Morphological subclassification of intrahepatic cholangiocarcinoma: etiological, clinicopathological, and molecular features

Integrative analysis reveals different feature of intrahepatic cholangiocarcinoma subtypes

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (iCCA) has two main histological subtypes: large and small duct-type iCCA, which are characterized by different clinicopathological features. This study was conducted with the purpose of expanding our understanding of their differences in molecular features and immune microenvironment.

METHODS

We selected 132 patients who underwent radical surgery at our department between 2015 and 2021 for clinical and survival analyses. Whole-exome sequencing was performed to analyse mutational landscapes. Bulk RNA sequencing and single-cell RNA sequencing data were used for pathway enrichment and immune infiltration analyses based on differentially expressed genes. The function of PPP1R1B was analysed both in vitro and in vivo and the gene mechanism was further investigated.

RESULTS

We found that large duct-type iCCA had worse overall survival and recurrence-free survival rates than small duct-type iCCA. Mutations in ARID1A, DOT1L and ELF3 usually occur in large duct-type iCCA, whereas mutations in IDH1 and BAP1 occur in small duct-type iCCA. Among the differentially expressed genes, we found that PPP1R1B was highly expressed in large duct-type iCCA tumour tissues. Expression of PPP1R1B promoted cell proliferation, migration and invasion and indicated a worse prognosis. A combination of USF2 with the promoter of PPP1R1B can enhance gene expression in iCCA, which may further affect the expression of genes such as AHNAK, C4BPA and activating the PI3K/AKT pathway.

CONCLUSIONS

Our findings extend our understanding of large and small duct-type iCCA. In addition, PPP1R1B may serve as a potential marker and therapeutic target for large duct-type iCCA.

Prognostic models for mucinous and non-specific adeno cholangiocarcinoma: a population-based retrospective study

Background

Clinically, the diagnosis and treatment of cholangiocarcinoma are generally different according to the location of occurrence, and the studies rarely consider the differences between different pathological types. Cholangiocarcinomas in large- and middle-sized intrahepatic bile ducts are mostly mucinous, while in small sized bile duct are not; mucinous extrahepatic cholangiocarcinomas are also more common than mucinous intrahepatic cholangiocarcinoma. However, it is unclear whether these pathological type differences are related to the prognosis.

Methods

Data of total 22509 patients was analyzed from Surveillance, Epidemiology, and End Results program database out of which 22299 patients were diagnosed with common adeno cholangiocarcinoma while 210 were diagnosed with mucinous cholangiocarcinoma. Based on the propensity score matching (PSM) analysis, between these two groups' clinical, demographic, and therapeutic features were contrasted. The data were analyzed using Cox and LASSO regression analysis and Kaplan-Meier survival curves. Ultimately, overall survival (OS) and cancer specific survival (CSS) related prognostic models were established and validated in test and external datasets and nomograms were created to forecast these patients' prognosis.

Results

There was no difference in prognosis between mucinous cholangiocarcinoma and adeno cholangiocarcinoma. Therefore, we constructed prognostic model and nomogram that can be used for mucinous and adeno cholangiocarcinoma at the same time. By comparing the 9 independent key characteristics i.e. Age, tumor size, the number of primary tumors, AJCC stage, Grade, lymph node status, metastasis, surgery and chemotherapy, risk scores were calculated for each individual. By integrating these two pathological types in OS and CSS prognostic models, effective prognosis prediction results could be achieved in multiple datasets (OS: AUC 0.70-0.87; CSS: AUC 0.74-0.89).

Conclusion

Age, tumor size, the number of primary tumors, AJCC stage, Grade, lymph node status, metastasis, surgery and chemotherapy are the independent prognostic factors in OS or CSS of the patients with mucinous and ordinary cholangiocarcinoma. Nomogram that can be used for mucinous and adeno cholangiocarcinoma at the same time is of significance in clinical practice and management of cholangiocarcinoma.

HNF6 and HNF4α expression in adenocarcinomas of the liver, pancreaticobiliary tract, and gastrointestinal tract: an immunohistochemical study of 480 adenocarcinomas of the digestive system

Hepatocyte nuclear factors (HNF) 6 and 4α are master transcriptional regulators of development and maintenance of the liver and pancreaticobiliary tract in mice and humans. However, little is known about the prevalence of HNF6 and HNF4α expression in carcinomas of the hepatobiliary tract and pancreas. We aimed to reveal the diagnostic utility of HNF6 and HNF4α immunolabelling in adenocarcinomas of these organs. We investigated HNF6 and HNF4α expression by immunohistochemistry using a total of 480 adenocarcinomas of the digestive system, including 282 of the hepatobiliary tract and pancreas and 198 of the gastrointestinal tract. HNF6 expression was primarily restricted to intrahepatic cholangiocarcinomas (CCs) (63%, n=80) and gallbladder adenocarcinomas (43%, n=88), among others. Notably, small duct intrahepatic CCs almost invariably expressed HNF6 (90%, n=42), showing stark contrast to a low prevalence in large duct intrahepatic CCs (10%, n=21; p<0.0001). HNF6 expression was infrequent in extrahepatic CCs (9%, n=55) and pancreatic ductal adenocarcinomas (7%, n=58), and it was rare in adenocarcinomas of the gastrointestinal tract [oesophagus/oesophagogastric junction (EGJ) (2%, n=45), stomach (2%, n=86), duodenum (0%, n=25), and colorectum (0%, n=42)]. In contrast, HNF4α was widely expressed among adenocarcinomas of the digestive system, including intrahepatic CCs (88%), extrahepatic CCs (94%), adenocarcinomas of the gallbladder (98%), pancreas (98%), oesophagus/EGJ (96%), stomach (98%), duodenum (80%), and colorectum (100%). HNF6 was frequently expressed in and almost restricted to intrahepatic CCs of small duct type and gallbladder adenocarcinomas, while HNF4α was expressed throughout adenocarcinomas of the digestive system. HNF6 immunolabelling may be useful in distinguishing small duct intrahepatic CCs from other types of CC as well as metastatic gastrointestinal adenocarcinomas.

An Immunohistochemical Analysis of Osteopontin and S100 Calcium-binding Protein P is Useful for Subclassifying Large- and Small-duct Type Intrahepatic Cholangiocarcinomas

Intrahepatic cholangiocarcinoma (iCCA) has been newly subclassified into two different subtypes: large-duct (LD) type and small-duct (SD) type. However, many cases are difficult to subclassify, and there is no consensus regarding subclassification criteria. LD type expresses the highly sensitive diagnostic marker S100 calcium-binding protein P (S100P), while SD type lacks sensitive markers. We identified osteopontin (OPN) as a highly sensitive marker for SD type. This study aimed to develop new subclassification criteria for LD-type and SD-type iCCA. We retrospectively investigated 74 patients with iCCA and subclassified them based on whole-section immunostaining of S100P and OPN. Of the 74 cases, 41 were subclassified as LD type, 32 as SD type, and one was indeterminate. Notably, all S100P-negative cases had OPN positivity. Seventy-three of the 74 cases (98.6%) were clearly and easily subclassified as LD or SD type using only these 2 markers. We also determined the value of immunohistochemistry in cases that were difficult to diagnose based on hematoxylin-eosin and Alcian blue-periodic acid-Schiff staining. Furthermore, we analyzed the clinicopathological characteristics and prognoses of these 2 subtypes. LD type was a poor prognostic factor on univariate analysis; it had significantly worse overall survival ( P = 0.007) and recurrence-free survival ( P < 0.001) than the SD type. In conclusion, we propose new subclassification criteria for iCCA based on immunostaining of S100P and OPN. These criteria may help pathologists to diagnose subtypes of iCCA, supporting future clinical trials and the development of medications for these 2 subtypes as distinct cancers.

Integrative genomic analyses of European intrahepatic cholangiocarcinoma: Novel ROS1 fusion gene and PBX1 as prognostic marker

BACKGROUND

Cholangiocarcinoma (CCA) is a fatal cancer of the bile duct with a poor prognosis owing to limited therapeutic options. The incidence of intrahepatic CCA (iCCA) is increasing worldwide, and its molecular basis is emerging. Environmental factors may contribute to regional differences in the mutation spectrum of European patients with iCCA, which are underrepresented in systematic genomic and transcriptomic studies of the disease.

