Integrative Genomic Analysis of Cholangiocarcinoma Identifies Distinct IDH-Mutant Molecular Profiles

Differential isocitrate dehydrogenase 1 and isocitrate dehydrogenase 2 mutation-related landscape in intrahepatic cholangiocarcinoma

BACKGROUND

Patients with intrahepatic cholangiocarcinoma (ICC) are prone to recurrence and poor survival. Targeted therapy related to isocitrate dehydrogenase (IDH) is an extremely important treatment. IDH1 and IDH2 mutations are generally thought to have similar effects on the tumor landscape. However, it is doubtful whether these 2 mutations have exactly the same effects on tumor cells and the tumor microenvironment.

METHODS

All collected tumor samples were subjected to simultaneous whole-exon sequencing and proteome sequencing.

RESULTS

IDH1 mutations accounted for 12.2%, and IDH2 mutations accounted for 5.5%, all missense mutations. Tumors with IDH mutations had lower proportions of KRAS and TP53 mutations. Mutated genes were obviously enriched in the kinase pathway in the tumors with IDH2 mutations. The signaling pathways were mainly enriched in the activation of cellular metabolic activities and an increase of inhibitory immune cells in the tumors with IDH mutations. Moreover, tumors had unique enrichment in DNA repair in IDH1 mutants and secretion of biological molecules in IDH2 mutants. Inhibitory immune cells might be more prominent in IDH2 mutants, and the expression of immune checkpoints PVR and HLA-DQB1 was more prominent in IDH1 mutants. IDH mutants were more related to metabolism-related and inflammation-immune response clusters, and some belonged to the DNA replication and repair cluster.

CONCLUSIONS

These results revealed the differential IDH1 and IDH2 mutation-related landscapes, and we have provided an important reference database to guide ICC treatment.

PUM1-TRAF3 fusion protein activates non-canonical NF-κB signaling via rescued NIK in biliary tract cancer

Discovery and verification of diagnostic or therapeutic biomarkers for biliary tract cancer (BTC) is challenging owing to the low prevalence of the disease. Here, we identified and investigated the clinical impact of a fusion gene, Pumilio1-tumor necrosis factor receptor-associated factor 3 (PUM1-TRAF3), caused by 1;14 chromosomal translocation in BTC. PUM1-TRAF3 was initially identified in the RNA-sequencing of five BTC surgical tissues and confirmed by fluorescence in situ hybridization. Expression of the fusion gene was validated in an expanded cohort (5/55, 9.1%). Establishment and molecular assessment of PUM1-TRAF3 expressing BTC cells revealed that PUM1-TRAF3 activates non-canonical NF-κB signaling via NF-κB-inducing kinase (NIK). Abnormal TRAF3 activity, driven by competitive binding of PUM1-TRAF3 and TRAF3 to NIK, led to NIK rescue followed by P52/RelB nuclear translocation, all of which were reverted by an NIK inhibitor. The elevated expression of NIK and activated NF-κB signaling was observed in the PUM1-TRAF3-expressing regions of patient tissues. Expression of the PUM1-TRAF3 fusion was significantly correlated with strong NIK expression, which is associated with a poorer prognosis for patients with BTC. Overall, our study identifies a new fusion gene, PUM1-TRAF3, that activates NIK and non-canonical NF-κB signaling, which may be beneficial for developing precise treatment strategies for BTC.

Identification of RNF213 as a Potential Suppressor of Local Invasion in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is a lethal cancer with poor survival especially when it spreads. The histopathology of its rare intraductal papillary neoplasm of the bile duct type (IPNB) characteristically shows cancer cells originating within the confined bile duct space. These cells eventually invade and infiltrate the nearby liver tissues, making it a good model to study the mechanism of local invasion, which is the earliest step of metastasis. To discover potential suppressor genes of local invasion in ICC, we analyzed the somatic mutation profiles and performed clonal evolution analyses of the 11 pairs of macrodissected locally invasive IPNB tissues (LI-IPNB) and IPNB tissues without local invasion from the same patients. We identified a protein-truncating variant in an E3 ubiquitin ligase, RNF213 (c.6967C>T; p.Gln2323X; chr17: 78,319,102 [hg19], exon 29), as the most common protein-truncating variant event in LI-IPNB samples (4/11 patients). Knockdown of RNF213 in HuCCT1 and YSCCC cells showed increased migration and invasion, and reduced vasculogenic mimicry but maintained normal proliferation. Transcriptomic analysis of the RNF213-knockdown vs control cells was then performed in the HuCCT1, YSCCC, and KKU-100 cells. Gene ontology enrichment analysis of the common differentially expressed genes revealed significantly altered cytokine and oxidoreductase-oxidizing metal ion activities, as confirmed by Western blotting. Gene Set Enrichment Analysis identified the most enriched pathways being oxidative phosphorylation, fatty acid metabolism, reactive oxygen species, adipogenesis, and angiogenesis. In sum, loss-of-function mutation of RNF213 is a common genetic alteration in LI-IPNB tissues. RNF213 knockdown leads to increased migration and invasion of ICC cells, potentially through malfunctions of the pathways related to inflammation and energy metabolisms.

