Mixed hepatocellular cholangiocarcinoma tumors: Cholangiolocellular carcinoma is a distinct molecular entity

Advancing precision medicine in hepatocellular carcinoma: current challenges and future directions in liquid biopsy, immune microenvironment, single nucleotide polymorphisms, and conversion therapy

Hepatocellular carcinoma (HCC) remains a health concern characterized by heterogeneity and high mortality. Surgical resection, radiofrequency ablation, trans-arterial chemoembolization, and liver transplantation offer potentially curative treatments for early-stage disease, but recurrence remains high. Most patients present with advanced-stage HCC, where locoregional therapies are less effective, and systemic treatments-primarily multi-kinase inhibitors and immune checkpoint inhibitors-often yield limited responses. Precision medicine aims to tailor therapy to molecular and genetic profiles, yet its adoption in HCC is hindered by inter-/intra-tumoral heterogeneity and limited biopsy availability. Advances in molecular diagnostics support reintroducing tissue sampling to better characterize genetic, epigenetic, and immunological features. Liquid biopsy offers a minimally invasive method for capturing real-time tumor evolution, overcoming spatial and temporal heterogeneity. Artificial intelligence and machine learning are revolutionizing biomarker discovery, risk stratification, and treatment planning by integrating multi-omics data. Immunological factors such as tumor-infiltrating lymphocytes, natural killer cells, macrophages, and fibroblasts have emerged as determinants of HCC progression and treatment response. Conversion therapy-combining systemic agents with locoregional treatments-has showndemonstrated promise in downstaging unresectable HCC. Ongoing efforts to refine biomarker-driven approaches and optimize multi-modality regimens underscore precision medicine's potential to improve outcomes. PubMed (January 2002-February 2025) was searched for relevant studies.

Genetic re-classification of combined hepatocellular-cholangiocarcinoma and small duct type intrahepatic cholangiocarcinoma

BACKGROUND

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) shares various features with small duct type intrahepatic cholangiocarcinoma (SmD-iCCA) and sometimes histological diagnosis may be difficult.

METHODS

We examined genetic alterations such as hTERT promoter (hTERT), p53, and fibroblast growth factor receptor 2 (FGFR2) in 103 PLCs diagnosed as cHCC-CCA or SmD-iCCA. A cluster analysis was performed on the R software for re-classification of PLCs including cHCC-CCA and SmD-iCCA.

RESULTS

The primary liver carcinomas (PLCs) were divided into 5 clusters; 19 tumors (18 %) in Cluster-1 (with alterations in hTERT and/or p53), 24 (23 %) in Cluster-2 (FGFR2 and/or p53), 13 (13 %) in Cluster-3 (IDH2 or null), 19 (18 %) in Cluster-4 (MTAP and/or FGFR2), 28 (27 %) in Cluster-5 (ARID1A and/or PBRM1), being based on genetic alterations. Cluster-1 and Clusters-2 to- 5 formed distinct 2 groups. Cluster-1 was characterized by significantly bigger size, rich and higher histological grade of HCC component, significantly less cholangiolocellular carcinoma (CLC)-component, ductal plate malformation pattern and bile duct adenoma in the background livers. No SmD-iCCA was included in Cluster-1, whereas SmD-iCCA distributed evenly in Clusters 2-5. Cluster-4 was characterized by higher prevalence of hepatitis B and higher histological diversity scores.

CONCLUSION

PLCs diagnosed as cHCC-CCA or SmD-iCCAs could be divided into 5 clusters based on genetic alterations. Cluster-1 was HCC-like cluster characterized by hTERT alteration, rich and higher grade of HCC and bigger size. Clusters-2-5 may be iCCA-like clusters characterized by different genetic alterations. cHCC-CCA in Cluster-1 and Clusters-2-5 may be handled separately for further analysis and treatment.

Other Primary Epithelial Neoplasms of the Liver

Primary liver carcinoma (PLC) is the sixth most common malignancy worldwide and the third leading cause of cancer-related mortalities. Hepatocellular carcinoma (HCC) is the most prevalent form of PLC, followed by intrahepatic cholangiocarcinoma (iCCA). In addition, there is a group of rarer PLCs that do not fit neatly into the HCC or iCCA categories. This review explores this heterogeneous group, including combined hepatocellular-cholangiocarcinoma (cHCC-CCA), intermediate cell carcinoma (ICC), mixed hepatocellular-neuroendocrine carcinoma, and undifferentiated primary liver carcinoma. cHCC-CCA is a rare subtype of PLC, characterized by both hepatocytic and cholangiocytic differentiation within the same tumor. The latest WHO classification (2019, fifth edition) redefined cHCC-CCA by eliminating the "stem cell subtypes" and emphasized that diagnosis should primarily rely on morphologic features, supported by immunohistochemical staining to better define subtypes. Intermediate cell carcinoma is a subtype of cHCC-CCA and is comprised of monomorphic tumor cells that exhibit characteristics intermediate between hepatocytes and cholangiocytes, with immunohistochemical expression of hepatocytic and cholangiocytic markers within the same cell. Another rare entity, combined HCC and neuroendocrine carcinoma (NEC), contains an admixture of HCC and NEC components within the same tumor. Undifferentiated primary liver carcinoma, on the other hand, lacks definitive lineage differentiation beyond an epithelial phenotype. These heterogeneous PLCs pose diagnostic challenges owing to their mixed/unusual histologic features and overlapping immunohistochemical markers. They tend to have poor prognoses, highlighting the critical importance of accurate and timely diagnosis.

NOTCH1 drives tumor plasticity and metastasis in hepatocellular carcinoma

Background & Aims

Liver cancer, the third leading cause of cancer-related mortality worldwide, has two main subtypes: hepatocellular carcinoma (HCC), accounting the majority of the cases, and cholangiocarcinoma (CAA). Notch pathway primarily regulates the intrahepatic development of bile ducts, which are lined with cholangiocytes, but it can also be upregulated in 1/3 of HCCs. To better understand the role of NOTCH1 in HCC, we developed a novel mouse model driven by activated Notch1 intracellular domain (NICD1) and MYC overexpression in hepatocytes.

Methods

Using the hydrodynamic tail-vein injection method for establishing primary liver tumors, we generated a novel murine model of liver cancer harboring MYC overexpression and NOTCH1 activation. We characterized this model histopathologically as well as transcriptomically, utilizing both bulk and single cell RNA-sequencing. We also performed functional experiments using monoclonal antibodies.

Results

MYC;NICD1 tumors displayed a combined HCC-CCA phenotype with temporal plasticity. At early time-points, histology was predominantly "cholangiocellular", which then progressed to mainly "hepatocellular". The "hepatocellular" component was enriched in mesenchymal genes and gave rise to lung metastasis. Metastatic cells were enriched in the TGFB and VEGF pathways and their inhibition significantly reduced the metastatic burden.

Conclusions

Our novel mouse model uncovered NOTCH1 as a driver of temporal plasticity and metastasis in HCC, the latter of which is, in part, mediated by angiogenesis and TGFß pathways.

Impact and Implications

This study develops a novel murine model of NOTCH1-driven liver cancer, an understudied oncogene in HCC. Using this model, we show that NOTCH1 drives plasticity in HCC and metastasis to the lungs that can be therapeutically targeted through inhibition of VEGF and TGFß pathways.

Highlights

NOTCH1 activation in combination with MYC overexpression drives combined HCC-CCA.NOTCH1 activation in hepatocytes drives temporal plasticity.NOTCH1 activation drives metastasis of HCC cells to the lungs, but not of CCA cells.Angiogenesis and TGFß pathways mediate NOTCH1-induced lung metastasis.

