Cholangiocarcinoma: recent progress. Part 2: molecular pathology and treatment

SRC-like adaptor protein negatively regulates Wnt signaling in intrahepatic cholangiocarcinoma

Currently, the molecular mechanisms underlying intrahepatic cholangiocarcinoma (IHCC) are poorly understood. In the present study, the focus was primarily on SRC-like adaptor protein (SLAP), an adaptor protein, which is aberrantly expressed in various cancer types. To the best of our knowledge, the present study was the first to demonstrate that SLAP was decreased in IHCC tissues and cells, compared with controls. Further study indicated that SLAP overexpression suppressed IHCC cell proliferation and induced cell cycle arrest, indicating the tumor suppressor role of SLAP in IHCC progression. To demonstrate the effects of SLAP on Wnt signaling, the β-catenin/T cell factor transcription reporter assay was conducted. Compared with the negative adenovirus vector control (Ad-NC), overexpression of SLAP reduced TOPflash activity, and no changes in FOPflash activity were identified. Furthermore, the expression levels of Wnt target genes, including β-catenin, c-Myc, cluster of differentiation 44, Slug, Vimentin and matrix metallopeptidase-9, were reduced in RBE and Huh28 cells overexpressing SLAP. Additionally, the effects of SLAP on IHCC cell invasion and migration were determined. Compared with the Ad-NC control, the migration and invasion capacity was reduced following overexpression of SLAP in RBE and Huh28 cells. In summary, reduced SLAP expression may enhance IHCC malignant progression by activating Wnt signaling.

The Role of Stroma in Cholangiocarcinoma: The Intriguing Interplay between Fibroblastic Component, Immune Cell Subsets and Tumor Epithelium

Cholangiocarcinoma (CCA) is a severe and mostly intractable adenocarcinoma of biliary epithelial cells. A typical feature of CCA is its highly desmoplastic microenvironment containing fibrogenic connective tissue and an abundance of immune cells (T lymphocytes, Natural Killer (NK) cells, and macrophages) infiltrating tumor epithelium. This strong desmoplasia is orchestrated by various soluble factors and signals, suggesting a critical role in shaping a tumor growth-permissive microenvironment that is responsible for CCA poor clinical outcome. Indeed stroma not only provides an abundance of factors that facilitate CCA initiation, growth and progression, but also a prejudicial impact on therapeutic outcome. This review will give an overview of tumor-stroma signaling in a microenvironment critically regulating CCA development and progression. Identification of CCA secreted factors by both the fibroblast component and immune cell subsets might provide ample opportunities for pharmacological targeting of this type of cancer.

Delivery of miR-200c Mimic with Poly(amido amine) CXCR4 Antagonists for Combined Inhibition of Cholangiocarcinoma Cell Invasiveness

Cholangiocarcinoma is the second most common primary liver malignancy with extremely poor prognosis due to early invasion and widespread metastasis. The invasion and metastasis are regulated by multiple factors including CXCR4 chemokine receptor and multiple microRNAs. The goal of this study was to test the hypothesis that inhibition of CXCR4 combined with the action of miR-200c mimic will cooperatively enhance the inhibition of the invasion of human cholangiocarcinoma cells. The results show that CXCR4-inhibition polycation PCX can effectively deliver miR-200c mimic and that the combination treatment consisting of PCX and miR-200c results in cooperative antimigration activity, most likely by coupling the CXCR4 axis blockade with epithelial-to-mesenchymal transition inhibition in the cholangiocarcinoma cells. The ability of the combined PCX/miR-200c treatment to obstruct two migratory pathways represents a promising antimetastatic strategy in cholangiocarcinoma.

Blockade of CXCL12/CXCR4 signaling inhibits intrahepatic cholangiocarcinoma progression and metastasis via inactivation of canonical Wnt pathway

Background

Intrahepatic cholangiocarcinoma (IHCC) is the second most frequent primary malignant liver tumor following hepatocellular carcinoma. It is a highly fatal disease and has few therapeutics. The CXC chemokine ligand-12 (CXCL12)/CXC chemokine receptor type 4 (CXCR4) axis has been shown to be involved in tumorgenesis, proliferation, and angiogenesis in a variety of cancers including IHCC. However, its prognostic significance in IHCC is unclear. The purpose of this study was to examine the functional role of CXCR4 in the progression and metastasis of IHCC and explore the underlying mechanism.

Methods

The CXCR4 expression, overall survival, and the clinical characteristics including age, sex, differentiation degree, tumor size, vascular invasion, lymph node metastasis, TNM stage, and T stage were analyzed for 122 IHCC patients. Short hairpin RNA (shRNA) against CXCR4 was used to disrupt the CXCL12/CXCR4 signal transduction pathways in IHCC cell lines. In vitro assays, including CCK-8 assay, flow cytometry, and colony formation assay, and in vivo tumor formation assay were utilized to detect the cell phenotype of CXCR4 knockdown cells. Transwell and wound healing assays were used to examine the IHCC cell invasion and migration ability. The Wnt pathway was assessed by Western blot and β-Catenin/Tcf transcription reporter assay.

Results

We demonstrated that CXCR4 expression was closely correlated with IHCC progression and metastasis characteristics. The overall survival of patients with high CXCR4 expression was significantly lower than that of patients with low CXCR4 expression. Furthermore, we showed that the abrogation of CXCR4 had significantly negative influence on the IHCC cell phenotype, including in vitro cell proliferation, cell cycle, colony formation, cell invasion, and in vivo tumorigenicity. In addition, CXCR4 knockdown downregulated Wnt target genes and mesenchymal markers such as Vimentin and Slug.

Conclusions

In conclusion, our result shows that high CXCR4 expression is associated with IHCC progression and metastasis via the canonical Wnt pathway, suggesting that CXCR4 may serve as a promising therapeutic target for IHCC.

Conditional knockout mouse models of cancer

In 2007, three scientists, Drs. Mario R. Capecchi, Martin J. Evans, and Oliver Smithies, received the Nobel Prize in Physiology or Medicine for their contributions of introducing specific gene modifications into mice. This technology, commonly referred to as gene targeting or knockout, has proven to be a powerful means for precisely manipulating the mammalian genome and has generated great impacts on virtually all phases of mammalian biology and basic biomedical research. Of note, germline mutations of many genes, especially tumor suppressors, often result in lethality during embryonic development or at developmental stages before tumor formation. This obstacle has been effectively overcome by the use of conditional knockout technology in conjunction with Cre-LoxP- or Flp-Frt-mediated temporal and/or spatial systems to generate genetic switches for precise DNA recombination. Currently, numerous conditional knockout mouse models have been successfully generated and applied in studying tumor initiation, progression, and metastasis. This review summarizes some conditional mutant mouse models that are widely used in cancer research and our understanding of the possible mechanisms underlying tumorigenesis.

