Pathology of peripheral intrahepatic cholangiocarcinoma with reference to tumorigenesis

Histopathological growth pattern and vessel co-option in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) exhibits different blood imaging features and prognosis depending on histology. To clarity histopathological growth patterns (HGPs) and vascularization processes of iCCA, we collected 145 surgical specimens and histologically classified them into large bile duct (LBD) (20 cases), small bile duct (SBD) (54), cholangiolocarcinoma (CLC) (35), combined SBD-CLC (cSBD-CLC) (26), and ductal plate malformation (DPM) (10) (sub)types. According to the invasive pattern at the interface between tumor and adjacent background liver, HGPs were classified into desmoplastic, pushing, and replacing HGPs. Desmoplastic HGP predominated in LBD type (55.5%), while replacing HGP was common in CLC (82.9%) and cSBD-CLC (84.6%) subtypes. Desmoplastic HGP reflected angiogenesis, while replacing HGP showed vessel co-option in addition to angiogenesis. By evaluating microvessel density (MVD) using vascular markers, ELTD1 identified vessel co-option and angiogenesis, and ELTD1-positive MVD at invasive margin in replacing HGP was significantly higher than those in desmoplastic and pushing HGPs. REDD1, an angiogenesis-related marker, demonstrated preferably higher MVD in the tumor center than in other areas. iCCA (sub)types and HGPs were closely related to vessel co-option and immune-related factors (lymphatic vessels, lymphocytes, and neutrophils). In conclusion, HGPs and vascular mechanisms characterize iCCA (sub)types and vessel co-option linked to the immune microenvironment.

Clinicopathological features of cholangiolocarcinoma and impact of tumor heterogeneity on prognosis: A single institution retrospective study

Cholangiolocarcinoma (CLC) is an extremely rare tumor classified as a subtype of small duct-type intrahepatic cholangiocarcinoma (iCCA). There are few detailed reports on CLC and the prognostic impact of tumor heterogeneity is not clear. Between April 2006 and June 2022, of the 774 primary liver cancer resection cases who presented at Kanazawa University Hospital, 14 patients were pathologically diagnosed with CLC through immunohistochemical analysis of their molecular and biological features. Clinicopathological features and prognoses were evaluated retrospectively. Additionally, tumor heterogeneity was assessed and tumors were classified into pure and partial types according to the CLC component proportion in a single tumor. Chronic liver disease was observed in nine patients (64.3%). All tumors were mass-forming, and pathological R0 resection was achieved in 11 patients (78.6%). Tumor heterogeneity was classified as pure in 11 (78.6%) and partial in three (21.4%) patients. The median follow-up was 59.5 months (12-114 months). There was no difference in the 5-year disease-specific survival rates between the pure and partial (90.0% vs. 100.0%; P=0.200) types, but rates were significantly higher in the R0 resection group compared with those in the R1 resection group (100.0% vs. 50.0%; P=0.025). In conclusion, these results suggest that it is important for CLC patients to achieve curative resection, and CLC may have a good prognosis regardless of the proportion of CLC components in a single tumor.

HBV infection effects prognosis and activates the immune response in intrahepatic cholangiocarcinoma

BACKGROUND

The impact of HBV infection on the prognosis of patients with intrahepatic cholangiocarcinoma (ICC) remains uncertain, and the underlying mechanism has not been elucidated. This study aims to explore the potential mechanism via clinical perspectives and immune features.

METHODS

We retrospectively reviewed 1308 patients with ICC treated surgically from January 2007 to January 2015. Then, we compared immune-related markers using immunohistochemistry staining to obtain the gene expression profile GSE107943 and related literature for preliminary bioinformatics analysis. Subsequently, we conducted a drug sensitivity assay to validate the role of TNFSF9 in the ICC organoid-autologous immune cell coculture system and in the patient-derived organoids-based xenograft platform.

RESULTS

The analysis revealed that tumors in patients without HBV infection exhibited greater size and a higher likelihood of lymphatic metastasis, tumor invasion, and relapse. After resection, HBV-infected patients had longer survival time than uninfected patients (p<0.01). Interestingly, the expression of immune-related markers in HBV-positive patients with ICC was higher than that in uninfected patients (p<0.01). The percentage of CD8+ T cells in HBV-positive tissue was higher than that without HBV infection (p<0.05). We screened 21 differentially expressed genes and investigated the function of TNFSF9 through bioinformatics analyses. The expression of TNFSF9 in ICC organoids with HBV infection was lower than that in organoids without HBV infection. The growth of HBV-negative ICC organoids was significantly inhibited by inhibiting the expression of TNFSF9 with a neutralizing antibody. Additionally, the growth rate was faster in HbsAg (-) ICC patient-derived organoids-based xenograft model than in HbsAg (+) group.

CONCLUSIONS

The activation of the immune response induced by HBV infection makes the prognosis of HBV-positive patients with ICC differ from that of uninfected patients.

Pathological, molecular, and clinical characteristics of cholangiocarcinoma: A comprehensive review

Cholangiocarcinomas are a heterogeneous group of highly aggressive cancers that may arise anywhere within the biliary tree. There is a wide geographical variation with regards to its incidence, and risk-factor associations which may include liver fluke infection, primary sclerosing cholangitis, and hepatolithiasis amongst others. These tumours are classified into intrahepatic, perihilar and distal based on their anatomical location. Morphologically, intrahepatic cholangiocarcinomas are further sub-classified into small and large duct variants. Perihilar and distal cholangiocarcinomas are usually mucin-producing tubular adenocarcinomas. Cholangiocarcinomas develop through a multistep carcinogenesis and are preceded by dysplastic and in situ lesions. While clinical characteristics and management of these tumours have been extensively elucidated in literature, their ultra-structure and tumour biology remain relatively unknown. This review focuses on the current knowledge of pathological characteristics, molecular alterations of cholangiocarcinoma, and its precursor lesions (including biliary intraepithelial neoplasia, intraductal papillary neoplasms of the bile duct, intraductal tubulopapillary neoplasms and mucinous cystic neoplasm).

Arterial enhancement pattern predicts survival in patients with resectable and unresectable intrahepatic cholangiocarcinoma

BACKGROUND

In patients undergoing resection of intrahepatic cholangiocarcinoma (ICC), hypervascularity during the arterial phase of contrast-enhanced computed tomography (CT) is associated with better prognosis than hypovascularity. However, the prognostic implications of arterial enhancement pattern in patients with unresectable ICC are unknown. We assessed the prognostic implications of arterial enhancement pattern in patients with resectable and unresectable ICC.

METHODS

Consecutive patients who underwent surgery or gemcitabine-plus-cisplatin chemotherapy for ICC during 2003-2015 and CT with dynamic enhancement for diagnosis were included. After review by 2 radiologists, tumors were categorized according to the percentage of the tumor exhibiting arterial enhancement as hypervascular (>50% of tumor exhibiting enhancement), peripherally enhancing (10%-50%), and hypovascular (<10%). In each cohort (surgical and medical), overall survival (OS) curves were generated using the Kaplan-Meier method, and differences between curves were evaluated with Cox analysis.

