC patient samples revealed that 58.6% of human HCC exhibited strong nuclear beta-catenin accumulation, which correlated with clinical features such as vascular invasion and recurrence of disease after orthotopic liver transplantation. These data suggest that activation of beta-catenin signaling causes dedifferentiation to malignant, immature hepatocyte progenitors and facilitates recurrence of human HCC after orthotopic liver transplantation.

PBK/TOPK in the differential diagnosis of cholangiocarcinoma from hepatocellular carcinoma and its involvement in prognosis of human cholangiocarcinoma

The increased expression of PDZ binding kinase/lymphokine-activated killer T-cell-originated protein kinase (PBK/TOPK) is associated with some human malignant tumors. In this study, we analyzed PBK/TOPK expression in hepatic primary tumor and explored its role in cholangiocarcinoma biology. Seventy-four cholangiocarcinomas, 33 hepatocellular carcinomas, and 10 normal liver tissues were prepared from paraffin-embedded specimens. PBK/TOPK protein was assessed by immunohistochemical staining, and the survival time was analyzed with the Kaplan-Meier method. The protein, mRNA of PBK/TOPK, and cell cycle of cholangiocarcinoma cell line after PBK/TOPK suppression with small interfere RNA were studied by Western blot, semiquantitative reverse transcriptase-polymerase chain reaction, and flow cytometry, respectively. PBK/TOPK was usually expressed in normal bile duct epithelial cells and much more frequently expressed in cholangiocarcinoma (68/74) but never expressed in hepatocytes and hepatocellular carcinomas (0/33). PBK/TOPK down-regulation was related to the poor prognosis of patients with cholangiocarcinoma (P = .013). Epidermal growth factor can enhance PBK/TOPK expression in cholangiocarcinoma QBC 939 cells, but suppression of PBK/TOPK in the cells did not affect their proliferation. PBK/TOPK protein could serve as a useful indicator for histopathologic differentiation between cholangiocarcinoma and hepatocellular carcinomas and the low expression of PBK/TOPK is predicative of poor survival in cholangiocarcinoma patients.

Profiling protein markers associated with the sensitivity to concurrent chemoradiotherapy in human cervical carcinoma

Concurrent chemoradiotherapy (CCRT) is recently recommended as the primary and standard treatment modality for cervical cancer. The aim of this study is to investigate the protein biomarkers associated with CCRT sensitivity, so as to better understand the mechanisms underlying CCRT resistance. Fresh tumor tissues from five cases for each group of CCRT-highly sensitive (CCRT-HS) and CCRT-lowly sensitive (CCRT-LS) were analyzed by 2-D electrophoresis coupled with MALDI-TOF-MS, followed by Western blot for four candidate proteins including S100A9, galectin-7, nuclear matrix protein-238 (NMP-238), and heat shock protein-70 (HSP-70). In randomly selected CCRT-HS (n = 60) and CCRT-LS (n = 35) cases, these four differentially expressed proteins were detected by tissue microarray with immunohistochemistry staining to explore the association between these interested proteins and CCRT sensitivity. Nineteen proteins differentially expressed more than four times between two groups were identified. An association was revealed between CCRT sensitivity and increased S100A9 and galectin-7, but decreased NMP-238 and HSP-70 expression (p < 0.001, respectively). Although none of these four protein markers could be used as an independent predictive factor, a recurrence prediction model was generated by combining S100A9, galectin-7, NMP-238, and HSP-70 as a full predictive factor. The proteomic analysis combined with tissue microarray provides us a dramatic tool in predicting CCRT response. The increased expression of S100A9 and galectin-7, but decreased expression of NMP-238 and HSP-70, suggests a significantly increased sensitivity to CCRT in cervical cancer.

Bile ductular cell reaction with senescent hepatocytes in chronic viral hepatitis is lost during hepatocarcinogenesis

Cellular senescence is defined as irreversible cell arrest and could work as a safeguard against tumorigenesis. This mechanism was examined in chronic viral hepatitis-related hepatocarcinogenesis. By using surgical resected or wedge biopsied liver specimens from 87 chronic viral hepatitis patients in whom 35 neoplastic nodules (dysplastic nodules and hepatocellular carcinoma) were complicated, P21 expression and senescence-associated beta galactosidase activity, a marker of senescence, were examined. All of these neoplastic nodules harbored portal tracts within the tumors. Hepatocytes expressing senescence markers and cytokeratin (CK)7-positive bile ductules including hepatic progenitor-like cells were increased in periseptal areas in cirrhosis. Interestingly, these cells appeared to form an anatomical complex that was completely lost in the periportal areas within the neoplastic nodules. In one-third of the neoplastic nodules, CK7-positive small neoplastic hepatocytes resembling hepatic progenitor cells proliferated zonally around the portal tracts. In conclusion, loss of a complex of senescent hepatocytes and ductular cell including hepatic progenitor-like cells in the periportal or periseptal areas may be associated with emergence of neoplastic hepatocytes and their proliferation followed by neoplastic nodules arising in liver cirrhosis. Zonal proliferation of CK7-positive small neoplastic hepatocytes resembling hepatic progenitor cells may develop during early hepatocarcinogenesis.

The amazing universe of hepatic microstructure

An informal review is presented by the author of his 50 years of involvement in practice and research in hepatopathology. Some background for the author's attitude and meandering pathway into his professional career serves as introduction to a short discussion of the main topics of his interest and expertise. Histogenesis of liver cancer was the theme of early work for a Ph.D. thesis, the results of which were lost into oblivion due to local rules and circumstances, but were rescued three decades later. His conclusions about the cells of origin of liver cancer remain concordant with the newer concepts in the field after nearly half a century. Studies in the field of chronic hepatitis became a long saga, involving the first classification of this syndrome by "the Gnomes" in 1968, histochemical investigations of viral antigens, lymphocyte subsets and adhesion molecules, and a quarter century later, the creation of a new classification presently in use. Cholestasis was a broadening field in diagnostic entities and involved the study of liver lesions, comprising pathways of bile regurgitation (including reversed secretory polarity of hepatocytes) and so-called ductular reaction. The latter topic has a high importance for the various roles it plays in modulating liver tissue of chronic cholestasis into biliary cirrhosis, and as the territory of hepatic progenitor cells, crucial for liver regeneration in adverse conditions and in development of liver cancer. Study of the embryology of intrahepatic bile ducts helped to clarify the strange appearance of the ducts in "ductal plate configuration" in several conditions, including some forms of biliary atresia with poor prognosis and all varieties of fibrocystic bile duct diseases with "ductal plate malformation" as the basic morphologic lesion.