Vascular biology of the biliary epithelium

Cholangiocytes are involved in a variety of processes essential for liver pathophysiology. To meet their demanding metabolic and functional needs, bile ducts are nourished by their own arterial supply, the peribiliary plexus. This capillary network originates from the hepatic artery and is strictly arranged around the intrahepatic bile ducts. Biliary and vascular structures are linked by a close anatomic and functional association necessary for liver development, normal organ physiology, and liver repair. This strong association is finely regulated by a range of angiogenic signals, enabling the cross talk between cholangiocytes and the different vascular cell types. This review will briefly illustrate the "vascular" properties of cholangiocytes, their underlying molecular mechanisms and the relevant pathophysiological settings.

Liver carcinogenesis: rodent models of hepatocarcinoma and cholangiocarcinoma

Hepatocellular carcinoma and cholangiocarcinoma are primary liver cancers, both represent a growing challenge for clinicians due to their increasing morbidity and mortality. In the last few years a number of in vivo models of hepatocellular carcinoma and cholangiocarcinoma have been developed. The study of these models is providing a significant contribution in unveiling the pathophysiology of primary liver malignancies. They are also fundamental tools to evaluate newly designed molecules to be tested as new potential therapeutic agents in a pre-clinical set. Technical aspects of each model are critical steps, and they should always be considered in order to appropriately interpret the findings of a study or its planning. The purpose of this review is to describe the technical and experimental features of the most significant rodent models, highlighting similarities or differences between the corresponding human diseases. The first part is dedicated to the discussion of models of hepatocellular carcinoma, developed using toxic agents, or through dietary or genetic manipulations. In the second we will address models of cholangiocarcinoma developed in rats or mice by toxin administration, genetic manipulation and/or bile duct incannulation or surgery. Xenograft or syngenic models are also proposed.

Intrahepatic cholangiocarcinomas in cirrhosis are hypervascular in comparison with those in normal livers

BACKGROUND AND AIMS

Intrahepatic cholangiocarcinomas (ICCs) are usually adenocarcinomas with fibrotic and hypovascular stroma. Intrahepatic cholangiocarcinomas in cirrhosis and precirrhotic liver (ICC-cirrhosis) are increasingly being diagnosed, and can display hypervascular enhancement resembling a hepatocellular carcinoma on dynamic imaging.

METHODS

In this study using ICC-cirrhosis (71 cases), ICC with non-specific reactive changes (ICC-reactive) (72 cases) and the cholangiocarcinoma component of combined hepatocellular cholangiocarcinoma (HCC-ICC) (30 cases), we tried to compare the tumour vasculature.

RESULTS

It was found that ICC-cirrhosis and the cholangiocarcinoma component of HCC-ICC showed a higher density of arteries and microvessels (1.59 ± 0.58/mm(2) (mean ± SD) and 140 ± 43/mm(2) in ICC-cirrhosis and 1.74 ± 0.67/mm(2) and 131 ± 46/mm(2) in the cholangiocarcinoma component of HCC-ICC) than in ICC-reactive (1.26 ± 0.61/mm(2) and 103 ± 45/mm(2) ). Dynamic computed tomography (CT) and magnetic resonance imaging (MRI) showed that a majority of ICC-cirrhosis displayed strong hypervascular enhancement, whereas one-third of ICC-reactive each showed strong, weak and no or minimal enhancement respectively. The increased vascular density was positively correlated with enhanced arterial phase of dynamic CT and MRI.

CONCLUSION

The density of arteries and microvessels of ICC-cirrhosis was higher than that in ICC-reactive and comparable to that in the cholangiocarcinoma component of HCC-ICC, and the higher density of arteries and microvessels in ICC may be responsible for the hypervascular enhancement of ICC-cirrhosis.

Molecular pathogenesis of cholangiocarcinoma

Epidemiological data from the last years show an increasing trend of incidence and mortality of cholangiocarcinoma (CC) worldwide. Many pathophysiologic aspects of this neoplasia are still unknown and need to be fully discovered. However, several progresses were recently made in order to establish the molecular mechanisms involved in the transformation and growth of malignant cholangiocytes. The principal concept that at least seems to be established is that cholangiocarcinogenesis is a multistep cellular process evolving from a normal condition of the epithelial biliary cells through a chronic inflammation status ending with malignant transformation. The bad prognosis related to CC justifies why a better identification of the molecular mechanisms involved in the growth and progression of this cancer is required for the development of effective preventive measures and valid treatment regimens. This Paper describes the scientific progresses made in the last years in defining the molecular pathways implicated in the generation of this devastating disease.

Expandable metal stents for malignant hilar biliary obstruction

Most patients with malignant hilar stenoses are candidates for palliation. For this purpose, biliary drainage plays a major role in improving liver function and managing or avoiding cholangitis. Endoscopic interventions are less invasive than the percutaneous approach and should be considered as the first-line drainage procedures in most cases. Transhepatic interventions should be reserved for endoscopic failures or performed as a complementary approach in a combined procedure. After successful endoscopic access to biliary obstruction, implantation of self-expandable metal stents offers advantages over plastic endoprostheses in terms of stent patency and number of reinterventions.

Microsomal prostaglandin E synthase-1 inhibits PTEN and promotes experimental cholangiocarcinogenesis and tumor progression

BACKGROUND & AIMS

Microsomal prostaglandin E synthase-1 (mPGES-1) is a rate-limiting enzyme that is coupled with cyclooxygenase (COX)-2 in the synthesis of prostaglandin E2. Although COX-2 is involved in the development and progression of various human cancers, the role of mPGES-1 in carcinogenesis has not been determined. We investigated the role of mPGES-1 in human cholangiocarcinoma growth.

METHODS

We used immunohistochemical analyses to examine the expression of mPGES-1 in formalin-fixed, paraffin-embedded human cholangiocarcinoma tissues. The effects of mPGES-1 on human cholangiocarcinoma cells were determined in vitro and in SCID mice. Immunoblotting and immunoprecipitation assays were performed to determine the levels of PTEN and related signaling molecules in human cholangiocarcinoma cells with overexpression or knockdown of mPGES-1.