Small molecule anticancer drugs approved during 2021-2022: Synthesis and clinical applications

Drugs have structural homology across similar biological targets. Small molecule drugs have the efficacy to target specific molecular targets within the cancer cells with enhanced cell membrane permeability, oral administration, selectivity, and specific affinity. The objective of this review is to highlight the clinical importance and synthetic routes of new small molecule oncology drugs approved by the FDA during the period 2021-2022. These marketed drugs are listed based on the month and year of approval in chronological order. We believed that an in-depth insight into the synthetic approaches for the construction of these chemical entities would enhance the ability to develop new drugs more efficiently.

Whole-Genome DNA Methylation Profiling of Intrahepatic Cholangiocarcinoma Reveals Prognostic Subtypes with Distinct Biological Drivers

Intrahepatic cholangiocarcinoma (iCCA) is the second most prevalent primary liver cancer. Although the genetic characterization of iCCA has led to targeted therapies for treating tumors with FGFR2 alterations and IDH1/2 mutations, only a limited number of patients can benefit from these strategies. Epigenomic profiles have emerged as potential diagnostic and prognostic biomarkers for improving the treatment of cancers. In this study, we conducted whole-genome bisulfite sequencing on 331 iCCAs integrated with genetic, transcriptomic, and proteomic analyses, demonstrating the existence of four DNA methylation subtypes of iCCAs (S1-S4) that exhibited unique postoperative clinical outcomes. The S1 group was an IDH1/2 mutation-specific subtype with moderate survival. The S2 subtype was characterized by the lowest methylation level and the highest mutational burden among the four subtypes and displayed upregulation of a gene-expression pattern associated with cell cycle/DNA replication. The S3 group was distinguished by high interpatient heterogeneity of tumor immunity, a gene-expression pattern associated with carbohydrate metabolism, and an enrichment of KRAS alterations. Patients with the S2 and S3 subtypes had the shortest survival among the four subtypes. Tumors in the S4 subtype, which had the best prognosis, showed global methylation levels comparable to normal controls, increased FGFR2 fusions/BAP1 mutations, and the highest copy-number variant burdens. Further integrative and functional analyses identified GBP4 demethylation, which is highly prevalent in the S2 and S3 groups, as an epigenetic oncogenic factor that regulates iCCA proliferation, migration, and invasion. Together, this study identifies prognostic methylome alterations and epigenetic drivers in iCCA.

SIGNIFICANCE

Characterization of the DNA methylome of intrahepatic cholangiocarcinoma integrated with genomic, transcriptomic, and proteomic analyses uncovers molecular mechanisms affected by genome-wide DNA methylation alterations, providing a resource for identifying potential therapeutic targets.

Syngeneic murine models with distinct immune microenvironments represent subsets of human intrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Cholangiocarcinoma (CCA) is a poorly immunogenic malignancy associated with limited survival. Syngeneic immunocompetent mouse models of CCA are an essential tool to elucidate the tumor immune microenvironment (TIME), understand mechanisms of tumor immune evasion, and test novel immunotherapeutic strategies. The scope of this study was to develop and characterize immunocompetent CCA models with distinct genetic drivers, and correlate tumor genomics, immunobiology, and therapeutic response.

METHODS

A multifaceted approach including scRNA-seq, CITE-seq, whole exome and bulk RNA sequencing was employed. FDA-approved PD-1/PD-L1 antibodies were tested in humanized PD-1/PD-L1 mice (HuPD-H1).