The management of hepatocellular carcinoma. Current expert opinion and recommendations derived from the 10th World Congress on Gastrointestinal Cancer, Barcelona, 2008

This article summarizes the expert discussion on the management of hepatocellular carcinoma (HCC), which took place during the 10th World Gastrointestinal Cancer Congress (WGICC) in Barcelona, June 2008. A multidisciplinary approach to a patient with HCC is essential, to guarantee optimal diagnosis and staging, planning of surgical options and selection of embolisation strategies or systemic therapies. In many patients, the underlying cirrhosis represents a challenge and determines therapeutic options. There is now robust evidence in favour of systemic therapy with sorafenib in patients with advanced HCC with preserved liver function. Those involved in the care for patients with HCC should be encouraged to participate in well-designed clinical trials, to increase evidence-based knowledge and to make further progress.

Promoter methylation and mRNA expression of DKK-3 and WIF-1 in hepatocellular carcinoma

AIM: To investigate the promoter methylation status and mRNA expression of DKK-3 and WIF-1 gene in hepatocellular carcinoma (HCC).

METHODS: DKK-3 and WIF-1 acted as Wnt-antagonists and tumor suppressors, but hypermethylation of the gene promoter and low mRNA expression activated Wnt signaling aberrantly and induced the development of HCC. Methylation status of the DKK-3 and WIF-1 gene promoter was investigated using methylation specific polymerase chain reaction (PCR) in tumor and adjacent non-cancerous tissues from 33 HCC patients and 20 normal liver tissues served as control. The expression of DKK-3 and WIF-1 mRNA was also determined by real-time quantitative reverse transcriptase PCR. The relationship between methylation, mRNA expression, and clinical data, as well as methylation and mRNA expression of the two genes were analyzed.

RESULTS: The methylation of DKK-3 and WIF-1 genes in HCC increased significantly compared with adjacent non-cancerous tissues and normal control tissues (χ² =7.79, P < 0.05; χ² = 4.89, P < 0.05), and no significant difference in methylation between adjacent non-cancerous tissues and normal control tissues was observed. In HCC tissues, significant differences in the DKK-3 promoter methylation were observed in age and cirrhosis, and significant differences of the WIF-1 promoter methylation were observed in HBsAg and cirrhosis. The average expression of DKK-3 mRNA in HCC and adjacent non-cancerous tissues was increased significantly compared with normal control tissues. The average expression of WIF-1 mRNA showed no significant difference among the three tissues. The mRNA expression of DKK-3 gene in HCC was decreased as the pathological grade increased.

CONCLUSION: The aberrant promoter methylation and decreased expression of DKK-3 and WIF-1 may be an important mechanism in HCC, and may be a far-reaching significance in early diagnosis and therapy of HCC.

A case of cholangiolocellular carcinoma asynchronously developing 3 years after the resection of hepatocellular carcinoma

Cholangiolocellular carcinoma (CLC) is a rare malignant primary liver tumor, categorized as a subtype of cholangiocellular carcinoma. CLC is considered to originate from hepatic progenitor cells, and sometimes accompanies a component of cholangiocellular carcinoma and/or hepatocellular carcinoma (HCC). We report herein a case of a 53-year-old Japanese male with CLC occurring asynchronously after a resection of HCC. At the age of 50, the patient underwent a first hepatectomy due to HCC, followed by intrahepatic recurrence. At 53, a new type of hepatic tumor was detected. Dynamic computed tomography revealed a multinodular enhanced tumor in the hepatic arterial phase, and an iso-density tumor in the portal venous and delayed phases. Living donor liver transplantation was performed for the treatment of this liver tumor because of his poor liver function. Histological findings confirmed the diagnosis of CLC. Nineteen months after the liver transplantation, bone metastasis of CLC was detected. Although the preoperative diagnosis of CLC is difficult in general, CLC should be considered as a differential diagnosis when a tumor with atypical image findings for HCC is observed after the resection of HCC. Once the diagnosis of CLC is made, postoperative surveillance of the patient must be performed, including the bone.

The epidemiology of hepatocellular cancer: from the perspectives of public health problem to tumor biology

The epidemiology of hepatocellular cancer (HCC) can be viewed from several important perspectives. The conventional perspective includes the overall public health impact of HCC, which is increasing in incidence in many regions of the world. The epidemiology of HCC can also be viewed from the perspective of variation in underlying disease associations such as viral hepatitis or the recently recognized link to nonalcoholic fatty liver disease (NAFLD). Of perhaps increasing importance with recent advances in therapy of HCC, the epidemiology of HCC can also be viewed from the perspective of variation in HCC biology. This lesser known perspective may depend in part on the underlying liver disease and the cell origin of the cancer, whether of hepatocyte or stem cell origin. This aspect is likely to become central to diagnosis and management of HCC with the further development of targeted therapeutics. The relative efficacy of these agents will likely depend on the biochemical pathways active in a given hepatocellular malignancy. This, in turn, is likely to be related to the epidemiological associations of HCC.