RESULTS

mPGES-1 is overexpressed in human cholangiocarcinoma tissues. Overexpression of mPGES-1 in human cholangiocarcinoma cells increased tumor cell proliferation, migration, invasion, and colony formation; in contrast, RNA interference knockdown of mPGES-1 inhibited tumor growth parameters. In SCID mice with tumor xenografts, mPGES-1 overexpression accelerated tumor formation and increased tumor weight (P<.01), whereas mPGES-1 knockdown delayed tumor formation and reduced tumor weight (P<.01). mPGES-1 inhibited the expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), leading to activation of the epidermal growth factor/phosphoinositide 3-kinase/AKT/mammalian target of rapamycin signaling pathways in cholangiocarcinoma cells. mPGES-1-mediated inhibition of PTEN is regulated through blocking of early growth response-1 sumoylation and binding to the 5'-untranslated region of the PTEN gene.

CONCLUSIONS

mPGES-1 promotes experimental cholangiocarcinogenesis and tumor progression by inhibiting PTEN.

Cholangiocarcinoma: new insights into disease pathogenesis and biology

Cholangiocarcinomas are rare malignant tumors whose incidence is increasing worldwide. Risk factors for this malignancy include both infectious and non-infectious diseases characterized by chronic inflammation of the bile duct epithelia. Diagnosis of these cancers remains difficult because of the lack of sensitive diagnostic tests. The prognosis is poor probably because of the lack of effective treatments for unresectable cancer.

Disseminated superficial porokeratosis in a patient with cholangiocarcinoma: a paraneoplastic manifestation?

Porokeratosis refers to a group of hereditary or acquired disorders of epidermal keratinization and is characterized histologically by the presence of a cornoid lamella. The clinical variant referred to as disseminated superficial porokeratosis has been described in the literature in association with immunosuppressive conditions that include organ transplant, infections and immunosuppressive treatments. The association of disseminated superficial porokeratosis with solid organ malignancies has seldom been described, only 5 such cases having been published. The present report refers to a patient with lesions of disseminated superficial porokeratosis of sudden onset shortly before diagnosis of a cholangiocarcinoma.

Molecular mechanisms of cholangiocarcinoma

Cholangiocarcinoma (CC), the malignant tumor of the epithelial cells lining the biliary ducts, has undergone a worldwide increase in incidence and mortality. The malignant transformation of the biliary cells originates from a multistep process evolving through chronic inflammation of the biliary tract to CC. In the last few years several advances have been towards understanding and clarifying the molecular mechanisms implicated in the cholangiocarcinogenesis process. However, many pathophysiologic aspects governing the growth of CC are still undefined. The poor prognosis of this tumor underlines the urgent need to codify the underlying molecular mechanisms involved in the growth and progression of CC in order to design effective preventive measures and valid treatment regimens. This review reports on progresses made in the last few years in clarifying the molecular pathways involved in the process of cholangiocarcinogenesis.

Epidemiology of cholangiocarcinoma: an update focusing on risk factors

Cholangiocarcinoma is relatively rare, but high incidence rates have been reported in Eastern Asia, especially in Thailand. The etiology of this cancer of the bile ducts appears to be mostly due to specific infectious agents. In 2009, infections with the liver flukes, Clonorchis sinensis or Opistorchis viverrini, were both classified as carcinogenic to humans by the International Agency for Research on Cancer for cholangiocarcinoma. In addition, a possible association between chronic infection with hepatitis B and C viruses and cholangiocarcinoma was also noted. The meta-analysis of published literature revealed the summary relative risks of infection with liver fluke (both Opistorchis viverrini and Clonorchis sinensis), hepatitis B virus, and hepatitis C virus to be 4.8 (95% confidence interval [95% CI]: 2.8-8.4), 2.6 (95% CI: 1.5-4.6), and 1.8 (95% CI: 1.4-2.4), respectively - liver fluke infection being the strongest risk factor for cholangiocarcinoma. Countries where human liver fluke infection is endemic include China, Korea, Vietnam, Laos, and Cambodia. The number of infected persons with Clonorchis sinensis in China has been estimated at 12.5 million with considerable variations among different regions. A significant regional variation in Opistorchis viverrini prevalence was also noted in Thailand (average 9.6% or 6 million people). The implementation of a more intensive preventive and therapeutic program for liver fluke infection may reduce incidence rates of cholangiocarcinoma in endemic areas. Recently, advances have been made in the diagnosis and management of cholangiocarcinoma. Although progress on cholangiocarcinoma prevention and treatment has been steady, more studies related to classification and risk factors will be helpful to develop an advanced strategy to cure and prevent cholangiocarcinoma.

Polycomb group protein Bmi1 is overexpressed and essential in anchorage-independent colony formation, cell proliferation and repression of cellular senescence in cholangiocarcinoma: tissue and culture studies

Polycomb-group proteins Bmi1 is regarded as a "stemness" gene involved in the maintenance of stem cells, malignant transformation, and biologic aggressiveness of several human carcinomas. We examined the significance of the Bmi1 expression in intrahepatic cholangiocarcinoma. The expression of Bmi1 was examined in intrahepatic cholangiocarcinoma (n = 30; 9 bile ductular carcinoma, 8 intrahepatic cholangiocarcinoma of peripheral type, and 13 of hilar type) by using immunohistochemistry and real-time polymerase chain reaction. The expression level of Bmi1 was assessed in 7 cholangiocarcinoma cell lines. The effect of Bmi1 knockdown was examined in cultured cholangiocarcinoma cells (HuCCT1 and TFK-1) using small interfering RNA. Bmi1 was consistently expressed in nonneoplastic biliary epithelial cells and in all intrahepatic cholangiocarcinoma, irrespective of the location and histological degree of differentiation. The level of mRNA expression was significantly higher in 13 (81.3%) of 16 intrahepatic cholangiocarcinoma compared with the corresponding nonneoplastic tissues. All 7 cultured cholangiocarcinoma cells overexpressed Bmi1 to various degrees. The knockdown of Bmi1 resulted in decreased colony formation, decreased cell proliferation activities, and increased cellular senescence. The overexpression of polycomb-group protein Bmi1 is essential for colony formation and cell proliferation, probably by the repression of cellular senescence in intrahepatic cholangiocarcinoma.

Tumorigenesis and phenotypic characteristics of mucin-producing bile duct tumors: an immunohistochemical approach

Intraductal papillary neoplasm of the bile duct (IPNB) is characterized by exophytic proliferation of neoplastic epithelial cells with fibrovascular stalks in bile duct lumen, mucin hypersecretion, and considerable dilatation or multilocular changes of the affected bile ducts. A mucin-producing bile duct tumor is an IPNB with excessive mucin production and clinical symptoms. Herein, the phenotypes as well as the tumorigenesis and progression of IPNB are reviewed with immunohistochemical assistance. The tumors are subdivided into three phenotypes: pancreatobiliary, intestinal, and gastric. About half of IPNB cases are of the pancreatobiliary type, and the remaining half are of the intestinal type. Aberrant expression of CDX2 with MUC2 and CK20 is related to the development of intestinal metaplasia. Inactivation of P16INK4a and nuclear expression of beta-catenin are related to the development of IPNB. Decreased expression of membranous beta-catenin and E-cadherin and aberrant expression of MMP-7 and -9 and of MUC1 are related to invasion of IPNB with tubular adenocarcinoma, whereas MUC2 is involved in the invasion of IPNB with mucinous carcinoma. IPNB can be regarded as a counterpart of intraductal papillary mucinous neoplasm (IPMN) of the pancreas, particularly the main duct type. More comparative studies between IPNB and pancreatic IPMN are recommended for further analysis of these papillary neoplasms.