RESULTS

The study included 56 patients treated surgically and 89 patients with unresectable ICC. Mean (standard deviation) tumor density in the hypervascular, peripherally enhancing, and hypovascular groups was 119.3 (45.2) Hounsfield units (HU), 72.1 (15.9) HU, and 59.9 (14.4) HU, respectively, in the surgical cohort and 93.6 (17.5) HU, 66.6 (16.2) HU, and 48.7 (14.3) HU, respectively, in the medical cohort. In both cohorts, the 5-year OS rate was significantly higher in the hypervascular group than in the hypovascular group (surgical, 67.6% vs 22.5%, P = .038; medical, 15.4% vs 0%, P = .030). In both cohorts, a Cox proportional hazards model analysis showed that hypervascularity was significantly associated with better OS.

CONCLUSION

Hypervascularity during the arterial CT phase is a prognostic biomarker in patients undergoing ICC resection and patients with unresectable ICC.

Prognostic impact of tumor vascularity on CT in resectable intrahepatic cholangiocarcinoma

BACKGROUND

We investigated the vascularity of intrahepatic cholangiocarcinoma (ICC) on computed tomography (CT) images and its association with ICC recurrence after surgery and prognosis after recurrence.

METHODS

In this retrospective study, the data of patients who underwent resection with curative intent for ICC between March 2001 and July 2017 were reviewed. Clinicopathologic factors including tumor vascularity (hypovascular, rim-enhancement, and hypervascular) on CT that could affect recurrence-free survival (RFS) were assessed. The association between the vascularity of recurrent ICC and survival after recurrence was also analyzed.

RESULTS

Overall, 147 patients were enrolled and followed up for a median of 36.1 months of which, 101 (68.7%) experienced ICC recurrence. Hypervascularity of ICC showed better RFS than other vascularities [rim-enhanced image hazard ratio (HR), 3.893; 95% confidence interval (CI), 1.700-8.915, p = 0.001; hypovascular image HR, 6.241; 95% CI, 2.670-14.586, p < 0.001]. The hypervascular recurrent ICC was also significantly associated with better survival after recurrence (log-rank test, p < 0.001).

CONCLUSION

Hypervascular ICC was associated with a longer RFS and better prognosis after recurrence. The vascularity of ICC on CT may be a noninvasive, accessible, and useful prognostic index, and should be considered while planning treatment.

Diversity in cell differentiation, histology, phenotype and vasculature of mass-forming intrahepatic cholangiocarcinomas

AIMS

Mass-forming intrahepatic cholangiocarcinomas (MF-iCCAs), involving small bile ducts, bile ductules or canals of Hering, remain treated as a single entity. We aimed to examine the diversity in histology, phenotype and tumour vasculature of MF-iCCAs.

METHODS AND RESULTS

Based on morphology and immunophenotype, we classified MF-iCCAs into small bile duct (SBD), cholangiolocarcinoma (CLC), ductal plate malformation (DPM) and hepatocellular carcinoma (HCC)-like subtypes. Genetic correlations among the histological subtypes were examined by multi-region tumour sequencing. Vasculatures and other clinicopathological features were compared among tumour groups with various proportions of the histological subtypes in 62 MF-iCCAs. Cases of pure SBD, CLC, DPM and HCC-like subtypes numbered 18 (29%), seven (11.3%), none (0%) and two (3%), respectively; the remaining 35 (56.4%) cases comprised several components. Genetic alterations, isocitrate dehydrogenase (IDH)1/2, KRAS, TP53, polybromo-1 (PBRM1) and BRCA1-associated protein 1 (BAP1), were shared among SBD, CLC, DPM and hepatoid components within a tumour. We uncovered distinct vascularisation mechanisms among SBD, CLC and DPM subtypes with a prominent vessel co-option in CLC tumours. iCCA with a DPM pattern had the highest vascular densities (mean microvascular density,140/mm² ; arterial vessel density, 18.3/mm² ). Increased CLC component was correlated with longer overall survival time (r = 0.44, P = 0.006). Pure SBD tumours had a lower 5-year overall survival rate compared with MF-iCCA with CLC pattern (30.5 versus 72.4%, P = 0.011).

CONCLUSIONS

MF-iCCAs comprise four histological subtypes. Given their sharing some driver gene alterations, indicating they can have a common cell origin, SBD, CLC and DPM subtypes, however, differ in cell differentiation, histology, phenotype or tumour vasculature.

Intrahepatic cholangiocarcinoma with clear cell type following laparoscopic curative surgery

Background

Intrahepatic cholangiocarcinoma (ICC) is the second most common malignancy of primary liver cancer. Among the several pathological types of ICC, only five cases of the clear cell type have been reported, including the one presented below. Here we report a unique case of clear cell type ICC following laparoscopic hepatectomy.

Case presentation

A 67-year-old woman had a history of hepatitis B virus. Computed tomography revealed a ring-like enhanced mass 35 mm in diameter at segment 7 in the early phase. The enhancement was prolonged to the late phase through the portal phase, while the shape was irregular. Ethoxybenzy magnetic resonance imaging revealed that the tumor had a low signal intensity on T1-weighted imaging and a high signal intensity on T2-weighted imaging. Diffusion-weighted images identified that the tumor had remarkably high signal intensity. Tumor enhancement was not detected throughout the tumor in the hepatocyte phase. Upon ICC diagnosis, a laparoscopic S7 subsegmentectomy was performed. The patient’s postoperative course was uneventful. An immunohistochemical examination revealed that the cells tested positive for cytokeratin 7 (CK7), CK19, and CD56 and negative for CK20, CD10, α-fetoprotein, thyroid transcription factor-1. At 2 years after surgery, the patient remains alive without recurrence.

Conclusions

Here we presented a case of clear cell ICC that was treated by laparoscopic hepatectomy. Immunological analysis, especially by CD56 and several CK markers, is helpful for diagnosing this disease.

Combined hepatocellular-cholangiocarcinoma after tetralogy of Fallot repair: a case report and review of literature

BACKGROUND

Liver fibrosis and cancer are serious hepatic complications for patients with congenital heart diseases. We present a rare case of combined hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) (cHCC-CCA) after the repair of tetralogy of Fallot (TOF).