RESULTS

A genetic mouse model of intrahepatic CCA (iCCA) driven by intrabiliary transduction of Fbxw7ΔF/Akt that mimics human iCCA was generated. From the Fbxw7ΔF/Akt tumors, a murine cell line (FAC) and syngeneic model with genetic and phenotypic characteristics of human iCCA were developed. Established SB1 (YAPS127A/Akt) and KPPC (KrasG12Dp53L/L) models were compared to the FAC model. Although the models had transcriptomic similarities, they had substantial differences as well. Mutation patterns of FAC, SB1, and KPPC cells matched different mutational signatures in Western and Japanese CCA patient cohorts. KPPC tumors had a high tumor mutation burden. FAC tumors had a T cell-infiltrated TIME, while SB1 tumors had a preponderance of suppressive myeloid cells. FAC, SB1, and KPPC tumors matched different immune signatures in human iCCA cohorts. Moreover, FAC, SB1, and KPPC tumor-bearing HuPD-H1 mice displayed differential responses to nivolumab or durvalumab.

CONCLUSIONS

Syngeneic iCCA models display a correlation between tumor genotype and TIME phenotype, with differential responses to FDA-approved immunotherapies. This study underscores the importance of leveraging multiple preclinical models to understand responses to immunotherapy in different genetic subsets of human CCA.

IMPACT AND IMPLICATIONS

Understanding the relationship between tumor genotype and the phenotype of the immune microenvironment is an unmet need in cholangiocarcinoma (CCA). Herein, we use syngeneic murine models of intrahepatic CCA with different genetic drivers to demonstrate a correlation between tumor genotype and immune microenvironment phenotype in murine models, which is associated with differential responses to FDA-approved immunotherapies. This information will help guide other preclinical studies. Additionally, it emphasizes that immune checkpoint inhibition in patients with CCA is not a "one-size-fits-all" approach. Our observations suggest that, as for targeted therapies, patients should be stratified and selected for treatment according to their tumor genetics.

How to incorporate new agents into precise medicine for cholangiocarcinoma?

Cholangiocarcinoma, a rare and aggressive form of cancer originating from the bile ducts in the liver, poses a significant challenge for treatment. However, the emergence of precision medicine has brought newfound hope for more effective therapies. Several precision medicine approaches have demonstrated promise in the treatment of cholangiocarcinoma. One such approach is targeted therapy, which involves utilizing drugs that specifically target the genetic mutations or alterations present in the tumor cells. In the case of cholangiocarcinoma, mutations in the IDH1 and IDH2 genes are frequently observed. Immunotherapy is another precision medicine approach being explored for the treatment of cholangiocarcinoma. Immune checkpoint inhibitors like pembrolizumab and nivolumab can be used to bolster the body's immune response against cancer cells. While the response to immunotherapy can vary among individuals, studies have shown promising results, particularly in patients with high levels of tumor-infiltrating lymphocytes or microsatellite instability. Moreover, molecular profiling of cholangiocarcinoma tumors can play a crucial role in identifying potential targets for precision medicine. Through advanced next-generation sequencing techniques, specific gene alterations or dysregulations in pathways can be identified, potentially guiding treatment decisions. This personalized approach enables tailored treatment plans based on the unique genetic characteristics of each patient's tumor. In conclusion, the advent of precision medicine has opened up new avenues for the treatment of cholangiocarcinoma. Targeted therapy and immunotherapy have exhibited promising results, and further molecular profiling is expected to uncover additional therapeutic options. Such advancements represent a significant step forward in the quest to enhance outcomes for individuals affected by cholangiocarcinoma.

Integrative multiomics enhancer activity profiling identifies therapeutic vulnerabilities in cholangiocarcinoma of different etiologies

OBJECTIVES

Cholangiocarcinoma (CCA) is a heterogeneous malignancy with high mortality and dismal prognosis, and an urgent clinical need for new therapies. Knowledge of the CCA epigenome is largely limited to aberrant DNA methylation. Dysregulation of enhancer activities has been identified to affect carcinogenesis and leveraged for new therapies but is uninvestigated in CCA. Our aim is to identify potential therapeutic targets in different subtypes of CCA through enhancer profiling.

DESIGN

Integrative multiomics enhancer activity profiling of diverse CCA was performed. A panel of diverse CCA cell lines, patient-derived and cell line-derived xenografts were used to study identified enriched pathways and vulnerabilities. NanoString, multiplex immunohistochemistry staining and single-cell spatial transcriptomics were used to explore the immunogenicity of diverse CCA.