Cyclooxygenase-2 is involved in the up-regulation of matrix metalloproteinase-9 in cholangiocarcinoma induced by tumor necrosis factor-alpha

Matrix metalloproteinase-9 (MMP-9) is an important enzyme in tumor invasion and metastasis in malignant tumors, including cholangiocarcinoma (CC). Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, was recently reported to induce the up-regulation of MMP-9 in cultured CC cells. We examined whether cyclooxygenase-2 (COX-2) and prostaglandin-E2 (PGE2), another endogenous tumor promoter, are involved in the up-regulation of MMP-9 in CC using CC tissue specimens and a CC cell line, HuCCT-1. MMP-9 and COX-2 were immunohistochemically expressed in 58% and 89% of 110 CC cases, respectively; the expression of MMP-9 and COX-2 was correlated (r = 0.32, P = 0.00072). Using zymography, latent MMP-9 was detectable in all cases and active MMP-9 was detected in 24% of cases of the CC specimens. The TNF-alpha/TNF-receptor 1 (TNF-R1) interaction induced MMP-9 production and activation, as well as COX-2 overexpression and PGE2 production, and increased the migration of CC cells. MMP-9 up-regulation was inhibited by COX inhibitors, antagonists of EP2/4 (receptors of PGE2), and COX-1 and COX-2 siRNAs. Inhibitors of both MMP-9 and MMP-9 siRNA treatment abrogated the increase in the migration of CC cells induced by TNF-alpha. In conclusion, we propose a novel signaling pathway of MMP-9 up-regulation in CC cells such that TNF-alpha induces the activation of COX-2 and PGE2 via TNF-R1 followed by the up-regulation of MMP-9 via the PGE2 (EP2/4) receptor.

Phosphorylation of extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase and nuclear translocation of nuclear factor-kappaB are involved in upregulation of matrix metalloproteinase-9 by tumour necrosis factor-alpha

BACKGROUND

Upregulation of matrix metalloproteinase-9 (MMP-9) induced by tumour necrosis factor-alpha (TNF-alpha) is reportedly involved in a variety of non-neoplastic and neoplastic diseases. In this study, we examined which signalling pathways are involved in TNF-alpha-induced MMP-9 upregulation in cholangiocarcinoma (CC).

METHODS

We used two CC cell lines: HuCCT-1 and CCKS-1.

RESULTS

In an ex vivo study using HuCCT-1 and CCKS-1 cells, TNF-alpha treatment induced MMP-9 production and activation via interaction with TNF receptor-1 (TNF-R1) but not with TNF receptor-2 (TNF-R2), shown by zymography, and increased MMP-9 promoter activity (luciferase assay). As for the signalling pathway, TNF-alpha stimulation led to the phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2) and p38 mitogen-activated protein kinase (p38MAPK) and translocation of nuclear factor kappaB (NF-kappaB) (p65) into the nuclei. Inhibition studies using SB203580 (inhibitor of p38MAPK), U0126 (inhibitor of mitogen-activated or extracellular signal-regulated protein kinase 1/2) and MG132 (inhibitor of NF-kappaB) showed that the phosphorylation of Erk1/2 and p38MAPK with activation of NF-kappaB was closely related to MMP-9 upregulation in both cell lines.

CONCLUSION

These data suggest that TNF-alpha/TNF-R1 interaction leads to the phosphorylation of Erk1/2 and p38MAPK and nuclear translocation of NF-kappaB, which is closely associated with the production and activation of MMP-9 in cultured CC cells of HuCTT-1 and CCKS-1. Upregulation of MMP-9 with NF-kappaB activation may be involved in the tumour invasion of CC.

Over-expression of polycomb group protein EZH2 relates to decreased expression of p16 INK4a in cholangiocarcinogenesis in hepatolithiasis

Polycomb group protein EZH2 and Bmi1 are reportedly involved in the progression of malignant tumours. We examined the participation of EZH2 in multi-step cholangiocarcinogenesis in hepatolithiasis with respect to tumour suppressor gene p16 INK4a. We examined 20 hepatolithiatic livers with intrahepatic cholangiocarcinoma (ICC) and 10 histologically normal livers. Neoplastic biliary lesions were classified into biliary intraepithelial neoplasm (BilIN-1, 2 and 3) and invasive carcinoma. We selected 15 foci of invasive carcinoma, 8 BilIN-3 (carcinoma in situ), 12 BilIN-2 (high-grade dysplasia), 32 BilIN-1 (low-grade dysplasia) and 37 non-neoplastic biliary epithelia from these livers. Expression of p16 INK4a, EZH2 and Bmi1 were surveyed in these foci. P16 INK4a promoter methylation was examined in microdissected tissues. Taking advantage of two cell lines of CC (HuCTT-1 and TFK-1) and small interfering RNA (siRNA), the effects of the knockdown of EZH2 on p16 INK4a methylation of CC cells were examined. Expression of p16 INK4a, which was frequent in BilIN1, was decreased in BilIN-2/3 and invasive carcinoma, while EZH2 expression showed step-wise increase from BilIN-1, -2 and -3 to invasive carcinoma (p < 0.01). P16 INK4a promoter hypermethylation was related to aberrant expression of EZH2. The knockdown of EZH2 in cultured CC cells decreased p16 INK4a methylation and decreased binding of EZH2 to the p16 INK4a gene promoter. The latter suggested that direct binding of EZH2 is involved in the regulation of the p16 INK4a gene. Our data suggest that over-expression of EZH2 may induce hypermethylation of p16 INK4a promoter followed by decreased expression of p16 INK4a in the multi-step cholangiocarcinogenesis through intraepithelial neoplasm in hepatolithiasis.

