Acquisition of Cholangiocarcinoma Traits during Advanced Hepatocellular Carcinoma Development in Mice

Bioengineered Organoids Offer New Possibilities for Liver Cancer Studies: A Review of Key Milestones and Challenges

Hepatic cancer is widely regarded as the leading cause of cancer-related mortality worldwide. Despite recent advances in treatment options, the prognosis of liver cancer remains poor. Therefore, there is an urgent need to develop more representative in vitro models of liver cancer for pathophysiology and drug screening studies. Fortunately, an exciting new development for generating liver models in recent years has been the advent of organoid technology. Organoid models hold huge potential as an in vitro research tool because they can recapitulate the spatial architecture of primary liver cancers and maintain the molecular and functional variations of the native tissue counterparts during long-term culture in vitro. This review provides a comprehensive overview and discussion of the establishment and application of liver organoid models in vitro. Bioengineering strategies used to construct organoid models are also discussed. In addition, the clinical potential and other relevant applications of liver organoid models in different functional states are explored. In the end, this review discusses current limitations and future prospects to encourage further development.

p53R245W Mutation Fuels Cancer Initiation and Metastases in NASH-driven Liver Tumorigenesis

Obesity is a significant global health concern. Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis (NASH) are common risk factors for hepatocellular carcinoma (HCC) and are closely associated with metabolic comorbidities, including obesity and diabetes. The TP53 tumor suppressor is the most frequently mutated gene in liver cancers, with half of these alterations being missense mutations. These mutations produce highly abundant proteins in cancer cells which have both inhibitory effects on wildtype (WT) p53, and gain-of-function (GOF) activities that contribute to tumor progression. A Western diet increases p53 activity in the liver. To elucidate the functional consequences of Trp53 mutations in a NASH-driven liver tumorigenesis model, we generated somatic mouse models with Trp53 deletion or the missense hotspot mutant p53R245W only in hepatocytes and placed mice on a high-fat, choline-deficient diet. p53R245W in the presence of diet increased fatty liver, compensatory proliferation in the liver parenchyma, and enriched genes of tumor-promoting pathways such as KRAS signaling, MYC, and epithelial-mesenchymal transition when compared with controls in the premalignant liver. Moreover, p53R245W suppressed transcriptional activity of WT p53 in the liver in vivo under metabolic challenges, and shortened survival and doubling of HCC incidence as compared with control heterozygous mice. Complete loss of Trp53 also significantly accelerated liver tumor incidence and lowered time-to-tumor development compared with WT controls. p53R245W GOF properties increased carcinoma initiation, fueled mixed hepatocholangial carcinoma incidence, and tripled metastatic disease. Collectively, our in vivo studies indicate that p53R245W has stronger tumor promoting activities than Trp53 loss in the context of NASH.

SIGNIFICANCE

Using somatic NASH-driven mouse models with p53 deletion or mutant p53R245W only in hepatocytes, we discovered that p53R245W increased carcinoma initiation, fueled hepatocholangial carcinoma incidence, and tripled metastases.

A Novel Mouse Model of Combined Hepatocellular-Cholangiocarcinoma Induced by Diethylnitrosamine and Loss of Ppp2r5d

Primary liver cancer (PLC) can be classified in hepatocellular (HCC), cholangiocarcinoma (CCA), and combined hepatocellular-cholangiocarcinoma (cHCC-CCA). The molecular mechanisms involved in PLC development and phenotype decision are still not well understood. Complete deletion of Ppp2r5d, encoding the B56δ subunit of Protein Phosphatase 2A (PP2A), results in spontaneous HCC development in mice via a c-MYC-dependent mechanism. In the present study, we aimed to examine the role of Ppp2r5d in an independent mouse model of diethylnitrosamine (DEN)-induced hepatocarcinogenesis. Ppp2r5d deletion (heterozygous and homozygous) accelerated HCC development, corroborating its tumor-suppressive function in liver and suggesting Ppp2r5d may be haploinsufficient. Ppp2r5d-deficient HCCs stained positively for c-MYC, consistent with increased AKT activation in pre-malignant and tumor tissues of Ppp2r5d-deficient mice. We also found increased YAP activation in Ppp2r5d-deficient tumors. Remarkably, in older mice, Ppp2r5d deletion resulted in cHCC-CCA development in this model, with the CCA component showing increased expression of progenitor markers (SOX9 and EpCAM). Finally, we observed an upregulation of Ppp2r5d in tumors from wildtype and heterozygous mice, revealing a tumor-specific control mechanism of Ppp2r5d expression, and suggestive of the involvement of Ppp2r5d in a negative feedback regulation restricting tumor growth. Our study highlights the tumor-suppressive role of mouse PP2A-B56δ in both HCC and cHCC-CCA, which may have important implications for human PLC development and targeted treatment.