CASE PRESENTATION

A 54-year-old Japanese woman had undergone biventricular repair for TOF at 7 years old. She presented with abdominal distension. Abdominal CT revealed ascites and a 90-mm tumor involving the liver's left lobe. Tumor marker values were: alpha-fetoprotein, 16,208 ng/mL and des-gamma-carboxy prothrombin, 33,920 mAU/mL. The preoperative diagnosis was malignant tumor of the liver (e.g., HCC or intrahepatic CCA). We performed a left lobectomy of the liver. Histopathologically, the tumor was composed of two components growing in trabecular and irregular tubular patterns accompanied by a transitional area; the tumor was diagnosed as cHCC-CCA. The non-cancerous area showed fibrous change mainly surrounding a central vein and sinusoid, expanding toward the portal area without inflammation.

CONCLUSIONS

We provide the details of our patient's cHCC-CCA that developed from fibrous congestive liver associated with right-sided heart failure after TOF repair, diagnosed based on histopathological features. We discuss liver fibrosis as a hepatic complication and a careful follow-up maneuver for improving the outcomes of patients with chronic hepatic congestion.

Intrahepatic Mass-Forming Cholangiocarcinoma: Relationship Between Computed Tomography Characteristics and Histological Subtypes

OBJECTIVE

The aim of this study was to determine the value of multi-detector row computed tomography (MDCT) in differentiating the small-duct (SD) and large-duct (LD) types of intrahepatic mass-forming cholangiocarcinomas (IMCCs) and predicting patient prognosis.

METHODS

The 4-phase MDCT image findings of 82 patients with surgically confirmed IMCCs (60 SD-type and 22 LD-type IMCCs) were compared between 2 types using univariate and multivariate analyses. Overall survival rates for 78 patients with available information were compared using the Kaplan-Meier method.

RESULTS

Arterial hyperenhancement, round or lobulated contour, and lack of bile duct encasement were significant MDCT features suggesting the SD type, and lymph node enlargement was significantly associated with the LD type (all P's < 0.05). The presence of those 3 SD-type-suggestive features (MDCT-suggested SD type) demonstrated high specificity (90.9% [20/22]) in differentiating the SD type. Patients of MDCT-suggested SD type without lymph node enlargement (n = 24) demonstrated significantly better overall survival than other groups.

CONCLUSIONS

Preoperative MDCT features of IMCCs can help differentiate the SD and LD types and predict patient prognosis.

Comparison of clinicopathological characteristics between cirrhotic and non-cirrhotic patients with intrahepatic cholangiocarcinoma: A large-scale retrospective study

The effect of cirrhosis on the characteristics of intrahepatic cholangiocarcinoma (ICC) has not been fully elucidated. The purpose of this study was to investigate how cirrhosis affects the clinicopathological characteristics and survival of surgically treated ICC patients. A total of 1,312 ICC patients surgically treated between January 2007 and December 2011 at a single institution were retrospectively reviewed and the clinicopathological data were compared between cirrhotic and non-cirrhotic patients. Univariate and multivariate analyses were performed to identify significant and independent prognostic factors in this cohort. A total of 302 patients (23.0%) were cirrhotic. Compared with cirrhotic patients, the tumors in non-cirrhotic patients were usually larger, less differentiated, and more likely to have lymphatic metastasis, vascular and perineural invasion. Following resection, cirrhotic patients achieved a longer survival compared with non-cirrhotic patients (16.0 vs. 13.0 months, respectively; P<0.038). Multivariate analysis demonstrated that hepatitis B virus infection and cirrhosis were independent favorable prognostic factors, while the presence of cholelithiasis, elevated carbohydrate antigen 19-9 and carcinoembryonic antigen levels, multiple tumors, lymphatic metastasis, vascular invasion and positive surgical margin status were independent unfavorable prognostic factors. Overall, the clinicopathological characteristics of ICC patients with and without cirrhosis differed significantly. Compared with cirrhotic patients, in whom the biological behavior of ICC was similar to that of HCC, non-cirrhotic patients exhibited higher-risk pathological characteristics, lower curative resection rate and worse survival.

Distinct Clinicopathologic and Genetic Features of 2 Histologic Subtypes of Intrahepatic Cholangiocarcinoma

Previous studies have identified 2 clinically significant morphologic subtypes of intrahepatic cholangiocarcinoma (ICC) on the basis of anatomic location and/or histologic appearances. Recognizing that these classification schemes are not always applicable practically, this study aimed to establish a novel classification system based on mucin productivity and immunophenotype and to determine the rationale of this classification by examining the clinicopathologic and genetic characteristics of the 2 subtypes defined by this method. We retrospectively investigated 102 consecutive ICC cases and classified them on the basis of mucin productivity and immunophenotype (S100P, N-cadherin, and NCAM). We found that 42 and 56 cases were classified as type 1 and type 2 ICCs, respectively, and only 4 cases were of indeterminate type. Type 1 ICC, generally characterized by mucin production and diffuse immunoreactivity to S100P, arose less frequently in chronic liver diseases and showed higher levels of serum CEA and CA 19-9 than did type 2 ICC, which generally showed little mucin production and exhibited immunoreactivity to N-cadherin and/or NCAM. Type 1 ICC was characterized by several pathologic features, including higher frequencies of perineural invasion and lymph node metastasis. Although the log-rank test demonstrated that type 1 ICC had significantly worse survival, the multivariate Cox regression analysis showed no prognostic significance of this histologic subtype. Genetic analyses revealed that KRAS mutation was significantly more frequent in type 1 ICC, whereas IDH mutation and FGFR2 translocation were restricted to type 2 ICC. In conclusion, the present classification of ICC based on mucin productivity and immunophenotype identified 2 subtypes with clinicopathologic significance.

Biliary Adenofibroma of Liver: Morphology, Tumor Genetics, and Outcomes in 6 Cases

Biliary adenofibroma is a rare primary hepatic neoplasm, recognized in the World Health Organization classification, although only 14 cases have been reported to date. This series includes extended follow-up from 2 of the early case reports and 4 novel cases. Clinical history and histology were reviewed in all 6 cases. Tumor DNA was analyzed for point mutations by multiplex polymerase chain reaction and copy number alterations by array comparative genomic hybridization. The patients included 4 females and 2 males presenting between 46 and 83 years of age, with tumors ranging from 7 to 16 cm in diameter. The tumors had similar morphology, with tubules and cysts lined mainly by bland to mildly atypical cuboidal epithelium embedded in fibrous stroma. Multiplex polymerase chain reaction did not identify mutations in 4 tumors tested. Three tumors tested by array comparative genomic hybridization showed chromosomal copy number alterations, including 1 with amplifications of CCND1 and ERBB2. Three patients underwent resection with no recurrence at 21, 20, and 3 years of follow-up. One patient is alive after 14 months with no resection. Two patients with margin-positive resections had local recurrence at 1 and 6 years after surgery. No patient had distant metastasis. The distinct morphology and multiple clonal cytogenetic alterations in biliary adenofibromas indicate that the lesions are neoplastic. Amplifications of CCND1 and ERBB2 are not typical of benign neoplasms, and suggest that these tumors may have the ability to behave aggressively. However, the clinical outcomes in these patients suggest the neoplasms are only slowly progressive.