Mechanisms of biliary carcinogenesis and growth

Cholangiocarcinoma is a rare cancer originating from the neoplastic transformation of the epithelial cells (i.e. cholangiocytes) that line the biliary tract. The prognosis for patients with cholangiocarcinoma is grim due to lack of viable treatment options. The increase in world-wide incidence and mortality from cholangiocarcinoma highlights the importance of understanding the intracellular mechanisms that trigger the neoplastic transformation of cholangiocytes and the growth of biliary cancers. The purpose of the following review is to address what has been learned over the past decade concerning the molecular basis of cholangiocarcinogenesis. The material presented is divided into two sections: (1) mechanisms regulating neoplastic transformation of cholangiocytes; and (2) factors regulating cholangiocarcinoma growth. An understanding of the growth regulatory mechanisms of cholangiocarcinoma will lead to the identification of therapeutic targets for this devastating cancer.

Pathology of peripheral intrahepatic cholangiocarcinoma with reference to tumorigenesis

Cholangiocarcinomas (CCs) are neoplasms with cholangiocyte differentiation, and may arise from cholangiocytes of the biliary tree and possibly cholangiocyte progenitor cells. Intrahepatic CCs can be divided into the perihilar and peripheral types. Peripheral CCs present grossly as a mass forming tumor, and histologically as an adenocarcinoma of varying shapes and phenotypes. Some peripheral CCs (ductular type) are characterized by: (i) a histological resemblance to reactive bile ductules; (ii) the expression of neural cell adhesion molecule (NCAM) and vimentin. This type shows: (i) grossly, a blurred border; and (ii) histologically, carcinoma cells replacing the adjoining hepatocytes at the border of the tumor. It is frequently associated with neutrophilic infiltration and also with granulocyte and granulocyte macrophage colony-stimulating factors. We propose to call this type "ductular CC." The other peripheral CC (duct type) includes ordinary adenocarcinoma with well to moderately differentiated tubular and micropapillary patterns and is negative for NCAM but positive for mucin. This type can be called "duct CC," and shows a rather compressive growth. Interestingly, CC components of combined hepatocellular CC share the features of ductular CC, suggesting that hepatic progenitor cells may be involved in the tumorigenesis of ductular CC. The biological behavior of ductular CC and duct CC remains obscure, and follow-up and molecular studies on these tumors are required in order for these two CCs to be recognized as disease entities, and so as to evaluate their carcinogenesis.

Cholangiocarcinoma

Cholangiocarcinoma is a primary hepatic malignancy originating from bile duct epithelium. It is the second most common primary hepatic neoplasia, and its incidence has increased within the last 3 decades. Although several risk factors have been identified, especially chronic biliary tract inflammation, most patients with cholangiocarcinoma have no identifiable risk factors. Recent developments in radiologic and molecular diagnostic methods have helped in the diagnosis of this disease. The only curative therapy is surgical resection or liver transplantation. For patients with advanced stage disease, survival remains limited. With growing understanding of the molecular and cellular etiology of this disease, new targeted therapies are being developed.

Evaluation of VEGF A expression and microvascular density as prognostic factors in extrahepatic cholangiocarcinoma

OBJECTIVES

Angiogenesis is essential for tumor growth and metastasis. An association between microvessel density, a measure of tumor angiogenesis, and conventional prognostic variables has been shown for many different tumor entities. In extrahepatic cholangiocarcinoma, the VEGF expression and microvessel density have rarely been investigated.

METHODS

Paraffin-embedded specimens from 51 resected adenocarcinomas of the extrahepatic bile duct were immunostained for vascular endothelial growth factor A (VEGF A) and CD 34 to evaluate the microvessel density (MVD). VEGF A staining was evaluated by combining intensity and percentage of positive tumor cells, as low (expression equal or below the median), or high (above the median). Microvessel density was assessed using a method published by Weidner et al.

RESULTS

Median disease free survival (DFS) of the study group was 12.5 months (range, 1-66.3 months). DFS was calculated in the 39 patients with complete resection. It was significantly better in patients with low microvessel density than DFS in patients with high microvessel density (33 months (range, 3-66.3 months) vs. 21.8 months (range, 1.6-31.6 months); p=0.022). In contrast, VEGF A expression did not correlate with survival. There was a trend toward a higher VEGF A expression in highly vascularized tumors (p=0.08), but failed to reach statistic significance.

CONCLUSIONS

The present study indicates, that vascularisation has an important impact on survival of extrahepatic cholangiocarcinoma patients. Other molecules than VEGF A are probably involved in neovascularization in extrahepatic cholangiocarcinoma.

Analysis of hTERT mRNA expression in biliary tract and pancreatic cancer

BACKGROUND/PURPOSE

Telomerase, an enzyme that prevents the loss of telomere regions consisting of TTAGGG repeats, which maintain the stability of cells, is considered to be involved in cell immortality and cancer growth. Recent genetic analysis has shown that the mRNA for the catalytic subunit of human telomerase reverse transcriptase (hTERT) is expressed in many cancer tissues.

METHODS

In this study, we measured hTERT mRNA levels in bile samples from patients with pancreatobiliary disease, and we combined the hTERT mRNA analysis with conventional cytology to achieve an accurate preoperative diagnosis. Bile samples were obtained from 19 patients with biliary tract cancer, 6 with gallbladder cancer, 10 with pancreatic cancer, 1 with gastric cancer, and 10 with benign disease. These samples were examined cytologically, and analyzed for hTERT mRNA levels.

RESULTS

The Combination of cytological examination and hTERT mRNA analysis achieved a positive rate of 78.9% in diagnosing biliary tract cancer, significantly improving the diagnostic accuracy over that for either method alone (P = 0.01). The diagnostic sensitivity for malignant disease was 66.6%, also significantly improving the diagnostic accuracy compared with either method alone (P = 0.001).

CONCLUSIONS

The combination of cytological examination and hTERT mRNA analysis appeared useful for the preoperative diagnosis of malignant biliary tract diseases, but was not superior to diagnostic imaging studies, and therefore remains an adjunct to cytological examination. Further studies should lead to improvements in the combination's diagnostic capabilities.

Enhanced RASGEF1A expression is involved in the growth and migration of intrahepatic cholangiocarcinoma

PURPOSE AND EXPERIMENTAL DESIGN

To identify novel molecular targets for the treatment of intrahepatic cholangiocarcinoma (ICC), the second most common type of primary hepatobiliary cancer, we earlier analyzed genome-wide expression profiles of genes in 25 ICCs. Among the genes whose expression levels were commonly elevated in the tumors, we identified a novel gene termed RASGEF1A that encodes a putative Ras guanine nucleotide exchange factor domain-containing protein.

RESULTS

We showed in this article that RASGEF1A protein has a guanine nucleotide exchange activity to K-RAS, H-RAS, and N-RAS proteins in vitro. Consistently, exogenous RASGEF1A expression increased the activity of Ras. In addition, suppression of RASGEF1A by small interfering RNA retarded the growth of cholangiocarcinoma cells. Interestingly, COS7 cells expressing exogenous RASGEF1A showed enhanced cellular motility in Transwell and wound-healing assays.