METHODS

We describe an integrated whole-exome sequencing and transcriptomic study of 37 iCCAs patients in Germany.

RESULTS

We observed as most frequently mutated genes ARID1A (14%), IDH1, BAP1, TP53, KRAS, and ATM in 8% of patients. We identified FGFR2::BICC1 fusions in two tumours, and FGFR2::KCTD1 and TMEM106B::ROS1 as novel fusions with potential therapeutic implications in iCCA and confirmed oncogenic properties of TMEM106B::ROS1 in vitro. Using a data integration framework, we identified PBX1 as a novel central regulatory gene in iCCA. We performed extended screening by targeted sequencing of an additional 40 CCAs. In the joint analysis, IDH1 (13%), BAP1 (10%), TP53 (9%), KRAS (7%), ARID1A (7%), NF1 (5%), and ATM (5%) were the most frequently mutated genes, and we found PBX1 to show copy gain in 20% of the tumours. According to other studies, amplifications of PBX1 tend to occur in European iCCAs in contrast to liver fluke-associated Asian iCCAs.

CONCLUSIONS

By analyzing an additional European cohort of iCCA patients, we found that PBX1 protein expression was a marker of poor prognosis. Overall, our findings provide insight into key molecular alterations in iCCA, reveal new targetable fusion genes, and suggest that PBX1 is a novel modulator of this disease.

Predicting prognosis in intrahepatic cholangiocarcinoma by the histopathological features

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a highly heterogeneous liver tumor. The associations between histopathological feature and prognosis of ICC are limited. The present study aimed to investigate the prognostic significance of glandular structure and tumor budding in ICC.

METHODS

Patients received radical hepatectomy for ICC were included. Glandular structure and tumor budding were detected by Hematoxylin-eosin staining. The Kaplan-Meier method and the Cox proportional hazards regression model were used to calculate the survival and hazard ratio. Based on the results of multivariate analysis, nomograms of OS and DFS were constructed. C-index and Akaike information criterion (AIC) were used to assess accuracy of models.

RESULTS

A total of 323 ICC patients who underwent surgery were included in our study. Glandular structure was associated with worse overall survival (OS) [hazard ratio (HR): 2.033, 95% confidence interval (CI): 1.047 to 3.945] and disease-free survival (DFS) [HR: 1.854, 95% CI: 1.082 to 3.176]. High tumor budding was associated with worse DFS [HR: 1.636, 95%CI: 1.060 to 2.525]. Multivariate analysis suggested that glandular structure, tumor number, lymph node metastasis, and CA19-9 were independent risk factors for OS. Independent predictor factors for DFS were tumor budding, glandular structure, tumor number, and lymph node metastasis. The c-index (0.641 and 0.642) and AIC (957.69 and 1188.52) showed that nomograms of OS and DFS have good accuracy.

CONCLUSION

High tumor budding and glandular structure are two important histopathological features that serve as prognostic factors for ICC patients undergoing hepatectomy.

Decreasing Albumin mRNA Expression in Cholangiocarcinomas along the Bile Duct Tree

INTRODUCTION

The progressive technologies in albumin in situ hybridization (ISH) changed the routine application and the differential diagnosis of hepatic malignancies in the last years. The aim of the present work was to assess the diagnostic utility of albumin ISH on different cholangiocarcinoma (CCA) subtypes, as well as to assess how albumin production changes along the biliary tree.

METHODS

Forty-five CCAs were retrospectively selected: 29 intrahepatic (15 small-duct and 14 large-duct subtypes), 7 perihilar, and 9 extrahepatic. Histology was revised in all cases, and albumin ISH was automatically performed by the RNAscope®.

RESULTS

ISH was always negative in extrahepatic CCAs, only 1 perihilar case was positive, and any positivity was observed in 25/29 (86.2%) intrahepatic CCAs (p < 0.001). Concerning CCA subtypes, mean cell positivity was 38.8 ± 29.8% in small-duct CCAs and 11.4 ± 21.9 in large-duct CCAs, respectively (p = 0.003); 12/15 (80.0%) small-duct and 3/14 (21.4%) large-duct CCAs showed >5% positive cells (p = 0.002; odds ratio 14.7).

CONCLUSIONS

The introduction of more sensitive techniques changed the indications for ISH since most small-duct intrahepatic CCAs show diffuse positivity. Albumin positivity decreases from liver periphery to the large ducts, suggesting that ISH can be helpful in the differential diagnosis between small-duct and large-duct CCAs, as well as between intrahepatic large-duct CCAs and metastases.

Heterogeneity of small duct- and large duct-type intrahepatic cholangiocarcinoma

AIMS

The histological subtype of intrahepatic cholangiocarcinoma (iCCA) is associated with different mutational characteristics that impact clinical management. So far, data are lacking on the presence of small duct iCCA (SD-iCCA) and large duct iCCA (LD-iCCA) in a single patient. The aim of the current study was to determine the presence and degree of intratumoural heterogeneity of SD- and LD-iCCA features in different tumour regions.

METHODS AND RESULTS

All patients treated with surgically resected iCCA at Frankfurt University Hospital between December 2005 and March 2023 were retrospectively analysed. Histomorphological features of SD- and LD-iCCA were evaluated by an expert hepatobiliary pathologist. Tissue samples suspicious for subtype heterogeneity were further investigated. Immunohistochemistry for N-cadherin, S100P, MUC5AC, MUC6, TFF1 and AGR2 and mutational profiling with the Illumina TruSight Oncology 500 (TSO500) assay were performed separately for the SD- and LD-iCCA regions. Of 129 patients with surgically resected iCCA, features of either SD- or LD-iCCA were present in 67.4% (n = 87) and 24.8% of the patients (n = 32), respectively; 7.8% (n = 10) had histomorphological features of both SD- and LD-iCCA, seven patients (5.4%) of which had sufficient formalin-fixed, paraffin-embedded tissue for further analysis. Heterogeneity of both subtypes could be confirmed with immunohistochemistry. In five of seven (71.4%) patients, molecular profiling revealed intratumoural differences in genetic alterations between the SD- and LD-iCCA region. In one patient, a BRAF mutation (p.V600E) was found in the SD-iCCA but not in the LD-iCCA region of the tumour.

CONCLUSIONS

A marked portion of patients with iCCA exhibits both SD- and LD-iCCA in different tumour regions. In case of the presence of histopathological heterogeneity, mutational profiling should be considered to avoid missing therapeutically relevant genetic alterations.

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.

Recent Advances in Pathology of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICCA) is a malignant epithelial neoplasm characterized by biliary differentiation within the liver. ICCA is molecularly heterogeneous and exhibits a broad spectrum of histopathological features. It is a highly aggressive carcinoma with high mortality and poor survival rates. ICCAs are classified into two main subtypes: the small-duct type and large-duct types. These two tumor types have different cell origins and clinicopathological features. ICCAs are characterized by numerous molecular alterations, including mutations in KRAS, TP53, IDH1/2, ARID1A, BAP1, BRAF, SAMD4, and EGFR, and FGFR2 fusion. Two main molecular subtypes-inflammation and proliferation-have been proposed. Recent advances in high-throughput assays using next-generation sequencing have improved our understanding of ICCA pathogenesis and molecular genetics. The diagnosis of ICCA poses a significant challenge for pathologists because of its varied morphologies and phenotypes. Accurate diagnosis of ICCA is essential for effective patient management and prognostic determination. This article provides an updated overview of ICCA pathology, focusing particularly on molecular features, histological subtypes, and diagnostic approaches.

Surgical interpretation of the WHO subclassification of intrahepatic cholangiocarcinoma: a narrative review

Intrahepatic cholangiocarcinoma (iCCA) has been subclassified by its gross morphology into the mass-forming (MF), periductal-infiltrating (PI), and intraductal growth (IG) types and their combinations. This classification correlates well with clinical features; for example, MF-iCCA has less lymph-node metastasis and a better prognosis than PI-iCCA. According to the recently accumulated evidence from histological investigations, the WHO classification endorsed a subclassification scheme in which iCCA cases are classified into small- and large-duct types. Small-duct iCCA is considered to originate from septal or smaller bile ducts and is characterized by less frequent lymph-node metastasis, a favorable prognosis, and an MF appearance. Large-duct iCCA arises around the second branch of the biliary tree and has more aggressive biology and distinct genetic abnormalities. According to the practice guidelines for iCCA from the Liver Cancer Study Group of Japan and the National Comprehensive Cancer Network, upfront surgery is recommended for iCCA without distant metastasis regardless of the morphological subtype, based on clinical experience. In consideration of the biological heterogeneity of iCCA, the treatment strategy for iCCA needs to be reconsidered based on the WHO subtypes.

