Primary liver carcinoma of intermediate (hepatocyte-cholangiocyte) phenotype

Liver transplantation for combined hepatocellular cholangiocarcinoma: Current evidence, selection criteria, and therapeutic controversies

Combined hepatocellular cholangiocarcinoma (cHCC-CCA) is a rare and aggressive primary liver malignancy characterized by features of both HCC and CCA. Preoperative diagnosis remains challenging because of overlapping imaging and histopathological features, which often lead to misclassification. Although liver resection is the primary curative therapy, the efficacy of liver transplantation (LT) remains controversial. Historically, LT has been considered contraindicated owing to the poor prognosis, high recurrence rate of cHCC-CCA, and the potential for organ wastage. Recent studies have suggested that LT may benefit carefully selected patients, particularly those with early-stage tumors or cirrhosis. However, there is no consensus on the criteria for LT in patients with cHCC-CCA. Lymphadenectomy and vascular resection strategies were discussed along with locoregional and systemic therapies. This review synthesized the current evidence on surgical strategies for cHCC-CCA, focusing on evolving LT criteria and outcomes.

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.

A Novel Approach to Quantify Heterogeneity of Intrahepatic Cholangiocarcinoma: The Hidden-Genome Classifier

PURPOSE

Intrahepatic cholangiocarcinoma (IHC) is a heterogeneous tumor. The hidden-genome classifier, a supervised machine learning-based algorithm, was used to quantify tumor heterogeneity and improve classification.

EXPERIMENTAL DESIGN

A retrospective review of 1,370 patients with IHC, extrahepatic cholangiocarcinoma (EHC), gallbladder cancer (GBC), hepatocellular carcinoma (HCC), or biphenotypic tumors was conducted. A hidden-genome model classified 527 IHC based on genetic similarity to EHC/GBC or HCC. Genetic, histologic, and clinical data were correlated.

RESULTS

In this study, 410 IHC (78%) had >50% genetic homology with EHC/GBC; 122 (23%) had >90% homology ("biliary class"), characterized by alterations of KRAS, SMAD4, and CDKN2A loss; 117 IHC (22%) had >50% genetic homology with HCC; and 30 (5.7%) had >90% homology ("HCC class"), characterized by TERT alterations. Patients with biliary- versus non-biliary-class IHC had median overall survival (OS) of 1 year (95% CI, 0.77, 1.5) versus 1.8 years (95% CI, 1.6, 2.0) for unresectable disease and 2.4 years (95% CI, 2.1, NR) versus 5.1 years (95% CI, 4.8, 6.9) for resectable disease. Large-duct IHC (n = 28) was more common in the biliary class (n = 27); the HCC class was composed mostly of small-duct IHC (64%, P = 0.02). The hidden genomic classifier predicted OS independent of FGFR2 and IDH1 alterations. By contrast, the histology subtype did not predict OS.

CONCLUSIONS

IHC genetics form a spectrum with worse OS for tumors genetically aligned with EHC/GBC. The classifier proved superior to histologic subtypes for predicting OS independent of FGFR2 and IDH1 alterations. These results may explain the differential treatment responses seen in IHC and may direct therapy by helping stratify patients in future clinical trials.

Transcriptomic profiling of intermediate cell carcinoma of the liver

BACKGROUND

Intermediate cell carcinoma (Int-CA) is a rare and enigmatic primary liver cancer characterized by uniform tumor cells exhibiting mixed features of both HCC and intrahepatic cholangiocarcinoma. Despite the unique pathological features of int-CA, its molecular characteristics remain unclear yet.

METHODS

RNA sequencing and whole genome sequencing profiling were performed on int-CA tumors and compared with those of HCC and intrahepatic cholangiocarcinoma.

RESULTS

Int-CAs unveiled a distinct and intermediate transcriptomic feature that is strikingly different from both HCC and intrahepatic cholangiocarcinoma. The marked abundance of splicing events leading to intron retention emerged as a signature feature of int-CA, along with a prominent expression of Notch signaling. Further exploration revealed that METTL16 was suppressed within int-CA, showing a DNA copy number-dependent transcriptional deregulation. Notably, experimental investigations confirmed that METTL16 suppression facilitated invasive tumor characteristics through the activation of the Notch signaling cascade.

CONCLUSIONS

Our results provide a molecular landscape of int-CA featured by METTL16 suppression and frequent intron retention events, which may play pivotal roles in the acquisition of the aggressive phenotype of Int-CA.

Cancer stem cells: advances in knowledge and implications for cancer therapy

Cancer stem cells (CSCs), a small subset of cells in tumors that are characterized by self-renewal and continuous proliferation, lead to tumorigenesis, metastasis, and maintain tumor heterogeneity. Cancer continues to be a significant global disease burden. In the past, surgery, radiotherapy, and chemotherapy were the main cancer treatments. The technology of cancer treatments continues to develop and advance, and the emergence of targeted therapy, and immunotherapy provides more options for patients to a certain extent. However, the limitations of efficacy and treatment resistance are still inevitable. Our review begins with a brief introduction of the historical discoveries, original hypotheses, and pathways that regulate CSCs, such as WNT/β-Catenin, hedgehog, Notch, NF-κB, JAK/STAT, TGF-β, PI3K/AKT, PPAR pathway, and their crosstalk. We focus on the role of CSCs in various therapeutic outcomes and resistance, including how the treatments affect the content of CSCs and the alteration of related molecules, CSCs-mediated therapeutic resistance, and the clinical value of targeting CSCs in patients with refractory, progressed or advanced tumors. In summary, CSCs affect therapeutic efficacy, and the treatment method of targeting CSCs is still difficult to determine. Clarifying regulatory mechanisms and targeting biomarkers of CSCs is currently the mainstream idea.

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.

Biphenotypic Immunohistochemical Features and NTRK1 Amplification in Intermediate Cell Carcinoma of the Liver

Intermediate cell carcinoma is one of the rarest forms of primary liver cancer comprising relatively monomorphic populations of neoplastic epithelial cells demonstrating simultaneous positivity of both hepatocyte and cholangiocyte immunohistochemical markers. Here in, we describe an adult male patient who underwent left hepatectomy for a large liver tumor. The pathological and immunohistochemical analysis revealed the malignant primary liver cancer with intermediate cell morphology and mixed immunophenotypic features consistent with intermediate cell carcinoma. Furthermore, the genomic profiling using the Next-generation sequencing (NGS) platform demonstrated that there is a novel amplification with copy number gain 12 (12 gene copies) in the Neurotrophic Receptor Tyrosine Kinase 1 (NTRK1) gene, being an oncogenic driver of intermediate cell carcinoma. This is the first case report with the amplification in NTRK1 and emphasizes the importance of molecular oncology.

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.

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: 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.

Emerging treatment evolutions and integrated molecular characteristics of biliary tract cancers

Biliary tract cancers (BTCs) consist of a group of highly heterogeneous malignancies that are characterized by genomic differences among tumors from different anatomic sites. The current treatment for BTC includes surgery, chemotherapy, target therapy, and immunotherapy. Although surgery remains the primary option for localized disease, representing the only potential curative treatment, a high risk of recurrence cannot be neglected. Chemotherapy has been considered the standard of care for both advanced and metastatic disease and in adjuvant settings. However, drug resistance is a major obstacle associated with chemotherapy. The development of genetic testing technologies, including next-generation sequencing, has opened the door for the identification of drug targets and candidate molecules. A series of preclinical studies has demonstrated the role of gene mutations, abnormal signaling pathways, and immunosuppression in the pathogenesis of BTC, laying the foundation for the application of targeted therapy and immunotherapy. A variety of molecularly targeted agents, including pemigatinib, have shown promising survival benefits in patients with advanced disease. The rapidly evolving role of multimodal therapy represents the subject of this review.