Liver organoids: a promising three-dimensional model for insights and innovations in tumor progression and precision medicine of liver cancer

Primary liver cancer (PLC) is one type of cancer with high incidence rate and high mortality rate in the worldwide. Systemic therapy is the major treatment for PLC, including surgical resection, immunotherapy and targeted therapy. However, mainly due to the heterogeneity of tumors, responses to the above drug therapy differ from person to person, indicating the urgent needs for personalized treatment for PLC. Organoids are 3D models derived from adult liver tissues or pluripotent stem cells. Based on the ability to recapitulate the genetic and functional features of in vivo tissues, organoids have assisted biomedical research to make tremendous progress in understanding disease origin, progression and treatment strategies since their invention and application. In liver cancer research, liver organoids contribute greatly to reflecting the heterogeneity of liver cancer and restoring tumor microenvironment (TME) by co-organizing tumor vasculature and stromal components in vitro. Therefore, they provide a promising platform for further investigation into the biology of liver cancer, drug screening and precision medicine for PLC. In this review, we discuss the recent advances of liver organoids in liver cancer, in terms of generation methods, application in precision medicine and TME modeling.

Ribonucleotide reductase subunit switching in hepatoblastoma drug response and relapse

Prognosis of children with high-risk hepatoblastoma (HB), the most common pediatric liver cancer, remains poor. In this study, we found ribonucleotide reductase (RNR) subunit M2 (RRM2) was one of the key genes supporting cell proliferation in high-risk HB. While standard chemotherapies could effectively suppress RRM2 in HB cells, they induced a significant upregulation of the other RNR M2 subunit, RRM2B. Computational analysis revealed distinct signaling networks RRM2 and RRM2B were involved in HB patient tumors, with RRM2 supporting cell proliferation and RRM2B participating heavily in stress response pathways. Indeed, RRM2B upregulation in chemotherapy-treated HB cells promoted cell survival and subsequent relapse, during which RRM2B was gradually replaced back by RRM2. Combining an RRM2 inhibitor with chemotherapy showed an effective delaying of HB tumor relapse in vivo. Overall, our study revealed the distinct roles of the two RNR M2 subunits and their dynamic switching during HB cell proliferation and stress response.

A hepatoprotective role of peritumoral non-parenchymal cells in early liver tumorigenesis

Various 3D models of hepatocytes (HCs) have been established to assess liver functions in vitro. The contribution of the hepatic non-parenchymal cells (NPCs), however, is largely neglected in these models. Here, we report a comparative study of hepatic spheroids generated from freshly isolated mouse whole liver cells (WLCs) and HCs (referred to as SphWLC and SphHC, respectively). We found that HC differentiation was preserved better in SphWLC than in SphHC, and, when co-cultured with liver tumor spheroids (SphT), SphWLC showed more potent suppression of SphT growth compared to SphHC. Histological characterization revealed marked activation and accumulation of hepatic stellate cells (HSCs) at the SphWLC:SphT interface. We found that mixing HSCs in both 3D and 2D HC:tumor co-cultures provided potent protection to HCs against tumor-induced cell death. Activation of HSCs at the tumor border was similarly found in liver tumors from both mice and patients. Overall, our study suggests a hepatoprotective role of peritumoral HSCs in liver tumorigenesis and the potential application of SphWLC as a useful 3D model for dissecting the liver's response to tumorigenesis in vitro.