Latest advances in the pathological understanding of cholangiocarcinomas

Cholangiocarcinomas (CCAs) are anatomically classified into intrahepatic, perihilar, and distal types. The gross pathological classification of intrahepatic CCAs divides them into mass-forming, periductal-infiltrating, and intraductal-growth types; and perihilar/distal CCAs into flat- and nodular-infiltrating and papillary types. Unique preinvasive lesions appear to precede individual gross types of CCA. Biliary intraepithelial neoplasia, a flat lesion, precedes periductal-, flat-, and nodular-infiltrating CCAs, whereas intraductal papillary neoplasm of the bile duct (IPNB) precedes the intraductal-growth and papillary type of CCAs. IPNBs are heterogeneous in their histological and pathological profiles along the biliary tree. Hepatobiliary cystadenomas/adenocarcinomas are reclassified as cystic IPNBs and hepatic mucinous cystic neoplasms. Peribiliary glands may participate in the development of CCAs. These latest findings present a new challenge for understanding the pathology of CCAs.

Intrahepatic Cholangiocarcinoma (ICC) Detected by Sonography

Intrahepatic cholangiocarcinoma (ICC) is a malignant disease process that develops within the small branches of the biliary system within the liver. It is one of two types of cholangiocarcinoma (CCA). The patient in this case study experienced general abdominal and pelvic discomfort when further sonographic evidence proved there to be a moderate amount of fluid within the pelvic and abdominal cavities, suggesting a malignant process. Three types of growth processes related to ICC require different methods of treatment, thus making it imperative for the sonographer to identify the origin of the disease process. Appropriate knowledge of sonographic landmarks such as the biliary tree, liver, hepatic veins, and portal system is an important factor when evaluating normal and abnormal right upper quadrant structures. This case study focuses on the importance of sonography when detecting the size and location of ICC to determine an appropriate treatment method for this disease process.

Multiple cellular origins and molecular evolution of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy associated with unfavorable prognosis and for which no effective treatments are available. Its molecular pathogenesis is poorly understood. Genome-wide sequencing and high-throughput technologies have provided critical insights into the molecular basis of ICC while sparking a heated debate on the cellular origin. Cancer exhibits variabilities in origin, progression and cell biology. Recent evidence suggests that ICC has multiple cellular origins, including differentiated hepatocytes; intrahepatic biliary epithelial cells (IBECs)/cholangiocytes; pluripotent stem cells, such as hepatic stem/progenitor cells (HPCs) and biliary tree stem/progenitor cells (BTSCs); and peribiliary gland (PBG). However, both somatic mutagenesis and epigenomic features are highly cell type-specific. Multiple cellular origins may have profoundly different genomic landscapes and key signaling pathways, driving phenotypic variation and thereby posing significant challenges to personalized medicine in terms of achieving the optimal drug response and patient outcome. Considering this information, we have summarized the latest experimental evidence and relevant literature to provide an up-to-date view of the cellular origin of ICC, which will contribute to establishment of a hierarchical model of carcinogenesis and allow for improvement of the anatomical-based classification of ICC. These new insights have important implications for both the diagnosis and treatment of ICC patients.

Global DNA methylation and hydroxymethylation differ in hepatocellular carcinoma and cholangiocarcinoma and relate to survival rate

In addition to DNA methylation, hydroxymethylation of DNA is recognized as a novel epigenetic mark. Primary liver cancers, i.e., hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC), are highly prevalent but epigenetically poorly characterized, so far. In the present study we measured global methylcytosine (mCyt) and hydroxymethylcytosine (hmCyt) in HCC and CC tissues and in peripheral blood mononuclear cell (PBMC) DNA to define mCyt and hmCyt status and, accordingly, the survival rate. Both mCyt and hmCyt were measured by a liquid chromatography/tandem mass spectrometry method in neoplastic and homologous nonneoplastic tissues, i.e., liver and gallbladder, and in PBMCs of 31 HCC and 16 CC patients. Content of mCyt was notably lower in HCC than in CC tissues (3.97% versus 5.26%, respectively; P < 0.0001). Significantly reduced mCyt was also detected in HCC compared to nonneoplastic tissue (3.97% versus 4.82% mCyt, respectively; P < 0.0001), but no such difference was found for CC versus homologous nonneoplastic tissue. Hydroxymethylation was significantly decreased in HCC versus nonneoplastic liver tissue (0.044 versus 0.128, respectively; P < 0.0001) and in CC versus both liver and gallbladder nonneoplastic tissue (0.030 versus 0.124, P = 0.026, and 0.030 versus 0.123, P = 0.006, respectively). When the survival rate was evaluated according to mCyt PBMC content by Kaplan-Meier analysis, patients with mCyt ≥5.59% had a significantly higher life expectancy than those with mCyt <5.59% (P = 0.034) at a follow-up period up to 48 months.

CONCLUSION

A significant DNA hypomethylation distinguishes HCC from CC, while DNA hypo-hydroxymethylation characterizes both HCC and CC, and a PBMC DNA mCyt content ≥5.59% relates to a favorable outcome in primary liver cancers.

Multidisciplinary Care of Patients with Intrahepatic Cholangiocarcinoma: Updates in Management

Cholangiocarcinoma is a highly fatal primary cancer of the bile ducts which arises from malignant transformation of bile duct epithelium. While being an uncommon malignancy with an annual incidence in the United States of 5000 new cases, the incidence has been increasing over the past 30 years and comprises 3% of all gastrointestinal cancers. Cholangiocarcinoma can be classified into intrahepatic (ICC) and extrahepatic (including hilar and distal bile duct) according to its anatomic location within the biliary tree with respect to the liver. This paper reviews the management of ICC, focusing on the epidemiology, risk factors, diagnosis, and surgical and nonsurgical management.

Pathologic classification of cholangiocarcinoma: New concepts

Herein, we propose a new pathologic classification of cholangiocarcinoma (CCA) based on recent progress in studies of preinvasive CCA lesions and the relationship of CCA to hepatic progenitor cells, as well as a new concept with respect to the pathologic similarities between biliary and pancreatic neoplasms. Depending on anatomical location, CCA is classifiable as intrahepatic (iCCA), perihilar (pCCA), and distal CCA (dCCA). iCCA is classifiable as the conventional type and the bile ductular type, whereas pCCA and dCCA mainly present as conventional adenocarcinoma. In addition, these three CCAs may present as the intraductal neoplasm type or rare variants. Bile ductular CCA resembles proliferating bile ductules and expressing hepatic progenitor cell phenotypes. Four types of preinvasive lesions are proposed: flat, papillary, tubular lesion, and cystic lesion. These lesions are eventually followed by invasive CCA. Interestingly, these preinvasive lesions have pancreatic counterparts. This CCA classification may introduce a new field of CCA research.