Impact of Tumor Subclassifications for Identifying an Appropriate Surgical Strategy in Patients with Intrahepatic Cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is subclassified into small and large duct types. The impact of these subclassifications for identifying appropriate surgical strategies remains unclear.

PATIENTS AND METHODS

This study included 118 patients with ICC who underwent liver resection. Based on the pathological examination results, the participants were divided into the small duct-type ICC group (n = 64) and large duct-type ICC group (n = 54). The clinicopathological features and postoperative outcomes were compared between the two groups to investigate the impact of subclassification for selecting appropriate surgical strategies.

RESULTS

Ten patients in the small duct-type ICC group had synchronous or metachronous hepatocellular carcinoma. The large duct-type ICC group had higher proportions of patients who underwent major hepatectomy, extrahepatic bile duct resection, portal vein resection, and lymph node sampling or dissection than the small duct-type ICC group. The large duct-type ICC group had significantly higher incidences of lymph node metastasis/recurrence and pathological major vessel invasion than the other. The small duct-type ICC group exhibited significantly higher recurrence-free and overall survival rates than the large duct-type ICC group. Further, the large duct-type ICC group had a significantly higher incidence of lymph node metastasis/recurrence than the small duct-type ICC at the perihilar region group.

CONCLUSIONS

Suitable surgical strategies may differ between the small and large duct-type ICCs. In patients with large duct-type ICCs, hepatectomy with lymph node dissection and/or biliary reconstruction should be considered, whereas hepatectomy without these advanced procedures can be suggested for patients with small duct-type ICCs.

Intrahepatic Mass-Forming Cholangiocarcinoma: Is There Additional Prognostic Value in Using Gd-EOB Enhanced MRI?

OBJECTIVE

To investigate the prognostic value of enhancement patterns of intrahepatic mass-forming cholangiocarcinomas (IMCCs) during the hepatobiliary phase (HBP) in gadoxetic acid (Gd-EOB)-enhanced MRI.

METHODS

We retrospectively identified 66 consecutive patients with histopathologically proven IMCCs (reference standard: resection) and preoperative Gd-EOB-enhanced MRI. Gd-EOB retention area was subjectively rated based on areas of intermediate signal intensity. Lesions were classified as either hypointense (0-25% retention area) or significantly-retaining (>25% retention area). Clinical, radiological, and prognostic features were compared between these groups. The primary endpoints were recurrence-free survival (RFS) and overall survival (OS) after primary surgical resection.

RESULTS

73% (48/66) of lesions were rated as hypointense and 29% (19/66) as significantly-retaining. While the hypointense subgroup more frequently featured local and distant intrahepatic metastases (p = 0.039 and p = 0.022) and an infiltrative growth pattern (p = 0.005), RFS, OS, and clinical features did not differ significantly with estimated Gd-EOB retention area or quantitatively measured HBP enhancement ratios. Lymph node metastasis was an independent predictor of poor RFS (p = 0.001).

CONCLUSIONS

Gd-EOB-enhanced MRI revealed two subtypes of IMCC in the HBP: hypointense and signal-retaining. The hypointense subtype is associated with more frequent intrahepatic metastases and an infiltrative growth pattern, indicating potential tumor aggressiveness. However, this did not result in a significant difference in survival after the primary resection of IMCC.

Prognostic implications of tumor histology and microenvironment in surgically resected intrahepatic cholangiocarcinoma: a single institutional experience

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive malignant neoplasm. Certain histologic features and the tumor microenvironment may impact disease progression. We aim to characterize the clinicopathologic features of ICC to identify prognostic factors. A total of 50 surgically resected ICC (partial or transplant) cases were analyzed. The cohort included 26 men and 24 women with a median age of 62 years. Eighteen (36%) cases were multifocal ICC with a mean largest tumor size of 6.5 cm. Neoadjuvant and adjuvant chemotherapy was done in eight (16%) and 33 (66%) patients, respectively. Histologically, 42 (84%) were small duct type, seven (14%) large duct type, and one mixed (2%). Thirty (60%) cases showed lymphovascular invasion (LVI) and 11 (22%) with perineural invasion (PNI). Twenty-eight (56%) cases demonstrated dense intratumoral hyaline fibrosis and 18 (36%) with tumor necrosis, each ≥ 10% tumor volume. On follow-up, 35 (70%) patients died of disease after a median disease-specific survival (DSS) of 21 months. Univariate analysis revealed that hyaline fibrosis and adjuvant chemotherapy were associated with better DSS, while tumor size, multifocality, necrosis, and peritumoral neutrophil to lymphocyte ratio were associated with worse DSS. In contrast, age, sex, small vs. large duct types, LVI, and individual inflammatory cell counts were not significant prognostic factors. In summary, ICC is a heterogeneous malignancy with variable clinical courses associated with tumor burden, histology, and microenvironment. Targeting specific components within the tumor microenvironments may be a promising approach for treatment in the future.

Intrahepatic cholangiocarcinoma: Evolving strategies in management and treatment

Intrahepatic cholangiocarcinoma is the second most frequent primary liver cancer after hepatocellular carcinoma. According to International Classification of Diseases-11 (ICD-11), intrahepatic cholangiocarcinoma is identified by a specific diagnostic code, different with respect to perihilar-CCA or distal-CCA. Intrahepatic cholangiocarcinoma originates from intrahepatic small or large bile ducts including the second-order bile ducts and has a silent presentation that combined with the highly aggressive nature and refractoriness to chemotherapy contributes to the alarming increasing incidence and mortality. Indeed, at the moment of the diagnosis, less than 40% of intrahepatic cholangiocarcinoma are suitable of curative surgical therapy, that is so far the only effective treatment. The main goals of clinicians and researchers are to make an early diagnosis, and to carry out molecular characterization to provide the patient with personalized treatment. Unfortunately, these goals are not easily achievable because of the heterogeneity of this tumor from anatomical, molecular, biological, and clinical perspectives. However, recent progress has been made in molecular characterization, surgical treatment, and management of intrahepatic cholangiocarcinoma and, this article deals with these advances.

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.

Classification of Intrahepatic Cholangiocarcinoma into Perihilar Versus Peripheral Subtype

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) constitutes a group of heterogeneous malignancies within the liver. We sought to subtype ICC based on anatomical origin of tumors, as well as propose modifications of the current classification system.

METHODS

Patients undergoing curative-intent resection for ICC, hilar cholangiocarcinoma (CCA), or hepatocellular carcinoma (HCC) were identified from three international multi-institutional consortia of databases. Clinicopathological characteristics and survival outcomes were assessed.

RESULTS

Among 1264 patients with ICC, 1066 (84.3%) were classified as ICC-peripheral subtype, whereas 198 (15.7%) were categorized as ICC-perihilar subtype. Compared with ICC-peripheral subtype, ICC-perihilar subtype was more often associated with aggressive tumor characteristics, including a higher incidence of nodal metastasis, macro- and microvascular invasion, perineural invasion, as well as worse overall survival (OS) (median: ICC-perihilar 19.8 vs. ICC-peripheral 37.1 months; p < 0.001) and disease-free survival (DFS) (median: ICC-perihilar 12.8 vs. ICC-peripheral 15.2 months; p = 0.019). ICC-perihilar subtype and hilar CCA had comparable OS (19.8 vs. 21.4 months; p = 0.581) and DFS (12.8 vs. 16.8 months; p = 0.140). ICC-peripheral subtype tumors were associated with more advanced tumor features, as well as worse survival outcomes versus HCC (OS, median: ICC-peripheral 37.1 vs. HCC 74.3 months; p < 0.001; DFS, median: ICC-peripheral 15.2 vs. HCC 45.5 months; p < 0.001).