Spatiotemporal regulation of cholangiocarcinoma growth and dissemination by peritumoral myofibroblasts in a Vcam1-dependent manner

Intrahepatic cholangiocarcinoma (iCCA) is characterized by its highly desmoplastic stroma. Myofibroblasts (MFs) are present both within the tumor mass (intratumoral MFs, iMFs) and at the tumor border (peritumoral MFs, pMFs). Using a spheroid-based coculture system, we show that the initial iCCA-pMF contact is growth suppressive to the tumor cells. However, prolonged iCCA-pMF interaction elicits significant tumor cell invasion and dissemination. We find that vascular cell adhesion molecule-1 (Vcam1) level is elevated in tumor cells in contact with pMFs but low in disseminated tumor cells both in vitro and in vivo. A gene regulatory network analysis of mouse and patient iCCA tumors and Vcam1 knockout (Vcam1^KO) demonstrate a heavy involvement of Vcam1 in epithelial-to-mesenchymal transition. While Vcam1^KO has only a limited impact on tumor cell growth in their monoculture, Vcam1^KO spheroids exhibit instant dissemination and a severe growth defect when cocultured with pMFs. When transplanted into the liver, Vcam1^KO iCCA cells show a similar increase in dissemination but a significant defect in establishing primary and metastatic tumors. Incomplete blocking of Vcam1 in vivo reduces the size but increase the number of metastatic lesions. Overall, our study shows a spatiotemporal regulation of iCCA growth and dissemination by pMFs in a Vcam1-dependent manner.

Ribonucleotide Reductase Subunit Switching in Hepatoblastoma Drug Response and Relapse

Prognosis of children with high-risk hepatoblastoma (HB), the most common pediatric liver cancer, remains poor. In this study, we found ribonucleotide reductase (RNR) subunit M2 ( RRM2 ) was one of the key genes supporting cell proliferation in high-risk HB. While standard chemotherapies could effectively suppress RRM2 in HB cells, they induced a significant upregulation of the other RNR M2 subunit, RRM2B . Computational analysis revealed distinct signaling networks RRM2 and RRM2B were involved in HB patient tumors, with RRM2 supporting cell proliferation and RRM2B participating heavily in stress response pathways. Indeed, RRM2B upregulation in chemotherapy-treated HB cells promoted cell survival and subsequent relapse, during which RRM2B was gradually replaced back by RRM2. Combining an RRM2 inhibitor with chemotherapy showed an effective delaying of HB tumor relapse in vivo. Overall, our study revealed the distinct roles of the two RNR M2 subunits and their dynamic switching during HB cell proliferation and stress response.

Unraveling the actin cytoskeleton in the malignant transformation of cholangiocyte biology

Correct actin cytoskeleton organization is vital in the liver organ homeostasis and disease control. Rearrangements of the actin cytoskeleton may play a vital role in the bile duct cells cholangiocytes. An abnormal actin network leads to aberrant cell morphology, deregulated signaling networks and ultimately triggering the development of cholangiocarcinoma (CCA) and paving the route for cancer cell dissemination (metastasis). In this review, we will outline alterations of the actin cytoskeleton and the potential role of this dynamic network in initiating CCA, as well as regulating the course of this malignancy. Actin rearrangements not only occur because of signaling pathways, but also regulate and modify cellular signaling. This emphasizes the importance of the actin cytoskeleton itself as cause for aberrant signaling and in promoting tumorigenic phenotypes. We will highlight the impact of aberrant signaling networks on the actin cytoskeleton and its rearrangement as potential cause for CCA. Often, these exact mechanisms in CCA are limited understood and still must be elucidated. Indeed, focusing future research on how actin affects and regulates other signaling pathways may provide more insights into the mechanisms of CCA development, progression, and metastasis. Moreover, manipulation of the actin cytoskeleton organization highlights the potential for a novel therapeutic area.

A developmentally prometastatic niche to hepatoblastoma in neonatal liver mediated by the Cxcl1/Cxcr2 axis

BACKGROUND AND AIMS

Hepatoblastoma (HB) is the most common pediatric liver cancer. Its predominant occurrence in very young children led us to investigate whether the neonatal liver provides a protumorigenic niche to HB development.