Graphical abstract

Morphomolecular Pathology and Genomic Insights into the Cells of Origin of Cholangiocarcinoma and Combined Hepatocellular-Cholangiocarcinoma

Cholangiocarcinomas are a highly heterogeneous group of malignancies that, despite recent progress in the understanding of their molecular pathogenesis and clinical management, continue to pose a major challenge to public health. The traditional view posits that cholangiocarcinomas derive from the neoplastic transformation of cholangiocytes lining the biliary tree. However, increasing genetic and experimental evidence has recently pointed to a more complex, and nuanced, scenario for the potential cell of origin of cholangiocarcinomas. Hepatocytes as well as hepatic stem/progenitor cells are being considered as additional potential sources, depending on microenvironmental contexts, including liver injury. The hypothesis of potentially diverse cells of origin for cholangiocarcinoma, albeit controversial, is certainly not surprising given the plasticity of the cells populating the liver as well as the existence of liver cancer subtypes with mixed histologic and molecular features. This review carefully examines the current pathologic, genomic, and experimental evidence supporting the existence of multiple cells of origin of liver and biliary tract cancers, with particular focus on cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma.

The Impact of Normal Hepatobiliary Cell Zonation Programs on the Phenotypes and Functions of Primary Liver Tumors

Background

Traditional tumor classifications have relied on cellular origin, pathological morphological features, gene expression profiles, and more recently, the tumor immune microenvironment. While these classifications provide valuable insights, incorporating physiological classifications focusing on liver metabolic functions may lead to new discoveries.

Summary

We proposed to reclassify benign and malignant hepatocellular neoplasms based on their physiological functions such as albumin production, bile acid production, glycolysis, glycogenesis, and adipogenesis. We further demonstrated the homology between signal pathways activated by the differentiation program of the normal hepatobiliary cells and those activated by genetic abnormalities in tumors. Specifically, Wnt/β-catenin, RAS, NOTCH, and TGF-β signaling not only contribute to cell differentiation via activation of liver-enriched transcription factors but also determine the tumor traits. Examining the distinctions between hepatocellular carcinomas (HCCs) that maintain or lose metabolic functions can yield valuable insights into the drivers of biological malignancy and tumor plasticity.

Key Messages

To confirm the homology between the differentiation programs of normal hepatobiliary cells, hepatocellular adenomas (HCA), and HCC we identify liver-specific functions such as catabolism and anabolism within tumors. HCCs and HCAs that have lost these metabolic functions exhibit characteristics such as dedifferentiation, resemblance to biliary cells, or increased glycolysis. Focusing on this underexplored area will likely stimulate active research into new tumor characteristics.

Precision models in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents a global health challenge, and ranks among one of the most prevalent and deadliest cancers worldwide. Therapeutic advances have expanded the treatment armamentarium for patients with advanced HCC, but obstacles remain. Precision oncology, which aims to match specific therapies to patients who have tumours with particular features, holds great promise. However, its implementation has been hindered by the existence of numerous 'HCC influencers' that contribute to the high inter-patient heterogeneity. HCC influencers include tumour-related characteristics, such as genetic alterations, immune infiltration, stromal composition and aetiology, and patient-specific factors, such as sex, age, germline variants and the microbiome. This Review delves into the intricate world of HCC, describing the most innovative model systems that can be harnessed to identify precision and/or personalized therapies. We provide examples of how different models have been used to nominate candidate biomarkers, their limitations and strategies to optimize such models. We also highlight the importance of reproducing distinct HCC influencers in a flexible and modular way, with the aim of dissecting their relative contribution to therapy response. Next-generation HCC models will pave the way for faster discovery of precision therapies for patients with advanced HCC.

Tumor burden score is superior to primary liver cancer stages in predicting prognosis for patients with combined hepatocellular-cholangiocarcinoma after surgery: A multi-center study

BACKGROUND

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is poorly understood, while the predictive value of the staging in which it is included is controversial.

METHODS

Patients with cHCC-CCA underwent radical hepatectomy in two medical centers in China were enrolled and staged based on optimal cut-off values of tumor burden score (TBS), determined using the X-Tile. The association between TBS and prognosis was evaluated by Cox proportional hazard models and Kaplan-Meier curves with Log-rank test. TBS model and primary liver cancer (PLC) stages were compared by discrimination, consistency, and clinical utility, which were further validated by a 5-folds cross-validation.

RESULTS

A total of 192 patients were stratified into low, medium, and high TBS, comprising 92, 51 and 49 patients, respectively. Prognoses worsened with elevated TBS in both the training and validation cohorts. TBS was not only an independent prognostic indicator in univariate and multivariate cox regression, but also a stable risk factor in subgroup analysis according to baseline variables. TBS exhibited best discrimination within these predictive models, as evidenced by the highest c-index and area under curve values of time-dependent receiver operating curves within 5 years post-surgery. TBS calibration plots revealed favorable consistency between prediction and observation. Decision curve analysis suggested higher net benefits for TBS. A 5-folds cross-validation revealed consistent results.

CONCLUSIONS

TBS could be applied to stratify cHCC-CCA patients after surgery into groups with statistically different prognoses. Moreover, TBS exhibited optimal prognostic value over all available PLC stages and may inform clinical decisions.

Tumour stemness and poor clinical outcomes in haemochromatosis patients with hepatocellular carcinoma

AIMS

Patients with haemochromatosis (HFE) are known to have an increased risk of developing hepatocellular carcinoma (HCC). Available data are conflicting on whether such patients have poorer prognosis, and there is lack of data regarding the biology of HFE-HCC. We compared the course of HFE-HCC with a matched non-HFE-HCC control group and examined tumour characteristics using immunohistochemistry.

METHODS

In this tertiary care-based retrospective analysis, 12 patients with HFE and 34 patients with alcohol/non-alcoholic steatohepatitis who underwent initially successful curative HCC therapy with ablation or resection were identified from our registry. Time to tumour progression was compared. Resected liver tissue from a separate cohort of 11 matched patients with HFE-HCC and without HFE-HCC was assessed for the expression of progenitor and epithelial-mesenchymal transition markers using immunohistochemistry.

RESULTS

The median follow-up was 24.39 and 24.28 months for patients with HFE-HCC and those without HFE-HCC, respectively (p>0.05). The mean time to progression was shorter in the HFE group compared with the non-HFE group (12.87 months vs 17.78 months; HR 3.322, p<0.05). Patients with HFE-HCC also progressed to more advanced disease by the end of follow-up (p<0.05). Immunohistochemical analysis of matched HFE-HCC and non-HFE-HCC explants demonstrated increased expression of the cancer stem cell markers EpCAM (epithelial cell adhesion molecule) and EpCAM/SALL4 (spalt-like transcription factor 4) coexpression in HFE-HCC specimens (p<0.05). There was a high frequency of combined tumour subtypes within the HFE cohort.

CONCLUSIONS

This study demonstrates that the clinical course of patients with HFE-HCC is more aggressive and provides the first data indicating that their tumours have increased expression of progenitor markers. These findings suggest patients with HFE-HCC may need to be considered for transplant at an earlier stage.

Targeting NPM1 inhibits proliferation and promotes apoptosis of hepatic progenitor cells via suppression of mTOR signalling pathway

BACKGROUND

Hepatic progenitor cells serve not only as the origin of combined hepatocellular cholangiocarcinoma (cHCC-CCA) but are also responsible for malignancy recurrence after surgical resection. Nucleophosmin 1 (NPM1) has been implicated in cancer metastasis and poor prognosis. This study aimed to determine the expression of NPM1 by hepatic progenitor cells in cHCC-CCA and the effects of targeting NPM1 on hepatic progenitor cells and BEL-7402 cells with characteristics of both progenitor cells and cHCC-CCA.