Stem cells in liver regeneration, fibrosis and cancer: the good, the bad and the ugly

The worldwide shortage of donor livers to transplant end stage liver disease patients has prompted the search for alternative cell therapies for intractable liver diseases, such as acute liver failure, cirrhosis and hepatocellular carcinoma (HCC). Under normal circumstances the liver undergoes a low rate of hepatocyte 'wear and tear' renewal, but can mount a brisk regenerative response to the acute loss of two-thirds or more of the parenchymal mass. A body of evidence favours placement of a stem cell niche in the periportal regions, although the identity of such stem cells in rodents and man is far from clear. In animal models of liver disease, adopting strategies to provide a selective advantage for transplanted hepatocytes has proved highly effective in repopulating recipient livers, but the poor success of today's hepatocyte transplants can be attributed to the lack of a clinically applicable procedure to force a similar repopulation of the human liver. The activation of bipotential hepatic progenitor cells (HPCs) is clearly vital for survival in many cases of acute liver failure, and the signals that promote such reactions are being elucidated. Bone marrow cells (BMCs) make, at best, a trivial contribution to hepatocyte replacement after damage, but other BMCs contribute to the hepatic collagen-producing cell population, resulting in fibrotic disease; paradoxically, BMC transplantation may help alleviate established fibrotic disease. HCC may have its origins in either hepatocytes or HPCs, and HCCs, like other solid tumours appear to be sustained by a minority population of cancer stem cells.

N-cadherin serves as diagnostic biomarker in intrahepatic and perihilar cholangiocarcinomas

As a definite immunoprofile of this tumor is missing, the histopathologic diagnosis of intrahepatic cholangiocarcinoma is difficult. The aim of this study was to explore E- and N-cadherin expressions in intrahepatic bile duct tumors, and to determine their potential interest in differential diagnosis. Normal liver tissue, 5 cirrhosis with ductular reaction, 5 focal nodular hyperplasia, 5 bile duct hamartomas, 5 bile duct adenomas, and 45 intrahepatic cholangiocarcinomas from Caucasian patients were studied. Tissue-microarrays including 20 esophageal, 86 gastric, 8 small bowel, 64 colonic, 18 pancreatic, 6 gallbladder, and 7 extrahepatic biliary tract adenocarcinomas, 22 hepatocellular carcinomas, and normal tissues were constructed. Immunohistochemistry was performed using E-cadherin, N-cadherin, NCAM, Hep Par1, and cytokeratins 7, 19 and 20. Immunoblot analysis of frozen liver tissues was performed to control the specificity of E- and N-cadherin antibodies used. In normal liver, epithelial cells of intrahepatic bile ducts, whatever their caliber, as well as hepatocytes, coexpressed E- and N-cadherins at their plasma membranes. In cirrhosis, ductular reactions completely expressed E- and N-cadherins. All the benign lesions and 30 of the 45 intrahepatic cholangiocarcinomas (23/29 peripheral and 7/16 hilar) also expressed N-cadherin. E-cadherin was detected in all the lesions. The expression of N-cadherin at the plasma membrane of tumor cells was significantly more frequent in peripheral than in hilar intrahepatic cholangiocarcinomas (P=0.003). Among noncholangiocarcinomas, only 1% gastric and 66% gallbladder adenocarcinomas and all the hepatocellular carcinomas expressed N-cadherin at the membrane of tumor cells. Finally, for the diagnosis of intrahepatic cholangiocarcinomas, the specificity value of membranous expression of N-cadherin was 88%, whereas that of the combination cytokeratin 7/membranous N-cadherin was 98%. In the gastrointestinal and liver tract, membranous N-cadherin is restricted to the hepatocytes and intrahepatic biliary cells. In combination with cytokeratin 7 and Hep Par1, N-cadherin is a reliable tool for the histopathological diagnosis of primary hepatic tumors.

Diagnostic use of cytokeratins, CD34, and neuronal cell adhesion molecule staining in focal nodular hyperplasia and hepatic adenoma

Cytokeratins 7 and 19 and neuronal cell adhesion molecule (CD56) are differentially expressed in the hepatocytes and biliary epithelium. CD34 is an endothelial marker that is expressed in hepatic sinusoids in conditions associated with altered vascular flow and neoplasms. Distinct staining patterns using these markers have been shown in resected specimens of focal nodular hyperplasia, telangiectatic focal nodular hyperplasia, and hepatic adenoma. The purpose of this study was to examine the diagnostic use of these markers in needle biopsies. Needle biopsies from focal nodular hyperplasia (n = 21), telangiectatic focal nodular hyperplasia (n = 2), and hepatic adenoma (n = 14) were included in the study. These cases represent typical examples of each entity that have been diagnosed on the basis of clinical, imaging, and histologic features. Corresponding resection specimens available in 9 cases were also included in the study for comparison. Immunohistochemical analysis was performed on 4-mum-thick formalin-fixed and paraffin-embedded sections using antibodies against cytokeratin 7, cytokeratin 19, neuronal cell adhesion molecule, and CD34. The staining patterns and intensity for each marker were analyzed in a blinded fashion, and the patterns were recorded as focal nodular hyperplasia-like, hepatic adenoma-like, or indeterminate for each case. Presence of normal tissue was also recorded in each case. The hepatic adenoma-like pattern is characterized by strong cytokeratin 7 positivity in hepatocytes in patches with a gradual decrease in the staining intensity as the cells differentiate toward mature hepatocytes. Hepatic adenomas lack bile ducts and ductules as highlighted by cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule stains. The focal nodular hyperplasia-like pattern is characterized by milder and focal cytokeratin 7 staining of hepatocytes. Cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule show a strong staining of bile ductules in the fibrous septa. Normal liver shows cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule staining of bile ducts, whereas the hepatocytes are generally negative. Of the 21 focal nodular hyperplasia cases, 20 cases (95.2%) showed a focal nodular hyperplasia-like pattern, whereas 13 (92.2%) of 14 hepatic adenoma cases showed a hepatic adenoma-like pattern. Both cases of telangiectatic focal nodular hyperplasia showed a hepatic adenoma-like pattern. CD34 stain showed areas of diffuse endothelial staining in 2 cases of hepatic adenoma, 3 cases of focal nodular hyperplasia, and both cases of telangiectatic focal nodular hyperplasia, whereas the remaining cases showed staining of endothelial cells only in the inflow areas of the sinusoids. A mixed (diffuse and inflow) pattern of CD34 staining was seen in 1 focal nodular hyperplasia, 1 hepatic adenoma, and 2 telangiectatic focal nodular hyperplasia cases. For statistical analysis, the telangiectatic focal nodular hyperplasia were considered as variants of hepatic adenoma. The findings were found to be highly statistically significant (P < .05) for cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule stains. An inflow staining pattern favors a diagnosis of focal nodular hyperplasia; however, overall, CD34 stain was not helpful in differentiating focal nodular hyperplasia and hepatic adenoma. Corresponding resection specimens (hepatic adenoma = 5, focal nodular hyperplasia = 2) showed staining patterns that were identical to the biopsy, whereas resections of the telangiectatic focal nodular hyperplasia cases showed both focal nodular hyperplasia and hepatic adenoma-like areas. Considering that telangiectatic focal nodular hyperplasia is now thought to be a variant of hepatic adenoma, the staining patterns correctly identified all cases, except one case each of focal nodular hyperplasia and hepatic adenoma. In summary, a combination of cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule immunostains performed on needle biopsies of liver shows distinctive patterns similar to that of resection specimen. The stains, especially cytokeratins 7 and 19, are very helpful in distinguishing normal from lesional tissue, as well as hepatic adenoma from focal nodular hyperplasia, and could be diagnostically helpful in challenging cases. Prospective studies to evaluate use of these stains in challenging cases are needed to validate these findings.