APPROACH AND RESULTS

HB development was compared between orthotopic transplantation models established in postnatal day 5 (P5) and 60 (P60) mice (P5Tx and P60Tx models). Single-cell RNA-sequencing (sc-RNAseq) was performed using tumor and liver tissues from both models and the top candidate cell types and genes identified are investigated for their roles in HB cell growth, migration, and survival.

CONCLUSIONS

We found that various HB cell lines including HepG2 cells were consistently and considerably more tumorigenic and metastatic in the P5Tx model than in the P60Tx models. Sc-RNAseq of the P5Tx and P60Tx HepG2 models revealed that the P5Tx tumor was more hypoxic and had a larger number of activated hepatic stellate cells (aHSCs) in the tumor-surrounding liver that express significantly higher levels of Cxcl1 than those from the P60Tx model. We found these differences were developmentally present in normal P5 and P60 liver. We showed that the Cxcl1/Cxcr2 axis mediated HB cell migration and was critical to HB cell survival under hypoxia. Treating HepG2 P60Tx model with recombinant CXCL1 protein induced intrahepatic and pulmonary metastasis and CXCR2 knockout (KO) in HepG2 cells abolished their metastatic potential in the P5Tx model. Lastly, we showed that in tumors from patients with metastatic HB, there was a similar larger population of aHSCs in the tumor-surrounding liver than in localized tumors, and tumor hypoxia was uniquely associated with prognosis of patients with HB among pediatric cancers. We demonstrated that the neonatal liver provides a prometastatic niche to HB development through the Cxcl1/Cxcr2 axis.

Combined Hepatocellular-Cholangiocarcinoma: An Update on Pathology and Diagnostic Approach

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver carcinoma displaying both hepatocytic and cholangiocytic differentiation within the same tumor. Relative to classic hepatocellular carcinoma (HCC), cHCC-CCA has more aggressive behavior and a poorer prognosis. Though recent advances have improved our understanding of the biology underlying cHCC-CCAs, they remain diagnostically challenging for pathologists because of their morphologic and phenotypic diversity. Accurate diagnosis of cHCC-CCA is important for patient management and prognostication. Herein, we review recent updates on cHCC-CCA, focusing on tumor classification, pathology, and diagnostic approach.

KIF2C promotes the proliferation of hepatocellular carcinoma cells in vitro and in vivo

Hepatocellular carcinoma (HCC) is one of the most common malignancies with high mortality and morbidity rates. In recent years, HCC targeted therapy has gained increasing attention. Due to the heterogeneity and high metastasis of HCC, more effective therapeutic targets are needed. Kinesin family member 2C (KIF2C), also known as mitotic centromere-associated kinesin, is a microtubule-based motor protein which is involved in a variety of important cellular processes, such as mitosis. The effects of KIF2C on cancer progression and development have been widely studied; however, its potential effects on HCC remains unclear. In the present study, high expression of KIF2C in human HCC tissues was demonstrated using The Cancer Genome Atlas database and immunohistochemistry assays. KIF2C expression was associated with HCC prognosis, including overall survival and disease-free survival. KIF2C expression was also associated with clinical pathological characteristics including the number of tumor nodes (P=0.015) and tumor size (P=0.009). KIF2C knockdown inhibited the proliferation of HCC cells in vitro, confirmed by MTT and colony formation assays, and suppressed tumor growth in mice which was confirmed by a xenograft mouse model. Together, the results suggested that KIF2C may serve as a promising therapeutic target for the treatment of HCC.