METHODS

First, NPM1 was detected by RT‒PCR, western blotting, and double-immunofluorescence staining in cHCC-CCA tissues. NPM1 expression was subsequently analysed in rat hepatic progenitor cells cultured in vitro and in interleukin 6 (IL6)-treated cells. The effects and mechanism of NPM1 on hepatic progenitor cells were determined by knocking down NPM1 and performing RNA sequencing analysis. Finally, NSC348884, a small-molecule inhibitor that disrupts NPM1 dimer formation, was used to confirm the function of NPM1 in BEL-7402 cells.

RESULTS

Both human hepatic progenitor cells in cHCC-CCA tissues and rat in vitro cultured hepatic progenitor cells highly expressed NPM1. IL6, a cytokine involved in the malignant transformation of hepatic progenitor cells, dose-dependently increased NPM1 and PCNA expression. Knocking down NPM1 reduced IL6R transcription (P < 0.0001) and inhibited the proliferation (P = 0.0065) of hepatic progenitor cells by suppressing the mTOR signalling pathway and activating the apoptosis pathway. Furthermore, knocking down NPM1 in hepatic progenitor cells resulted in more apoptotic cells (7.33 ± 0.09% vs. 3.76 ± 0.13%, P < 0.0001) but fewer apoptotic cells in the presence of NSC348884 (47.57 ± 0.49% vs. 63.40 ± 0.05%, P = 0.0008) than in the control cells, suggesting that low-NPM1-expressing cells are more resistant to NSC348884. In addition, NSC348884 induced the apoptosis of BEL-7402 cells with an IC50 of 2.77 μmol/L via the downregulation of the IL-6R and mTOR signalling pathways and inhibited the growth of BEL-7402 cells in a subcutaneous xenograft tumour model (P = 0.0457).

CONCLUSIONS

Targeting NPM1 inhibits proliferation and induces apoptosis in hepatic progenitor cells and BEL-7402 cells, thus serving as a potential therapy for cHCC-CCA.

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.

Context-Dependent Distinct Roles of SOX9 in Combined Hepatocellular Carcinoma-Cholangiocarcinoma

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) is a challenging primary liver cancer subtype with limited treatment options and a devastating prognosis. Recent studies have underscored the context-dependent roles of SOX9 in liver cancer formation in a preventive manner. Here, we revealed that liver-specific developmental Sox9 elimination using Alb-Cre;Sox9(flox/flox) (LKO) and CRISPR/Cas9-based tumor-specific acute Sox9 elimination (CKO) in SB-HDTVI-based Akt-YAP1 (AY) and Akt-NRAS (AN) cHCC-CCA models showed contrasting responses. LKO abrogates the AY CCA region while stimulating poorly differentiated HCC proliferation, whereas CKO prevents AY and AN cHCC-CCA development irrespective of tumor cell fate. Additionally, AN, but not AY, tumor formation partially depends on the Sox9-Dnmt1 cascade. SOX9 is dispensable for AY-mediated, HC-derived, LPC-like immature CCA formation but is required for their maintenance and transformation into mature CCA. Therapeutic Sox9 elimination using the OPN-CreERT2 strain combined with inducible Sox9 iKO specifically reduces AY but not AN cHCC-CCA tumors. This necessitates the careful consideration of genetic liver cancer studies using developmental Cre and somatic mutants, particularly for genes involved in liver development. Our findings suggest that SOX9 elimination may hold promise as a therapeutic approach for a subset of cHCC-CCA and highlight the need for further investigation to translate these preclinical insights into personalized clinical applications.

Overcoming treatment resistance in cholangiocarcinoma: current strategies, challenges, and prospects

Significant advancements in our understanding and clinical treatment of cholangiocarcinoma (CCA) have been achieved over the past 5 years. Groundbreaking studies have illuminated the immune landscape and pathological characteristics of the tumor microenvironment in CCA. The development of immune- and metabolism-based classification systems has enabled a nuanced exploration of the tumor microenvironment and the origins of CCA, facilitating a detailed understanding of tumor progression modulation. Despite these insights, targeted therapies have not yet yielded satisfactory clinical results, highlighting the urgent need for innovative therapeutic strategies. This review delineates the complexity and heterogeneity of CCA, examines the current landscape of therapeutic strategies and clinical trials, and delves into the resistance mechanisms underlying targeted therapies. Finally, from a single-cell and spatial transcriptomic perspective, we address the challenge of therapy resistance, discussing emerging mechanisms and potential strategies to overcome this barrier and enhance treatment efficacy.

Aberrant differentiation and proliferation of hepatocytes in chronic liver injury and liver tumors

Chronic liver injury induces liver cirrhosis and facilitates hepatocarcinogenesis. However, the effects of this condition on hepatocyte proliferation and differentiation are unclear. We showed that rodent hepatocytes display a ductular phenotype when they are cultured within a collagenous matrix. This process involves transdifferentiation without the emergence of hepatoblastic features and is at least partially reversible. During the ductular reaction in chronic liver diseases with progressive fibrosis, some hepatocytes, especially those adjacent to ectopic ductules, demonstrate ductular transdifferentiation, but the majority of increased ductules originate from the existing bile ductular system that undergoes extensive remodeling. In chronic injury, hepatocyte proliferation is weak but sustained, and most regenerative nodules in liver cirrhosis are composed of clonally proliferating hepatocytes, suggesting that a small fraction of hepatocytes maintain their proliferative capacity in chronic injury. In mouse hepatocarcinogenesis models, hepatocytes activate the expression of various fetal/neonatal genes, indicating that these cells undergo dedifferentiation. Hepatocyte-specific somatic integration of various oncogenes in mice demonstrated that hepatocytes may be the cells of origin for a broad spectrum of liver tumors through transdifferentiation and dedifferentiation. In conclusion, the phenotypic plasticity and heterogeneity of mature hepatocytes are important for understanding the pathogenesis of chronic liver diseases and liver tumors.

Combined hepatocellular cholangiocarcinoma: A clinicopathological update

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer associated with an appalling prognosis. The diagnosis and management of this entity have been challenging to physicians, radiologists, surgeons, pathologists, and oncologists alike. The diagnostic and prognostic value of biomarkers such as the immunohistochemical expression of nestin, a progenitor cell marker, have been explored recently. With a better understanding of biology and the clinical course of cHCC-CCA, newer treatment modalities like immune checkpoint inhibitors are being tried to improve the survival of patients with this rare disease. In this review, we give an account of the recent developments in the pathology, diagnostic approach, and management of cHCC-CCA.