Epithelial cell adhesion molecule-positive human hepatic neoplastic cells: development of combined hepatocellular-cholangiocarcinoma in mice

BACKGROUND AND AIM

Human combined hepatocellular-cholangiocarcinoma (CHC) expresses several hepatic stem/progenitor cell (HSPC) markers, suggesting this neoplasm originates from HSPCs. We examined the significance of HSPC marker in CHC using a human CHC cell line.

METHODS

We used a human CHC cell line (KMCH-1) previously established in our laboratory. The original tumor was classified as CHC, showing areas of typical hepatocellular carcinoma (HCC) and cholangiocarcinoma (ChC). We examined the expression of HSPC markers and hepatocyte markers in KMCH-1 by flow cytometry (FCM) and quantitative real-time polymerase chain reaction. EpCAM(+) and EpCAM(-) KMCH-1 cells were isolated. Subsequently, their morphological features, HSPC marker expression, and biological characteristics were examined in vitro and in vivo.

RESULTS

FCM showed expression of EpCAM, K7, K19, and ABCG2 in KMCH-1, with various degrees. EpCAM(+) cells expressed K19 mRNA, but did not express α-fetoprotein (AFP). In contrast, EpCAM(-) cells expressed AFP mRNA, but did not express K19. EpCAM(+) cells produced both EpCAM(+) and EpCAM(-) cells, but EpCAM(-) cells produced only EpCAM(-) cells in vitro. EpCAM(+) cells showed higher tumorigenicity and formed larger tumors than EpCAM(-) cells. Inoculation of EpCAM(+) and EpCAM(-) cells produced both ChC and HCC-like component and HCC-like component only, respectively.

CONCLUSION

It is speculated that some CHCs may originate from EpCAM(+) neoplastic cells, and that these cells may affect malignant behavior and progression in such CHCs.

Histopathological characteristics of hypervascular cholangiocellular carcinoma as an early stage of cholangiocellular carcinoma

AIM

Prognosis of hypervascular cholangiocellular carcinoma (h-CCC) is reportedly better than that of ordinary hypovascular CCC (o-CCC). The aim of this study is to clarify the histopathological characteristics of h-CCC.

METHODS

On the basis of the findings in the arterial phase of contrast-enhanced computed tomography, 16 cases of mass-forming-type CCC were divided into two groups (h-CCC, n = 8; o-CCC, n = 8). Areas of high (Area H-a) and low (Area H-b) attenuation in h-CCC cases and areas of low attenuation in o-CCC cases (Area O) were delineated. These areas were then evaluated histopathologically to determine the proportion of tumor cells, fibrous stroma, arterial vessel density, and immunohistochemical expression of Vascular endothelial growth factor; angiopoietin-2; cytokeratin 7, CK19, SOX9 and SOX17 genes; epithelial cell adhesion molecule; and the Bmi-1, Ki-67, epithelial membrane antigen and polyclonal carcinoembryonic antigen.

RESULTS

The areal ratio of tumor cells decreased and that of fibrous stroma increased in the following order: Area H-a, Area H-b and Area O. Values for AVD and neural cell adhesion molecule positivity rate were significantly higher in Area H-a than in Areas H-b or O. Expressions of vascular endothelial growth factor and angiopoietin-2 were significantly higher in Areas H-a and H-b than in Area O. The Ki-67 labeling index increased in the following order: Area H-a, Area H-b and Area O.

CONCLUSION

A high areal ratio of tumor cells and AVD as well as a high expression of stem cells and angiogenic markers were observed in cases of h-CCC, whereas the areal ratio of fibrous stroma and malignant potential were low. These results suggest that h-CCC may represent the early stage of CCC.

Distinct miRNA signatures associate with subtypes of cholangiocarcinoma from infection with the tumourigenic liver fluke Opisthorchis viverrini

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (ICC) is a significant public health problem in East Asia, where it is strongly associated with chronic infection by the food-borne parasite Opisthorchis viverrini (OV). We report the first comprehensive miRNA expression profiling by microarray of the most common histologic grades and subtypes of ICC: well differentiated, moderately differentiated, and papillary ICC.

METHODS

MicroRNA expression profiles from FFPE were compared among the following: ICC tumour tissue (n = 16), non-tumour tissue distally macrodissected from the same ICC tumour block (n = 15), and normal tissue (n = 13) from individuals undergoing gastric bypass surgery. A panel of deregulated miRNAs was validated by qPCR.

RESULTS

Each histologic grade and subtype of ICC displayed a distinct miRNA profile, with no cohort of miRNAs emerging as commonly deregulated. Moderately differentiated ICC showed the greatest miRNA deregulation in quantity and magnitude, followed by the papillary subtype, and then well differentiated ICC. Moreover, when ICC tumour tissues were compared to adjacent non-tumour tissue, similar miRNA dysregulation profiles were observed.

CONCLUSIONS

We show that common histologic grades and subtypes of ICC have distinct miRNA profiles. As histological grade and subtypes are associated with ICC aggressiveness, these profiles could be used to enhance the early detection and improve the personalised treatment for ICC. These findings also suggest the involvement of specific miRNAs during ICC tumour progression and differentiation. We plan to use these insights to (a) detect these profiles in circulation and (b) conduct functional analyses to decipher the roles of miRNAs in ICC tumour differentiation.

Imaging bile duct tumors: pathologic concepts, classification, and early tumor detection

Cholangiocarcinoma is the most common primary malignancy of the bile ducts which has several predisposing factors such as hepatolithiasis and primary sclerosing cholangitis, and can develop from precancerous conditions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. As surgical resection of early stage cholangiocarcinoma or precancerous lesions may provide better prognosis, early detection of those lesions is very important. Imaging studies play important roles in the diagnosis of bile duct tumors followed by appropriate management. Indeed, not only diagnosis of cholangiocarcinoma but also appropriate categorization of bile duct tumors based on their morphologic features and location on cross-sectional imaging studies, including computed tomography and magnetic resonance imaging, is important to predict their biologic behaviors, and choose relevant treatment strategies. We herein review the classification system of the bile duct tumors with their radiologic and pathologic findings as well as role of imaging in the early detection of bile duct tumors.