Generation of combined hepatocellular-cholangiocarcinoma through transdifferentiation and dedifferentiation in p53-knockout mice

The two principal histological types of primary liver cancers, hepatocellular carcinoma (HCC) and cholangiocarcinoma, can coexist within a tumor, comprising combined hepatocellular‐cholangiocarcinoma (cHCC‐CCA). Although the possible involvement of liver stem/progenitor cells has been proposed for the pathogenesis of cHCC‐CCA, the cells might originate from transformed hepatocytes that undergo ductular transdifferentiation or dedifferentiation. We previously demonstrated that concomitant introduction of mutant HRAS^V12 (HRAS) and Myc into mouse hepatocytes induced dedifferentiated tumors that expressed fetal/neonatal liver genes and proteins. Here, we examine whether the phenotype of HRAS‐ or HRAS/Myc‐induced tumors might be affected by the disruption of the Trp53 gene, which has been shown to induce biliary differentiation in mouse liver tumors. Hepatocyte‐derived liver tumors were induced in heterozygous and homozygous p53‐knockout (KO) mice by hydrodynamic tail vein injection of HRAS‐ or Myc‐containing transposon cassette plasmids, which were modified by deleting loxP sites, with a transposase‐expressing plasmid. The HRAS‐induced and HRAS/Myc‐induced tumors in the wild‐type mice demonstrated histological features of HCC, whereas the phenotype of the tumors generated in the p53‐KO mice was consistent with cHCC‐CCA. The expression of fetal/neonatal liver proteins, including delta‐like 1, was detected in the HRAS/Myc‐induced but not in the HRAS‐induced cHCC‐CCA tissues. The dedifferentiation in the HRAS/Myc‐induced tumors was more marked in the homozygous p53‐KO mice than in the heterozygous p53‐KO mice and was associated with activation of Myc and YAP and suppression of ERK phosphorylation. Our results suggest that the loss of p53 promotes ductular differentiation of hepatocyte‐derived tumor cells through either transdifferentiation or Myc‐mediated dedifferentiation.

Combined hepatocellular-cholangiocarcinoma and its mimickers: Diagnostic pitfalls in surgical pathology

BACKGROUND

The diagnosis of combined hepatocellular-cholangiocarcinoma (cHCC-CCA) requires histomorphological detection of both hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). However, these primary liver cancers (PLCs) have a wide variety of microscopic appearances resulting in difficulties and uncertainties in cHCC-CCA's diagnosis. This study aims to perform a clinicopathologic analysis on the diagnosis of PLCs at a tertiary referral hospital in Thailand using traditional morphologic studies.

METHODS

A 5-year retrospective analysis of pathologically diagnosed PLCs was conducted. Pathological features and clinical characteristics of cHCC-CCA and other PLCs with the histopathologic resemblance to cHCC-CCA were studied. The pathological diagnosis was rendered based on histomorphological context rather than immunoreactivity. A literature review containing diagnostic pitfalls of cHCC-CCA was carried out.

RESULTS

PLCs from a total of 295 patients were retrieved, and cHCC-CCA accounted for 1.4% (n = 4) of the malignancies. Histomorphological evaluation is the most reliable diagnostic modality for cHCC-CCA. Extremely uncommon variants of iCCA (i.e., mucinous iCCA and adenosquamous iCCA) and iCCA arising with hepatocellular nodular lesions (i.e., iCCA with nodular regenerative hyperplasia (NRH), and iCCA in cirrhosis) could have a histomorphologic resemblance to that of cHCC-CCA.

CONCLUSIONS

Although there has been an exceedingly high incidence of iCCA in Thailand, such a commonness is not valid for cHCC-CCA in our series. Rare forms of iCCA could have a morphologic resemblance to that of cHCC-CCA. Regardless of the differentiation and immunophenotype, iCCA without a distinct HCC component should never be diagnosed as cHCC-CCA.

Update on Pathologic and Radiologic Diagnosis of Combined Hepatocellular-Cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a malignant primary liver carcinoma characterized by the unequivocal presence of both hepatocytic and cholangiocytic differentiation within the same tumor. Recent research has highlighted that cHCC-CCAs are more heterogeneous than previously expected. In the updated consensus terminology and WHO 2019 classification, "classical type" and "subtypes with stem-cell features" of the WHO 2010 classification are no longer recommended. Instead, it is recommended that the presence and percentages of various histopathologic components and stem-cell features be mentioned in the pathologic report. The new terminology and classification enable the exchange of clearer and more objective information about cHCC-CCAs, facilitating multi-center and multi-national research. However, there are limitations to the diagnosis of cHCC-CCA by imaging and biopsy. cHCC-CCAs showing typical imaging findings of HCC could be misdiagnosed as HCC and subjected to inappropriate treatment, if other clinical findings are not sufficiently considered. cHCC-CCAs showing at least one of the CCA-like imaging features or unusual clinical features should be subjected to biopsy. There may be a sampling error for the biopsy diagnosis of cHCC-CCA. An optimized diagnostic algorithm integrating clinical, radiological, and histopathologic information of biopsy is required to resolve these diagnostic pitfalls.