Re-Recognizing the Cellular Origin of the Primary Epithelial Tumors of the Liver

The primary epithelial tumors of the liver (PETL) are composed of a series of heterogeneous tumors. Although the classification of PETLs has been updated several times by the World Health Organization, the cellular origins of some tumors in this family remain to be precisely depicted. In addition, certain tumors in different categories have similar histology, molecular phenotypes and biological characteristics, suggesting that they may have the same cellular origin. In this work, a narrative review method was adopted to review the relevant papers. By comparing the expression profiles of biomarkers of liver epithelium at different lineages and stages of differentiation, the cells-of-origin of some major members of the PETL family were reassessed. We propose that 1) hepatic adenomas, hepatocellular carcinomas (HCCs) and pure fetal hepatoblastomas (HBs) share the same spectrum in their cellular origin including the hepatocytic-committed progenitors (HCP) and their differentiated descendants. 2) Bile duct adenomas, peribiliary cysts and intrahepatic cholangiocellular carcinomas (ICCs) can share the same spectrum in their cellular origin including the cholangiocytic-committed progenitors (CCP) and their differentiated descendants. 3) The cells-of-origin of embryonal HBs include liver stem cells (LSCs), hepatoblasts, and transitional cells between them. Embryonal HB with small cell element, small cell undifferentiated HB and small cell neuroendocrine carcinoma of the liver can have the same or similar cells-of-origin from LSC. Embryonal HB lacking the small cell component of the LSC phenotype and presenting both hepatocytic and bile duct/ductule components may originate from actual hepatoblasts/hepatic progenitor cells (HPCs) as the combined HCC-ICC does. 4) Teratoid hepatoblastoma and mixed epithelial/mesenchymal HBs can be derived from the LSCs or even less committed extrahepatic pluripotent stem cell. 5) Many members of the PETLs family, including those derived from LSCs, hepatoblasts/HPCs, early HCPs and CCPs, have neuroendocrine potentiality. Except for those primary hepatic neuroendocrine tumor (PHNET) exhibit hepatocytic and/or cholangiocytic phenotypes, other PHNETs subtype may be derived from the descendants of LSC that differentiate towards the upper digestive tract, pancreas or other lineages.

Diagnostic and prognostic impact of cytokeratin 19 expression analysis in human tumors: a tissue microarray study of 13,172 tumors

To evaluate cytokeratin 19 (CK19) expression in normal and cancerous tissues, 15,977 samples from 122 tumor types and 608 samples of 76 normal tissue types were analyzed by immunohistochemistry (IHC). In normal tissues, CK19 expression occurred in epithelial cells of most glandular organs but was strictly limited to the basal cell layer of nonkeratinizing squamous epithelium and absent in the skin. CK19 expression in ≥90% of cases was seen in 34% of the tumor entities including the adenocarcinomas of the pancreas (99.4%), colorectum (99.8%), esophagus (98.7%), and stomach (97.7%), as well as breast cancer (90.0%-100%), high-grade serous (99.1%) or endometrioid (97.8%) ovarian cancer, and urothelial carcinoma (92.6%-100%). A low CK19 positivity rate (0.1-10%) was seen in 5 of 122 tumor entities including hepatocellular carcinoma and seminoma. A comparison of tumor versus normal tissue findings demonstrated that upregulation and downregulation of CK19 can occur in cancer and that both alterations can be linked to unfavorable phenotypes. CK19 downregulation was linked to high grade (p = 0.0017) and loss of estrogen receptor- and progesterone receptor-expression (p < 0.0001 each) in invasive breast carcinoma of no special type. CK19 upregulation was linked to nodal metastases in neuroendocrine tumors and papillary thyroid carcinomas (p < 0.05 each) and to poor grade in clear cell renal cell carcinoma (p < 0.05). CK19 upregulation was particularly common in squamous cell carcinomas. We concluded that CK19 IHC might separate primary liver cell carcinoma from liver metastases, seminoma from other testicular tumors, and helps in the detection of early neoplastic transformation in squamous epithelium.

Combined hepatocellular-cholangiocarcinoma: An update

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a tumour that exhibits both hepatocytic and biliary differentiation. Classical risk factors for hepatocellular carcinoma (HCC) seem to also predispose patients to the development of cHCC-CCA. The pathological definition of cHCC-CCA has significantly evolved over time. The last 2019 WHO classification highlighted that the diagnosis of cHCC-CCA should be primarily based on morphology using routine stainings, with additional immunostaining used to refine the identification of subtypes. Among them, "intermediate cell carcinoma" is recognised as a specific subtype, while "cholangiolocellular carcinoma" is now considered a subtype of iCCA. Increasing molecular evidence supports the clonal nature of cHCC-CCA and parallels its biphenotypic histological appearance, with genetic alterations that are classically observed in HCC and/or iCCA. That said, the morphological diagnosis of cHCC-CCA is still challenging for radiologists and pathologists, especially on biopsy specimens. Identification of cHCC-CCA's cell of origin remains an area of active research. Its prognosis is generally worse than that of HCC, and similar to that of iCCA. Resection with lymph node dissection is unfortunately the only curative option for patients with cHCC-CCA. Thus, there remains an urgent need to develop specific therapeutic strategies for this unique clinical entity.

Postresection prognosis of combined hepatocellular carcinoma-cholangiocarcinoma according to the 2010 World Health Organization classification: single-center experience of 168 patients

Purpose

Combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC) has wide histologic diversity. This study investigated the effects of cHCC-CC histology, according to the 2010 World Health Organization (WHO) classification, on patient prognosis.

Methods

The medical records of patients who underwent surgical resection for cHCC-CC at our institution between July 2012 and June 2019 were retrospectively evaluated.

Results

During the study period, 168 patients, 122 males (72.6%) and 46 females (27.4%), underwent surgical resection for cHCC-CC, including 159 patients (94.6%) who underwent R0 resection. Mean tumor diameter was 4.4 ± 2.8 cm, and 161 patients (95.8%) had solitary tumors. Histologically, 86 patients (51.2%) had classical type, and 82 (48.8%) had tumors with stem cell (SC) features, including 33 (19.6%) with intermediate-cell and 23 (13.7%) each with typical SC and cholangiolocellular features; 3 tumors (1.8%) were unclassifiable. At 1, 3, and 5 years, tumor recurrence rates were 31.9%, 49.6%, and 58.1%, respectively, and patient survival rates were 91.0%, 70.2%, and 60.3%, respectively. Univariate analysis showed that tumor size of >5 cm, microscopic and macroscopic vascular invasion, lymph node metastasis, 8th edition of the American Joint Committee on Cancer (AJCC) tumor stage, and 2010 WHO classification were significantly prognostic. Multivariate analysis showed that the 8th AJCC tumor stage and 2010 WHO histologic classification were independently prognostic for tumor recurrence and patient survival. There were no significant prognostic differences among the 3 SC subtypes.