RESULTS

We identified three distinct groups, associated with different etiologies and unique pathways. Drug inhibitors of identified pathways reduced tumour growth in in vitro and in vivo models. The first group (ESTRO), with mostly fluke-positive CCAs, displayed activation in estrogen signalling and were sensitive to MTOR inhibitors. Another group (OXPHO), with mostly BAP1 and IDH-mutant CCAs, displayed activated oxidative phosphorylation pathways, and were sensitive to oxidative phosphorylation inhibitors. Immune-related pathways were activated in the final group (IMMUN), made up of an immunogenic CCA subtype and CCA with aristolochic acid (AA) mutational signatures. Intratumour differences in AA mutation load were correlated to intratumour variation of different immune cell populations.

CONCLUSION

Our study elucidates the mechanisms underlying enhancer dysregulation and deepens understanding of different tumourigenesis processes in distinct CCA subtypes, with potential significant therapeutics and clinical benefits.

Precision Oncology in Hepatopancreatobiliary Cancer Surgery

Advances in technology have allowed for the characterization of tumors at the genomic, transcriptomic, and proteomic levels. There are well-established targets for biliary tract cancers, with exciting new targets emerging in pancreatic ductal adenocarcinoma and potential targets in hepatocellular carcinoma. Taken together, these data suggest an important role for molecular profiling for personalizing cancer therapy in advanced disease and need for design of novel neoadjuvant studies to leverage these novel therapeutics perioperatively in the surgical patient.

Comprehensive Immunogenomic Profiling of IDH1-/2-Altered Cholangiocarcinoma

PURPOSE

Isocitrate dehydrogenase (IDH)1/2 genomic alterations (GA) occur in 20% of intrahepatic cholangiocarcinoma (iCCA); however, the immunogenomic landscape of IDH1-/2-mutated iCCA is largely unknown.

METHODS

Comprehensive genomic profiling (CGP) was performed on 3,067 cases of advanced iCCA. Tumor mutational burden (TMB), PD-L1 expression (Dako 22C3), microsatellite instability (MSI), and genomic loss of heterozygosity (gLOH) as a surrogate marker for homologous recombination deficiency were examined. RNA sequencing of 73 patient samples was analyzed for differences in stromal/immune cell infiltration, immune marker expression, and T-cell inflammation. Tissue microarray arrays were subjected to multiplex immunohistochemistry and colocalization analysis in 100 surgical samples. Retrospective clinical data were collected for 501 patients with cholangiocarcinoma to examine median overall survival (mOS) in IDH1/2+ versus IDHwt.

RESULTS

Of 3,067 iCCA cases subjected to CGP, 426 (14%) were IDH1+ and 125 (4%) were IDH2+. IDH1 GA included R132C (69%) and R132L/G/S/H/F (16%/7%/4%/3%/<1%). IDH2 GA occurred at R172 (94.4%) and R140 (6.6%). No significant difference was seen in median gLOH between IDH1+ versus IDHwt iCCA (P = .37), although patterns of comutations differed. MSI-High (P = .009), TMB ≥10 mut/Mb (P < .0001), and PD-L1 positivity were lower in IDH1/2+ versus IDHwt iCCA. Resting natural killer cell population, CD70, and programmed cell death 1 expression were significantly higher in non-IDH1-mutated cases, whereas V-set domain containing T-cell activation inhibitor 1 (B7-H4) expression was significantly higher in IDH1+. No significant difference in mOS was observed between IDH1/2+ versus IDHwt patients.

CONCLUSION

Significant differences in GA and immune biomarkers are noted between IDH1/2+ and IDHwt iCCA. IDH1-/2-mutated tumors appear immunologically cold without gLOH. These immunogenomic data provide insight for precision targeting of iCCA with IDH alterations.

IDH1-mutated Crohn's disease-associated small bowel adenocarcinomas: Distinctive pathological features and association with MGMT methylation and serrated-type dysplasia

AIMS

Patients with Crohn's disease (CrD) have an elevated risk for the development of small bowel adenocarcinomas (SBAs). Actionable isocitrate dehydrogenase 1 (IDH1) mutations have been reported to be more frequent in CrD-SBAs than in sporadic SBAs. The present study aimed to investigate the clinicopathological and immunophenotypical features, as well as methylation profiles, of IDH1-mutated CrD-SBAs.