Therapeutic potential of SOX9 dysruption in Combined Hepatocellular Carcinoma-Cholangiocarcinoma

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) represents a challenging subtype of primary liver cancer with limited treatment options and a poor prognosis. Recently, we and others have highlighted the context-dependent roles of the biliary-specific transcription factor SOX9 in the pathogenesis of liver cancers using various Cre applications in Sox9 (flox/flox) strains, to achieve elimination for exon 2 and 3 of the Sox9 gene locus as a preventive manner. Here, we reveal the contrasting responses of developmental Sox9 elimination using Alb-Cre;Sox9 (flox/flox) ( Sox9 LKO) versus CRISPR/Cas9 -based tumor specific acute Sox9 CKO in SB-HDTVI-based Akt-YAP1 and Akt-NRAS cHCC-CCA formation. Sox9 LKO specifically abrogates the Akt-YAP1 CCA region while robustly stimulating the proliferation of remaining poorly differentiated HCC pertaining liver progenitor cell characteristics, whereas Sox9 CKO potently prevents Akt-YAP1 and Akt-NRAS cHCC-CCA development irrespective of fate of tumor cells compared to respective controls. Additionally, we find that Akt-NRAS , but not Akt-YAP1 , tumor formation is partially dependent on the Sox9-Dnmt1 cascade. Pathologically, SOX9 is indispensable for Akt-YAP1 -mediated HC-to-BEC/CCA reprogramming but required for the maintenance of CCA nodules. Lastly, therapeutic elimination of Sox9 using the OPN-CreERT2 strain combined with an inducible CRISPR/Cas9 -based Sox9 iKO significantly reduces Akt-YAP1 cHCC-CCA tumor burden, similar to Sox9 CKO. Thus, we contrast the outcomes of acute Sox9 deletion with developmental Sox9 knockout models, emphasizing the importance of considering adaptation mechanisms in therapeutic strategies. This necessitates the careful consideration of genetic liver cancer studies using developmental Cre and somatic mutant lines, particularly for genes involved in hepatic commitment during development. Our findings suggest that SOX9 elimination may hold promise as a therapeutic approach for cHCC-CCA and underscore the need for further investigation to translate these preclinical insights into clinical applications.

Integrated analyses of the genetic and clinicopathological features of cholangiolocarcinoma: cholangiolocarcinoma may be characterized by mismatch-repair deficiency

Cholangiolocarcinoma (CLC) is a primary liver carcinoma that resembles the canals of Hering and that has been reported to be associated with stem cell features. Due to its rarity, the nature of CLC remains unclear, and its pathological classification remains controversial. To clarify the positioning of CLC in primary liver cancers and identify characteristics that could distinguish CLC from other liver cancers, we performed integrated analyses using whole-exome sequencing (WES), immunohistochemistry, and a retrospective review of clinical information on eight CLC cases and two cases of recurrent CLC. WES demonstrated that CLC includes IDH1 and BAP1 mutations, which are characteristic of intrahepatic cholangiocarcinoma (iCCA). A mutational signature analysis showed a pattern similar to that of iCCA, which was different from that of hepatocellular carcinoma (HCC). CLC cells, including CK7, CK19, and EpCAM, were positive for cholangiocytic differentiation markers. However, the hepatocytic differentiation marker AFP and stem cell marker SALL4 were completely negative. The immunostaining patterns of CLC with CD56 and epithelial membrane antigen were similar to those of the noncancerous bile ductules. In contrast, mutational signature cluster analyses revealed that CLC formed a cluster associated with mismatch-repair deficiency (dMMR), which was separate from iCCA. Therefore, to evaluate MMR status, we performed immunostaining of four MMR proteins (PMS2, MSH6, MLH1, and MSH2) and detected dMMR in almost all CLCs. In conclusion, CLC had highly similar characteristics to iCCA but not to HCC. CLC can be categorized as a subtype of iCCA. In contrast, CLC has characteristics of dMMR tumors that are not found in iCCA, suggesting that it should be treated distinctly from iCCA. © 2024 The Pathological Society of Great Britain and Ireland.

Current advances and future directions in combined hepatocellular and cholangiocarcinoma

The low incidence of combined hepatocellular cholangiocarcinoma (cHCC-CCA) is an important factor limiting research progression. Our study extensively included nearly three decades of relevant literature and assembled the most comprehensive database comprising 5,742 patients with cHCC-CCA. We summarized the characteristics, tumor markers, and clinical features of these patients. Additionally, we present the evolution of cHCC-CCA classification and explain the underlying rationale for these classification standards. We reviewed cHCC-CCA diagnostic advances using imaging features, tumor markers, and postoperative pathology, as well as treatment options such as surgical, adjuvant, and immune-targeted therapies. In addition, recent advances in more effective chemotherapeutic regimens and immune-targeted therapies were explored. Furthermore, we described the molecular mutation features and potential specific markers of cHCC-CCA. The prognostic value of Nestin has been proven, and we speculate that Nestin will also play a role in classification and diagnosis. However, further research is needed. Moreover, we believe that the possibility of using machine learning liquid biopsy for preoperative diagnosis and establishing a scoring system are directions for future research.

SALL4 in gastrointestinal tract cancers: upstream and downstream regulatory mechanisms

Effective therapeutic targets and early diagnosis are major challenges in the treatment of gastrointestinal tract (GIT) cancers. SALL4 is a well-known transcription factor that is involved in organogenesis during embryonic development. Previous studies have revealed that SALL4 regulates cell proliferation, survival, and migration and maintains stem cell function in mature cells. Additionally, SALL4 overexpression is associated with tumorigenesis. Despite its characterization as a biomarker in various cancers, the role of SALL4 in GIT cancers and the underlying mechanisms are unclear. We describe the functions of SALL4 in GIT cancers and discuss its upstream/downstream genes and pathways associated with each cancer. We also consider the possibility of targeting these genes or pathways as potential therapeutic options for GIT cancers.

Molecular Insights of Cholestasis in MDR2 Knockout Murine Liver Organoids

MDR3 (multidrug resistance 3) deficiency in humans (MDR2 in mice) causes progressive familial intrahepatic cholestasis type 3 (PFIC3). PFIC3 is a lethal disease characterized by an early onset of intrahepatic cholestasis progressing to liver cirrhosis, a preneoplastic condition, putting individuals at risk of hepatocellular carcinoma (HCC). Hepatocyte-like organoids from MDR2-deficient mice (MDR2KO) were used in this work to study the molecular alterations caused by the deficiency of this transporter. Proteomic analysis by mass spectrometry allowed characterization of 279 proteins that were differentially expressed in MDR2KO compared with wild-type organoids. Functional enrichment analysis indicated alterations in three main cellular functions: (1) interaction with the extracellular matrix, (2) remodeling intermediary metabolism, and (3) cell proliferation and differentiation. The affected cellular processes were validated by orthogonal molecular biology techniques. Our results point to molecular mechanisms associated with PFIC3 that may drive the progression to liver cirrhosis and HCC and suggest proteins and cellular processes that could be targeted for the development of early detection strategies for these severe liver diseases.

Update on the Diagnosis and Treatment of Combined Hepatocellular Cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a unique type of liver tumor that contains both hepatocellular carcinoma and cholangiocarcinoma components within a single tumor. The fifth edition of the World Health Organization classification provides a definition and diagnostic criteria for cHCC-CCA. However, the heterogeneous histomorphology and presentation resulting from variation of the proportion of each component poses challenges for clinical diagnosis and treatment. A diagnosis of cHCC-CCA may be suggested by the synchronous elevation of serum tumor markers for hepatocellular carcinoma and cholangiocarcinoma, a mixed enhancement pattern on imaging, and a discrepancy between the elevation of tumor marker and the imaging enhancement pattern. Histopathological examination using hematoxylin and eosin staining is considered the gold standard for diagnosing cHCC-CCA, and comprehensive examination of resection or biopsy specimens is crucial for an accurate diagnosis. Currently, there is no standard treatment for cHCC-CCA, and surgery is the mainstay. Anatomic hepatectomy with lymphadenectomy is among the recommended surgical procedures. The role of liver transplantation in the management of cHCC-CCA is still uncertain. Transarterial chemoembolization may be effective for unresectable cHCC-CCA, particularly for hypervascular tumors. However, the available evidence does not support systemic therapy for advanced cHCC-CCA. The prognosis of cHCC-CCA is generally poor, and there is no established staging system. Further research is needed to better understand the histogenesis and clinical management of cHCC-CCA. This review provides an overview of the current literature on cHCC-CCA with a focus on its clinical characteristics, pathological diagnosis, and management.