CONCLUSIONS

ICC should be classified as ICC-perihilar and ICC-peripheral subtype based on distinct clinicopathological features and survival outcomes. ICC-perihilar subtype behaved more like carcinoma of the bile duct (i.e., hilar CCA), whereas ICC-peripheral subtype had features and a prognosis more akin to a primary liver malignancy.

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.

Role of immunophenotypic characterisation in prognostic subtyping of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is classified by the 5th WHO classification of tumours of the digestive system as large duct type (LDT) and small duct type (SDT), based on the anatomical location, morphological appearances, immunophenotype, and gene events. We evaluated the subtyping system using real-world data and established a supplementary method using immunohistochemical (IHC) detection. We retrospectively investigated 190 cases of surgically resected iCCA and classified them according to histological evaluations and gene detection. The prognostic value of the IHC markers were evaluated according to the relapse-free survival (RFS) and overall survival (OS). Basic histological classification was insufficient, with 61 cases classified as uncertain. This method showed no prognostic value for RFS or OS. The four-marker IHC detection, including EMA, S100P, N-cadherin, and CRP, which classified 68 cases as LDT, 108 cases as SDT, and 14 cases as uncertain, was highly efficient in subtyping and prognosis. The seven-marker method, including CD56, MUC5AC and MUC6, was consistent with the four-marker method. FGFR2 gene fusion was exclusively detected in 20 cases of SDT iCCA, according to the four- and seven-marker IHC detection. This novel method of iCCA classification exhibited diagnostic, prognostic and therapeutic value in clinical practice.

Molecular Detection of FGFR2 Rearrangements in Resected Intrahepatic Cholangiocarcinomas: FISH Could Be An Ideal Method in Patients with Histological Small Duct Subtype

Background and Aims

Intrahepatic cholangiocarcinoma (ICC) is a subtype of primary liver cancer for which effective therapeutic agents are lacking. Fibroblast growth factor receptor 2 (FGFR2) has become a promising therapeutic target in ICC; however, its incidence and optimum testing method have not been fully assessed. This study investigated the rearrangement of FGFR2 in intrahepatic cholangiocarcinoma using multiple molecular detection methods.

Methods

The samples and clinical data of 167 patients who underwent surgical resection of intrahepatic cholangiocarcinoma in Zhongshan hospital, Fudan university were collected. The presence of FGFR2 gene rearrangement was confirmed using fluorescence in situ hybridization (FISH) and targeted next-generation sequencing (NGS). FGFR2 protein expression was determined using immunohistochemistry (IHC). The concordance between the methods was statistically compared. PD-L1 expression was also assessed in this cohort. The clinicopathological characteristics and genomic profile related to FGFR2 rearrangements were also analyzed to assist candidate-screening for targeted therapies.

Results

FGFR2 rearrangement was detected in 21 of the 167 ICC cases (12.5%) using FISH. NGS analysis revealed that FGFR2 rearrangement was present in 16 of the 20 FISH-positive cases, which was consistent with the FISH results (kappa value=0.696, p<0.01). IHC showed that 80 of the 167 cases (48%) were positive for FGFR2 expression, which was discordant with both FISH and NGS results. By comparison, FGFR2-positivity tended to correlate with unique clinicopathological subgroups, featuring early clinical stage, histologically small duct subtype, and reduced mucus production (P<0.05), with improved overall survival (p<0.05). FGFR2-positivity was not associated with PD-L1 expression in ICCs. In genome research, we identified eight partner genes fused with FGFR2, among which FGFR2-BICC1 was the most common fusion type. BAP1, CDKN2A, and CDKN2B were the most common concomitant genetic alterations of FGFR2, whereas KRAS and IDH1 mutations were mutually exclusive to FGFR2 rearrangements.

Conclusions

FISH achieved satisfactory concordance with NGS, has potential value for FGFR2 screening for targeted therapies. FGFR2 detection should be prioritized for unique clinical subgroups in ICC, which features a histological small duct subtype, early clinical stage, and reduced mucus production.

Deep Learning-Enabled Diagnosis of Liver Adenocarcinoma

BACKGROUND & AIMS

Diagnosis of adenocarcinoma in the liver is a frequent scenario in routine pathology and has a critical impact on clinical decision making. However, rendering a correct diagnosis can be challenging, and often requires the integration of clinical, radiologic, and immunohistochemical information. We present a deep learning model (HEPNET) to distinguish intrahepatic cholangiocarcinoma from colorectal liver metastasis, as the most frequent primary and secondary forms of liver adenocarcinoma, with clinical grade accuracy using H&E-stained whole-slide images.

METHODS

HEPNET was trained on 714,589 image tiles from 456 patients who were randomly selected in a stratified manner from a pool of 571 patients who underwent surgical resection or biopsy at Heidelberg University Hospital. Model performance was evaluated on a hold-out internal test set comprising 115 patients and externally validated on 159 patients recruited at Mainz University Hospital.

RESULTS

On the hold-out internal test set, HEPNET achieved an area under the receiver operating characteristic curve of 0.994 (95% CI, 0.989-1.000) and an accuracy of 96.522% (95% CI, 94.521%-98.694%) at the patient level. Validation on the external test set yielded an area under the receiver operating characteristic curve of 0.997 (95% CI, 0.995-1.000), corresponding to an accuracy of 98.113% (95% CI, 96.907%-100.000%). HEPNET surpassed the performance of 6 pathology experts with different levels of experience in a reader study of 50 patients (P = .0005), boosted the performance of resident pathologists to the level of senior pathologists, and reduced potential downstream analyses.

CONCLUSIONS

We provided a ready-to-use tool with clinical grade performance that may facilitate routine pathology by rendering a definitive diagnosis and guiding ancillary testing. The incorporation of HEPNET into pathology laboratories may optimize the diagnostic workflow, complemented by test-related labor and cost savings.

Ancillary tests for hepatobiliary neoplasms: what we know and what we need to know

Ancillary tests are commonly used in the surgical pathology setting for diagnosing challenging neoplastic diseases of the liver and biliary tract, while histology and clinical correlation remain to be critically important. With continuous discoveries, more and more useful ancillary tests have become available, which can help distinguish between malignant and benign hepatocellular neoplasms, malignant and benign biliary tract entities, and intrahepatic and metastatic carcinomas. This review will focus on existing and emerging biomarkers (such as glutamine synthetase, organic anion transporting polypeptide 1B3, insulin-like growth factor-II mRNA binding protein-3, S100P, SMAD4, enhancer of zeste homolog 2, albumin, hepatocyte nuclear factor-1β, etc.) that can be used for the diagnosis, classification and prognostication of hepatobiliary neoplasms.

Challenges in Diagnosing and Reporting Cholangiocarcinoma

Intrahepatic cholangiocarcinoma is a challenge to the practicing surgical pathologist for several reasons. It is rare in many parts of the world, and thus practical exposure may be limited. Related to the fact of its rarity is the fact that more common tumors which frequently metastasize to the liver can be morphologically indistinguishable (eg, pancreatic ductal adenocarcinoma). Immunohistochemical testing is generally non-contributory in this context. Other difficulties arise from the protean morphologic manifestations of cholangiocarcinoma (ie, small duct vs. large duct) and the existence of combined cholangiocarcinoma and hepatocellular carcinoma. These, and other issues of concern to the practicing diagnostic pathologist are discussed herein.

A preoperative scoring system to predict lymph node metastasis in intrahepatic cholangiocarcinoma

BACKGROUND

The abnormality of imaging finding of lymph node (LN) has demonstrated unsatisfactory diagnostic accuracy for pathologic lymph node metastasis (LNM). We aimed to develop and validate a simple scoring system predicting LNM in patients with intrahepatic cholangiocarcinoma (iCCA) prior to surgery based on MRI and clinical findings.

METHODS

We retrospectively enrolled consecutive patients who underwent surgical resection for treatment-naïve iCCA from six institutions between January 2009 and December 2015. Patients who underwent lymph node dissection (LND) were randomly assigned to the training and validation cohorts at a 2:1 ratio, an¹ìd pathologic LN status was evaluated. Patients who did not undergo LND were assigned to the test cohort, and clinical LN status was evaluated. Using MRI and clinical findings, a preoperative LNM score was developed in the training cohort and validated in the validation and test cohorts.