METHODS AND RESULTS

An international multicentre series of surgically resected CrD-SBAs was tested for IDH1 mutation. Clinicopathological features, immunophenotypical marker expression and O6-methylguanine-DNA methyltransferase (MGMT) and long interspersed nuclear element-1 (LINE-1) methylation were compared between IDH1-mutated and IDH1 wild-type CrD-SBAs. Ten (20%) of the 49 CrD-SBAs examined harboured an IDH1 mutation and all the mutated cancers harboured the R132C variant. Compared to IDH1 wild-type cases, IDH1-mutated CrD-SBAs showed significantly lower rates of cytokeratin 7 expression (P = 0.005) and higher rates of p53 overexpression (P = 0.012) and MGMT methylation (P = 0.012). All three dysplastic growths associated with IDH1-mutated SBAs harboured the same IDH1 variant (R132C) of the corresponding invasive cancer, and all were of non-conventional subtype (two serrated dysplastic lesions and one goblet cell-deficient dysplasia). In particular, non-conventional serrated dysplasia was significantly associated with IDH1-mutated CrD-SBAs (P = 0.029). No significant cancer-specific survival difference between IDH1-mutated CrD-SBA patients and IDH1 wild-type CrD-SBA patients was found (hazard ratio = 0.55, 95% confidence interval = 0.16-1.89; P = 0.313).

CONCLUSIONS

IDH1-mutated CrD-SBAs, which represent approximately one-fifth of total cases, are characterised by distinctive immunophenotypical features and methylation profiles, with potential therapeutic implications. Moreover, IDH1-mutated non-conventional, serrated dysplasia is likely to represent a precursor lesion to such CrD-SBAs.

Oncometabolite 2-hydroxyglutarate regulates anti-tumor immunity

"Oncometabolite" 2-hydroxyglutarate (2-HG) is an aberrant metabolite found in tumor cells, exerting a pivotal influence on tumor progression. Recent studies have unveiled its impact on the proliferation, activation, and differentiation of anti-tumor T cells. Moreover, 2-HG regulates the function of innate immune components, including macrophages, dendritic cells, natural killer cells, and the complement system. Elevated levels of 2-HG hinder α-KG-dependent dioxygenases (α-KGDDs), contributing to tumorigenesis by disrupting epigenetic regulation, genome integrity, hypoxia-inducible factors (HIF) signaling, and cellular metabolism. The chiral molecular structure of 2-HG produces two enantiomers: D-2-HG and L-2-HG, each with distinct origins and biological functions. Efforts to inhibit D-2-HG and leverage the potential of L-2-HG have demonstrated efficacy in cancer immunotherapy. This review delves into the metabolism, biological functions, and impacts on the tumor immune microenvironment (TIME) of 2-HG, providing a comprehensive exploration of the intricate relationship between 2-HG and antitumor immunity. Additionally, we examine the potential clinical applications of targeted therapy for 2-HG, highlighting recent breakthroughs as well as the existing challenges.

Exploring the Genomic Landscape of Hepatobiliary Cancers to Establish a Novel Molecular Classification System

Taxonomy of hepatobiliary cancer (HBC) categorizes tumors by location or histopathology (tissue of origin, TO). Tumors originating from different TOs can also be grouped by overlapping genomic alterations (GA) into molecular subtypes (MS). The aim of this study was to create novel HBC MSs. Next-generation sequencing (NGS) data from the AACR-GENIE database were used to examine the genomic landscape of HBCs. Machine learning and gene enrichment analysis identified MSs and their oncogenomic pathways. Descriptive statistics were used to compare subtypes and their associations with clinical and molecular variables. Integrative analyses generated three MSs with different oncogenomic pathways independent of TO (n = 324; p < 0.05). HC-1 "hyper-mutated-proliferative state" MS had rapidly dividing cells susceptible to chemotherapy; HC-2 "adaptive stem cell-cellular senescence" MS had epigenomic alterations to evade immune system and treatment-resistant mechanisms; HC-3 "metabolic-stress pathway" MS had metabolic alterations. The discovery of HBC MSs is the initial step in cancer taxonomy evolution and the incorporation of genomic profiling into the TNM system. The goal is the development of a precision oncology machine learning algorithm to guide treatment planning and improve HBC outcomes. Future studies should validate findings of this study, incorporate clinical outcomes, and compare the MS classification to the AJCC 8th staging system.