Practical guidelines for molecular testing of cholangiocarcinoma in clinical practice: Italian experts' position paper

Biliary tract cancers (BTCs) represent a spectrum of malignancies associated with a dismal prognosis. Recent genomic profiling studies have provided a deeper understanding of the complex and heterogenous molecular landscape of BTCs, identifying several actionable genetic alterations, and expanding treatment options. Due to the high number and complexity of genetic alterations which require testing, next-generation sequencing (NGS) is currently the preferred approach over conventional methods (i.e., immunohistochemistry, fluorescence in-situ hybridization and PCR) for molecular profiling of BTCs and should be performed upfront in all BTC patients. However, BTC sampling often yields low tumor cellularity tissue, hampering NGS analysis. Future perspectives to overcome this obstacle include liquid biopsy and optimization of biopsy protocols. In this position paper, the authors discuss the current histopathologic, molecular, and therapeutic landscape of BTCs, provide a critical overview of the available testing methods for molecular diagnostics, and propose a practical diagnostic algorithm for molecular testing of BTC samples.

Intrahepatic cholangiocarcinoma biomarkers: Towards early detection and personalized pharmacological treatments

Cholangiocarcinoma (CCA) is a rare malignancy originating from the biliary tree and is anatomically categorized as intrahepatic (iCCA), perihilar, and extrahepatic or distal. iCCA, the second most prevalent hepatobiliary cancer following hepatocellular carcinoma (HCC), constitutes 5-20 % of all liver malignancies, with an increasing incidence. The challenging nature of iCCA, combined with nonspecific symptoms, often leads to late diagnoses, resulting in unfavorable outcomes. The advanced phase of this neoplasm is difficult to treat with dismal results. Early diagnosis could significantly reduce mortality attributed to iCCA but remains an elusive goal. The identification of biomarkers specific to iCCA and their translation into clinical practice could facilitate diagnosis, monitor therapy response, and potentially reveal novel interventions and personalized medicine. In this review, we present the current landscape of biomarkers in each of these contexts. In addition to CA19.9, a widely recognized biomarker for iCCA, others such as A1BG, CYFRA 21-1, FAM19A5, MMP-7, RBAK, SSP411, TuM2-PK, WFA, etc., as well as circulating tumor DNA, RNA, cells, and exosomes, are under investigation. Advancing our knowledge and monitoring of biomarkers may enable us to improve diagnosis, prognostication, and apply treatments dynamically and in a more personalized manner.

Combined Hepatocellular-Cholangiocarcinoma: Biology, Diagnosis, and Management

BACKGROUND

Combined hepatocellular-cholangiocarcinoma (cHCC-iCCA) is a rare type of primary liver cancer displaying characteristics of both hepatocytic and cholangiocytic differentiation.

SUMMARY

Because of its aggressive nature, patients with cHCC-iCCA exhibit a poorer prognosis than those with HCC. Surgical resection and liver transplantation may be considered curative treatment approaches; however, only a minority of patients are eligible at the time of diagnosis, and postoperative recurrence rates are high. For cases that are not eligible for surgery, locoregional and systemic therapy are often administered based on treatment protocols applied for HCC or iCCA. Owing to the rarity of this cancer, there are still no established standard treatment protocols; therefore, the choice of therapy is often personalized and guided by the suspected predominant component. Further, the genomic and molecular heterogeneity of cHCC-iCCA can severely compromise the efficacy of the available therapies.

KEY MESSAGES

In the present review, we summarize the latest advances in cHCC-iCCA and attempt to clarify its terminology and molecular biology. We provide an overview of the etiology of cHCC-iCCA and present new insights into the molecular pathology of this disease that could contribute to further studies aiming to improve the patient outcomes through new systemic therapies.

Expert Consensus on Pathological Diagnosis of Intrahepatic Cholangiocarcinoma (2022 version)

Intrahepatic cholangiocarcinoma (iCCA) can originate from the large bile duct group (segment bile ducts and area bile ducts), small bile duct group (septal bile ducts and interlobular bile ducts), and terminal bile duct group (bile ductules and canals of Hering) of the intrahepatic biliary tree, which can be histopathological corresponding to large duct type iCCA, small duct type iCCA and iCCA with ductal plate malformation pattern, and cholangiolocarcinoma, respectively. The challenge in pathological diagnosis of above subtypes of iCCA falls in the distinction of cellular morphologies, tissue structures, growth patterns, invasive behaviors, immunophenotypes, molecular mutations, and surgical prognoses. For these reasons, this expert consensus provides nine recommendations as a reference for standardizing and refining the diagnosis of pathological subtypes of iCCA, mainly based on the 5th edition of the World Health Organization Classification of Tumours of the Digestive System.

British Society of Gastroenterology guidelines for the diagnosis and management of cholangiocarcinoma

These guidelines for the diagnosis and management of cholangiocarcinoma (CCA) were commissioned by the British Society of Gastroenterology liver section. The guideline writing committee included a multidisciplinary team of experts from various specialties involved in the management of CCA, as well as patient/public representatives from AMMF (the Cholangiocarcinoma Charity) and PSC Support. Quality of evidence is presented using the Appraisal of Guidelines for Research and Evaluation (AGREE II) format. The recommendations arising are to be used as guidance rather than as a strict protocol-based reference, as the management of patients with CCA is often complex and always requires individual patient-centred considerations.

Genome-wide profiling of transcription factor activity in primary liver cancer using single-cell ATAC sequencing

Primary liver cancer (PLC) consists of two main histological subtypes; hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). The role of transcription factors (TFs) in malignant hepatobiliary lineage commitment between HCC and iCCA remains underexplored. Here, we present genome-wide profiling of transcription regulatory elements of 16 PLC patients using single-cell assay for transposase accessible chromatin sequencing. Single-cell open chromatin profiles reflect the compositional diversity of liver cancer, identifying both malignant and microenvironment component cells. TF motif enrichment levels of 31 TFs strongly discriminate HCC from iCCA tumors. These TFs are members of the nuclear/retinoid receptor, POU, or ETS motif families. POU factors are associated with prognostic features in iCCA. Overall, nuclear receptors, ETS and POU TF motif families delineate transcription regulation between HCC and iCCA tumors, which may be relevant to development and selection of PLC subtype-specific therapeutics.

Synchronous Double Primary Combined Hepatocellular-cholangiocarcinoma and Cholangiolocarcinoma in a Cirrhotic Liver

Both combined hepatocellular-cholangiocarcinoma (cHCC-CCA) and cholangiolocarcinoma are rare primary liver cancers. cHCC-CCA is believed to originate from transformed hepatocellular carcinoma or liver stem/progenitor cells. Cholangiolocarcinoma is characterized by ductular reaction-like anastomosing cords and glands resembling cholangioles or canals containing hepatocellular carcinoma components and adenocarcinoma cells. According to the 2019 revision of the World Health Organization criteria, a subtype with stem cell features as a subclassification of cHCC-CCA was abolished for lack of conclusive evidence of the stem cell origin theory. That led to the classification of cholangiolocarcinoma with hepatocytic differentiation as cHCC-CCA. Consequently, cholangiolocarcinoma without hepatocytic differentiation is classified as a subtype of small-duct cholangiocarcinoma and is assumed to originate from the bile duct. Herein, we report the first case of double primary cHCC-CCA and cholangiolocarcinoma without hepatocytic differentiation in different hepatic segments of a cirrhotic liver. We believe this case supports the validity of the new World Health Organization criteria because the pathological finding of cHCC-CCA in this case shows the transformation of hepatocellular carcinoma to cholangiocarcinoma. Furthermore, this case may demonstrate that immature ductular cell stemness and mature hepatocyte cell stemness in hepatocarcinogenesis can coexist in the same environment. The results provide valuable insights into the mechanisms of growth, differentiation, and regulation of liver cancers.