CONCLUSIONS

These data suggest that elevated expression of RASGEF1A may play an essential role for proliferation and progression of ICC. Our data indicate that RASGEF1A may be a promising therapeutic target for the majority of ICCs.

Molecular pathology of biliary tract cancers

The molecular mechanisms underlying the development, growth and metastatic diffusion of biliary tract cancers are still undefined. The increase in worldwide incidence and mortality of cholangiocarcinoma justifies the impellent need to clarify the intracellular mechanisms triggering the malignant transformation of the biliary epithelium and growth of biliary malignancies. A more complete characterization of the molecular pathology of bile duct cancers could lead to the identification of valid targets for the diagnosis and therapy of these devastating malignancies. This review describes the scientific progress made over the past decades with regard to the understanding of the molecular processes of cholangiocarcinogenesis.

The associated expression of Maspin and Bax proteins as a potential prognostic factor in intrahepatic cholangiocarcinoma

Background

Maspin, a member of the serpin family, is a suppressor of tumor growth, an inhibitor of angiogenesis and an inducer of apoptosis. Maspin induces apoptosis by increasing Bax, a member of the Bcl-2 family of apoptosis-regulating proteins. In this exploratory study, we investigated the associated expression of Maspin and Bax proteins as a potential prognostic factor in intrahepatic cholangiocarcinoma (IHCCA).

Methods

Twenty-two paraffin-embedded samples were analyzed by immunohistochemical methods using Maspin, Bax and CD34 antibodies. Maspin was scored semiquantitatively (HSCORE). Apoptosis was assessed using an antibody against cleaved caspase-3.

Results

The strong relationship observed between the expression of Maspin and Bax, indicates that Bax is likely to be the key effector of Maspin-mediated induction of apoptosis as indicated by the activation of cleaved caspase-3. We categorized Maspin HSCORE by calculating the optimal cutpoint. A Maspin HSCORE above the cutpoint was inversely related with tumor dimension, depth of tumor and vascular invasion. Uni/multivariate analysis suggests that a Maspin HSCORE below the cutpoint significantly worsens the patients' prognosis. Tumors with Maspin HSCORE below the cutpoint had a shorter survival (11+/-5 months) than did patients with Maspin HSCORE above the cutpoint (27+/-4 months), whereas Kaplan-Meier analysis and logrank test showed no significant difference in overall survival between the patients.

Conclusion

The associated expression of Maspin and Bax might delay tumor progression in IHCCA. Maspin above the cutpoint might counteract tumor development by increasing cell apoptosis, and by decreasing tumor mass and cell invasion. The combined expression of Maspin and Bax appears to influence the susceptibility of tumor cholangiocytes to apoptosis and thus may be involved in delaying IHCCA progression.

Chronic bile duct injury associated with fibrotic matrix microenvironment provokes cholangiocarcinoma in p53-deficient mice

Intrahepatic cholangiocarcinoma (CCA) is a lethal malignancy of the biliary epithelium associated with p53 mutations, bile duct injury, inflammation, and fibrosis. Here, to validate these processes in CCA, we developed a liver cirrhosis model driven by chronic intermittent toxin exposure, which provokes bile duct injury/necrosis and proliferation, fibroblast recruitment, and progressive extracellular matrix (ECM) changes. Fibrotic changes in the matrix microenvironment, typified by increased type I and III collagens and fibroblast recruitment, were shown to stimulate biliary epithelium hyperplasia with subsequent progression to malignant intrahepatic CCA only in mice harboring a p53 mutant allele. These murine CCAs bear histologic and genetic features of human intrahepatic CCA, including dense peritumoral fibrosis, increased inducible nitric oxide synthase, nitrotyrosine, and cyclooxygenase-2 expression, c-Met activation, cErbB2 overexpression, down-regulation of membrane-associated E-cadherin, and p53 codon 248 mutation. Thus, p53 deficiency, chronic bile duct injury/proliferation, and the fibrotic matrix microenvironment cooperate to induce intrahepatic CCA, highlighting the key role of the ECM microenvironment in this common liver cancer.

EUS-guided FNA of proximal biliary strictures after negative ERCP brush cytology results

BACKGROUND

Accurate nonoperative diagnosis of proximal biliary strictures (PBSs) is often difficult.

OBJECTIVE

To report our experience with EUS-guided FNA (EUS-FNA) of PBSs following negative or unsuccessful results with brush cytology during ERCP.

DESIGN

Retrospective cohort study.

SETTING

Single, tertiary referral hospital in Indianapolis, Indiana.

PATIENTS

Consecutive subjects from January 2001 to November 2004 who underwent EUS-FNA of a PBS documented by ERCP.

INTERVENTIONS

EUS-FNA of PBS.

MAIN OUTCOME MEASURES

Performance of EUS-FNA, with the final diagnosis determined by surgical pathology study or the results of EUS-FNA and follow-up.

RESULTS

A total of 291 biliary strictures undergoing EUS were identified. Of these, 26 (9%) had PBSs and 2 were excluded. EUS-FNA was not attempted in 1 because no mass was visualized. The second had a PBS seen on magnetic resonance cholangiopancreatography, but no ERCP was performed. Twenty-four patients (14 men; mean age, 68 years) underwent EUS-FNA of a PBS following ERCP brush cytology studies that were either negative/nondiagnostic (20) or unable to be performed (4). EUS visualized a mass in 23 (96%) patients, including 13 in whom previous imaging detected no lesion. EUS-FNA (median, 4 passes; range, 1-11) demonstrated malignancy in 17 of 24 (71%) patients with findings showing adenocarcinoma (15), lymphoma (2), atypical cytology (3), or benign cells (4). No complications were noted. Pathology results from 8 of 24 (33%) patients who underwent surgery showed hilar cholangiocarcinoma (6), gallbladder cancer (1), and a benign, inflammatory stricture (1). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of EUS-FNA were 77% (95% confidence interval [CI], 54%-92%), 100% (95% CI, 15%-100%), 100% (95% CI, 83%-100%), 29% (95% CI, 4%-71%), and 79% (95% CI, 58%-93%), respectively.

LIMITATIONS

Histopathologic correlation of EUS-FNA findings was limited to 8 of 24 (33%) patients who underwent surgery.

CONCLUSIONS

EUS-FNA is a sensitive method for the diagnosis of PBSs following negative results or unsuccessful ERCP brush cytology. The low negative predictive value does not permit reliable exclusion of malignancy following a negative biopsy.