RESULTS

The training, validation, and test cohorts included 102, 53, and 118 patients, respectively. The preoperative LNM score consisted of serum carcinoembryonic antigen and two MRI findings (suspicious LN and bile duct invasion). The preoperative LNM score was associated with pathologic LNM in training (p < 0.001) and validation (p = 0.010) cohorts and clinical LNM in test cohort (p < 0.001). The preoperative LNM score outperformed MRI-suspicious LN alone in predicting pathologic LNM (area under the curve, 0.703 vs. 0.604, p = 0.004). The preoperative LNM score was also associated with overall survival in all cohorts (p < 0.001).

CONCLUSIONS

Our preoperative LNM score was significantly associated with pathologic or clinical LNM and outperformed MRI-suspicious LN alone.

EASL-ILCA Clinical Practice Guidelines on the management of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) develops inside the liver, between bile ductules and the second-order bile ducts. It is the second most frequent primary liver cancer after hepatocellular carcinoma, and its global incidence is increasing. It is associated with an alarming mortality rate owing to its silent presentation (often leading to late diagnosis), highly aggressive nature and resistance to treatment. Early diagnosis, molecular characterisation, accurate staging and personalised multidisciplinary treatments represent current challenges for researchers and physicians. Unfortunately, these challenges are beset by the high heterogeneity of iCCA at the clinical, genomic, epigenetic and molecular levels, very often precluding successful management. Nonetheless, in the last few years, progress has been made in molecular characterisation, surgical management, and targeted therapy. Recent advances together with the awareness that iCCA represents a distinct entity amongst the CCA family, led the ILCA and EASL governing boards to commission international experts to draft dedicated evidence-based guidelines for physicians involved in the diagnostic, prognostic, and therapeutic management of iCCA.

Refining Classification of Cholangiocarcinoma Subtypes via Proteogenomic Integration Reveals New Therapeutic Prospects

BACKGROUND & AIMS

Intrahepatic cholangiocarcinomas (iCCs) are characterized by their rarity, difficult diagnosis, and overall poor prognosis. The iCC molecular classification for developing precision medicine strategies was investigated.

METHODS

Comprehensive genomic, transcriptomic, proteomic, and phosphoproteomic analyses were performed on treatment-naïve tumor samples from 102 patients with iCC who underwent surgical resection with curative intent. An organoid model was constructed for testing therapeutic potential.

RESULTS

Three clinically supported subtypes (stem-like, poorly immunogenic, and metabolism) were identified. NCT-501 (aldehyde dehydrogenase 1 family member A1 [ALDH1A1] inhibitor) exhibited synergism with nanoparticle albumin-bound-paclitaxel in the organoid model for the stem-like subtype. The oncometabolite dysregulations were associated with different clinical outcomes in the stem-like and metabolism subtypes. The poorly immunogenic subtype harbors the non-T-cell tumor infiltration. Integrated multiomics analysis not only reproduced the 3 subtypes but also showed heterogeneity in iCC.

CONCLUSIONS

This large-scale proteogenomic analysis provides information beyond that obtained with genomic analysis, allowing the functional impact of genomic alterations to be discerned. These findings may assist in the stratification of patients with iCC and in developing rational therapeutic strategies.

Unraveling the heterogeneity of cholangiocarcinoma and identifying biomarkers and therapeutic strategies with single-cell sequencing technology

Cholangiocarcinoma (CCA) is a common malignant tumor of the biliary tract that carries a high burden of morbidity and a poor prognosis. Due to the lack of precise diagnostic methods, many patients are often diagnosed at advanced stages of the disease. The current treatment options available are of varying efficacy, underscoring the urgency for the discovery of more effective biomarkers for early diagnosis and improved treatment. Recently, single-cell sequencing (SCS) technology has gained popularity in cancer research. This technology has the ability to analyze tumor tissues at the single-cell level, thus providing insights into the genomics and epigenetics of tumor cells. It also serves as a practical approach to study the mechanisms of cancer progression and to explore therapeutic strategies. In this review, we aim to assess the heterogeneity of CCA using single-cell sequencing technology, with the ultimate goal of identifying possible biomarkers and potential treatment targets.

Endoscopic Ultrasound in the Diagnosis of Extrahepatic Cholangiocarcinoma: What Do We Know in 2023?

Extrahepatic cholangiocarcinoma (CCA) is a rare and aggressive type of cancer, presenting as a mass or as a biliary stricture. This review summarizes the utility of endoscopic ultrasound (EUS) in the detection, staging, and determination of the differential diagnosis, especially when no cause of bile duct dilatation is revealed by cross-sectional imaging. The EUS detection rate for distal CCAs is higher than that for the proximal CCAs. The accuracy of T staging varies between 60 and 80%, and vascular involvement is correctly assessed by conventional EUS. EUS-tissue acquisition from the primary tumors is reserved for unresectable or metastatic CCA, especially in distal strictures or mass CCAs. For proximal lesions, EUS could be performed as an adjunctive to ERCP sampling when the latter is inconclusive. EUS is not appropriate for assessing the malignant features of lymph nodes in CCAs. Lymph node EUS-tissue acquisition should be performed only if it changes the surgical decision. Perhaps the development of EUS-fine needle biopsy and the detection of molecular genetic alteration will increase the diagnostic yield in CCAs.

Asbestos exposure as an additional risk factor for small duct intrahepatic cholangiocarcinoma: a pilot study

Intrahepatic cholangiocarcinoma (iCCA) is a rare malignancy, recently classified in small duct and large duct morphological subtypes. Growing evidence suggests asbestos as a putative risk factor for iCCA, albeit no correlation between asbestos and iCCA morphology has been investigated so far. The aim of the present study was to assess the relationship between asbestos exposure and iCCA morphological subtype. Forty patients with surgically removed iCCA were prospectively enrolled: asbestos exposure was assessed according to the Italian National Mesothelioma Register questionnaire. From the surgical iCCA specimens the main histopathological variables were collected, including the small duct (sd-iCCA, 32 patients) and large duct subtypes (ld-iCCA, 8 patients). Five sd-iCCA cases had a definite/probable occupational exposure to asbestos, while no cases of ld-iCCA were classified as being occupationally exposed (definite/probable). Other kind of asbestos exposure (i.e. possible occupational, familial, environmental) were recorded in 16 sd-iCCA and 3 ld-iCCA. Cases with unlikely exposure to asbestos were 11 sd-iCCA (35.5%) and 5 ld-iCCA (62.5%). In conclusion, these findings seem to indicate that sd-iCCA might be more frequently associated to asbestos exposure rather than ld-iCCA, suggesting that asbestos fibres might represent a parenchymal, rather than a ductal risk factor for iCCA. This pilot study must be confirmed by further case-control studies or large independent cohorts.

Preoperative subcategorization based on magnetic resonance imaging in intrahepatic cholangiocarcinoma

BACKGROUND

Appropriate preoperative identification of iCCA subtype is essential for personalized management, so the aim of this study is to investigate the role of MR imaging features in preoperatively differentiating the iCCA subtype.

METHODS

Ninety-three patients with mass-forming intrahepatic cholangiocarcinoma (iCCA, 63 small duct type and 30 large duct type) were retrospectively enrolled according to the latest 5th WHO classification (mean age, males vs. females: 60.66 ± 10.53 vs. 61.88 ± 12.82, 50 men). Significant imaging features for differentiating large duct iCCA and small duct iCCA were identified using univariate and multivariate logistic regression analyses, and a regression-based predictive model was then generated. Furthermore, diagnostic performance parameters of single significant imaging features and the predictive model were obtained, and corresponding receiver operating characteristic (ROC) curves were subsequently presented.

RESULTS

The univariate analysis showed that tumor in vein, arterial phase hypoenhancement, intrahepatic duct dilatation, lack of targetoid restriction and lack of targetoid appearance in T2 were predictors of large duct type iCCA. Arterial phase hypoenhancement, intrahepatic duct dilatation and lack of targetoid restriction were independent predictors for large duct type iCCA in multivariate analysis. The regression-based predictive model has achieved the best preoperative prediction performance in iCCA subcategorization so far. The area under the ROC curve of the regression-based predictive model was up to 0.91 (95% CI: 0.85, 0.98), and it was significantly higher than every single significant imaging feature.

CONCLUSIONS

Arterial phase hypoenhancement, intrahepatic duct dilatation and lack of targetoid restriction could be considered reliable MR imaging indicators of large duct type iCCA. MR imaging features can facilitate noninvasive prediction of iCCA subtype with satisfactory predictive performance.