Refining Liver Biopsy in Hepatocellular Carcinoma: An In-Depth Exploration of Shifting Diagnostic and Therapeutic Applications

The field of hepatocellular carcinoma (HCC) has faced significant change on multiple levels in the past few years. The increasing emphasis on the various HCC phenotypes and the emergence of novel, specific therapies have slowly paved the way for a personalized approach to primary liver cancer. In this light, the role of percutaneous liver biopsy of focal lesions has shifted from a purely confirmatory method to a technique capable of providing an in-depth characterization of any nodule. Cancer subtype, gene expression, the mutational profile, and tissue biomarkers might soon become widely available through biopsy. However, indications, expectations, and techniques might suffer changes as the aim of the biopsy evolves from providing minimal proof of the disease to high-quality specimens for extensive analysis. Consequently, a revamped position of tissue biopsy is expected in HCC, following the reign of non-invasive imaging-only diagnosis. Moreover, given the advances in techniques that have recently reached the spotlight, such as liquid biopsy, concomitant use of all the available methods might gather just enough data to improve therapy selection and, ultimately, outcomes. The current review aims to discuss the changing role of liver biopsy and provide an evidence-based rationale for its use in the era of precision medicine in HCC.

Radiomics Based on Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Preoperative Differentiation of Combined Hepatocellular-Cholangiocarcinoma from Hepatocellular Carcinoma: A Multi-Center Study

Purpose

To explore whether texture features based on magnetic resonance can distinguish diseases combined hepatocellular-cholangiocarcinoma (cHCC-CC) from hepatocellular carcinoma (HCC) before operation.

Methods

The clinical baseline data and MRI information of 342 patients with pathologically diagnosed cHCC-CC and HCC in two medical centers were collected. The data were divided into the training set and the test set at a ratio of 7:3. MRI images of tumors were segmented with ITK-SNAP software, and python open-source platform was used for texture analysis. Logistic regression as the base model, mutual information (MI) and Least Absolute Shrinkage and Selection Operator (LASSO) regression were used to select the most favorable features. The clinical, radiomics, and clinic-radiomics model were constructed based on logistic regression. The model's effectiveness was comprehensively evaluated by the receiver operating characteristic (ROC) curve, area under the curve (AUC), sensitivity, specificity, and Youden index which is the main, and the model results were exported by SHapley Additive exPlanations (SHAP).

Results

A total of 23 features were included. Among all models, the arterial phase-based clinic-radiomics model showed the best performance in differentiating cHCC-CC from HCC before an operation, with the AUC of the test set being 0.863 (95% CI: 0.782 to 0.923), the specificity and sensitivity being 0.918 (95% CI: 0.819 to 0.973) and 0.738 (95% CI: 0.580 to 0.861), respectively. SHAP value results showed that the RMS was the most important feature affecting the model.

Conclusion

Clinic-radiomics model based on DCE-MRI may be useful to distinguish cHCC-CC from HCC in a preoperative setting, especially in the arterial phase, and RMS has the greatest impact.

Non-invasive imaging in the diagnosis of combined hepatocellular carcinoma and cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare type of primary liver cancer. It is a complex "biphenotypic" tumor type consisting of bipotential hepatic progenitor cells that can differentiate into cholangiocytes subtype and hepatocytes subtype. The prognosis of patients with cHCC-CC is quite poor with its specific and more aggressive nature. Furthermore, there are no definite demographic or clinical features of cHCC-CC, thus a clear preoperative identification and accurate non-invasive imaging diagnostic analysis of cHCC-CC are of great value. In this review, we first summarized the epidemiological features, pathological findings, molecular biological information and serological indicators of cHCC-CC disease. Then we reviewed the important applications of non-invasive imaging modalities-particularly ultrasound (US)-in cHCC-CC, covering both diagnostic and prognostic assessment of patients with cHCC-CC. Finally, we presented the shortcomings and potential outlooks for imaging studies in cHCC-CC.

Hepatocellular-Cholangiocarcinoma Collision Tumors: An Update of Current Management Practices

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare form of primary hepatic collision tumor, with an incidence ranging from 0.4 to 14.2%. Given the diagnostic challenges and lack of randomized trials, standardized treatment has yet to be established. We aim to review the literature to summarize the diagnosis, molecular characteristics, current treatment modalities, and challenges for cHCC-CC. A literature review was performed using PubMed. We included studies investigating and describing cHCC-CC, focusing on surgical, medical, and radiologic treatments. Overall prognosis is poor, with a 5-year survival rate under 30%. Minor or major hepatectomy with R0 resection is the only curative treatment; however, recurrence is likely (as high as 50% within 5 years). The role of liver transplantation is also highly debated given the biliary nature of these tumors, with cHCC-CC as a relative contraindication for liver transplantation. Although gemcitabine-based treatments had higher progression-free survival over sorafenib, there is no standard chemotherapy regimen. Treatment with gemcitabine and platinum demonstrates improved disease control rates compared to gemcitabine in conjunction with 5-fluorouracil (78.4% verse 38.5% respectively). Additionally, platinum-containing chemotherapy regimens exhibit a higher overall response rate than non-platinum regimens (21.4% verse 7.0% respectively). These molecular-directed therapies have prolonged survival for HCC, but further investigation needs to be done to assess their utility in patients with cHCC-CC. cHCC-CC is a rare and complex subset of primary hepatic neoplasms with a dismal prognosis and unstandardized treatment options. Further trials need to be performed to investigate systemic chemotherapy and immunotherapy options for patients with unresectable disease.

Prognostic Analysis on Different Tumor Sizes for 14634 Hepatocellular Carcinoma Patients

Aim. This study investigated the effect of tumor size and other factors on the survival and prognosis of hepatocellular carcinoma (HCC). Methods. All HCC populations based on the National Cancer Institute’s SEER database to receive from 2010 to 2016 were employed in the study. Results. This study enrolled a total of 14,634 HCC. Among them, 1,686 patients had tumors ≤ 2 cm, 6,169 patients had tumors 2–5 cm, and 6,779 patients had tumors > 5 cm. The results using univariate analysis showed that all factors were significant prognostic factors for overall survival and specific survival. Patients with tumor size ≤ 2 cm were more likely to survive, while patients with tumor size > 5 cm had a lower survival rate. Patients who had surgery or surgery plus chemotherapy had a higher chance of survival in stages I-II, and the survival rate declined smoothly during the 80 months. The change rate of the mortality rate increased rapidly during the period of 1–12 cm; afterwards, the mortality rate’s HR was basically and smoothly maintained at a high level. Conclusions. Tumor size was positively correlated with the mortality rate of HCC. Survival rates were greater in patients with tumors ≤ 2 cm who underwent surgery or surgery plus chemotherapy. Patients with HCC in the early stage had a higher survival probability particularly when they had experienced surgery or surgery plus chemotherapy.