Local balance of transforming growth factor-beta1 secreted from cholangiocarcinoma cells and stromal-derived factor-1 secreted from stromal fibroblasts is a factor involved in invasion of cholangiocarcinoma

Tumor-stromal interactions are important for the progression of malignant tumors. The purpose of the present study was to examine interactions of cholangiocarcinoma (CC) cells and stromal fibroblasts with respect to stromal-derived factor-1 (SDF-1) and transforming growth factor (TGF)-beta1. Two cell lines of CC (HuCCT-1 and CCKS-1) and WI-38 fibroblast cell line were used for cell culture, and 12 CC tissue specimens for immunohistochemical studies. Invasion of CC cells was increased significantly by the supernatant from fibroblast cultures, but not by the supernatant from fibroblasts cocultured with CC cells. Expression of SDF-1 in cultured fibroblasts was downregulated by TGF-beta1 treatment, and coculture with CC cells and anti-TGF-beta1 neutralizing antibody restored the decreased SDF-1 expression, suggesting that TGF-beta1 secreted from CC cells might have reduced the expression of SDF-1 by fibroblasts and might have reduced the increased invasion of CC cells induced by the supernatant from fibroblasts. Immunohistochemical expression of TGF-beta1 in CC cells was focal or negative and that of SDF-1 was evident in stromal fibroblasts at the invasive front of CC. In conclusion, local mutual influence of TGF-beta1 secreted from carcinoma cells and SDF-1 expressed by stromal fibroblasts may be involved in invasion of CC cells.

Induction of intrahepatic cholangiocellular carcinoma by liver-specific disruption of Smad4 and Pten in mice

Cholangiocellular carcinoma (CC), the second most common primary liver cancer, is associated with a poor prognosis. It has been shown that CCs harbor alterations of a number of tumor-suppressor genes and oncogenes, yet key regulators for tumorigenesis remain unknown. Here we have generated a mouse model that develops CC with high penetrance using liver-specific targeted disruption of tumor suppressors SMAD4 and PTEN. In the absence of SMAD4 and PTEN, hyperplastic foci emerge exclusively from bile ducts of mutant mice at 2 months of age and continue to grow, leading to tumor formation in all animals at 4-7 months of age. We show that CC formation follows a multistep progression of histopathological changes that are associated with significant alterations, including increased levels of phosphorylated AKT, FOXO1, GSK-3beta, mTOR, and ERK and increased nuclear levels of cyclin D1. We further demonstrate that SMAD4 and PTEN regulate each other through a novel feedback mechanism to maintain an expression balance and synergistically repress CC formation. Finally, our analysis of human CC detected PTEN inactivation in a majority of p-AKT-positive CCs, while about half also lost SMAD4 expression. These findings elucidate the relationship between SMAD4 and PTEN and extend our understanding of CC formation.

Possible regulation of migration of intrahepatic cholangiocarcinoma cells by interaction of CXCR4 expressed in carcinoma cells with tumor necrosis factor-alpha and stromal-derived factor-1 released in stroma

Intrahepatic cholangiocarcinoma (ICC) is highly fatal because of early invasion, widespread metastasis, and lack of an effective therapy. We examined roles of CXCR4 and its ligand, stromal cell-derived factor (SDF)-1, in migration of ICC with respect to tumor-stromal interaction by using two ICC cell lines, a fibroblast cell line (WI-38), and 28 human ICC tissues. The two ICC cell lines expressed CXCR4 mRNA and protein, and WI-38 fibroblasts expressed SDF-1 mRNA and protein. Migration of cultured ICC cells in Matrigel was induced by co-culture with WI-38 fibroblasts and by incubation with SDF-1. Anti-SDF-1 antibody suppressed migration, demonstrating that SDF-1 released from WI-38 fibroblasts was responsible for this migration. Tumor necrosis factor (TNF)-alpha pretreatment of ICC cells up-regulated CXCR4 mRNA and protein expression in a concentration-dependent manner. Administration of SDF-1 and TNF-alpha increased synergistically ICC cell migration, which was suppressed by the CXCR4 antagonist AMD3100. In ICC tissue, TNF-alpha was mainly expressed in infiltrated macrophages, CXCR4 in ICC cells, and SDF-1 in stromal fibroblasts. In conclusion, the interaction of SDF-1 released from fibroblasts and CXCR4 expressed on ICC cells may be actively involved in ICC migration, and TNF-alpha may enhance ICC cell migration by increasing CXCR4 expression. CXCR4 could be a therapeutic target to prevent ICC invasion.

Genome-wide analysis of gene expression in human intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma is a neoplasm arising in the liver, and its incidence is increasing in Japan as well as in Western countries. Prognosis of patients with this type of tumor remains unsatisfactory because no effective chemotherapeutic drugs are available, we have no sensitive tumor markers to detect this tumor in its early stage, and it is difficult to identify a high-risk group for the disease. To clarify the molecular mechanism of tumorigenesis and identify molecular targets for diagnosis and treatment, we analyzed global gene-expression profiles of 25 intrahepatic cholangiocarcinomas using tumor cell populations purified by laser microbeam microdissection and a cDNA microarray containing 27,648 genes. We identified 52 genes that were commonly upregulated and 421 that were downregulated in intrahepatic cholangiocarcinomas compared with noncancerous biliary epithelial cells. From the 52 upregulated genes, we selected P-cadherin and survivin for further investigation and corroborated enhanced expression of their products in cancer tissues by immunohistochemical staining. Furthermore, comparison between tumors with lymph node metastasis and those without metastasis identified 30 genes that were associated with lymph node involvement. In conclusion, these data should be helpful for a better understanding of the tumorigenesis of intrahepatic cholangiocarcinoma and should contribute to the development of diagnostic and therapeutic strategies for this type of tumor. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Expression of Bag-1 and Bcl-2 and its significance in gastric cancer

AIM: To investigate the expression of Bag-1 and Bcl-2 protein and its clinical significance in gastric cancer (GC).

METHODS: Immunohistochemistry was used to detect the expressison of Bag-1 and Bcl-2 protein in 92 patients with gastric cancer and 40 normal tissues as control.

RESULTS: Compared with normal mucosa, Bag-1 and Bcl-2 were over-expressed in gastric cancerous tissues (60.9% vs 7.5%, 72.8% vs 10%, P<0.01). The expression of Bcl-2 protein was significantly correlated with the differentiation degree (r_s = 0.513, P<0.05) and the expression of Bag-1 was significantly associated with Bcl-2 level in gastric cancer (r_s = 0.522, P<0.01).

CONCLUSION: The over-expression of Bcl-2 leads to uncontrolled growth and unceasingly increases of GC cells by accelerating cell transformation and proliferation. Bag-1 promotes the function of Bcl-2 and co-expression of Bag-1 and Bcl-2 may mean poor prognosis of GC patients.