Conclusion

Postresection outcomes are better in patients with SC-type than with classical-type cHCC-CC.

Clinico-Radio-Pathological and Molecular Features of Hepatocellular Carcinomas with Keratin 19 Expression

Hepatocellular carcinoma (HCC) is a heterogeneous neoplasm, both from the molecular and histomorphological aspects. One example of heterogeneity is the expression of keratin 19 (K19) in a subset (4-28%) of HCCs. The presence of K19 expression in HCCs has important clinical implications, as K19-positive HCCs have been associated with aggressive tumor biology and poor prognosis. Histomorphologically, K19-positive HCCs demonstrate a more infiltrative appearance, poor histological differentiation, more frequent vascular invasion, and more intratumoral fibrous stroma than K19-negative conventional HCCs. From the molecular aspect, K19-positive HCCs have been matched with various gene signatures that have been associated with stemness and poor prognosis, including the G1-3 groups, S2 class, cluster A, proliferation signature, and vascular invasion signature. K19-positive HCCs also show upregulated signatures related to transforming growth factor-β pathway and epithelial-to-mesenchymal transition. The main regulators of K19 expression include hepatocyte growth factor-MET paracrine signaling by cancer-associated fibroblast, epidermal growth factor-epidermal growth factor receptor signaling, laminin, and DNA methylation. Clinically, higher serum alpha-fetoprotein levels, frequent association with chronic hepatitis B, more invasive growth, and lymph node metastasis have been shown to be characteristics of K19-positive HCCs. Radiologic features including atypical enhancement patterns, absence of tumor capsules, and irregular tumor margins can be a clue for K19-positive HCCs. From a therapeutic standpoint, K19-positive HCCs have been associated with poor outcomes after curative resection or liver transplantation, and resistance to systemic chemotherapy and locoregional treatment, including transarterial chemoembolization and radiofrequency ablation. In this review, we summarize the currently available knowledge on the clinico-radio-pathological and molecular features of K19-expressing HCCs, including a detailed discussion on the regulation mechanism of these tumors.

Combined hepatocellular-cholangiocarcinoma: An update on epidemiology, classification, diagnosis and management

BACKGROUND

Combined hepatocellular-cholangiocarcinoma (CHC) is a rare subtype of primary hepatic malignancies, with variably reported incidence between 0.4%-14.2% of primary liver cancer cases. This study aimed to systematically review the epidemiological, clinicopathological, diagnostic and therapeutic data for this rare entity.

DATA SOURCES

We reviewed the literature of diagnostic approach of CHC with special reference to its clinical, molecular and histopathological characteristics. Additional analysis of the recent literature in order to evaluate the results of surgical and systemic treatment of this entity has been accomplished.

RESULTS

The median age at CHC's diagnosis appears to be between 50 and 75 years. Evaluation of tumor markers [alpha fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA)] along with imaging patterns provides better opportunities for CHC's preoperative diagnosis. Reported clinicopathologic prognostic parameters possibly correlated with increased tumor recurrence and grimmer survival odds include advanced age, tumor size, nodal and distal metastases, vascular and regional organ invasion, multifocality, decreased capsule formation, stem-cell features verification and increased GGT as well as CA19-9 and CEA levels. In case of inoperable or recurrent disease, combinations of cholangiocarcinoma-directed systemic agents display superior results over sorafenib. Liver-directed methods, such as transarterial chemoembolization (TACE), percutaneous ethanol injection (PEI), hepatic arterial infusion chemotherapy (HAIC), radioembolization and ablative therapies, demonstrate inferior efficacy than in cases of hepatocellular carcinoma (HCC) due to CHC's common hypovascularity.

CONCLUSIONS

CHC demonstrates an overlapping clinical and biological pattern between its malignant ingredients. Natural history of the disease seems to be determined by the predominant tumor element. Gold standard for diagnosis is histology of surgical specimens. Regarding therapeutic interventions, major hepatectomy is acknowledged as the cornerstone of treatment whereas minor hepatectomy and liver transplantation may be applied in patients with advanced cirrhosis. Despite all therapeutic attempts, prognosis of CHC remains dismal.

Factors associated with 5-year survival of combined hepatocellular and cholangiocarcinoma

BACKGROUND

Combined hepatocellular and cholangiocarcinoma (HCC/CC) is a rare primary hepatic malignancy which carries a poor prognosis due to its aggressive nature. Few centers have enough cases to draw definitive conclusions and there is limited understanding of prognosis. Given the rarity of HCC/CC, an analysis of large national cancer database was needed to obtain larger number of HCC/CC cases.

AIM

To identify associated factors for 5-year survival of HCC/CC.

METHODS

We conducted a retrospective study of The Surveillance, Epidemiology, and End Results (SEER) database obtained from SEER*Stat 8.3.6 software. Previously defined histology code 8180 for the International Classification of Disease for Oncology, 3rd edition was used to identify HCC/CC cases from 2004 to 2015. We collected demographics, American Joint Committee on Cancer (AJCC) stage, treatment, tumor size, and survival data. These data were converted to categorical variables. The Shapiro-Wilk normality test was used to assess normal distribution. Mann-Whitney U test was used to compare continuous variables without normal distribution, and t-test was used to compare continuous variables with a normal distribution. The Kaplan-Meier survival curve analyzed 5-year survival. Univariate and multivariate logistic regression model was used to analyze factors associated with 5-year survival. Multivariate Cox proportional hazard regression was done on 5-year survival. We defined P < 0.05 was statistically significant.

RESULTS

We identified 497 patients with the following characteristics: Mean age 62.4 years (SD: 11.3), 149 (30.0%) were female, racial distribution was: 276 (55.5%) white, 53 (10.7%) black, 84 (16.9%) Asian and Pacific Islander (API), 77 (15.5%) Hispanic, and 7 (1.4%) others or unknown. Stage I/II disease occurred in 41.5% and tumor size < 50 mm was seen in 35.6% of patients. Twenty-four (4.8%) received locoregional therapy (LRT), 119 (23.9%) underwent resection, and 50 (10.1%) underwent liver transplantation. The overall median survival was 6 mo [Interquartile range (IQR): 1-22]. After multivariate logistic regression, tumor size < 50 mm [Odds ratios (OR): 2.415, P = 0.05], resection (OR: 12.849, P < 0.01), and transplant (OR: 27.129, P < 0.01) showed significance for 5-year survival. Age > 60, sex, race, AJCC stages, metastasis, and LRT were not significant. However, API vs white showed significant OR of 2.793 (CI: 1.120-6.967). Cox proportional hazard regression showed AJCC stages, tumor size < 50 mm, LRT, resection, and transplant showed significant hazard ratio.

CONCLUSION

HCC/CC patients with tumor size < 50 mm, resection, and transplant were associated with an increase in 5-year survival. API showed advantageous OR and hazard ratios over white, black.