Poor-prognosis molecular subtypes in adenocarcinomas of pancreato-biliary and gynecological origin: A systematic review

Pancreato-biliary and gynecological adenocarcinomas need better tools to predict clinical outcome. Potential prognostic mesenchymal(-like) transcriptome-based subtypes have been identified in these cancers. In this systematic review, we include studies into molecular subtyping and summarize biological and clinical features of the subtypes within and across sites of origin, searching for suggestions to improve classification and prognostication. PubMed and Embase were searched for original research articles describing potential mesenchymal(-like) mRNA-based subtypes in pancreato-biliary or gynecological adenocarcinomas. Studies limited to supervised clustering were excluded. Fourty-four studies, discussing cholangiocarcinomas, gallbladder, ampullary, pancreatic, ovarian, and endometrial adenocarcinomas were included. There was overlap in molecular and clinical features in mesenchymal(-like) subtypes across all adenocarcinomas. Approaches including microdissection were more likely to identify prognosis-associating subtypes. To conclude, molecular subtypes in pancreato-biliary and gynecological adenocarcinomas share biological and clinical characteristics. Furthermore, separation of stromal and epithelial signals should be applied in future studies into biliary and gynecological adenocarcinomas.

Pediatric combined hepatocellular-cholangiocarcinoma (cHCC-CC) with neuroendocrine features: distinguishing genetic alterations detected by chromosomal microarray

BACKGROUND

Liver tumors exhibiting hepatocellular, cholangiocarcinoma, and neuroendocrine features are extremely rare, with only five cases reported in the literature.

CASE PRESENTATION

We present an unusual case of a combined hepatocellular-cholangiocarcinoma (cHCC-CC) with neuroendocrine features in a pediatric patient. A 16-year-old presented with abdominal pain and a 21.0 cm mass in the right hepatic lobe with extension into the left lobe. Histology showed a poorly differentiated tumor with a solid, tubuloglandular, and microcystic architecture. Immunohistochemistry results were negative for hepatic markers, positive for markers of biliary differentiation, and positive for neuroendocrine differentiation. The neoplasm was reviewed at several institutions with differing diagnoses. Single nucleotide polymorphism (SNP) chromosomal microarray (CMA) showed large deletions within chromosomes 6q and 13q in both the hepatocellular-like areas and the cholangiocarcinoma-like areas, with additional large deletions in the cholangiocarcinoma-like areas, supporting origin from hepatocellular carcinoma. The final diagnosis was a cHCC-CC with neuroendocrine features.

CONCLUSIONS

Diagnosis of cHCC-CCs relies predominately on histomorphology, as per the 2018 International Consensus Group on the nomenclature of cHCC-CC. These findings in this case support that the pathological classification of these lesions be based on molecular data, which could better direct treatment. Further classification of cHCC-CCs and determination of their clinicopathological relevance will require more interobserver consistency and continued molecular profiling of these lesions.

Management of Locally Advanced or Metastatic Combined Hepatocellular Cholangiocarcinoma

Combined hepatocellular cholangiocarcinoma (cHCC-CC) is a rare primary liver malignancy that comprises features of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). Due to the rarity of this tumor, the treatment of choice has not yet been defined. For resectable disease, liver resection is the mainstay treatment. However, most patients relapse or display advanced disease and were not surgical candidates. Although the majority of patients are either primarily or secondarily treated in palliative intent, no guideline recommendations or prospective trial reports exist to allow reliable evaluation of debated treatment options. We review different locoregional or medical treatment options for advanced combined hepatocellular cholangiocarcinoma (cHCC-CC) in the neoadjuvant, adjuvant, or palliative setting and discuss the possibility of predictive biomarker-guided therapeutic options.

Bioinformatics Analysis Identifies ASCL1 as the Key Transcription Factor in Hepatocellular Carcinoma Progression

Methods

Differentially transcription factors (DETFs) were identified from differentially expressed genes (DEGs) in GSE62232 and transcription factors. Then, they were analyzed by regulatory networks, prognostic risk model, and overall survival analyses to identify the key DETF. Combined with the regulatory networks and binding site analysis, the target mRNA of key DETF was determined, and its prognostic value in HCC was evaluated by survival, clinical characteristics analyses, and experiments. Finally, the expressions and functions of the key DETF on the DEmRNAs were investigated in HCC cells.

Results

Through multiple bioinformatics analyses, ASCL1 was identified as the key DETF, and SLC6A13 was predicted to be its target mRNA with the common binding site of CCAGCAACTGGCC, both downregulated in HCC. In survival analysis, high SLC6A13 was related to better HCC prognosis, and SLC6A13 was differentially expressed in HCC patients with clinical characteristics. Furthermore, cell experiments showed the mRNA expressions of ASCL1 and SLC6A13 were both reduced in HCC, and their overexpressions suppressed the growth, invasion, and migration of HCC cells. Besides, over-ASCL1 could upregulate SLC6A13 expression in HCC cells.

Conclusion

This study identifies two suppressor genes in HCC progression, ASCL1 and SLC6A13, and the key transcription factor ASCL1 suppresses HCC progression by targeting SLC6A13 mRNA. They are both potential treatment targets and prognostic biomarkers for HCC patients, which provides new clues for HCC research.

Pathology of Combined Hepatocellular Carcinoma-Cholangiocarcinoma: An Update

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer that is composed of both hepatocellular and cholangiocellular differentiated cells. It is slightly more common in men and among Asian and Pacific islanders. Overall, risk factors are similar to classic risk factors of hepatocellular carcinoma (HCC). The classification has significantly evolved over time. The last WHO classification (2019) mainly emphasized diagnosis on morphological basis with routine stainings, discarded previously recognized classifications with carcinomas with stem cell features, introduced intermediate cell carcinoma as a specific subtype and considered cholangiolocarcinoma as a subtype of cholangiocellular carcinoma. Immunohistochemical markers may be applied for further specification but have limited value for diagnosis. Recent discoveries in molecular pathway regulation may pioneer new therapeutic approaches for this poor prognostic and challenging diagnosis.

Current view of liver cancer cell-of-origin and proposed mechanisms precluding its proper determination

Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are devastating primary liver cancers with increasing prevalence in many parts of the world. Despite intense investigation, many aspects of their biology are still largely obscure. For example, numerous studies have tackled the question of the cell-of-origin of primary liver cancers using different experimental approaches; they have not, however, provided a clear and undisputed answer. Here, we will review the evidence from animal models supporting the role of all major types of liver epithelial cells: hepatocytes, cholangiocytes, and their common progenitor as liver cancer cell-of-origin. Moreover, we will also propose mechanisms that promote liver cancer cell plasticity (dedifferentiation, transdifferentiation, and epithelial-to-mesenchymal transition) which may contribute to misinterpretation of the results and which make the issue of liver cancer cell-of-origin particularly complex.

Cholangiocarcinoma: Molecular Abnormalities and Cells of Origin

Cholangiocarcinomas (CCAs) are a group of heterogeneous epithelial malignancies that can originate at the level of any location of the biliary tree. These tumors are relatively rare but associated with a high rate of mortality. CCAs are morphologically and molecularly heterogeneous and for their location can be distinguished as intracellular and extracellular, subdivided into perihilar and distal. Recent epidemiological, molecular, and cellular studies have supported that the consistent heterogeneity observed for CCAs may result from the convergence of various key elements mainly represented by risk factors, heterogeneity of the associated molecular abnormalities at genetic and epigenetic levels and by different potential cells of origin. These studies have consistently contributed to better defining the pathogenesis of CCAs and to identify in some instances new therapeutic targets. Although the therapeutic progress were still limited, these observations suggest that a better understanding of the molecular mechanisms underlying CCA in the future will help to develop more efficacious treatment strategies.