A rodent model of NASH with cirrhosis, oval cell proliferation and hepatocellular carcinoma

BACKGROUND/AIMS

Hepatocellular carcinoma (HCC) is a well recognized complication of advanced NASH (non-alcoholic steatohepatitis). We sought to produce a rat model of NASH, cirrhosis and HCC.

METHODS

Adult Sprague-Dawley rats, weighing 250-300g, were fed a choline-deficient, high trans-fat diet and exposed to DEN in drinking water. After 16 weeks, the animals underwent liver ultrasound (US), sacrifice and assessment by microscopy, immunohistochemistry and transmission electron microscopy (TEM).

RESULTS

US revealed steatosis and focal lesions in 6 of 7. All had steatohepatitis defined as inflammation, advanced fibrosis and ballooning with Mallory-Denk bodies (MDB) with frank cirrhosis in 6. Areas of more severe injury were associated with anti-CK19 positive ductular reaction. HCC, present in all, were macro-trabecullar or solid with polyhedral cells with foci of steatosis and ballooned cells. CK19 was positive in single or solid nests of oval cells and in neoplastic hepatocytes. TEM showed ballooning with small droplet fat, dilated endoplasmic reticulum and MDB in non-neoplastic hepatocytes and small droplet steatosis in some cancer cells.

CONCLUSIONS

This model replicated many features of NASH including steatohepatitis with ballooning, fibrosis, cirrhosis and hepatocellular carcinoma. Oval cell proliferation was evident and the presence anti-CK 19 positivity in the cancer suggests oval cell origin of the malignancy.

Biliary phenotype of hepatocellular carcinoma after preoperative transcatheter arterial chemoembolization

BACKGROUND AND AIM

Transcatheter arterial chemoembolization (TACE) is now the mainstay of treatment for non-curative hepatocellular carcinoma (HCC), and hoped to have chemotherapeutic and ischemic effects; however, the histopathological changes of HCC caused by TACE have not been sufficiently discussed so far. We aimed to assess the morphological and immunohistochemical features of HCC treated with TACE by immunostaining cytokeratin (CK) 7, CK14, CK19 and vimentin, and to correlate these data with observed clinicopathological characteristics.

METHODS

Eighty cases of surgically resected HCC with preoperative TACE and 146 cases of HCC resected without TACE as a control were analyzed.

RESULTS

The incidences of intrahepatic metastasis, poorly differentiated histology, multinucleated giant cells, mitotic figures and cytoplasmic inclusion bodies in the TACE group were significantly higher than those in the non-TACE group. The TACE group showed reactivity for CK7 in 56.3% (45/80) of patients, CK14 in 12.5% (10/80), CK19 in 23.8% (19/80) and vimentin in 6.3% (5/80) of patients. CK19 expression in the TACE group was significantly higher than in the non-TACE group (P = 0.0423). There was no correlation between immunoreactivity and the number of times TACE was carried out, but the expression of CK19 and vimentin in the massive necrotic group was higher than that in the mild necrotic group (P = 0.0197, P = 0.0229, respectively). Only TACE was an independent determinant of CK19 expression in all cases by multivariate analysis.

CONCLUSIONS

These results suggest that preoperative TACE may have an impact on the biliary phenotype of HCC. Some post-therapeutic HCC patients might develop HCC with a biliary phenotype indicating more aggressive malignancies.

Expression of multidrug resistance-associated protein 1 in hepatocellular carcinoma is associated with a more aggressive tumour phenotype and may reflect a progenitor cell origin

BACKGROUND

Hepatocellular carcinoma (HCC) responds poorly to chemotherapy owing to multidrug resistance (MDR). Recent studies showed that part of HCC could be of progenitor cell origin. Because some MDR-conferring transporters [multidrug resistance-associated protein 1 (MRP1), MDR1, MRP3 and breast cancer resistance protein (BCRP)] are expressed in hepatic progenitor cells (HPCs), expression in HCC might reflect a progenitor cell origin and provide the tumour cells with a MDR phenotype.

METHODS

The transcriptional profile of transporter genes was assessed in 139 HCCs earlier subjected to global gene expression analysis. In addition, we performed real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry for MRP1, MRP3, MDR1, BCRP and biliary/HPC markers keratin 7 and/or keratin 19 (K7/K19) on an independent set of 23 HCCs and surrounding liver.

RESULTS

Micro-array analysis showed that MRP1 was the only transporter with increased mRNA levels in HCC compared with the surrounding tissue. MRP1 mRNA levels were significantly higher in HCCs with poor survival and the 'hepatoblast subtype' of HCC, thought to be derived from HPCs. In 11 of 23 HCCs of the independent set, we found a diffuse protein expression of MRP1 compared with negative hepatocytic expression observed in normal (surrounding) hepatocytes. MRP1 was expressed in K19(+) non-neoplastic HPCs and K19(+) tumour cells. In addition, MRP3 and BCRP were expressed in K7/K19(+) tumour cells. MRP1 expression was high in poorly differentiated HCCs, large tumours (>7 cm) and microvascular invasive tumours.