Is the outcome after hepatectomy for transitional hepatocholangiocarcinoma different from that of hepatocellular carcinoma and mass-forming cholangiocarcinoma? A case-matched analysis

Hepatocholangiocarcinoma (HCC-CC) is a rare malignancy containing features of both hepatocellular carcinoma (HCC) and mass-forming cholangiocarcinoma (MFCCC), of which the outcome after hepatectomy remains to be clarified. The aim of this study was to analyze the characteristics and outcomes of patients with transitional HCC-CC and compare them with those of patients with HCC and MFCCC. Our prospectively maintained database was queried, and 14 transitional HCC-CC patients were identified over a total of 406 consecutive hepatic resections. A 1:1:1 match was performed with HCC and MFCCC patients operated in the same period. A total of 42 patients were matched according to tumor stage (T1-2-3, N0, M0), number of tumors, R0 resection, no 90-day mortality, and follow-up. Primary endpoints were disease-free survival (DFS) and overall survival (OS). Disease-free survival rates at 1-, 3-, and 5-year were 71.4%, 57.1%, 35.7% for transitional HCC-CC patients; 85.7%, 40.4%, 10.1% for HCC patients; 85.1%, 34.0%, 22.7% for MFCCC patients (5-year DFS: HCC-CC vs. HCC, p = 0.575; HCC-CC vs. MFCCC, p = 0.766, respectively). Similarly, OS rates at 1-, 3-, and 5-year were 92.9%, 71.4%, 64.3% for transitional HCC-CC patients; 100%, 64.3%, 41.7% for HCC patients; 100%, 54.5%, 43.6% for MFCCC patients (5-year OS: HCC-CC vs. HCC, p = 0.891; HCC-CC vs. MFCCC, p = 0.673, respectively). When accurately matched with respect to tumor burden, transitional HCC-CC patients show similar outcomes to those of HCC and MFCCC patients. Further evaluations of differences in tumor biology are necessary to better characterize the prognosis of transitional HCC-CC patients.

Can machine learning radiomics provide pre-operative differentiation of combined hepatocellular cholangiocarcinoma from hepatocellular carcinoma and cholangiocarcinoma to inform optimal treatment planning?

OBJECTIVE

To differentiate combined hepatocellular cholangiocarcinoma (cHCC-CC) from cholangiocarcinoma (CC) and hepatocellular carcinoma (HCC) using machine learning on MRI and CT radiomics features.

METHODS

This retrospective study included 85 patients aged 32 to 86 years with 86 histopathology-proven liver cancers: 24 cHCC-CC, 24 CC, and 38 HCC who had MRI and CT between 2004 and 2018. Initial CT reports and morphological evaluation of MRI features were used to assess the performance of radiologists read. Following tumor segmentation, 1419 radiomics features were extracted using PyRadiomics library and reduced to 20 principle components by principal component analysis. Support vector machine classifier was utilized to evaluate MRI and CT radiomics features for the prediction of cHCC-CC vs. non-cHCC-CC and HCC vs. non-HCC. Histopathology was the reference standard for all tumors.

RESULTS

Radiomics MRI features demonstrated the best performance for differentiation of cHCC-CC from non-cHCC-CC with the highest AUC of 0.77 (SD 0.19) while CT was of limited value. Contrast-enhanced MRI phases and pre-contrast and portal-phase CT showed excellent performance for the differentiation of HCC from non-HCC (AUC of 0.79 (SD 0.07) to 0.81 (SD 0.13) for MRI and AUC of 0.81 (SD 0.06) and 0.71 (SD 0.15) for CT phases, respectively). The misdiagnosis of cHCC-CC as HCC or CC using radiologists read was 69% for CT and 58% for MRI.

CONCLUSIONS

Our results demonstrate promising predictive performance of MRI and CT radiomics features using machine learning analysis for differentiation of cHCC-CC from HCC and CC with potential implications for treatment decisions.

KEY POINTS

• Retrospective study demonstrated promising predictive performance of MRI radiomics features in the differentiation of cHCC-CC from HCC and CC and of CT radiomics features in the differentiation of HCC from cHCC-CC and CC. • With future validation, radiomics analysis has the potential to inform current clinical practice for the pre-operative diagnosis of cHCC-CC and to enable optimal treatment decisions regards liver resection and transplantation.

Combined Hepatocellular-Cholangiocarcinoma: Changes in the 2019 World Health Organization Histological Classification System and Potential Impact on Imaging-Based Diagnosis

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a primary liver cancer (PLC) with both hepatocytic and cholangiocytic phenotypes. Recently, the World Health Organization (WHO) updated its histological classification system for cHCC-CCA. Compared to the previous WHO histological classification system, the new version no longer recognizes subtypes of cHCC-CCA with stem cell features. Furthermore, some of these cHCC-CCA subtypes with stem cell features have been recategorized as either hepatocellular carcinomas (HCCs) or intrahepatic cholangiocarcinomas (ICCs). Additionally, distinctive diagnostic terms for intermediate cell carcinomas and cholangiolocarcinomas (previous cholangiolocellular carcinoma subtype) are now recommended. It is important for radiologists to understand these changes because of its potential impact on the imaging-based diagnosis of HCC, particularly because cHCC-CCAs frequently manifest as HCC mimickers, ICC mimickers, or as indeterminate on imaging studies. Therefore, in this review, we introduce the 2019 WHO classification system for cHCC-CCA, illustrate important imaging features characteristic of its subtypes, discuss the impact on imaging-based diagnosis of HCC, and address other important considerations.

Resection of Mixed Hepatocellular-Cholangiocarcinoma, Hepatocellular Carcinoma, and Intrahepatic Cholangiocarcinoma

Mixed hepatocellular-cholangiocarcinoma (HCC-CC) is a biphenotypic liver cancer thought to have unfavorable tumor biology and a poor prognosis. Surgical outcomes of HCC-CC remain unclear. We aimed to evaluate the clinical characteristics and surgical outcomes of HCC-CC. We analyzed a series of patients undergoing resection for HCC-CC (n = 47), hepatocellular carcinoma (HCC; n = 468), and intrahepatic cholangiocarcinoma (ICC; n = 108) at a single Western center between 2001 and 2015. Patients with HCC-CC were matched to patients with HCC and ICC on important clinical factors including tumor characteristics (size, vascular invasion, and differentiation) and underlying cirrhosis. Patients with HCC-CC had rates of viral hepatitis comparable to patients with HCC (78.7% versus 80.0%), and 42.5% had underlying cirrhosis. When matched on tumor size, HCC-CC was more poorly differentiated than HCC (68.3% versus 27.3%; P < 0.001) and ICC (68.3% versus 34.8%; P = 0.01) but had similar postresection survival (5-year survival: HCC-CC 49.7%, HCC 54.8%, ICC 68.7%; P = 0.61) and recurrence (3-year recurrence: HCC-CC 57.9%, HCC 61.5%, and ICC 56%; P = 0.58). Outcomes were similar between HCC-CC and HCC when matched on underlying cirrhosis and tumor size. Cancer type was not predictive of survival or tumor recurrence. Survival after resection of HCC-CC is similar to HCC when matched for tumor size, despite HCC-CC tumors being more poorly differentiated. Exclusion of HCC-CC from management strategies recommended for HCC, including consideration for liver transplantation, may not be warranted.

Surgical Treatment of Hepatocholangiocarcinoma: A Systematic Review

BACKGROUND

Hepatocholangiocarcinoma (HCC-CC) is a rare liver malignancy that contains features of both hepatocellular carcinoma (HCC) and mass-forming cholangiocarcinoma (MFCCC). Three classification systems for HCC-CC are described in literature and the majority of these tumors appear to be of the transitional type. The aim of this study is to evaluate the characteristics of transitional HCC-CC and to compare long-term oncological outcomes with HCC and MFCCC in surgically treated patients.