Cellular heterogeneity and plasticity in liver cancer

Hepatocarcinogenesis involves complex genetic and cellular dysregulations which drive the formation of hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, with extensive heterogeneity. In contrast to the broad spectrum of molecularly driven therapies available for defined patient groups in certain cancer types, unfortunately the treatment options for HCC are highly limited. The lack of representative molecular and cellular signatures in the heterogeneous HCC tumors that can effectively guide the choice of the most appropriate treatment among the patients unavoidably limits the treatment outcome. Advancement and wide availability of the next-generation sequencing technologies have empowered us to examine and capture not only the detailed genetic alterations of the HCC cells but also the precise composition of different cell types within the tumor microenvironment and their interactions with the HCC cells at an unprecedented level. The information generated has provided new insight and better defined the inter-patient intertumoral heterogeneity, intra-patient intratumoral heterogeneity as well as the plasticity of HCC cells. These collectively provide a robust scientific basis in guiding the development and use of targeted therapy and immunotherapy. To complement, liquid biopsy coupled with high-sensitivity sequencing could potentially be adopted as a more practical and safer approach to detect and reflect the tumor heterogeneity in HCC patients in guiding the choice of treatment and monitoring disease progression.

Organoids for the Study of Liver Cancer

Liver cancer is the second most lethal malignancy worldwide. Cell lines and murine models are the most common tools for modeling human liver carcinogenesis. Most recently, organoids with a three-dimensional structure derived from primary tissues or cells have been applied to liver cancer research. Organoids can be generated from induced pluripotent stem cells, embryonic or adult, healthy or diseased tissues. In particular, liver organoids have been widely employed in mechanistic studies aimed at delineating the molecular pathways responsible for hepatocarcinogenesis. The introduction of clustered regularly interspaced palindromic repeats (CRISPR)-associated protein 9 (Cas9) and microengineered miniorganoid technologies into liver organoids for cancer study has significantly accelerated these investigations. Translational advances have been made by utilizing liver tumor organoids for anticancer drug screening, biobanking, omics profiling, and biomarker discovery. This review summarizes the latest advances and the remaining challenges in the use of organoid models for the study of liver cancer.

Application and research progress of organoids in cholangiocarcinoma and gallbladder carcinoma

Both cholangiocarcinoma (CCA) and gallbladder carcinoma (GBC) are belong to biliary tract carcinomas (BTCs) with a high degree of malignancy and a poor prognosis. Therefore, an in vitro model is urgently needed to increase our understanding of the pathogenesis of BTCs. Tumor organoids are a novel three-dimensional (3D) culture technology that utilizes samples from removed tumors. Therefore, it can maintain the histological features, expression profiles and marker expression of the parental tissues. Recently, with the widespread use of this technique, increasing research is beginning to use organoid to study the cellular metabolism, pathogenesis, chemotherapy resistance, and new therapy methods of BTCs. In this review, we will discuss the advantages and disadvantages of BTC organoids compared with other cell culture techniques. In addition, the construction methods, research directions and current limitations of BTC organoids will be described.

Evolution of the Experimental Models of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare, aggressive disease with poor overall survival. In advanced cases, surgery is often not possible or fails; in addition, there is a lack of effective and specific therapies. Multidisciplinary approaches and advanced technologies have improved the knowledge of CCA molecular pathogenesis, highlighting its extreme heterogeneity and high frequency of genetic and molecular aberrations. Effective preclinical models, therefore, should be based on a comparable level of complexity. In the past years, there has been a consistent increase in the number of available CCA models. The exploitation of even more complex CCA models is rising. Examples are the use of CRISPR/Cas9 or stabilized organoids for in vitro studies, as well as patient-derived xenografts or transgenic mouse models for in vivo applications. Here, we examine the available preclinical CCA models exploited to investigate: (i) carcinogenesis processes from initiation to progression; and (ii) tools for personalized therapy and innovative therapeutic approaches, including chemotherapy and immune/targeted therapies. For each model, we describe the potential applications, highlighting both its advantages and limits.