The Diagnostic Approach towards Combined Hepatocellular-Cholangiocarcinoma-State of the Art and Future Perspectives

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer which displays clinicopathologic features of both hepatocellular (HCC) and cholangiocellular carcinoma (CCA). The similarity to HCC and CCA makes the diagnostic workup particularly challenging. Alpha-fetoprotein (AFP) and carbohydrate antigen 19-9 (CA 19-9) are blood tumour markers related with HCC and CCA, respectively. They can be used as diagnostic markers in cHCC-CCA as well, albeit with low sensitivity. The imaging features of cHCC-CCA overlap with those of HCC and CCA, dependent on the predominant histopathological component. Using the Liver Imaging and Reporting Data System (LI-RADS), as many as half of cHCC-CCAs may be falsely categorised as HCC. This is especially relevant since the diagnosis of HCC may be made without histopathological confirmation in certain cases. Thus, in instances of diagnostic uncertainty (e.g., simultaneous radiological HCC and CCA features, elevation of CA 19-9 and AFP, HCC imaging features and elevated CA 19-9, and vice versa) multiple image-guided core needle biopsies should be performed and analysed by an experienced pathologist. Recent advances in the molecular characterisation of cHCC-CCA, innovative diagnostic approaches (e.g., liquid biopsies) and methods to analyse multiple data points (e.g., clinical, radiological, laboratory, molecular, histopathological features) in an all-encompassing way (e.g., by using artificial intelligence) might help to address some of the existing diagnostic challenges.

Combined hepatocellular-cholangiocarcinoma derives from liver progenitor cells and depends on senescence and IL-6 trans-signaling

BACKGROUND & AIMS

Primary liver cancers include hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (CCA) and combined HCC-CCA tumors (cHCC-CCA). It has been suggested, but not unequivocally proven, that hepatic progenitor cells (HPCs) can contribute to hepatocarcinogenesis. We aimed to determine whether HPCs contribute to HCC, cHCC-CCA or both types of tumors.

METHODS

To trace progenitor cells during hepatocarcinogenesis, we generated Mdr2-KO mice that harbor a yellow fluorescent protein (YFP) reporter gene driven by the Foxl1 promoter which is expressed specifically in progenitor cells. These mice (Mdr2-KO^{Foxl1-CRE;RosaYFP}) develop chronic inflammation and HCCs by the age of 14-16 months, followed by cHCC-CCA tumors at the age of 18 months.

RESULTS

In this Mdr2-KO^{Foxl1-CRE;RosaYFP} mouse model, liver progenitor cells are the source of cHCC-CCA tumors, but not the source of HCC. Ablating the progenitors, caused reduction of cHCC-CCA tumors but did not affect HCCs. RNA-sequencing revealed enrichment of the IL-6 signaling pathway in cHCC-CCA tumors compared to HCC tumors. Single-cell RNA-sequencing (scRNA-seq) analysis revealed that IL-6 is expressed by immune and parenchymal cells during senescence, and that IL-6 is part of the senescence-associated secretory phenotype. Administration of an anti-IL-6 antibody to Mdr2-KO^{Foxl1-CRE;RosaYFP} mice inhibited the development of cHCC-CCA tumors. Blocking IL-6 trans-signaling led to a decrease in the number and size of cHCC-CCA tumors, indicating their dependence on this pathway. Furthermore, the administration of a senolytic agent inhibited IL-6 and the development of cHCC-CCA tumors.

CONCLUSION

Our results demonstrate that cHCC-CCA, but not HCC tumors, originate from HPCs, and that IL-6, which derives in part from cells in senescence, plays an important role in this process via IL-6 trans-signaling. These findings could be applied to develop new therapeutic approaches for cHCC-CCA tumors.

LAY SUMMARY

Combined hepatocellular carcinoma-cholangiocarcinoma is the third most prevalent type of primary liver cancer (i.e. a cancer that originates in the liver). Herein, we show that this type of cancer originates in stem cells in the liver and that it depends on inflammatory signaling. Specifically, we identify a cytokine called IL-6 that appears to be important in the development of these tumors. Our results could be used for the development of novel treatments for these aggressive tumors.

Prognosis-Related Molecular Subtypes and Immune Features Associated with Hepatocellular Carcinoma

Bioinformatics tools were used to identify prognosis-related molecular subtypes and biomarkers of hepatocellular carcinoma (HCC). Differential expression analysis of four datasets identified 3330 overlapping differentially expressed genes (DEGs) in the same direction in all four datasets. Those genes were involved in the cell cycle, FOXO signaling pathway, as well as complement and coagulation cascades. Based on non-negative matrix decomposition, two molecular subtypes of HCC with different prognoses were identified, with subtype C2 showing better overall survival than subtype C1. Cox regression and Kaplan-Meier analysis showed that 217 of the overlapping DEGs were closely associated with HCC prognosis. The subset of those genes showing an area under the curve >0.80 was used to construct random survival forest and least absolute shrinkage and selection operator models, which identified seven feature genes (SORBS2, DHRS1, SLC16A2, RCL1, IGFALS, GNA14, and FANCI) that may be involved in HCC occurrence and prognosis. Based on the feature genes, risk score and recurrence models were constructed, while a univariate Cox model identified FANCI as a key gene involved mainly in the cell cycle, DNA replication, and mismatch repair. Further analysis showed that FANCI had two mutation sites and that its gene may undergo methylation. Single-sample gene set enrichment analysis showed that Th2 and T helper cells are significantly upregulated in HCC patients compared to controls. Our results identify FANCI as a potential prognostic biomarker for HCC.

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.

[The role of molecular genetic factors in the development of cholangiocellular carcinoma]

The article lists the main inducers of cholangiocarcinogenesis. The main inflammatory mediators (IL-6, nitric oxide, COX2) have been considered. Data on the study of gene mutations in cholangiocarcinomas are presented. The spectrum of genetic mutations depends on the biliary cancer origin (FGFR2 with intrahepatic cholangiocarcinoma, PRKACA, PRKACB with extrahepatic cholangiocarcinoma). Mutations in the KRAS, TP53, ARIAD1A genes are common in extrahepatic bile duct cancer. The role of epigenetic changes such as DNA hypermethylation, histone modifications, chromatin remodeling, as well as disturbances in miRNA expression is presented. A number of epigenetic features, such as the presence of a TP53 mutations with hypermethylation of p14ARF, DAPK, and/or ASC, correlate with a more aggressive course of the disease. The role of the SOX17 gene in the development of drug resistance is highlighted. The study of the molecular genetic features of extrahepatic bile duct cancer can help to better understand the pathogenesis of this type of tumor, to establish new prognostic and diagnostic markers of the disease.

Mutational signatures and processes in hepatobiliary cancers

The evolutionary history of hepatobiliary cancers is embedded in their genomes. By analysing their catalogue of somatic mutations and the DNA sequence context in which they occur, it is possible to infer the mechanisms underpinning tumorigenesis. These mutational signatures reflect the exogenous and endogenous origins of genetic damage as well as the capacity of hepatobiliary cells to repair and replicate DNA. Genomic analysis of thousands of patients with hepatobiliary cancers has highlighted the diversity of mutagenic processes active in these malignancies, highlighting a prominent source of the inter-cancer-type, inter-patient, intertumour and intratumoural heterogeneity that is observed clinically. However, a substantial proportion of mutational signatures detected in hepatocellular carcinoma and biliary tract cancer remain of unknown cause, emphasizing the important contribution of processes yet to be identified. Exploiting mutational signatures to retrospectively understand hepatobiliary carcinogenesis could advance preventative management of these aggressive tumours as well as potentially predict treatment response and guide the development of therapies targeting tumour evolution.