Clinicopathologic analysis of combined hepatocellular-cholangiocarcinoma according to the latest WHO classification

Combined hepatocellular-cholangiocarcinoma comprises <1% of all liver carcinomas. The histogenesis of combined hepatocellular-cholangiocarcinoma has remained unclear for many years. However, recent advances in hepatic progenitor cell (HPC) investigations have provided new insights. The concept that combined hepatocellular-cholangiocarcinoma originates from HPCs is adopted in the chapter "combined hepatocellular-cholangiocarcinoma" of the latest World Health Organization (WHO) classification. In this study, we conducted clinicopathologic analysis of combined hepatocellular-cholangiocarcinoma according to the latest WHO classification. Fifty-four cases were included in this study. Pathologic diagnosis was made according to the WHO classification. When a tumor contained plural histologic patterns, predominant histologic pattern (≥50%) was defined. Minor histologic patterns were also appended. Immunohistochemical staining with biliary markers (CK7, CK19, and EMA), hepatocyte paraffin (HepPar)-1, HPC markers (CD56, c-kit, CD133, and EpCAM), and vimentin was performed. Forty-five and 50 patients were analyzed for progression-free survival and overall survival, respectively. Ten, 1, 32, and 11 cases were diagnosed as: combined hepatocellular-cholangiocarcinoma, classical type; combined hepatocellular-cholangiocarcinoma, stem cell features, typical subtype; combined hepatocellular-cholangiocarcinoma, stem cell features, intermediate cell subtype; and combined hepatocellular-cholangiocarcinoma, stem cell features, cholangiolocellular type, respectively. Combined hepatocellular-cholangiocarcinomas usually have high expression of biliary markers. CD56, c-kit, and EpCAM were expressed to various degrees in all combined hepatocellular-cholangiocarcinomas apart from the hepatocellular carcinoma component of combined hepatocellular-cholangiocarcinoma, classical type. The expression of CD133 and vimentin was observed only in combined hepatocellular-cholangiocarcinoma, stem cell features of intermediate cell subtype and cholangiolocellular subtype. The expression of CD133, EpCAM, and vimentin was significantly high in combined hepatocellular-cholangiocarcinoma, subtypes with stem cell features, especially cholangiolocellular subtype. Minor histologic patterns were significantly frequent in combined hepatocellular-cholangiocarcinoma, subtypes with stem cell features, compared with combined hepatocellular-cholangiocarcinoma, classical type. There was no significant difference in clinical outcome between each subtype. Combined hepatocellular-cholangiocarcinoma has wide histologic diversity and shows immunophenotypic expression of not only biliary markers but also HPC markers to various degrees, suggesting that the histogenesis of combined hepatocellular-cholangiocarcinoma could be strongly associated with HPCs. Our results pathologically validate the latest WHO classification of combined hepatocellular-cholangiocarcinoma. However, the complex mixture of histologic subtypes has presented a challenge to the classification of combined hepatocellular-cholangiocarcinoma. Further study should be conducted using a large cohort to support this classification.

Intrahepatic cholangiocarcinoma with predominant "ductal plate malformation" pattern: a new subtype

Ten cases of intrahepatic cholangiocarcinoma showing a highly differentiated adenocarcinoma mimicking ductal plate malformation (DPM) are reported. The patients included 7 males and 3 females with an average age of 69.5 years. Six cases were associated with chronic liver disease and the remaining 4 cases showed mild fatty change in the parenchyma and/or minimal to mild portal inflammation. Grossly, the tumor was a single nodule 1.5 to 6.6 cm in diameter, and was whitish and solid without a fibrous capsule. Microscopically, the tumor was composed of many vague, small nodular carcinomatous areas with desmoplastic reactions, and neoplastic glands had an irregularly dilated lumen lined with a single layer of cuboidal or low columnar carcinoma cells and irregular protrusions and bulges, resembling DPM. At its border, the carcinoma seemed to replace the non-neoplastic hepatic lobules or regenerative nodules. The central parts of the tumor were variably hypocellular and fibrotic. Although these carcinomas were negative for mucin and HepParI, they were frequently positive for CK19, epithelial cell adhesion molecule, and epithelial membrane antigen. Neural cell adhesion molecule was also expressed variably. The Ki-67 labeling index was <10% and p53 was scarcely expressed. In conclusion, a new subtype of intrahepatic cholangiocarcinoma with predominant DPM pattern was identified.

Current management of cholangiocarcinoma

Cholangiocarcinoma is the second most common primary hepatobiliary malignancy after hepatocellular carcinoma and remains among the most difficult management problems faced by surgeons. Curative surgery is achieved in only 25% to 30% of patients. Local tumor extent, such as portal vein invasion and hepatic lobar atrophy, does not preclude resection. Long-term survival has been seen only in patients who underwent extensive liver resections, suggesting that bile-duct excision alone is less effective. The majority of patients have unresectable disease, with 20% to 30% incidence of distant metastasis at presentation. Unresectable patients should be referred for nonsurgical biliary decompression, and in potential curative resection candidates the use of biliary stents should be reduced. Liver transplantation provides the option of wide resection margins, expanding the indication of surgical intervention for selected patients who otherwise are not surgical candidates due to lack of functional hepatic reserve.

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.

Pathological spectrum of intrahepatic cholangiocarcinoma arising in non-biliary chronic advanced liver diseases

Intrahepatic cholangiocarcinoma (ICC) is reported to develop in non-biliary chronic advanced liver diseases (CALD). Herein, we characterize the pathological features of ICC arising in CALD in comparison with those in non-CALD livers. Of 471 surgically resected cases of ICC in Kanazawa, Japan and Seoul, Korea, 53 were associated with CALD (group A), while the remaining 418 arose in otherwise normal livers (group B). When ICC were classified into bile duct type, bile ductular type, variants, and intraductal papillary neoplasm of the bile duct (IPNB), the whole spectrum of subtypes were found in group A; the majority of ICC belonged to the bile duct type in both groups. In group A, bile ductular type was rather frequent (22.6%) compared with group B (8.4%). IPNB was more frequent in group B (22.5%) than group A (3.8%), and in group B, frequent in Seoul cases (24.8%), but rare in Kanazawa cases (2.3%). Variants of ICC were rare in both groups. These results imply that cholangiocarcinogenesis itself is upregulated in group A in comparison with group B and that the bile ductular type is specifically related to group A. Some unique environmental factors in Seoul may be responsible for the frequent development of IPNB.

Development of intrahepatic cholangiocarcinoma after a 14-year follow-up of a patient with primary sclerosing cholangitis and ulcerative colitis

Intrahepatic cholangiocarcinoma (ICC) is one of the life-threatening complications of primary sclerosing cholangitis (PSC). However, the incidence of ICC in Japanese PSC patients is low, and the association between the development of ICC and morbidity duration of PSC is largely unknown. Here, we describe a case of ICC that developed after a long-term follow-up of a patient with PSC and ulcerative colitis (UC). At the age of 10 years, the patient was first diagnosed with UC and its remission was achieved with systemic steroid therapy. Since then, he was routinely followed-up. At the age of 19 years, laboratory tests showed abnormalities in liver function parameters, and the patient was diagnosed with PSC. Although treatment with ursodeoxycholic acid improved the abnormalities in serum levels of biliary enzymes and no PSC-related symptoms were seen for 13 years, calculous cholecystitis frequently occurred in the patient since the age of 32 years. He developed ICC, which expressed some hepatic progenitor cell markers such as CD133, neural cell adhesion molecule, keratin 7, and keratin 19 at the age of 33 years. ICC was treated by curative partial hepatectomy and adjuvant chemotherapy with gemcitabine. Eight months later, however, the patient developed multiple metastases in the abdominal lymph nodes and lungs, and died 21 months after the onset of ICC. Here, we report a case of ICC that developed after a 14-year follow-up of a patient with PSC and UC.