Decreased expression of type II tumor suppressor gene RARRES3 in tissues of hepatocellular carcinoma and cholangiocarcinoma

AIM: To analyze the expression of retinoic acid receptor responder 3 (RARRES3) protein in paraffin-embedded tissues of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC), and the correlation of RARRES3 production with tumor differentiation.

METHODS: Expression of RARRES3 in tissues from 21 CC (10 well-, 7 moderately- and 4 poorly-differentiated) and 32 HCC was determined by immunohistochemistry.

RESULTS: Among 21 CC tissues, RARRES3 was detected in 8 (80%) of 10 well-differentiated tumors. Only 2 (18.2%) out of 11 tumors with moderate or poor differentiation showed positive RARRES3 expression. RARRES3 expression in well-differentiated CC was significantly higher than that in tumors with moderate or poor differentiation (Fisher exact test, P<0.01). Expression of RARRES3 was not different between early (I and II) and late (III and IV) stages of CC. Among 30 HCC tissues, 17 (56.7%) weakly expressed RARRES3 in HCC cells, and 25 (83.3%) normal tissues adjacent to HCC expressed the protein. RARRES3 expression was significantly decreased in HCC tissues compared to that in adjacent normal tissues (logistic regression analysis, OR = 0.27, 95% CI (0.11-0.62), P<0.01).

CONCLUSION: Expression of RARRES3 is positively correlated to well-differentiated CC, which supports the role of RARRES3 in malignant epithelial differentiation of the tumor. The decrease in RARRES3 expression in tissues of HCC and CC with moderate and poor differentiation suggests that altered RARRES3 expression may play a role in the carcinogenesis of the liver and biliary tract.

[Intra-hepatic cholangiocarcinoma]

Intra-hepatic cholangiocarcinoma (IHCC) is a rare tumor which arises from the epithelial cells of the intra-hepatic bile ducts; it may develop in a healthy liver and bile ducts or in bile ducts with malignant predisposition (Caroli's syndrome, primary sclerosing cholangitis). It has the worst prognosis of any tumor arising in the liver. Unlike hepatocellular carcinoma, no predisposing factors or high-risk populations have been demonstrated for cholangiocarcinoma other than intraphepatic choledocholithiasis such as is seen in east Asian populations. The most common clinical sign is a palpable tumor mass emphasizing that the tumor is usually detected at an advanced stage. CT scanning yields much clinical information but ultrasound-guided needle biopsy is necessary for diagnosis. Aggressive surgical resection is the only treatment modality which has afforded even slight prolongation of survival; hepatic resection must be large with uninvolved resection margins. When an IHCC is deemed resectable (localized tumor without hepatic metastases or intrahepatic or extrahepatic lymph node spread), pre-operative tumor embolization may be useful; when jaundice is present, percutaneous drainage of the dilated biliary system of the liver to be spared may also be necessary. Neither adjuvant nor neo-adjuvant chemotherapy or radiotherapy have shown proof of efficacity. Cholangiocarcinoma complicates sclerosing cholangitis in 10-15% of cases and is very difficult to diagnose. IHCC may also develop in Caroli's syndrome, where it is commonly found incidentally on pathologic examination of a resection specimen after surgery for a complication of the disease.

Cholangiocarcinoma: molecular targeting strategies for chemoprevention and therapy

Cholangiocarcinomas are devastating cancers that are increasing in both their worldwide incidence and mortality rates. The challenges posed by these often lethal biliary tract cancers are daunting, with conventional treatment options being limited and the only hope for long-term survival being that of complete surgical resection of the tumor. Unfortunately, the vast majority of patients with cholangiocarcinoma typically seek treatment with advanced disease, and often these patients are deemed poor candidates for curative surgery. Moreover, conventional chemotherapy and radiation therapy have not been shown to be effective in prolonging long-term survival, and although photodynamic therapy combined with stenting has been reported to be effective as a palliative treatment, it is not curative. Thus, there is a real need to develop novel chemopreventive and adjuvant therapeutic strategies for cholangiocarcinoma based on exploiting select molecular targets that would impact in a significant way on clinical outcome. This review focuses on potential preventive targets in cholangiocarcinogenesis, such as inducible nitric oxide synthase, cyclooxygenase-2, and altered bile acid signaling pathways. In addition, molecular alterations related to dysregulation of cholangiocarcinoma cell growth and survival, aberrant gene expression, invasion and metastasis, and tumor microenvironment are described in the context of various clinical and pathological presentations. Moreover, an emphasis is placed on the importance of critical signaling pathways and postulated interactions, including those of ErbB-2, hepatocyte growth factor/Met, interleukin-6/glycoprotein130, cyclooxygenase-2, vascular endothelial growth factor, transforming growth factor-beta, MUC1 and MUC4, beta-catenin, telomerase, and Fas pathways as potential molecular therapeutic targets in cholangiocarcinoma.

Diabetes Mellitus As The Presenting Feature Of Extrahepatic Cholangiocarcinoma In Situ: Case Report And Review Of Literature

OBJECTIVE

To report a case of newly recognized diabetes, manifested by hyperglycemic crisis, as the presenting feature of an extrahepatic cholangiocarcinoma in situ.

METHODS

We summarize the initial clinical manifestations and pertinent laboratory, radiologic, and pathologic findings in a patient with hyperglycemic emergency and a biliary carcinoma in situ. A review of the literature involving cholangiocarcinoma, pancreatic tumors, and diabetes mellitus is also presented.

RESULTS

An 85-year-old woman with no prior history of hyperglycemia presented to the hospital in hyperglycemic crisis, without identifiable precipitants. Further work-up disclosed a tumor in the common bile duct. Pathologic analysis, after pancreatoduodenectomy, demonstrated a carcinoma in situ without extension to nearby structures. Adjacent pancreatic islet cells appeared normal. Screening for all relevant islet cell autoantibodies was negative. After tumor removal, mild hyperglycemia persisted, although without insulin requirements.

CONCLUSION

Extrahepatic cholangiocarcinoma and diabetes are not usually associated, and to our knowledge, this is the first reported case of a hyperglycemic emergency with this specific type of tumor. The cause-and-effect relationship between the patient's biliary carcinoma in situ and diabetes obviously cannot be confirmed; however, in the absence of other identifiable conditions, it is reasonable to speculate that some factor (or factors) produced by the tumor had a role in the metabolic decompensation. Such a relationship has been considered by others concerning the well-described association between diabetes and carcinoma of the pancreas, in which the underlying pathophysiologic process seems to be insulin resistance. This unusual case of secondary diabetes emphasizes the importance of considering the precise "cause" of the hyperglycemia when the presentation is atypical, as it was in this older, lean patient without risk factors for diabetes.