The clinical value of identifying genetic abnormalities that can be targeted in cholangiocarcinomas

INTRODUCTION

Cholangiocarcinomas (CCAs) are a heterogenous group of epithelial malignancies originating at any level of the biliary tree and are subdivided according to their location into intrahepatic (iCCA) and extrahepatic (eCCA).

AREAS COVERED

This review provides an updated analysis of studies of genetic characterization of CCA at the level of gene mutation profiling, copy number alterations and gene expression, with definition of molecular subgroups and identification of some molecular biomarkers and therapeutic targets.

EXPERT OPINION

With the development of genetic sequencing, several driver mutations have been identified and targeted as novel therapeutic approaches, including FGFR2, IDH1, BRAF, NTRK, HER2, ROS, and RET. Furthermore, identification of the cellular and molecular structure of the tumor microenvironment has contributed to the development of novel therapies, such as tumor immunotherapy. Combination therapies of chemotherapy plus targeted molecules or immunotherapy are under evaluation and offer the unique opportunity to improve the outcomes of CCA patients with advanced disease.

Intrahepatic cholangiocarcinoma: typical features, uncommon variants, and controversial related entities

Pathologists play a central role in the diagnosis and classification of intrahepatic cholangiocarcinoma (iCCA). iCCA is currently classified into small- and large-duct types. Small-duct iCCA is characterized by a mass-forming gross appearance, mucus-poor ductule-like histology, and frequent association with chronic parenchymal liver diseases (eg, cirrhosis). Large-duct iCCA is an infiltrative duct-forming adenocarcinoma with a fibrotic stroma, similar to perihilar cholangiocarcinoma. Chronic cholangiopathies (eg, primary sclerosing cholangitis, liver flukes) are associated with an increased risk of large-duct iCCA. Alterations in IDH1/2, BAP1, or FGFR2 are characteristic molecular features of small-duct iCCA, whereas mutations in KRAS and SMAD4 and the amplification of MDM2 are mainly observed in large-duct iCCA. C-reactive protein and N-cadherin are commonly expressed in small-duct iCCA, and S100P is a good marker for large-duct iCCA. In addition to well-known subtypes (eg, cholangiolocellular carcinoma), uncommon variants are recognized. A tubulocystic variant is often misinterpreted as a benign neoplasm. Mucoepidermoid and enteroblastic variants are under-recognized and pose a diagnostic challenge. Cholangioblastic cholangiocarcinoma characterized by inhibin-A expression was recently found to have an NIPBL-NACC1 gene fusion. Despite significant advances in hepatobiliary pathology, there are still controversial premalignant entities that require large comprehensive studies. There are morphological overlaps between biliary adenofibroma and the tubulocystic variant of iCCA. Type 2 intraductal papillary neoplasm of the bile duct (IPNB) is typically associated with invasive malignancy at the initial presentation and lacks unique molecular features. Therefore, some pathologists prefer the term "papillary cholangiocarcinoma" over type 2 IPNB.

Bile duct dysplasia and associated invasive carcinoma: clinicopathological features, diagnosis, and practical challenges

Cholangiocarcinoma represents the second most frequent type of primary liver cancer that develops through a multistep histopathologic sequence. Dysplasia in the biliary tract epithelium is a precursor lesion of cholangiocarcinoma. This review provides a practical overview of bile duct dysplasia in relation to invasive carcinoma, covering clinicopathological features, diagnostic criteria, differential diagnosis, useful testing modalities, and challenges in daily practice. The key features of biliary intraepithelial neoplasia, intraductal papillary neoplasm, intraductal tubulopapillary neoplasm, and mucinous cystic neoplasm are described. Important differential diagnoses are included. Common pitfalls in histopathologic interpretation of bile duct biopsies and frozen sections are discussed.

Risk Assessment and Cholangiocarcinoma: Diagnostic Management and Artificial Intelligence

Intrahepatic cholangiocarcinoma (iCCA) is the second most common primary liver tumor, with a median survival of only 13 months. Surgical resection remains the only curative therapy; however, at first detection, only one-third of patients are at an early enough stage for this approach to be effective, thus rendering early diagnosis as an efficient approach to improving survival. Therefore, the identification of higher-risk patients, whose risk is correlated with genetic and pre-cancerous conditions, and the employment of non-invasive-screening modalities would be appropriate. For several at-risk patients, such as those suffering from primary sclerosing cholangitis or fibropolycystic liver disease, the use of periodic (6-12 months) imaging of the liver by ultrasound (US), magnetic Resonance Imaging (MRI)/cholangiopancreatography (MRCP), or computed tomography (CT) in association with serum CA19-9 measurement has been proposed. For liver cirrhosis patients, it has been proposed that at-risk iCCA patients are monitored in a similar fashion to at-risk HCC patients. The possibility of using Artificial Intelligence models to evaluate higher-risk patients could favor the diagnosis of these entities, although more data are needed to support the practical utility of these applications in the field of screening. For these reasons, it would be appropriate to develop screening programs in the research protocols setting. In fact, the success of these programs reauires patient compliance and multidisciplinary cooperation.

Integrative analysis of multiple genomic data from intrahepatic cholangiocarcinoma organoids enables tumor subtyping

As genomic analysis technology has advanced, it has become possible to sub-classify intrahepatic cholangiocarcinoma (ICC) at the histological or molecular level. Here, we verify the recently suggested two subgroups of ICC in the organoids model, compare the characteristics between types. ICC patients are subclassified into small-duct (SD) and large-duct (LD) subtype according to histological characteristics. ICC organoids are established, and unsupervised principal component analysis clustering separates each type of ICC. Differential gene expression reveals enrichment on KRAS, TGFβ and ERBB2 signaling pathways in LD-type compared with SD-type (P < 0.05). Gene set enrichment analysis demonstrates that the cholangiocarcinoma class 2 signature, defined by Andersen et al., is enriched in the LD-type (enrichment Score = 2.19, P < 0.001). A protein-protein interaction network analysis identifies ZNF217 as a significant hub protein (odds ratio = 4.96, P = 0.0105). We perform prospective modeling of histological subtype using patient-derived organoids. Moreover, gene expression profiling of ICC organoids enables identification of type-specific targetable pathways.

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.

Tumor-derived exosomes induce immunosuppressive macrophages to foster intrahepatic cholangiocarcinoma progression

BACKGROUND AND AIMS

Macrophages are prominent components of solid tumors and exhibit distinct functions in different tumor microenvironments. Exosomes are emerging as necessary mediators of the cross-talk between tumor cells and the microenvironment. However, the underlying mechanisms of exosomes involving into crosstalk between tumor cells and macrophages during disease progression of intrahepatic cholangiocarcinoma (ICC) have not been yet fully realized.

APPROACH AND RESULTS

We found that the macrophages of ICC tumor tissues up-regulated the expression levels of immunosuppressive molecule programmed death-ligand 1 (PD-L1). Increased PD-L1⁺ macrophages in tumor tissues effectively suppressed T-cell immunity and correlated with poor survival rates in patients with ICC. High-throughput RNA-sequencing analysis that was performed to identify differential levels of microRNAs (miRNAs) between exosomes derived from ICC cells and primary human intrahepatic biliary epithelial cells revealed that miR-183-5p was increased in ICC cell-derived exosomes. Exosomal miR-183-5p inhibited phosphatase and tensin homolog (PTEN) expression, to subsequently affect the elevations on both phosphorylated AKT and PD-L1 expression in macrophages. Furthermore, macrophages that treated with ICC cell-derived exosomes significantly suppressed T-cell immunity in vitro and contributed to the growth and progression of ICC in vivo, which were reversible through blockages on PD-L1 of these macrophages. Finally, clinical data showed that up-regulated levels of plasma exosomal miR-183-5p correlated with poor prognosis of patients with ICC after curative resection.

CONCLUSIONS

Tumor-derived exosomal miR-183-5p up-regulates PD-L1-expressing macrophages to foster immune suppression and disease progression in ICC through the miR-183-5p/PTEN/AKT/PD-L1 pathway. Exosomal miR-183-5p is a potential predictive biomarker for ICC progression and a potential target for development of therapeutic strategies against immune tolerance feature of ICC.