Expression of hepatocyte markers in mass-forming peripheral and periductal-infiltrating hilar intrahepatic cholangiocarcinomas

In this study, the expression of hepatocyte markers, including α-fetoprotein (AFP), HepPar-1 antigen and arginase-1, was examined immunohistochemically in 14 mass-forming peripheral intrahepatic cholangiocarcinomas (ICCs) that arose from the peripheral portion of the biliary tree, and in 14 periductal-infiltrating hilar ICCs that arose from intrahepatic large bile ducts. Only 2 (14.3%) of the 14 hilar ICCs and 2 (14.3%) of the 14 peripheral ICCs expressed AFP or HepPar-1 antigen. Conversely, arginase-1 was expressed in 8 (57.1%) and 11 (78.6%) of the hilar and peripheral ICCs, respectively, and 4 (28.6%) hilar ICCs and 7 (50%) peripheral ICCs expressed arginase-1 in more than 10% of the cancer cells. The expression of arginase-1 did not differ between peripheral ICCs showing major histology of poorly differentiated adenocarcinoma and those showing other major histologies, including well-or moderately differentiated tubular adenocarcinoma or papillary adenocarcinoma. Results of the present study showed that common hepatocyte markers, including AFP and HepPar-1 antigen, are rarely but definitely expressed in hilar and peripheral ICCs, and that a third hepatocyte marker, arginase-1, is expressed at a high rate in both hilar and peripheral ICCs, irrespective of their histology. These results indicate that care should be taken when using arginase-1 as a hepatocyte marker for distinguishing between a poorly differentiated hepatocellular carcinoma and a mass-forming peripheral ICC showing the histology of poorly differentiated adenocarcinoma.

Evaluation of risk factors and clinicopathologic features for intrahepatic cholangiocarcinoma in Southern China: a possible role of hepatitis B virus

BACKGROUND

Recent efforts suggest an etiologic role of hepatitis B virus (HBV) infection in intrahepatic cholangiocarcinoma (ICC) and the involvement of hepatic progenitor cell in ICC development, without definitive conclusions. This case-control study was undertaken to investigate risk factors for ICC, and clinicopathological features of HBV-associated ICC were analyzed.

METHODS

The report comprised 98 patients with pathologically confirmed ICC and 196 healthy control subjects. Logistic regression was used to determine odds ratios and 95% confidence intervals. The sex and age distributions of HBV-related and unrelated ICC patients were compared respectively with those of 882 HBV-associated hepatocellular carcinoma patients from a random selection, and the clinicopathological data of 62 ICC patients with or without HBV infection undergoing surgical resection were compared.

RESULTS

There was an association between ICC and each of HBV infection, liver cirrhosis, hepatolithiasis, and liver fluke infestation with the odds ratios (95% confidence intervals) of 2.75 (1.27-5.95), 8.42 (2.50-28.37), 22.81 (7.16-72.68), and 3.55 (1.60-7.89), respectively, with a marked synergism of cirrhosis and HBV infection (20.67; 5.40-79.06). Compared with HBV-unrelated ICC patients, HBV-related ICC patients were more common in male and younger subjects, had a higher incidence of abnormal serum alfa-fetoprotein level, cirrhosis, and neutrophilic infiltration, and had a lower proportion of elevated carbohydrate antigen 19-9 (CA19-9) values.

CONCLUSIONS

The independent association of HBV infection with ICC, synergy between cirrhosis and HBV infection, and some clinicopathological similarities between HBV-related ICC and hepatocellular carcinoma suggests that both may share similar or common tumorigenic process and may possibly originate from malignant transformation of hepatic progenitor cell.

Pathological classification of intrahepatic cholangiocarcinoma based on a new concept

Intrahepatic cholangiocarcinoma (ICC) arises from the lining epithelium and peribiliary glands of the intrahepatic biliary tree and shows variable cholangiocytic differentiation. To date, ICC was largely classified into adenocarcinoma and rare variants. Herein, we propose to subclassify the former, based on recent progress in the study of ICC including the gross classification and hepatic progenitor/stem cells and on the pathological similarities between biliary and pancreatic neoplasms. That is, ICC is classifiable into the conventional (bile duct) type, the bile ductular type, the intraductal neoplasm type and rare variants. The conventional type is further divided into the small duct type (peripheral type) and large bile duct type (perihilar type). The former is a tubular or micropapillary adenocarcinoma while the latter involves the intrahepatic large bile duct. Bile ductular type resembles proliferated bile ductules and shows a replacing growth of the hepatic parenchyma. Hepatic progenitor cell or stem cell phenotypes such as neural cell adhesion molecule expression are frequently expressed in the bile ductular type. Intraductal type includes papillary and tubular neoplasms of the bile duct (IPNBs and ITNBs) and a superficial spreading type. IPNB and ITNB show a spectrum from a preneoplastic borderline lesion to carcinoma and may have pancreatic counterparts. At invasive sites, IPNB is associated with the conventional bile duct ICC and mucinous carcinoma. Biliary mucinous cystic neoplasm with ovarian-like stroma in its wall is different from IPNB, particularly IPNB showing cystic dilatation of the affected ducts. Rare variants of ICC include squamous/adenosquamous cell carcinoma, mucinous/signet ring cell carcinoma, clear cell type, undifferentiated type, neuroendocrine carcinoma and so on. This classification of ICC may open up a new field of research of ICC and contribute to the clinical approach to ICC.

A novel approach to biliary tract pathology based on similarities to pancreatic counterparts: is the biliary tract an incomplete pancreas?

There are peribiliary glands around the biliary tract, and these glands drain into the bile duct lumen. Interestingly, small amounts of pancreatic exocrine acini are intermingled with these glands. Experimental studies using animals suggest that the biliary tract shows some potential for pancreatic differentiation. It is noteworth that the biliary tract and pancreas have similar pathological features. IgG4-related sclerosing cholangitis and autoimmune pancreatitis are representative inflammatory diseases with similar features. Intraductal papillary neoplasms are found in the biliary tract and also in the pancreas: intraductal papillary neoplasm of the bile duct (IPNB) and intraductal papillary mucinous neoplasm of the pancreas (IPMN). IPNB and IPMN share common histologic and phenotypic features and biological behaviors. Interestingly, mucinous cystic neoplasm (MCN) arises in both the pancreas and the hepatobiliary system. Intraductal tubular neoplasia is found in both the biliary tract and pancreas as well. Intraepithelial neoplasm is found in the biliary tract and pancreas: biliary intraepithelial neoplasm (BilIN) and pancreatic intraepithelial neoplasm (PanIN). BilIN and PanIN are followed by conventional invasive adenocarcinoma, while IPNB and IPMN are followed by tubular adenocarcinoma and mucinous carcinoma in both organs. Further study of the biliary tract's pathophysiology based on its similarity to pancreatic counterparts is warranted.