SUMMARY

A systematic literature search was conducted to identify relevant studies analyzing demographic and clinical characteristics of patients with transitional HCC-CC and evaluating treatments and outcomes associated with this neoplasm. Only comparative, retrospective analyses were included. A total of 14 studies, involving 13,613 patients with primary liver malignancy, were analyzed. All patients underwent surgery, either liver resection or transplantation. Four hundred and thirty-seven patients were affected by transitional HCC-CC (3.2%). For further analysis, patients with transitional HCC-CC were divided into 2 groups, the resection group and the transplantation group. Disease-free survival (DFS) and overall survival (OS) of these patients were analyzed and compared to long-term oncological outcomes of patients with HCC and/or MFCCC, who underwent the same treatment. In the resection group, DFS rate at 5-year was 15, 31.6, and 20.3% for patients with transitional HCC-CC, HCC, and MFCCC, respectively; OS rate at 5-year was 32.7, 47.5, and 30.3% for patients with transitional HCC-CC, HCC, and MFCCC, respectively. In the transplantation group, DFS rate at 5-year was 40.9 and 87.4% for patients with transitional HCC-CC and HCC, respectively; OS rate at 5-year was 49.4 and 80.3% for patients with transitional HCC-CC and HCC, respectively.

KEY MESSAGES

Transitional HCC-CC patients have significantly worse DFS and OS rates compared to HCC patients in both the resection group and the transplantation group. However, in the resection group, both DFS and OS rates of transitional HCC-CC patients are not statistically different from those of MFCCC patients.

Modeling liver cancer and therapy responsiveness using organoids derived from primary mouse liver tumors

The current understanding of cancer biology and development of effective treatments for cancer remain far from satisfactory. This in turn heavily relies on the availability of easy and robust model systems that resemble the architecture/physiology of the tumors in patients to facilitate research. Cancer research in vitro has mainly been based on the use of immortalized 2D cancer cell lines that deviate in many aspects from the original primary tumors. The recent development of the organoid technology allowing generation of organ-buds in 3D culture from adult stem cells has endowed the possibility of establishing stable culture from primary tumors. Although culturing organoids from liver tumors is thought to be difficult, we now convincingly demonstrate the establishment of organoids from mouse primary liver tumors. We have succeeded in culturing 91 lines from 129 liver tissue/tumors. These organoids can be grown in long-term cultures in vitro. About 20% of these organoids form tumors in immunodeficient mice upon (serial) transplantation, confirming their tumorigenic and self-renewal properties. Interestingly, single cells from the tumor organoids have high efficiency of organoid initiation, and a single organoid derived from a cancer cell is able to initiate a tumor in mice, indicating the enrichment of tumor-initiating cells in the tumor organoids. Furthermore, these organoids recapitulate, to some extent, the heterogeneity of liver cancer in patients, with respect to phenotype, cancer cell composition and treatment response. These model systems shall provide enormous opportunities to advance our research on liver cancer (stem cell) biology, drug development and personalized medicine.

IGF2 mRNA Binding Protein 2 Transgenic Mice Are More Prone to Develop a Ductular Reaction and to Progress Toward Cirrhosis

The insulin-like growth factor 2 (IGF2) mRNA binding proteins (IMPs/IGF2BPs) IMP1 and 3 are regarded as oncofetal proteins, whereas the hepatic IMP2 expression in adults is controversially discussed. The splice variant IMP2-2/p62 promotes steatohepatitis and hepatocellular carcinoma. Aim of this study was to clarify whether IMP2 is expressed in the adult liver and influences progression toward cirrhosis. IMP2 was expressed at higher levels in embryonic compared to adult tissues as quantified in embryonic, newborn, and adult C57BL/6J mouse livers and suggested by analysis of publicly available human data. In an IMP2-2 transgenic mouse model microarray and qPCR analyses revealed increased expression of liver progenitor cell (LPC) markers Bex1, Prom1, Spp1, and Cdh1 indicating a de-differentiated liver cell phenotype. Induction of these LPC markers was confirmed in human cirrhotic tissue datasets. The LPC marker SPP1 has been described to play a major role in fibrogenesis. Thus, DNA methylation was investigated in order to decipher the regulatory mechanism of Spp1 induction. In IMP2-2 transgenic mouse livers single CpG sites were differentially methylated, as quantified by amplicon sequencing, whereas human HCC samples of a human publicly available dataset showed promoter hypomethylation. In order to study the impact of IMP2 on fibrogenesis in the context of steatohepatitis wild-type or IMP2-2 transgenic mice were fed either a methionine-choline deficient (MCD) or a control diet for 2-12 weeks. MCD-fed IMP2-2 transgenic mice showed a higher incidence of ductular reaction (DR), accompanied by hepatic stellate cell activation, extracellular matrix (ECM) deposition, and induction of the LPC markers Spp1, Cdh1, and Afp suggesting the occurrence of de-differentiated cells in transgenic livers. In human cirrhotic samples IMP2 overexpression correlated with LPC marker and ECM component expression. Progression of liver disease was induced by combined MCD and diethylnitrosamine (DEN) treatment. Combined MCD-DEN treatment resulted in shorter survival of IMP2-2 transgenic compared to wild-type mice. Only IMP2-2 transgenic livers progressed to cirrhosis, which was accompanied by strong DR. In conclusion, IMP2 is an oncofetal protein in the liver that promotes DR characterized by de-differentiated cells toward steatohepatitis-associated cirrhosis development with poor survival.

Malic enzyme 1 is a potential marker of combined hepatocellular cholangiocarcinoma, subtype with stem-cell features, intermediate-cell type

AIM

Combined hepatocellular cholangiocarcinoma, subtype with stem-cell features, intermediate-cell subtype (INT) shows various histological appearances and could be misdiagnosed as intrahepatic cholangiocarcinoma (iCCA). In the present study, we aimed to identify specific histological diagnostic markers of INT.

METHODS

We extracted RNA from FFPE sections of six INT, five iCCA, and five hepatocellular carcinoma (HCC) cases and compared gene expression between INT, iCCA, and HCC by microarray analysis. We then undertook immunohistochemical (IHC) staining of potential key molecules identified by microarray analysis, the conventional hepatocytic marker, hepatocyte paraffin (HepPar)-1, and the cholangiocytic markers, keratin (K) 7 and K19, on 35 INT, 25 iCCA, and 60 HCC cases.

RESULTS

Microarray analysis suggested that malic enzyme 1 (ME1) was significantly upregulated in INT. Immunohistochemical analysis revealed that the positive rates of ME1 in INT, iCCA, and HCC were 77.1% (27/35), 28.0% (7/25), and 61.7% (37/60), respectively. Analysis of classification and regression trees based on IHC scores indicated that HepPar-1 could be a good candidate for discriminating HCC from the others with high sensitivity (93.3%) and high specificity (96.7%). A multiple logistic regression model and receiver operating characteristic curve analysis based on the IHC scores of ME1, K7, and K19 generated a composite score that can discriminate between INT and iCCA. Using this composite score, INT could be discriminated from iCCA with high sensitivity (88.6%) and high specificity (88.0%).

CONCLUSIONS

We propose that ME1 is a useful diagnostic marker of INT when used in combination with other hepatocytic and cholangiocytic markers.