Biomarkers for response to immunotherapy in hepatobiliary malignancies

BACKGROUND

The advent of immune checkpoint inhibitors (ICIs) has revolutionized the therapeutic options of hepatobiliary malignancies. However, the clinical benefit provided by immunotherapy seems limited to a small subgroup of patients with hepatobiliary malignancies. The identification of reliable predictors of the response to immunotherapy is urgently needed.

DATA SOURCES

Literature search was conducted in PubMed for relevant articles published up to May 2022. Information of clinical trials was obtained from https://clinicaltrials.gov/.

RESULTS

Biomarkers for ICI response of hepatobiliary malignancies remain in the exploration stage and lack compelling evidence. Tumor programmed death-ligand 1 (PD-L1) expression is the most widely studied biomarker in hepatocellular carcinoma (HCC) and biliary tract cancers (BTCs), but there are conflicting results on its predictive potential. Tumor mutational burden (TMB) is generally low both in HCC and BTCs, and the clinical trials of TMB are rare in hepatobiliary malignancies. Promisingly, mismatch repair deficiency (dMMR)/high microsatellite instability (MSI-H) may be a predictive biomarker of response to anti-PD-1 therapy in BTCs. Furthermore, some emerging biomarkers, such as gut microbiota, show predictive potential in the preliminary studies. Radiomics and liquid-biopsy biomarkers, including circulating tumor cells, circulating tumor DNA (ctDNA) and exosomal PD-L1 provide a quick and non-invasive approach for monitoring the ICI response, showing a new promising direction.

CONCLUSIONS

Multiple potential biomarkers for predicting ICI response of hepatobiliary malignancies have been explored and tried to apply in clinic. Yet there is no robust evidence to prove their clinical value in predicting immunotherapeutic response for patients with hepatobiliary malignancies. The identification of predictors for response to ICIs is an urgent need and major challenge. Further studies are warranted to validate the role of emerging biomarkers in predicting immunotherapeutic responses.

Impact of small duct- and large duct type on survival in patients with intrahepatic cholangiocarcinoma: Results from a German tertiary center

BACKGROUND & AIMS

In recent years, histopathological characterization of intrahepatic cholangiocarcinoma revealed small duct type (SD-iCCA) and large duct type (LD-iCCA). Data on the prevalence of the subtypes are limited and highly varying. The aim of this study was to assess the prevalence of SD-iCCA and LD-iCCA and their impact on survival for the first time in a European cohort.

MATERIALS AND METHODS

All patients with surgically resected iCCA diagnosed between December 2005 and December 2021 at the University Hospital Frankfurt were analyzed by an expert hepatobiliary pathologist. For overall survival (OS) and progression-free survival (PFS), Kaplan-Meier curves and Cox-regression analyses were performed.

RESULTS

In total, 116 patients with surgically resected iCCA treated in our tertiary hospital were classified as SD-iCCA (73.3%, n = 85) and LD-iCCA (26.7%, n = 31). Subgroup analyses revealed median OS of 54.4 months (95% CI = 38.3 - 70.4 months) and 25.4 months (95% CI = 15.1 - 35.7 months) for SD-iCCA and LD-iCCA, respectively (p = 0.027). The median PFS for patients receiving gemcitabine-based chemotherapy with SD- and LD-iCCA was 8.4 months (95% CI = 4.7 - 12 months) and 3.3 months (95% CI = 1.8 - 4.7 months), respectively (p = 0.011). While LD-iCCA was as a significant risk factor of OS (HR = 1.7, 95% CI = 1 - 2.8, p = 0.031) in univariate analysis, it was not significant in multivariate analysis.

CONCLUSION

In contrast to data from Asia, SD-iCCA is more prevalent than LD-iCCA in our cohort. LD-iCCA is associated with impaired OS after surgical resection and decreased PFS for patients receiving chemotherapy. These findings may suggest including the histological subtype in clinical routine diagnostics.

KRAS mutation in intrahepatic cholangiocarcinoma: Linkage with metastasis-free survival and reduced E-cadherin expression

BACKGROUND AND AIMS

Although KRAS mutations are the major driver of intrahepatic cholangiocarcinoma (ICC), their role remains unexplored. This study aimed to elucidate the prognostic effects, association with clinicopathologic characteristics and potent functions of KRAS mutations in ICC.

METHODS

A hundred and seven resected stage I-III ICCs were analysed for KRAS mutation status and its link with clinicopathological features. An independent validation cohort (n = 138) was included. In vitro analyses using KRAS-mutant ICC cell lines were performed.

RESULTS

KRAS mutation was significantly associated with worse overall survival in stage I-III ICCs, which was validated in an independent cohort. Recurrence-free survival did not significantly differ between cases with and without KRAS mutations, but if limited to recurrence with extrahepatic metastasis, KRAS-mutant cases showed significantly worse distant metastasis-free survival than KRAS-wild cases showed. KRAS mutations were associated with frequent tumour budding with reduced E-cadherin expression. In vitro, KRAS depletion caused marked inhibition of cell growth and migration together with E-cadherin upregulation in KRAS-mutant ICC cells. The RNA-sequencing assay revealed that KRAS depletion caused MYC pathway downregulation and interferon pathway upregulation.

CONCLUSIONS

Our observations suggest that KRAS mutations are associated with aggressive behaviour of ICC, especially the development of extrahepatic metastasis. Mutant KRAS is likely to change the adhesive status of ICC cells, affect the responsiveness of tumour cells to interferon immune signals, and consequently promote extrahepatic metastasis. KRAS mutation status, which predicts the prognoses of patients with ICC after surgical resection, is expected to help stratify patients better for individual postoperative treatment strategies.

Quantitative Proteomics Reveals Down-Regulated Glycolysis/Gluconeogenesis in the Large-Duct Type Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is a lethal hepatobiliary malignancy that arises from the epithelial cells of the intrahepatic bile ducts, accounting for approximately 10% of cholangiocarcinoma (CCA). According to the 2019 World Health Organization (WHO) classification of tumors of the digestive system, iCCA is divided into small-duct type (SD-type) and large-duct type (LD-type). However, it remains unknown which molecular events contribute to the disparity. To explore the proteomic characteristics of iCCA, we used an isobaric tag for relative and absolute quantitation (iTRAQ) based quantitative proteomics strategy to investigate stably dysregulated proteins in the SD-type and LD-type of iCCA tissues. Importantly, we found three glycolysis/gluconeogenesis-related enzymes, triosephosphate isomerize 1 (TPI1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and phosphoglycerate kinase 1 (PGK1), were significantly down-regulated in the LD-type iCCA, which were further confirmed by immunohistochemistry using tissue microarray. Moreover, we demonstrated that the knockdown of these three candidate proteins by siRNAs notably increased the ability of proliferation in two CCA cell lines (HuH28 and RBE), suggesting that effective down-regulation of the glycolysis/gluconeogenesis pathway might be an underlying novel mechanism contributing to the LD-type iCCA.

Genomic architecture of FGFR2 fusions in cholangiocarcinoma and its implication for molecular testing

Background

Cholangiocarcinoma (CCA) is a primary malignancy of the biliary tract with a dismal prognosis. Recently, several actionable genetic aberrations were identified with significant enrichment in intrahepatic CCA, including FGFR2 gene fusions with a prevalence of 10–15%. Recent clinical data demonstrate that these fusions are druggable in a second-line setting in advanced/metastatic disease and the efficacy in earlier lines of therapy is being evaluated in ongoing clinical trials. This scenario warrants standardised molecular profiling of these tumours.

Methods

A detailed analysis of the original genetic data from the FIGHT-202 trial, on which the approval of Pemigatinib was based, was conducted.

Results

Comparing different detection approaches and displaying representative cases, we described the genetic landscape and architecture of FGFR2 fusions in iCCA and show biological and technical aspects to be considered for their detection. We elaborated parameters, including a suggestion for annotation, that should be stated in a molecular diagnostic FGFR2 report to allow a complete understanding of the analysis performed and the information provided.

Conclusion

This study provides a detailed presentation and dissection of the technical and biological aspects regarding FGFR2 fusion detection, which aims to support molecular pathologists, pathologists and clinicians in diagnostics, reporting of the results and decision-making.