CONCLUSIONS

MRP1 correlated with K19 mRNA and protein expression in two independent series of HCC. In addition, MRP1 was, together with MRP3 and BCRP, colocalized with K7/K19 in the tumour. Therefore, MRP1 expression could be a reflection of the HPC origin of this subgroup of HCCs and may result in an aggressive tumour phenotype.

Cytokeratin 10 and cytokeratin 19: predictive markers for poor prognosis in hepatocellular carcinoma patients after curative resection

PURPOSE

Cytokeratin 10 (CK10) was found to be expressed differently in human hepatocellular carcinoma (HCC) cell lines with different metastatic potentials in our previous research. The aim of this study was to assess the value of CK10 alone or in combination with cytokeratin 19 (CK19) in predicting tumor recurrence after curative resection in HCC patients.

EXPERIMENTAL DESIGN

CK10 expression in stepwise metastatic HCC cell lines and tumor tissues from 50 HCC patients was investigated using immunofluorescence assay, quantitative real-time reverse transcription-PCR, and Western blot analyses. Tumor tissue microarrays of 300 HCC patients who underwent curative resection between 1997 and 2000 were used to detect the expressions of CK10 and CK19. Clinicopathologic data for these patients were evaluated. The prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests.

RESULTS

CK10 was overexpressed in the high metastatic HCC cell line and in tumor tissues of recurrent patients. Both univariate and multivariate analyses revealed that CK10 was a significant predictor for overall survival (OS) and disease-free survival, and that CK19 was a significant predictor for OS. CK10 expression was correlated with poor prognosis regardless of alpha-fetoprotein, tumor-node-metastasis stage, and vascular invasion. The 7-year OS and disease-free survival rates in CK10+ and/or CK19+ patients were 30.0% and 37.6%, respectively, which were significantly lower than that of CK10-/CK19- patients (56.1% and 60.0%, respectively; P < 0.001).

CONCLUSION

CK10 is associated with HCC invasiveness. CK10 alone, or in combination with CK19, can be a novel predictor for poor prognosis of HCC patients after curative resection.

[Hepatitis C, cirrhosis and hepatocellular carcinoma]

The screening for the detection of hepatocellular carcinoma is based on ultrasound sonography which should be realised in patients with post-hepatitis C cirrhosis with a delay between 3 and 6 months according to the most identified risk factors, in particular age and sex male. In the case of discovery of hypoechogen nodule < or = 1cm, a follow-up is mandatory because it is usually untypical by ultrasound sonography and to propose a liver biopsy in the case of an increasing in size is shown. The ultrasound guided cutting biopsy can precise the histological characteristics of the nodule, the grade, and indicate prognostic factors. The liver biopsy is also mandatory in the case of a nodule > 2 cm and when the ultrasound sonography is not contributive, especially when the nodule is between 1 and 2 cm in size.

Ezrin expression is associated with hepatocellular carcinoma possibly derived from progenitor cells and early recurrence after surgical resection

Heterogeneous biological characteristics of hepatocellular carcinoma may be attributed to the cellular origin of the tumor. Patients with hepatocellular carcinoma probably derived from hepatic progenitor cells had early tumor recurrence after surgical resection or liver transplantation, suggesting that these tumors have aggressive characteristics. Ezrin, a member of the ERM (ezrin-radixin-moesin) cytoskeleton-associated protein family, is highly expressed in several types of human cancers and correlations between its immunoreactivity and patient outcome have been shown. In this study, ezrin expression, as well as cytokeratin19 and cytokeratin 7 expression, which are regarded as progenitor cell/ductular markers were immunohistochemically assessed in cases of hepatocellular carcinoma. In normal livers, ezrin expression was not found in any cell types, whereas cytokeratin 7 and cytokeratin 19 were exclusively stained in bile duct cells. In contrast, in livers with chronic hepatitis or cirrhosis, positive ezrin expression was observed in ductular reactions with strong intensity and intermediate hepatobiliary cells with various intensity. Of 77 cases of hepatocellular carcinoma, 28 (36%) had positive ezrin expression, 32 (42%) had cytokeratin 7 expression, and 11 (14%) had cytokeratin 19 expression. Ezrin expression in hepatocellular carcinoma was significantly associated with cytokeratin 19 expression, but not with cytokeratin 7 expression. Patients with ezrin-positive hepatocellular carcinoma had a significantly higher prevalence of elevated serum alpha-fetoprotein. Patients with immunohistochemical ezrin-positive hepatocellular carcinoma demonstrated significantly shorter recurrence-free and overall survival compared to patients with ezrin-negative hepatocellular carcinoma. Multivariate analysis revealed positive ezrin expression and multiple tumors to be independently associated with early recurrence in patients with hepatocellular carcinoma after curative surgical resection. These results suggested that hepatocellular carcinoma with ezrin expression might be at least partly derived from hepatic progenitor cells. Measurement of ezrin expression might be used to identify patients with an increased risk of early recurrence.

Telomeric 3' overhangs in chronic HBV-related hepatitis and hepatocellular carcinoma

Telomeric 3' overhang is a key component of telomere structure, but little is known about its role in hepatocarcinogenesis. We examined the 3' overhang and telomere length, mRNA levels of hTERT, POT1, TRF1 and cytokeratin 19 (CK19) in 41 hepatitis B virus (HBV)-related hepatocellular carcinomas (HCCs) and adjacent non-HCCs of B viral chronic hepatitis/cirrhosis. 3' overhang length was positively correlated with telomere length (p < 0.001). In non-HCCs, the 3' overhang shortened with increasing age (p = 0.043). Twenty-six HCCs had shorter and 15 HCCs had longer 3' overhangs than the adjacent non-HCCs. The mRNA levels of hTERT, POT1 and TRF1 were upregulated in HCCs than in non-HCCs. HCCs with lengthened 3' overhangs expressed higher hTERT mRNA levels than those with shortened 3' overhangs, when compared to 3' overhangs in non-HCCs (p = 0.044). POT1 and TRF1 showed no significant difference according to the 3' overhangs. HCCs with long 3' overhangs had higher mitosis (p = 0.046) and more frequent multipolar mitosis compared to those with short 3' overhangs (p = 0.034). HCCs with high cytokeratin 19 mRNA levels, a marker for hepatic progenitor cells, had longer 3' overhangs than HCCs with low cytokeratin 19 mRNA levels (p= 0.019). In conclusion, the 3' overhang erosion might be closely related to the number of cell divisions in telomerase-negative hepatocytes of chronic hepatitis/cirrhosis. In telomerase-positive HCCs, an altered 3' overhang are involved in HBV-related hepatocarcinogenesis and hTERT might be involved in regulation of 3' overhang.