Clinicopathological characteristics of combined hepatocellular cholangiocarcinoma from the viewpoint of patient prognosis after hepatic resection: High rate of early recurrence and its predictors

AIM

Combined hepatocellular cholangiocarcinoma (cHCC-CCA) is a very rare subtype of primary liver carcinoma; therefore, its clinicopathological characteristics have not yet been elucidated in detail. The aim of the study was to reveal the clinicopathological characteristics and prognostic factors of cHCC-CCA after hepatic resection (HR) METHODS: A total of 124 patients who underwent curative HR for cHCC-CCA between 2000 and 2016 were enrolled in this multi-institutional study conducted by the Kyushu Study Group of Liver Surgery. Clinicopathological analysis was performed from the viewpoint of patient prognosis.

RESULTS

A total of 62 patients (50%) had early recurrence within 1.5 years after HR, including 36 patients (58%) with extrahepatic recurrence. In contrast, just four patients (3%) had late recurrence occurring >3 years after HR. The independent predictors of early recurrence were as follows: des-gamma carboxyprothrombin >40 mAU/mL (odds ratio 26.2, P = 0.0117), carbohydrate antigen 19-9>37 IU/l (odds ratio 18.0, P = 0.0200), and poorly differentiated HCC or CCA (odds ratio 11.2, P = 0.0259).

CONCLUSIONS

Half of the patients with cHCC-CCA had early recurrence after HR. Preoperative elevation of des-gamma carboxyprothrombin or carbohydrate antigen 19-9 and the existence of poorly differentiated components of HCC or CCA in resected specimens are predictors of its early recurrence.

Organoid models of gastrointestinal cancers in basic and translational research

Cancer is a major public health problem worldwide. Gastrointestinal cancers account for approximately one-third of the total global cancer incidence and mortality. Historically, the mechanisms of tumour initiation and progression in the gastrointestinal tract have been studied using cancer cell lines in vitro and animal models. Traditional cell culture methods are associated with a strong selection of aberrant genomic variants that no longer reflect the original tumours in terms of their (metastatic) behaviour or response to therapy. Organoid technology has emerged as a powerful alternative method for culturing gastrointestinal tumours and the corresponding normal tissues in a manner that preserves their genetic, phenotypic and behavioural traits. Importantly, accumulating evidence suggests that organoid cultures have great value in predicting the outcome of therapy in individual patients. Herein, we review the current literature on organoid models of the most common gastrointestinal cancers, including colorectal cancer, gastric cancer, oesophageal cancer, liver cancer and pancreatic cancer, and their value in modelling tumour initiation, metastatic progression and therapy response. We also explore the limitations of current organoid models and discuss how they could be improved to maximally benefit basic and translational research in the future, especially in the fields of drug discovery and personalized medicine.

Genetically engineered animal models of biliary tract cancers

PURPOSE OF REVIEW

Biliary tract cancers which include intrahepatic and extrahepatic cholangiocarcinomas and gallbladder cancer, are characterized by poor outcome. Therefore, identifying the molecular mechanisms of the disease has become a priority. However, such identification has to cope with extreme heterogeneity of the disease, which results from the variable anatomical location, the numerous cell types of origin and the high number of known genetic alterations.

RECENT FINDINGS

Animal models can develop invasive and metastatic tumours that recapitulate as faithfully as possible the molecular features of the human tumours. To generate animal models of cholangiocarcinoma, investigators resorted to the administration of carcinogens, induction of cholestasis, grafting of tumour cells and induction of genetic modifications.

SUMMARY

Here, we summarize the currently available genetically engineered animal models, and focus on mice and zebrafish. The experimental strategies that were selected to induce cholangiocarcinoma in a time-controlled and cell-type-specific manner are critically examined. We discuss their strengths and limitations while considering their relevance to human pathophysiology.