Role of Cancer Stem Cells in Cholangiocarcinoma and Therapeutic Implications

Cholangiocarcinoma (CCA) is the second most common type of liver cancer, and is highly aggressive with very poor prognosis. CCA is classified into intrahepatic cholangiocarcinoma (iCCA) and extra-hepatic cholangiocarcinoma (eCCA), which is further stratified into perihilar (pCCA) and distal (dCCA). Cancer stem cells (CSCs) are a subpopulation of cancer cells capable of tumor initiation and malignant growth, and are also responsible for chemoresistance. Thus, CSCs play an important role in CCA carcinogenesis. Surface markers such as CD133, CD24, CD44, EpCAM, Sox2, CD49f, and CD117 are important for identifying and isolating CCA CSCs. CSCs are present in the tumor microenvironment (TME), termed ‘CSC niche’, where cellular components and soluble factors interact to promote tumor initiation. Epithelial-to-mesenchymal transition (EMT) is another important mechanism underlying carcinogenesis, involved in the invasiveness, metastasis and chemoresistance of cancer. It has been demonstrated that EMT plays a critical role in generating CSCs. Therapies targeting the surface markers and signaling pathways of CCA CSCs, proteins involved in TME, and immune checkpoint proteins are currently under investigation. Therefore, this review focuses on recent studies on the roles of CSCs in CCA; the possible therapeutic strategies targeting CSCs of CCA are also discussed.

Clinical and pathological features of combined hepatocellular-cholangiocarcinoma compared with other liver cancers

BACKGROUND AND AIM

Combined hepatocellular-cholangiocarcinoma (CHC) is a primary liver cancer containing both hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) elements. Its reported clinicopathological features and prognoses have varied because of its low prevalence. This study aimed to clarify these aspects of CHC.

METHODS

We enrolled 28 patients with CHC, 1050 with HCC, and 100 with ICC and compared the clinicopathological characteristics and prognosis of CHC with HCC and ICC. We also analyzed prognostic factors, recurrence patterns, and management in CHC patients.

RESULTS

The incidences of hepatitis B virus and high α-fetoprotein and protein induced by vitamin K absence or antagonists-II levels were significantly higher among CHC compared with ICC patients. Multiple tumors were more frequent in CHC compared with the other groups, while vascular invasion and lymph node metastasis were more frequent in the CHC than the HCC group. The 5-year overall survival and disease-free survival rates for CHC were 25.1% and 22.6%, respectively. Overall survival was significantly lower than for HCC (P < 0.001) but not ICC (P = 0.152), while disease-free survival was significantly lower than for HCC and ICC (P = 0.008 and P = 0.005, respectively). Multivariate analysis identified carcinoembryonic antigen levels and tumor size as independent predictors in patients with CHC.

CONCLUSIONS

The clinical features of CHC, including sex, hepatitis B virus infection, α-fetoprotein, and protein induced by vitamin K absence or antagonists-II levels, were similar to HCC, while its prognosis and pathological features, including vascular invasion and lymph node metastasis, were similar to ICC. Carcinoembryonic antigen levels and tumor size were independent prognostic factors in patients with CHC.

Conversion of Stem Cells to Cancer Stem Cells: Undercurrent of Cancer Initiation

Cancer stem cells (CSCs) also known as cancer-initiating cells (CIC), are responsible for the sustained and uncontrolled growth of malignant tumors and are proposed to play significant roles in metastasis and recurrence. Several hypotheses have proposed that the events in either stem and/or differentiated cells, such as genomic instability, inflammatory microenvironment, cell fusion, and lateral gene transfer, should be considered as the possible origin of CSCs. However, until now, the exact origin of CSC has been obscure. The development of induced pluripotent stem cells (iPSCs) in 2007, by Yamanaka's group, has been met with much fervency and hailed as a breakthrough discovery by the scientific and research communities, especially in regeneration therapy. The studies on the development of CSC from iPSCs should also open a new page of cancer research, which will help in designing new therapies applicable to CSCs. Currently most reviews have focused on CSCs and CSC niches. However, the insight into the niche before the CSC niche should also be of keen interest. This review introduces the novel concept of cancer initiation introducing the conversion of iPSCs to CSCs and proposes a relationship between the inflammatory microenvironment and cancer initiation as the key concept of the cancer-inducing niche responsible for the development of CSC.

Combined hepatocellular-cholangiocarcinoma: a population level analysis of incidence and mortality trends

Background

The purpose of this study was to explore trends in incidence, incidence-based (IB) mortality, and survival for combined hepatocellular-cholangiocarcinoma (cHCC-CC) utilizing a population-based database to attract people’s attention to this disease.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was utilized to investigate the incidence and IB mortality for cHCC-CC from 2000 to 2014. Trends in age-adjusted incidence and IB mortality were characterized by the Joinpoint Regression program. The Kaplan-Meier method and log-rank test were utilized to implement survival analyses. Cox regression was utilized to estimate independent predictors of mortality.

Results

The incidence of cHCC-CC was 0.26 per 1,000,000 individuals in 2000 and 0.59 per 1,000,000 individuals in 2014, with an annual percent change (APC) (i.e., the extent of increase in incidence) of 3.84% (95% confidence interval [CI] 1.7–6.1; P < 0.05). The IB mortality also displayed a sustained increase (APC was 4.59%, 95% CI 1.9–7.4; P < 0.05). Compared to patients not undergoing surgery, patients undergoing surgical treatment experienced a significant increase in median survival (3 vs. 28 months; P < 0.001). However, the median survival decreased in patients with tumor size > 5 cm (20 vs. 9 months; P < 0.001). Based on univariate Cox regression analysis, African-American race, distant stage, regionalized stage, tumor size ≥ 5 cm, and no surgery were risk factors for death.

Conclusions

We identified an overall steady increase in the incidence of cHCC-CC, which indicates that primary prevention strategies for cHCC-CC have not improved much in recent years and that cHCC-CC needs to be taken seriously.

Combined hepatocellular cholangiocarcinoma (cHCC-CC): an update of genetics, molecular biology, and therapeutic interventions

Combined hepatocellular cholangiocarcinoma (CC) is a rare and aggressive primary hepatic malignancy with significant histological and biological heterogeneity. It presents with more aggressive behavior and worse survival outcomes than either hepatocellular carcinoma or CC and remains a diagnostic challenge. An accurate diagnosis is crucial for its optimal management. Major hepatectomy with hilar node resection remains the mainstay of treatment in operable cases. Advances in the genetic and molecular characterization of this tumor will contribute to the better understanding of its pathogenesis and shape its future management.

Evaluation of NCAM and c-Kit as hepatic progenitor cell markers for intrahepatic cholangiocarcinomas

BACKGROUND

Intrahepatic cholangiocarcinomas (ICCs) are primary liver malignancies and are the second most common type of malignancy after hepatocellular carcinoma. ICCs are heterogeneous in clinical features, genotype, and biological behavior, suggesting that ICCs can initiate in different cell lineages.

AIM

We investigated intrahepatic cholangiocarcinoma RBE cell lines for the markers neural cell adhesion molecule (NCAM) and c-Kit, which possess hepatic progenitor cells properties.

METHODS

NCAM + c-Kit + cells were tested for hepatic progenitor cell properties including proliferation ability, colony formation, spheroid formation, and invasiveness in NOD/SCID mice. The Agilent Whole Human Genome Microarray Kit was used to evaluate differences in gene expression related to stem cell signaling pathways between NCAM + c-Kit + and NCAM-c-Kit- subset cells. Microarray results were further confirmed by real-time RT-PCR.