Accumulation of hedgehog-responsive progenitors parallels alcoholic liver disease severity in mice and humans

BACKGROUND & AIMS

Improving outcomes in alcoholic liver disease (ALD) necessitates better understanding of how habitual ethanol (EtOH) consumption alters normal regenerative mechanisms within the liver. Hedgehog (Hh) pathway activation promotes expansion of progenitor populations in other tissues. We evaluated the hypothesis that chronic EtOH exposure activates Hh signaling in liver.

METHODS

Hh signaling, liver progenitors, transforming growth factor (TGF)-beta induction, and liver damage were compared in mice fed chow, high-fat diets (HF), or HF + EtOH for 4 weeks. Susceptibility to TGF-beta-mediated apoptosis was compared in Hh-responsive liver cells (eg, immature cholangiocytes and oval cells) and mature hepatocytes (which are unresponsive to Hh). Hepatic accumulation of Hh-responsive cells were compared in controls and ALD patients and correlated with a discriminant function (DF) that predicts subacute mortality.

RESULTS

Hh signaling and numbers of Hh-responsive cells were increased in HF mice and greatest in HF+EtOH mice. In both, progenitor and stromal cell populations harbored Hh-responsive cells. More ductular-type progenitors and fibrosis markers were noted in HF+EtOH mice than in HF mice. The former also expressed more TGF-beta-1. TGF-beta-1 treatment selectively promoted the viability of Hh-responsive immature liver cells and caused mature hepatocytes that survived to produce Hh ligands. Hh-responsive cells were increased in ALD patients. Lobular accumulation of Hh-responsive immature ductular cells was greater in those with a DF >32 than those with a DF <32.

CONCLUSIONS

Hh signaling is increased in ALD and may influence ALD outcomes by promoting hepatic accumulation of immature ductular cells.

Clinicopathological study on cholangiolocellular carcinoma suggesting hepatic progenitor cell origin

Cholangiolocellular carcinoma (CLC), a subtype of cholangiocellular carcinoma (CC), is thought to originate from the ductules/canals of Hering, where hepatic progenitor cells (HPCs) are located. We investigated the clinicopathological features of 30 CLCs and their relationship to HPCs. We evaluated the expression of hepatocytic markers (hepatocyte paraffin-1, canalicular polyclonal carcinoembryonic antigen, and CD10), biliary/HPC markers (keratin [K]7, K19, and neural cell adhesion molecule), the adenosine triphosphate binding cassette transporters: multidrug resistance protein 1, multidrug resistance-associated protein (MRP)1, MRP3, and breast cancer resistance protein, using immunohistochemistry and electron microscopy. In addition, gene expression profiling of CLC was performed and compared with the profile of hepatocellular carcinoma (HCC) with or without HPC features (K19 expression). In surrounding nontumoral tissue, K7-positive and K19-positive HPCs/ductular reaction were observed. More than 90% of the tumor was composed of CLC areas that showed small monotonous and/or anastomosing glands, strongly positive for K7 and K19. Especially at the tumor boundary, all cases showed a HCC-like trabecular area characterized by canalicular CD10/polyclonal carcinoembryonic antigen expression, and submembranous K7 expression, similar to intermediate hepatocytes. K7-positive/K19-positive HPCs were also seen. Out of 30 cases, 19 showed papillary and/or clear glandular formation with mucin production, representing CC areas. These three different areas showed transitional zones with each other. We observed an increased expression of MRP1, MRP3, and breast cancer resistance protein in the tumor. Electron microscopy findings in HCC-like trabecular areas confirmed the presence of HPCs and intermediate hepatocytes. HPC markers, K7, K19, prominin-1, receptor for stem cell factor c-kit, octamer-4 transcription factor, and leukemia inhibitory factor were upregulated (P < 0.05), while albumin was downregulated in CLC (P = 0.007) toward K19-negative HCCs. Comparison of CLC with K19-positive HCCs indicated a high homology.

CONCLUSION

All these findings highly suggest a progenitor cell origin of CLC.

Altered regulation of Prox1-gene-expression in liver tumors

Background

Prospero-related homeobox 1 (Prox1) transcription factor was described as a tumor-suppressor gene in liver tumors. In contrast, Prox1 knock out in murine embryos drastically reduces proliferation of hepatoblasts.

Methods

We have studied the expression of Prox1 in normal liver, liver cirrhosis and peritumoral liver samples in comparison to hepatocellular (HCC) and cholangiocellular carcinoma (CCC) at mRNA, protein and functional levels.

Results

Prox1 was found in hepatocytes of normal liver, while normal bile duct epithelial cells were negative. However, Prox1⁺ cells, which co-expressed biliary epithelial makers and showed ductular morphology, could be detected within fibrotic septa of cirrhotic livers, and in both HCC and CCC. Two Prox1 mRNA isoforms (2.9 kb and 7.9 kb) were identified with a prevalence of the longer isoform in several HCC samples and the shorter in most CCC samples. Evidence was provided that Myc-associated zinc finger protein (MAZ) might significantly contribute to the gene expression of Prox1 in HCC, while neo-expression of Prox1 in CCC remains to be resolved. A point mutation in the prospero domain of Prox1 was found in one HCC sample.

Conclusion

Our study shows dysregulation of Prox1 in liver cirrhosis, HCC and CCC, such as neo-expression in cells with biliary epithelial phenotype in liver cirrhosis, and in CCC. Altered Prox1 mRNA expression is partly regulated by MAZ, and mutation of the prospero domain in HCC indicates an involvement for Prox1 during tumor progression.