Precision Medicine in Biliary Tract Cancer

Precision medicine has become a dominant theme in the treatment of biliary tract cancers (BTCs). Although prognosis remains poor, technologies for improved molecular characterization along with the US Food and Drug Administration approval of several targeted therapies have changed the therapeutic landscape of advanced BTC. The hallmark of BTC oncogenesis is chronic inflammation of the liver and biliary tract regardless of the anatomical subtype. Subtypes of BTC correspond to distinct molecular characteristics, making BTC a molecularly heterogenous collection of tumors. Collectively, up to 40% of BTCs harbor a potentially targetable molecular abnormality, and the National Comprehensive Cancer Network guidelines recommend molecular profiling for all patients with advanced BTC. Use of circulating tumor DNA, immunohistochemistry, and next-generation sequencing continues to expand the utility for biomarker-driven management and molecular monitoring of BTC. Improving outcomes using biomarker-agnostic treatment for nontargetable tumors also remains a priority, and combinational treatment strategies such as immune checkpoint inhibition plus chemotherapy hold promise for this subgroup of patients.

Integrative Analysis of Intrahepatic Cholangiocarcinoma Subtypes for Improved Patient Stratification: Clinical, Pathological, and Radiological Considerations

Simple Summary

Liver cancer subtypes differ in prognosis and genetic alterations. An accurate diagnosis made on time is the key aspect of clinical decision-making. Hence, a correct diagnosis is of pivotal importance for individual patients. In this study, we identified the most relevant clinical, radiological, and histological parameters for an improved subtype diagnosis of intrahepatic cholangiocarcinoma. As a result of our study, the radiologist should consider factors such as growth pattern, location, and contrast agent behavior. For the pathologist, precursor lesions, mucin secretion, and a periductal-infiltrating growth are of utmost importance, while immunohistochemical analyses are essential for exclusion of extrahepatic malignancies, but have so far only value for iCCA subtype analysis in the context with other parameters.

Abstract

Intrahepatic cholangiocarcinomas (iCCAs) may be subdivided into large and small duct types that differ in etiology, molecular alterations, therapy, and prognosis. Therefore, the optimal iCCA subtyping is crucial for the best possible patient outcome. In our study, we analyzed 148 small and 84 large duct iCCAs regarding their clinical, radiological, histological, and immunohistochemical features. Only 8% of small duct iCCAs, but 27% of large duct iCCAs, presented with initial jaundice. Ductal tumor growth pattern and biliary obstruction were significant radiological findings in 33% and 48% of large duct iCCAs, respectively. Biliary epithelial neoplasia and intraductal papillary neoplasms of the bile duct were detected exclusively in large duct type iCCAs. Other distinctive histological features were mucin formation and periductal-infiltrating growth pattern. Immunohistochemical staining against CK20, CA19-9, EMA, CD56, N-cadherin, and CRP could help distinguish between the subtypes. To summarize, correct subtyping of iCCA requires an interplay of several factors. While the diagnosis of a precursor lesion, evidence of mucin, or a periductal-infiltrating growth pattern indicates the diagnosis of a large duct type, in their absence, several other criteria of diagnosis need to be combined.

Tumor-matrix interaction induces phenotypic switching in liver cancer cells

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is characterized by fibrous stroma and clinical behavior more aggressive than that of hepatocellular carcinoma (HCC). Scirrhous HCC is a subtype of HCC with fibrous stroma, frequently has partial cholangiocytic differentiation, and is more likely to have an aggressive behavior. This study explored the interaction of liver cancer cells with the extracellular matrix.

METHODS AND RESULTS

Liver cancer cells grown on collagen 1-coated plates showed upregulation of cholangiocytic marker expression but downregulation of hepatocytic marker expression. Three-dimensional sphere culture and Boyden chamber assay showed enhanced invasion and migration ability in collagen 1-conditioned liver cancer cells. Interaction with collagen 1 reduced liver cancer cell proliferation. RNA sequencing showed that in the liver cancer cells, collagen 1 upregulated cell cycle inhibitor expression and cell-matrix interaction, tumor migration, and angiogenesis pathways, but downregulated liver metabolic function pathways. Cholangiocytic differentiation and invasiveness induced by collagen 1 was mediated by the mitogen-activated protein kinase (MAPK) pathway, which was regulated by cell-matrix interaction-induced Src activation. Analysis of the Cancer Genome Atlas cohort showed that collagen 1 induced and suppressed genes were highly enriched in ICC and HCC, respectively. In HCC samples, collagen 1-regulated genes were strongly coexpressed and correlated with COL1A1 expression.

CONCLUSIONS

Liver cancer cell-matrix interaction induces cholangiocytic differentiation and switches liver cancer cells from a proliferative to an invasive phenotype through the Src/MAPK pathway, which may partly explain the differences in the behaviors of HCC and ICC.

Biology of IDH mutant cholangiocarcinoma

Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are the most frequently mutated metabolic genes across human cancers. These hotspot gain-of-function mutations cause the IDH enzyme to aberrantly generate high levels of the oncometabolite, R-2-hydroxyglutarate, which competitively inhibits enzymes that regulate epigenetics, DNA repair, metabolism, and other processes. Among epithelial malignancies, IDH mutations are particularly common in intrahepatic cholangiocarcinoma (iCCA). Importantly, pharmacological inhibition of mutant IDH (mIDH) 1 delays progression of mIDH1 iCCA, indicating a role for this oncogene in tumor maintenance. However, not all patients receive clinical benefit, and those who do typically show stable disease rather than significant tumor regressions. The elucidation of the oncogenic functions of mIDH is needed to inform strategies that can more effectively harness mIDH as a therapeutic target. This review will discuss the biology of mIDH iCCA, including roles of mIDH in blocking cell differentiation programs and suppressing antitumor immunity, and the potential relevance of these effects to mIDH1-targeted therapy. We also cover opportunities for synthetic lethal therapeutic interactions that harness the altered cell state provoked by mIDH1 rather than inhibiting the mutant enzyme. Finally, we highlight key outstanding questions in the biology of this fascinating and incompletely understood oncogene.

Up-to-Date Pathologic Classification and Molecular Characteristics of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is an aggressive primary liver malignancy with an increasing incidence worldwide. Recently, histopathologic classification of small duct type and large duct type iCCA has been introduced. Both these types of tumors exhibit differences in clinicopathological features, mutational profiles, and prognosis. Small duct type iCCA is composed of non-mucin-producing cuboidal cells, whereas large duct type iCCA is composed of mucin-producing columnar cells, reflecting different cells of origin. Large duct type iCCA shows more invasive growth and poorer prognosis than small duct type iCCA. The background liver of small duct type iCCA often shows chronic liver disease related to hepatitis B or C viral infection, or alcoholic or non-alcoholic fatty liver disease/steatohepatitis, in contrast to large duct type iCCA that is often related to hepatolithiasis and liver fluke infection. Cholangiolocarcinoma is a variant of small duct type iCCA composed of naïve-looking cuboidal cells forming cords or ductule-like structures, and shows better prognosis than the conventional small duct type. Fibrous tumor stroma, one of the characteristic features of iCCA, contains activated fibroblasts intermixed with innate and adaptive immune cells. The types of stroma (mature versus immature) are related to tumor behavior and prognosis. Low tumor-infiltrating lymphocyte density, KRAS alteration, and chromosomal instability are related to immune-suppressive tumor microenvironments with resistance to programmed death 1/ programmed death ligand 1 blockade. Data from recent large-scale exome analyses have revealed the heterogeneity in the molecular profiles of iCCA, showing that small duct type iCCA exhibit frequent BAP1, IDH1/2 hotspot mutations and FGFR2 fusion, in contrast to frequent mutations in KRAS, TP53, and SMAD4 observed in large duct type iCCA. Multi-omics analyses have proposed several molecular classifications of iCCA, including inflammation class and proliferation class. The inflammation class is enriched in inflammatory signaling pathways and expression of cytokines, while the proliferation class has activated oncogenic growth signaling pathways. Diverse pathologic features of iCCA and its associated multi-omics characteristics are currently under active investigation, thereby providing insights into precision therapeutics for patients with iCCA. This review provides the latest knowledge on the histopathologic classification of iCCA and its associated molecular features, ranging from tumor microenvironment to genomic and transcriptomic research.