Futibatinib, an Irreversible FGFR1-4 Inhibitor for the Treatment of FGFR-Aberrant Tumors

Fibroblast growth factor receptors (FGFR) are emerging as an important therapeutic target for patients with advanced, refractory cancers. Most selective FGFR inhibitors under investigation show reversible binding, and their activity is limited by acquired drug resistance. This review summarizes the preclinical and clinical development of futibatinib, an irreversible FGFR1-4 inhibitor. Futibatinib stands out among FGFR inhibitors because of its covalent binding mechanism and low susceptibility to acquired resistance. Preclinical data indicated robust activity of futibatinib against acquired resistance mutations in the FGFR kinase domain. In early-phase studies, futibatinib showed activity in cholangiocarcinoma, and gastric, urothelial, breast, central nervous system, and head and neck cancers harboring various FGFR aberrations. Exploratory analyses indicated clinical benefit with futibatinib after prior FGFR inhibitor use. In a pivotal phase II trial, futibatinib demonstrated durable objective responses (42% objective response rate) and tolerability in previously treated patients with advanced intrahepatic cholangiocarcinoma harboring FGFR2 fusions or rearrangements. A manageable safety profile was observed across studies, and patient quality of life was maintained with futibatinib treatment in patients with cholangiocarcinoma. Hyperphosphatemia, the most common adverse event with futibatinib, was well managed and did not lead to treatment discontinuation. These data show clinically meaningful benefit with futibatinib in FGFR2-rearrangement-positive cholangiocarcinoma and provide support for further investigation of futibatinib across other indications. Future directions for this agent include elucidating mechanisms of resistance and exploration of combination therapy approaches.

Metabolic reprogramming and its clinical implication for liver cancer

Cancer cells often encounter hypoxic and hypo-nutrient conditions, which force them to make adaptive changes to meet their high demands for energy and various biomaterials for biomass synthesis. As a result, enhanced catabolism (breakdown of macromolecules for energy production) and anabolism (macromolecule synthesis from bio-precursors) are induced in cancer. This phenomenon is called "metabolic reprogramming," a cancer hallmark contributing to cancer development, metastasis, and drug resistance. HCC and cholangiocarcinoma (CCA) are 2 different liver cancers with high intertumoral heterogeneity in terms of etiologies, mutational landscapes, transcriptomes, and histological representations. In agreement, metabolism in HCC or CCA is remarkably heterogeneous, although changes in the glycolytic pathways and an increase in the generation of lactate (the Warburg effect) have been frequently detected in those tumors. For example, HCC tumors with activated β-catenin are addicted to fatty acid catabolism, whereas HCC tumors derived from fatty liver avoid using fatty acids. In this review, we describe common metabolic alterations in HCC and CCA as well as metabolic features unique for their subsets. We discuss metabolism of NAFLD as well, because NAFLD will likely become a leading etiology of liver cancer in the coming years due to the obesity epidemic in the Western world. Furthermore, we outline the clinical implication of liver cancer metabolism and highlight the computation and systems biology approaches, such as genome-wide metabolic models, as a valuable tool allowing us to identify therapeutic targets and develop personalized treatments for liver cancer patients.

Dissecting the tumor ecosystem of liver cancers in the single-cell era

Primary liver cancers (PLCs) are a broad class of malignancies that include HCC, intrahepatic cholangiocarcinoma, and combined hepatocellular and intrahepatic cholangiocarcinoma. PLCs are often associated with a poor prognosis due to their high relapse and low therapeutic response rates. Importantly, PLCs exist within a dynamic and complex tumor ecosystem, which includes malignant, immune, and stromal cells. It is critical to dissect the PLC tumor ecosystem to uncover the underlying mechanisms associated with tumorigenesis, relapse, and treatment resistance to facilitate the discovery of novel therapeutic targets. Single-cell and spatial multi-omics sequencing techniques offer an unprecedented opportunity to elucidate spatiotemporal interactions among heterogeneous cell types within the complex tumor ecosystem. In this review, we describe the latest advances in single-cell and spatial technologies and review their applications with respect to dissecting liver cancer tumor ecosystems.