A case of intrahepatic clear cell cholangiocarcinoma

Intrahepatic clear cell cholangiocarcinoma is very rare - only 8 cases have been reported. A 56-year-old Japanese man with chronic hepatitis B infection was diagnosed with a 2.2 cm hepatocellular carcinoma on imaging, and hepatic segmentectomy was performed. Histopathologically, the tumor cells had copious clear cytoplasm and formed glandular structures or solid nests. These pathological findings suggested the tumor was a clear cell variant of intrahepatic cholangiocarcinoma. Particular stains and radiological images suggested that the cause of the clear cell change had been glycogen, not mucin nor lipid. On immunohistochemical staining, cytokeratin (CK) 7 and CK19 were positive, whereas CK20 was negative. Vimentin was detected on the cell membranes, and CD56 was focally positive. The patient was given adjuvant chemotherapy and is currently free from the tumor 7 mo postoperatively. Careful follow-up with adequate postoperative supplementary chemotherapy is necessary because the characteristics of this type of tumor are unknown.

Fascin is involved in tumor necrosis factor-alpha-dependent production of MMP9 in cholangiocarcinoma

Fascin is an actin-binding protein involved in the cell motility. Recently, aberrant expression of fascin in carcinoma cells was reported to participate in their invasive growth in cooperation with proteinases such as matrix metalloproteinases (MMPs). This study examined the participation of fascin in the progression of cholangiocarcinoma (CC) with reference to MMPs and tumor necrosis factor-alpha (TNF-alpha). Expression levels of fascin and MMP2 and 9 were examined immunohistochemically in human non-neoplastic biliary epithelium (13 cases) and CC (87 cases). The relationship between fascin and MMP9-expression levels was examined using two CC cell lines (CCKS-1 and HuCCT1). It was also examined whether or not fascin was involved in TNF-alpha-induced overproduction of MMP9 in CC. Fascin and MMP9 were expressed in 49 and 53% of CC samples, respectively, and the expression of these genes was frequent in intrahepatic CC. Fascin expression was correlated significantly with MMP9 expression. In particular, these two molecules were expressed more intensely at the invasive fronts of CC. Fascin expression was an unfavorable prognostic factor for patients with intrahepatic CC. In vitro studies showed that TNF-alpha could induce the overexpression of fascin and MMP9 in two CC cell lines. A knockdown study of fascin by siRNA showed that TNF-alpha induced the overproduction of fascin, which in turn upregulated MMP9 expression. Overexpression of fascin may have an important function in the progression of CC, and fascin expression might be involved in the signaling pathway in TNF-alpha-dependent production of MMP9 in CC.

Multistep carcinogenesis of perihilar cholangiocarcinoma arising in the intrahepatic large bile ducts

Flat-type "biliary intraepithelial neoplasia (BilIN)" and papillary-type "intraductal papillary neoplasm of the bile duct (IPN-B)" are proposed as precursors of invasive, perihilar intrahepatic cholangiocarcinoma (ICC). Three carcinogenetic pathways are proposed: BilIN progressing to tubular adenocarcinoma, and IPN-B progressing to tubular adenocarcinoma or to colloid carcinoma. Carcinogenesis via BilIN was characterized by mucin core protein 2-/cytokeratin 20-(MUC2-/CK20-) with MUC1 expression, while carcinogenesis via IPN-B leading to tubular adenocarcinoma was associated with MUC1 expression or that to colloid carcinoma with MUC1-negativity. In both the BilIN and IPNB series, the expression of p21, p53, and cyclin D1 was upregulated with histological progression. Interestingly, p53 expression was upregulated at the invasive stage of BilIN, but was low in noninvasive BilIN, while p53 expression was upregulated in IPN-B1 and reached a plateau in IPN-B2 and invasive ICC. Expression of p16(INK4a), which was frequent in BilIN1, was decreased in BilIN-2/3 and invasive carcinoma. EZH2 expression showed a stepwise increase from BilIN to invasive carcinoma. Membranous expression of β-catenin and E-cadherin was more markedly decreased in ICC with BilIN than in ICC with IPNB. Interestingly, disruption of the membranous distribution of β-catenin and E-cadherin seems to result in the invasion and metastasis of carcinoma cells of BilIN and IPN-B expressing MMP-7 and MT1-MMP. Increased expression of cyclin D1 and c-myc was more frequent in the IPNB lineage than BilIN lineage, possibly related to the Wnt signaling pathway associated with the nuclear accumulation of β-catenin. In conclusion, BilIN and IPN-B progress to invasive ICC through characteristic multistep processes.

Expression of stem cell factor and its receptor c-Kit during the development of intrahepatic cholangiocarcinoma

Stem cell factor (SCF) and its receptor, c-Kit, constitute an important signal transduction system with proliferative and anti-apoptotic functions. Besides regulating hemopoietic stem cell proliferation and liver regeneration, it has been implicated in the regulation of human malignancies. However, the cellular expression of the SCF-c-Kit gene system in the liver during cholangiocarcinogenesis has not been studied to date. The protein- and mRNA-expression levels of SCF and c-Kit genes were examined in normal rat liver, in isolated normal rat liver cells and in a thioacetamide-induced rat model of intrahepatic cholangiocarcinoma (CC). Immunohistochemical analysis of the normal liver showed that SCF is expressed in the wall of the hepatic artery and in some cells, which were located along the sinusoids, although it was absent from hepatocytes and biliary epithelial cells. The mRNA analysis of isolated normal liver cell populations revealed a co-expression of SCF- and c-Kit-mRNA in sinusoidal endothelial cells and in Kupffer cells, whereas passaged and cultured liver myofibroblasts (MFs) expressed only SCF. Low levels of the SCF- and c-Kit-mRNA expression could be detected in isolated hepatocytes of the normal liver. Immunohistochemical analysis of the CC tissue showed SCF positivity in proliferating biliary cells (CK-19(+)), in macrophages (ED-1(+)) and in MFs (alpha-smooth-muscle-actin, alpha-SMA(+)) of the tumoral microenvironment. c-Kit-positivity could be detected on hepatocytes of the regenerating nodules and on the proliferating bile ducts of CC. Compared with the normal liver tissue, SCF-mRNA from the CC tissue was upregulated up to 20-fold, whereas c-Kit-mRNA was upregulated up to fivefold. These data indicate that several cell populations may become able to express SCF and/or c-Kit during cholangiocarcinogenesis. Therefore, the SCF-c-Kit system may contribute to tumor development, for instance, by inducing proliferation of hepatocytes and of biliary cells and by acting as a surviving factor for CC cells.