Immunolabeling pattern of cytokeratin 19 expression may distinguish sebaceous tumors from basal cell carcinomas

BACKGROUND

Distinction between sebaceous tumors and basal cell carcinomas can often pose diagnostic problems. Recent work with the antibody to cytokeratin 19 (CK 19) has shown that this marker has high specificity for undifferentiated basaloid cells. Our aim was to evaluate the use of CK 19 staining patterns in differentiating between sebaceous tumors and basal cell carcinomas. The sebaceous tumors that were examined in this study included sebaceous adenomas, sebaceous epitheliomas (sebaceomas) and sebaceous carcinomas.

METHODS

Thirty-seven cases including 5 sebaceous adenomas, 16 sebaceous epitheliomas, 6 sebaceous carcinomas and 14 basal cell carcinomas (7 being of the morpheaform type and 7 nodular basal cell carcinomas) were tested with a monoclonal mouse antibody to human CK 19.

RESULTS

CK 19 was focally positive in 1/5 (20%) sebaceous adenomas, 8/16 (50%) of sebaceous epitheliomas and 1/6 (17%) of sebaceous carcinomas. Strongly positive expression of CK 19 was not seen in any of the sebaceous adenoma, sebaceous epithelioma or sebaceous carcinoma specimens. CK 19 was found to be strongly positive in 9/14 (64%) and focally positive in 2/14 (14%) of basal cell carcinomas.

CONCLUSION

CK 19 expression can be helpful in differentiating sebaceous tumors (including sebaceous adenomas, sebaceous epitheliomas and sebaceous carcinomas) from basal cell carcinomas and may be a useful adjunct when these entities are included in the differential diagnosis.

Combined hepatocellular cholangiocarcinoma originating from hepatic progenitor cells: immunohistochemical and double-fluorescence immunostaining evidence

AIMS

Combined hepatocellular cholangiocarcinoma (CHC) is a rare form of primary liver cancer, showing a mixture of hepatocellular and biliary features. Data suggest that most CHC arise from hepatic progenitor cells (HPCs). The aim was to investigate the origin of CHC.

METHODS AND RESULTS

Twelve cases of CHC were studied by immunohistochemistry for hepatocytic (hepPar1, alpha-fetoprotein), cholangiocytic cytokeratin [(CK) 7, CK19], hepatic progenitor cell (OV-6), haematopoietic stem cell (c-kit, CD34), as well as CD45 and chromogranin-A markers. The combination of double-fluorescence immunostaining consisted of HepPar1 with CK19, and c-kit with OV-6. All 12 cases demonstrated more or less transitional areas, with strands/trabeculae of small, uniform, oval-shaped cells including scant cytoplasm and hyperchromatic nuclei embedded within a thick, desmoplastic stroma; however, two cases were found to consist entirely of such transitional areas. Simultaneous co-expression of hepPar1 and CK7, or CK19, was demonstrated in 10/12 (83.3%) cases of CHC. c-kit expression was noted in 10/12 (83.3%) cases, of which 7/10 (70%) showed co-expression of OV-6.

CONCLUSIONS

The results suggest that CHC are of HPC origin, supporting the concept that human hepatocarcinogenesis may originate from the transformation of HPCs.

Progenitor/stem cells give rise to liver cancer due to aberrant TGF-beta and IL-6 signaling

Cancer stem cells (CSCs) are critical for the initiation, propagation, and treatment resistance of multiple cancers. Yet functional interactions between specific signaling pathways in solid organ "cancer stem cells," such as those of the liver, remain elusive. We report that in regenerating human liver, two to four cells per 30,000-50,000 cells express stem cell proteins Stat3, Oct4, and Nanog, along with the prodifferentiation proteins TGF-beta-receptor type II (TBRII) and embryonic liver fodrin (ELF). Examination of human hepatocellular cancer (HCC) reveals cells that label with stem cell markers that have unexpectedly lost TBRII and ELF. elf(+/-) mice spontaneously develop HCC; expression analysis of these tumors highlighted the marked activation of the genes involved in the IL-6 signaling pathway, including IL-6 and Stat3, suggesting that HCC could arise from an IL-6-driven transformed stem cell with inactivated TGF-beta signaling. Similarly, suppression of IL-6 signaling, through the generation of mouse knockouts involving a positive regulator of IL-6, Inter-alpha-trypsin inhibitor-heavy chain-4 (ITIH4), resulted in reduction in HCC in elf(+/-) mice. This study reveals an unexpected functional link between IL-6, a major stem cell signaling pathway, and the TGF-beta signaling pathway in the modulation of mammalian HCC, a lethal cancer of the foregut. These experiments suggest an important therapeutic role for targeting IL-6 in HCCs lacking a functional TGF-beta pathway.

High telomerase activity and long telomeres in advanced hepatocellular carcinomas with poor prognosis

Telomerase reactivation and telomere maintenance are crucial in carcinogenesis and tumor progression. In this study, the relationships between telomere parameters, chromosomal instability and clinicopathological features were evaluated in hepatocellular carcinomas (HCCs). Telomere length (TL), telomerase activity (TA) and human telomerase reverse transcriptase (hTERT) mRNA levels were measured in 49 hepatitis B virus (HBV)-related HCCs and corresponding non-tumorous tissues. The results were compared with clinicopathological data, including differentiation, multipolar mitosis (MM), anaphase bridge, immunohistochemical stain results for cytokeratin 19 (CK19) and patient outcome. TL of HCCs ranged from 4.7 to 13.1 kb, and 44.4% of HCCs showed telomere lengthening. hTERT mRNA levels and TA were closely related (P=0.008), and were significantly higher in HCCs than non-tumorous tissues. TL was significantly higher in HCCs with strong TA (P=0.048), high hTERT mRNA levels (P=0.001) and poor differentiation (P=0.041). Frequent MM was associated with poor differentiation (P=0.007) and advanced stage (P<0.001). TA was positively correlated with MM, anaphase bridges and advanced stage (P=0.019, P=0.017 and P=0.029). Thirteen (28.3%) HCCs were CK19+ and demonstrated longer telomeres than CK19- HCCs (P=0.046). Overall survival was poor in HCCs with MM >0.4 per field (P=0.016), high TA (P=0.009) and high TL ratio (HCC/non-HCC) >0.8 (P=0.044). Our results show that long telomeres, high TA and high mitotic instability are poor prognostic markers for HBV-related HCCs and their close association suggests that telomere maintenance may be important for the progression of HCCs with high chromosomal instability to more aggressive ones.