The Emerging Role of Circulating Tumor DNA in Non-Colorectal Gastrointestinal Cancers

Assays to detect circulating tumor DNA (ctDNA) have multiple clinically important applications in management of multiple types of gastrointestinal cancers. Different methodologies of ctDNA detection have varying sensitivities and potential applications in different contexts. For patients with localized cancers treated for curative intent, ctDNA detection is associated with prognosis in multiple cancer types, and persistent detection of ctDNA after surgical resection is highly concerning for minimal residual disease (MRD) and forebodes impending radiographic and clinical recurrence. CtDNA assays for comprehensive genomic profiling enable genotyping of cancers in the absence of tumor tissue data, and longitudinal testing can also characterize clonal evolution and emergence of putative resistance mechanisms upon treatment with targeted agents. These applications have proven instructive in patients with HER2-amplified gastric and esophageal cancers and in patients with FGFR2 fusion cholangiocarcinomas. In this review, we summarize data supporting the role of ctDNA as a novel predictive and prognostic biomarker and potential impacts on current management of patients with pancreatic, gastroesophageal, and hepatobiliary cancers.

Genomics driven precision oncology in advanced biliary tract cancer improves survival

BACKGROUND

Biliary tract cancers (BTCs) including intrahepatic, perihilar, and distal cholangiocarcinoma as well as gallbladder cancer, are rare but aggressive malignancies with few effective standard of care therapies.

METHODS

We implemented integrative clinical sequencing of advanced BTC tumors from 124 consecutive patients who progressed on standard therapies (N=92 with MI-ONCOSEQ and N=32 with commercial gene panels) enrolled between 2011-2020.

RESULTS

Genomic profiling of paired tumor and normal DNA and tumor transcriptome (RNA) sequencing identified actionable somatic and germline genomic alterations in 54 patients (43.5%), and potentially actionable alterations in 79 (63.7%) of the cohort. Of these, patients who received matched targeted therapy (22; 40.7%) had a median overall survival of 28.1 months compared to 13.3 months in those who did not receive matched targeted therapy (32; P < 0.01), or 13.9 months in those without actionable mutations (70; P < 0.01). Additionally, we discovered recurrent activating mutations in FGFR2, and a novel association between KRAS and BRAF mutant tumors with high expression of immune modulatory protein NT5E (CD73) that may represent novel therapeutic avenues.

CONCLUSIONS

Overall, the identification of actionable/ potentially actionable aberrations in a large proportion of cases, and improvement in survival with precision oncology supports molecular analysis and clinical sequencing for all patients with advanced BTC.

Epigenome-wide development and validation of a prognostic methylation score in intrahepatic cholangiocarcinoma based on machine learning strategies

Background

Clinical parameter-based nomograms and staging systems provide limited information for the prediction of survival in intrahepatic cholangiocarcinoma (ICC) patients. In this study, we developed a methylation signature that precisely predicts overall survival (OS) after surgery.

Methods

An epigenome-wide study of DNA methylation based on whole-genome bisulfite sequencing (WGBS) was conducted for two independent cohorts (discovery cohort, n=164; validation cohort, n=170) from three hepatobiliary centers in China. By referring to differentially methylated regions (DMRs), we proposed the concept of prognostically methylated regions (PMRs), which were composed of consecutive prognostically methylated CpGs (PMCs). Using machine learning strategies (Random Forest and the least absolute shrinkage and selector regression), a prognostic methylation score (PMS) was constructed based on 14 PMRs in the discovery cohort and confirmed in the validation cohort.

Results

The C-indices of the PMS for predicting OS in the discovery and validation cohorts were 0.79 and 0.74, respectively. In the whole cohort, the PMS was an independent predictor of OS [hazard ratio (HR) =8.12; 95% confidence interval (CI): 5.48-12.04; P<0.001], and the C-index (0.78) of the PMS was significantly higher than that of the Johns Hopkins University School of Medicine (JHUSM) nomogram (0.69, P<0.001), the Eastern Hepatobiliary Surgery Hospital (EHBSH) nomogram (0.67, P<0.001), American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging system (0.61, P<0.001), and MEGNA prognostic score (0.60, P<0.001). The patients in quartile 4 of PMS could benefit from adjuvant therapy (AT) (HR =0.54; 95% CI: 0.32-0.91; log-rank P=0.043), whereas those in the quartiles 1-3 could not. However, other nomograms and staging system failed to do so. Further analyses of potential mechanisms showed that the PMS was associated with tumor biological behaviors, pathway activation, and immune microenvironment.

Conclusions

The PMS could improve the prognostic accuracy and identify patients who would benefit from AT for ICC patients, and might facilitate decisions in treatment of ICC patients.