RESULTS

NCAM + c-Kit + cells showed hepatic progenitor cell-like traits including the abilities to self-renew and differentiate and tumorigenicity in NOD/SCID mice. Differences were observed in the expression of 421 genes related to stem cell signaling pathways (fc ≥ 2 or fc ≤ 0.5), among which 231 genes were upregulated and 190 genes were downregulated.

CONCLUSION

NCAM + c-Kit + subset cells in RBE may have properties of hepatic progenitor cells. NCAM combined with c-Kit may be a valuable marker for isolating and purifying ICC stem/progenitor cells.

Very Rare Liver Neoplasm: Lymphoepithelioma-Like (LEL) Hepatocellular Carcinoma

A case of lymphoepithelioma-like (LEL) hepatobiliary carcinoma is reported. To date, only 89 cases of this rare neoplasm have been reported, with both hepatocellular and cholangiocellular histotype. The case reported here could be classified as LEL mixed hepatobiliary carcinoma (Hepato-Cholangio), a histotype not reported so far in the LEL variant.

Stochastic phenotype switching leads to intratumor heterogeneity in human liver cancer

Intratumor heterogeneity is increasingly recognized as a major factor impacting diagnosis and personalized treatment of cancer. We characterized stochastic phenotype switching as a mechanism contributing to intratumor heterogeneity and malignant potential of liver cancer. Clonal analysis of primary tumor cell cultures of a human sarcomatoid cholangiocarcinoma identified different types of self-propagating subclones characterized by stable (keratin-7-positive or keratin-7-negative) phenotypes and an unstable phenotype consisting of mixtures of keratin-7-positive and keratin-7-negative cells, which lack stem cell features but may reversibly switch their phenotypes. Transcriptome sequencing and immunohistochemical studies with the markers Zeb1 and CD146/MCAM demonstrated that switching between phenotypes is linked to changes in gene expression related but not identical to epithelial-mesenchymal transition. Stochastic phenotype switching occurred during mitosis and did not correlate with changes in DNA methylation. Xenotransplantation assays with different cellular subclones demonstrated increased tumorigenicity of cells showing phenotype switching, resulting in tumors morphologically resembling the invasive component of primary tumor and metastasis.

CONCLUSION

Our data demonstrate that stochastic phenotype switching contributes to intratumor heterogeneity and that cells with a switching phenotype have increased malignant potential. (Hepatology 2017).

cHCC-CCA: Consensus terminology for primary liver carcinomas with both hepatocytic and cholangiocytic differentation

Primary liver carcinomas with both hepatocytic and cholangiocytic differentiation have been referred to as "combined (or mixed) hepatocellular-cholangiocarcinoma." These tumors, although described over 100 years ago, have attracted greater attention recently because of interest in possible stem cell origin and perhaps because of greater frequency and clinical recognition. Currently, because of a lack of common terminology in the literature, effective treatment and predictable outcome data have been challenging to accrue. This article represents a consensus document from an international community of pathologists, radiologists, and clinicians who have studied and reported on these tumors and recommends a working terminology for diagnostic and research approaches for further study and evaluation.

CONCLUSION

It is recommended that diagnosis is based on routine histopathology with hematoxylin and eosin (H&E); immunostains are supportive, but not essential for diagnosis. (Hepatology 2018;68:113-126).

Whole-exome sequencing reveals the origin and evolution of hepato-cholangiocarcinoma

Hepatocellular-cholangiocarcinoma (H-ChC) is a rare subtype of liver cancer with clinicopathological features of both hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). To date, molecular mechanisms underlying the co-existence of HCC and iCCA components in a single tumor remain elusive. Here, we show that H-ChC samples contain substantial private mutations from WES analyses, ranging from 33.1 to 86.4%, indicative of substantive intratumor heterogeneity (ITH). However, on the other hand, numerous ubiquitous mutations shared by HCC and iCCA suggest the monoclonal origin of H-ChC. Mutated genes identified herein, e.g., VCAN, ACVR2A, and FCGBP, are speculated to contribute to distinct differentiation of HCC and iCCA within H-ChC. Moreover, immunohistochemistry demonstrates that EpCAM is highly expressed in 80% of H-ChC, implying the stemness of such liver cancer. In summary, our data highlight the monoclonal origin and stemness of H-ChC, as well as substantial intratumoral heterogeneity.

Hepatocellular-cholangiocarcinoma (H-ChC) is a rare subtype of liver cancer with features of hepatocellular carcinoma and intrahepatic cholangiocarcinoma. Here, the authors utilize whole exome sequencing to highlight the monoclonal origin and stemness of H-ChC, as well as substantial intratumoral heterogeneity.

Gemcitabine plus platinum-based chemotherapy for first-line treatment of hepatocholangiocarcinoma: an AGEO French multicentre retrospective study

BACKGROUND

Hepatocholangiocarcinoma (cHCC-ICC) is a rare liver tumour for which no data on chemosensitivity exist. The aims of this multicentre study were to evaluate overall survival (OS), progression-free survival (PFS), and prognostic factors in cHCC-ICC treated by gemcitabine plus platinum as first-line.

METHODS

Unresectable cHCC-ICC treated by gemcitabine plus platinum-based chemotherapy between 2008 and 2017 were retrospectively analysed. Diagnosis was based on histology or, in case of ICC or HCC histology, on discordant computerised tomography scan enhancement patterns associated with discordant serum tumour marker elevation suggesting the alternative tumour. OS and PFS were evaluated by Kaplan-Meier method and prognostic factors by Log-rank test and Cox model.

RESULTS

Among 30 patients included, cHCC-ICC was histologically proven in 22 (73.3%). 18 (60%) received gemcitabine plus oxaliplatin (GEMOX), 9 (30%) GEMOX plus bevacizumab, and 3 (10%) gemcitabine plus cisplatin. RECIST criteria were reported in 28 patients: 8 (28.6%) showed partial response, 14 (50%) stable disease, and 6 (21.4%) tumour progression at first evaluation. Median PFS and OS were 9.0 and 16.2 months, respectively. Serum bilirubin ⩾30 μmol l-1 (P=0.001) and positive serology for HBV and/or HCV (P=0.014) were independent poor prognostic factors for OS.

CONCLUSIONS

Gemcitabine plus platinum-based chemotherapy is effective as first-line for advanced cHCC-ICC.

Clinical features, histology, and histogenesis of combined hepatocellular-cholangiocarcinoma

Combined hepatocellular-cholangiocarcinoma (CHC) is a rare tumor with poor prognosis, with incidence ranging from 1.0%-4.7% of all primary hepatic tumors. This entity will be soon renamed as hepato-cholangiocarcinoma. The known risk factors for hepatocellular carcinoma (HCC) have been implicated for CHC including viral hepatitis and cirrhosis. It is difficult to diagnose this tumor pre-operatively. The predominant histologic component within the tumor largely determines the predominant radiographic features making it a difficult distinction. Heterogeneous and overlapping imaging features of HCC and cholangiocarcinoma should raise the suspicion for CHC and multiple core biopsies (from different areas of tumor) are recommended before administering treatment. Serum tumor markers CA19-9 and alpha-fetoprotein can aid in the diagnosis, but it remains a challenging diagnosis prior to resection. There is sufficient data to support bipotent hepatic progenitor cells as the cell of origin for CHC. The current World Health Organization classification categorizes two main types of CHC based on histo-morphological features: Classical type and CHC with stem cell features. Liver transplant is one of the available treatment modalities with other management options including transarterial chemoembolization, radiofrequency ablation, and percutaneous ethanol injection. We present a review paper on CHC highlighting the risk factors, origin, histological classification and therapeutic modalities.