The multidisciplinary management of gastrointestinal cancer. The diagnostic and therapeutic approach for primary solid liver tumours in adults

The finding of a focal solid liver lesion represents a challenge for the clinician in terms of the most optimal diagnostic and therapeutic algorithm. Tumours may arise from hepatocytes (hepatocellular adenoma, dysplastic nodules and carcinoma), bile ducts (cholangiocarcinoma) or mesenchymal tissue (hemangioma, epithelioid haemangioendothelioma), or are metastases from primary tumours outside the liver. Focal nodular hyperplasia is the most frequent tumour-like lesion. Imaging techniques are able to detect and characterise most lesions. However, small hypervascular lesions in a cirrhotic liver may be difficult to characterise. More insight has been gathered recently in the histological classification of hepatocellular adenomas, but the differential diagnosis by imaging of adenoma versus FNH or well-differentiated hepatocellular carcinoma remains often difficult. The therapy of a focal liver lesion is determined by its natural history and the functional status of the surrounding liver parenchyma. Selected patients with primary liver cancer are candidates for liver transplantation, while patients with advanced malignant tumours have a poor outcome.

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.

Origin of cancer stem cells: the role of self-renewal and differentiation

BACKGROUND

Self-renewal and differentiation potential is the feature of stem cells. Differentiation is usually considered to be a one-way process of specialization as cells develop the functions of their ultimate fate and lose their immature characteristics, such as self-renewal. Progenitor cells, the products of stem cells losing the activity of self-renewal, could differentiate to mature cells, which have the feature of differentiation and lose the activity of self-renewal. The roles for cancer stem cells have been demonstrated for some cancers. However, the origin of the cancer stem cells remains elusive.

METHODS

This review focuses on current scientific controversies related to the establishment of the cancer stem cells--in particular, how self-renewal and differentiation block might contribute to the evolution of cancer.

RESULTS

Cancer stem cells may be caused by transforming mutations occurring in multi-potential stem cells, tissue-specific stem cells, progenitor cells, mature cells and cancer cells. Progenitor cells obtain the self-renewal activity by activating the self-renewal-associated genes rather than dedifferentiate to tissue special stem cells. The transform multi-potential stem cells gain the differentiation feature of special tissue by differentiating to cancer cells. Mature cells and cancer cells may dedifferentiate or reprogram to cancer stem cells by genetic and / or epigenetic events to gain the self-renewal activity and lose some features of differentiation. The cancer-derived stem cells are not the "cause", but the "consequence" of carcinogenesis. The genetic program controlling self-renewal and differentiation is a key unresolved issue.

CONCLUSION

Cancer stem cells may be caused by disturbance of self-renewal and differentiation occurring in multi-potential stem cells, tissue-specific stem cells, progenitor cells, mature cells and cancer cells.

Best practices in diagnostic immunohistochemistry: hepatocellular carcinoma versus metastatic neoplasms

CONTEXT

Immunohistochemistry plays a crucial role in the diagnosis of hepatocellular carcinoma and in its distinction from other primary and metastatic neoplasms. Because limited tissue is available with fine-needle and core biopsies, appropriate selection of antibodies is imperative.

OBJECTIVE

To review the antibodies used for the diagnosis of hepatocellular carcinoma and to outline an immunohistochemical approach in commonly encountered clinical situations.

DATA SOURCES

Our experience and review of research articles published in the English literature between 1987 and 2006.

CONCLUSIONS

Hep Par 1 and polyclonal carcinoembryonic antigen are the most reliable markers for hepatocellular differentiation, but they have low sensitivity for poorly differentiated cases. Immunohistochemistry for glypican-3 shows promise for the diagnosis of poorly differentiated hepatocellular carcinoma and for its distinction from benign processes such as hepatic adenoma. Further studies with a large number of cases are required before it can be widely used. The combination of Hep Par 1 and MOC-31 will allow for the diagnosis of hepatocellular carcinoma in most cases and will guide the selection of immunohistochemical markers for further workup.

Intratumoral sampling variability in hepatocellular carcinoma: A case report

The differential diagnosis between hepatocellular carcinoma (HCC) and regenerative liver nodules and other primary liver tumors may be very difficult, particularly when performed on liver biopsies. Difficulties in histological typing may be often minimized by immunohistochemistry. Among the numerous markers proposed, CK18, Hep Par1 and glypican 3 (GPC3) are considered the most useful in HCC diagnosis. Here we report a case of HCC in a 72-year-old male with HBV-related chronic liver disease, characterized by a marked morphological and immunohistochemical intratumoral variability. In this case, tumor grading ranged from areas extremely well differentiated, similar to regenerative nodule, to undifferentiated regions, with large atypical multinucleated cells. While almost all sub nodules were immunostained by Hep Par 1, immunoreactivity for glypican 3 and for Ck18 was patchy, with negative tumor region adjacent to the highly immunoreactive areas. Our case stresses the relevance of sampling variability in the diagnosis of HCC, and indicates that caution should be taken in grading an HCC and in the interpretation of immunohistochemical stains when only small core biopsies from liver nodules are available.

Hepatic progenitor cells in human liver tumor development

In recent years, the results of several studies suggest that human liver tumors can be derived from hepatic progenitor cells rather than from mature cell types. The available data indeed strongly suggest that most combined hepatocellular-cholangiocarcinomas arise from hepatic progenitor cells that retained their potential to differentiate into the hepatocytic and biliary lineages. Hepatic progenitor cells could also be the basis for some hepatocellular carcinomas and hepatocellular adenomas, although it is very difficult to determine the origin of an individual hepatocellular carcinoma. There is currently not enough data to make statements regarding a hepatic progenitor cell origin of cholangiocarcinoma. The presence of hepatic progenitor cell markers and the presence and extent of the cholangiocellular component are factors that are related to the prognosis of hepatocellular carcinomas and combined hepatocellular-cholangiocarcinomas, respectively.