Variant differentiation patterns in primary liver carcinoma

Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are two distinct forms of primary liver carcinoma recognizable at the microscope by their architectural and cytological characteristics, as well as specific immunohistochemical profiles. This straightforward concept however, is increasing imperiled by the recognition of primary liver carcinomas that do not subscribe to a dichotomous paradigm of differentiation, and instead demonstrate biphenotypic differentiation, stem/progenitor cell like features or other variant patterns of differentiation. Appropriate nomenclature, diagnostic criteria, prognostic significance and optimal therapeutic approach for these variant tumors are not completely defined, not leasyt because they are not always identified correctly and when they are, lack of uniform terminology hinders collection of adequate number of cases to facilitate their study. Similar to hepatocellular carcinoma and in contrast with intrahepatic cholangiocarcinoma, primary liver tumors showing biphenotypic differentiation, stem/progenitor cell features or variant differentiation occur mainly, but not always, on a background of chronic liver disease. They are particularly frequent after neo-adjuvant therapy. Whether they represent trans-differentiation of malignant cells, or whether they derive from a stem/progenitor cell that gives rise to divergent differentiation remains yet another area of uncertainty.

Mutational landscape of combined hepatocellular carcinoma and cholangiocarcinoma, and its clinicopathological significance

AIMS

Combined hepatocellular carcinoma and cholangiocarcinoma (cHC-CC), which generally has a poor prognosis, comprises hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and diverse components with intermediate features between HCC and CC. Histological subtypes with stem cell (SC) features (the SC subtype) have different clinicopathological significance in cHC-CC. The mutational status may reflect the clinicopathological subgroup of cHC-CC together with the histological subtype.

METHODS AND RESULTS

We examined the mutational statuses of KRAS, IDH1 or IDH2 (IDH1/2), ARID1A, the TERT promoter, and TP53, and their relationships with clinicopathological features in 53 patients with cHC-CC. Background liver diseases were hepatitis B (n = 9), hepatitis C (n = 22), alcoholic liver disease (n = 5), non-alcoholic fatty liver disease (NAFLD) (n = 8), and unknown (n = 9). Mutations in KRAS, IDH1/2, ARID1A, the TERT promoter and TP53 were detected in four (7.5%), six (11.8%) seven (13.2%), 16 (31.3%), and 24 patients (45.3%), respectively. KRAS mutations correlated with higher histological diversity scores and a higher M-factor (P < 0.05). ARID1A mutations correlated with alcoholic liver disease, smaller tumour size, a lower grade of coexistent HCC, and α-fetoprotein (AFP) positivity, and were associated with cholangiolocellular carcinoma subtype predominance (P < 0.05). TERT promoter mutations correlated with hepatitis B, an intermediate subtype-predominant histology, higher clinical stage, and a higher N-factor (P < 0.05), and were associated with gender (female-predominant) and previous therapy. TP53 mutations correlated with AFP positivity (P < 0.05).

CONCLUSIONS

The results of the mutational analysis revealed that cHC-CC has diverse types of mutations, and also that mutations in the TERT promoter and ARID1A may reflect aetiological impact, different histological subtypes, histogenesis, and tumour aggressiveness. These results suggest the potential efficacy of molecular-based subclassification of cHC-CC.

Immunohistochemical study of hepatocyte, cholangiocyte and stem cell markers of hepatocellular carcinoma: the second report: relationship with tumor size and cell differentiation

Background

The purpose of this study is to investigate whether ordinary hepatocellular carcinomas (HCCs) show positivity of stem/progenitor cell markers and cholangiocyte markers during the process of tumor progression.

Methods

Ninety‐four HCC lesions no larger than 8 cm from 94 patients were immuno‐histochemically studied using two hepatocyte markers (Hep par 1 and α‐fetoprotein), five cholangiocyte markers (cytokeratin CK7, CK19, Muc1, epithelial membrane antigen and carcinoembryonic antigen) and three hepatic stem/progenitor cell markers (CD56, c‐Kit and EpCAM). The tumors were classified into three groups by tumor size: S1, < 2.0 cm; S2, 2.0–5.0 cm; S3, 5.0–8.0 cm. The tumors were also classified according to tumor differentiation: well, moderately and poorly differentiated. The relationship between the positive ratios of these markers, tumor size and tumor differentiation was examined.

Results

The positive ratios of cholangiocyte markers tended to be higher in larger sized and more poorly differentiated tumors (except for CK7). The positive ratios of stem/progenitor cell markers tended to be higher in larger sized and more poorly differentiated tumors (except for c‐Kit).

Conclusion

Ordinary HCC can acquire the characteristic of positivity of cholangiocyte and stem/progenitor cell markers during the process of tumor progression.

Nonalcoholic steatohepatitis and hepatocellular carcinoma: Brazilian survey

OBJECTIVE

The majority of cases of hepatocellular carcinoma have been reported in individuals with cirrhosis due to chronic viral hepatitis and alcoholism, but recently, the prevalence has become increasingly related to nonalcoholic steatohepatitis around the world. The study aimed to evaluate the clinical and histophatological characteristics of hepatocellular carcinoma in Brazilians' patients with nonalcoholic steatohepatitis at the present time.

METHODS

Members of the Brazilian Society of Hepatology were invited to complete a survey regarding patients with hepatocellular carcinoma related to nonalcoholic steatohepatitis. Patients with a history of alcohol intake (>20 g/day) and other liver diseases were excluded. Hepatocellular carcinoma diagnosis was performed by liver biopsy or imaging methods according to the American Association for the Study of Liver Diseases' 2011 guidelines.

RESULTS

The survey included 110 patients with a diagnosis of hepatocellular carcinoma and nonalcoholic fatty liver disease from nine hepatology units in six Brazilian states (Bahia, Minas Gerais, Rio de Janeiro, São Paulo, Paraná and Rio Grande do Sul). The mean age was 67±11 years old, and 65.5% were male. Obesity was observed in 52.7% of the cases; diabetes, in 73.6%; dyslipidemia, in 41.0%; arterial hypertension, in 60%; and metabolic syndrome, in 57.2%. Steatohepatitis without fibrosis was observed in 3.8% of cases; steatohepatitis with fibrosis (grades 1-3), in 27%; and cirrhosis, in 61.5%. Histological diagnosis of hepatocellular carcinoma was performed in 47.2% of the patients, with hepatocellular carcinoma without cirrhosis accounting for 7.7%. In total, 58 patients with cirrhosis had their diagnosis by ultrasound confirmed by computed tomography or magnetic resonance imaging. Of these, 55% had 1 nodule; 17%, 2 nodules; and 28%, ≥3 nodules.

CONCLUSIONS

Nonalcoholic steatohepatitis is a relevant risk factor associated with hepatocellular carcinoma in patients with and without cirrhosis in Brazil. In this survey, hepatocellular carcinoma was observed in elevated numbers of patients with steatohepatitis without cirrhosis.