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.

Convergent genomic diversity and novel BCAA metabolism in intrahepatic cholangiocarcinoma

BACKGROUND

Driver alterations may represent novel candidates for driver gene-guided therapy; however, intrahepatic cholangiocarcinoma (ICC) with multiple genomic aberrations makes them intractable. Therefore, the pathogenesis and metabolic changes of ICC need to be understood to develop new treatment strategies. We aimed to unravel the evolution of ICC and identify ICC-specific metabolic characteristics to investigate the metabolic pathway associated with ICC development using multiregional sampling to encompass the intra- and inter-tumoral heterogeneity.

METHODS

We performed the genomic, transcriptomic, proteomic and metabolomic analysis of 39-77 ICC tumour samples and eleven normal samples. Further, we analysed their cell proliferation and viability.

RESULTS

We demonstrated that intra-tumoral heterogeneity of ICCs with distinct driver genes per case exhibited neutral evolution, regardless of their tumour stage. Upregulation of BCAT1 and BCAT2 indicated the involvement of 'Val Leu Ile degradation pathway'. ICCs exhibit the accumulation of ubiquitous metabolites, such as branched-chain amino acids including valine, leucine, and isoleucine, to negatively affect cancer prognosis. We revealed that this metabolic pathway was almost ubiquitously altered in all cases with genomic diversity and might play important roles in tumour progression and overall survival.

CONCLUSIONS

We propose a novel ICC onco-metabolic pathway that could enable the development of new therapeutic interventions.

Novel microenvironment-based classification of intrahepatic cholangiocarcinoma with therapeutic implications

OBJECTIVE

The diversity of the tumour microenvironment (TME) of intrahepatic cholangiocarcinoma (iCCA) has not been comprehensively assessed. We aimed to generate a novel molecular iCCA classifier that incorporates elements of the stroma, tumour and immune microenvironment ('STIM' classification).

DESIGN

We applied virtual deconvolution to transcriptomic data from ~900 iCCAs, enabling us to devise a novel classification by selecting for the most relevant TME components. Murine models were generated through hydrodynamic tail vein injection and compared with the human disease.

RESULTS

iCCA is composed of five robust STIM classes encompassing both inflamed (35%) and non-inflamed profiles (65%). The inflamed classes, named immune classical (~10%) and inflammatory stroma (~25%), differ in oncogenic pathways and extent of desmoplasia, with the inflammatory stroma showing T cell exhaustion, abundant stroma and KRAS mutations (p<0.001). Analysis of cell-cell interactions highlights cancer-associated fibroblast subtypes as potential mediators of immune evasion. Among the non-inflamed classes, the desert-like class (~20%) harbours the lowest immune infiltration with abundant regulatory T cells (p<0.001), whereas the hepatic stem-like class (~35%) is enriched in 'M2-like' macrophages, mutations in IDH1/2 and BAP1, and FGFR2 fusions. The remaining class (tumour classical: ~10%) is defined by cell cycle pathways and poor prognosis. Comparative analysis unveils high similarity between a KRAS/p19 murine model and the inflammatory stroma class (p=0.02). The KRAS-SOS inhibitor, BI3406, sensitises a KRAS-mutant iCCA murine model to anti-PD1 therapy.

CONCLUSIONS

We describe a comprehensive TME-based stratification of iCCA. Cross-species analysis establishes murine models that align closely to human iCCA for the preclinical testing of combination strategies.

Criteria for preclinical models of cholangiocarcinoma: scientific and medical relevance

Cholangiocarcinoma (CCA) is a rare malignancy that develops at any point along the biliary tree. CCA has a poor prognosis, its clinical management remains challenging, and effective treatments are lacking. Therefore, preclinical research is of pivotal importance and necessary to acquire a deeper understanding of CCA and improve therapeutic outcomes. Preclinical research involves developing and managing complementary experimental models, from in vitro assays using primary cells or cell lines cultured in 2D or 3D to in vivo models with engrafted material, chemically induced CCA or genetically engineered models. All are valuable tools with well-defined advantages and limitations. The choice of a preclinical model is guided by the question(s) to be addressed; ideally, results should be recapitulated in independent approaches. In this Consensus Statement, a task force of 45 experts in CCA molecular and cellular biology and clinicians, including pathologists, from ten countries provides recommendations on the minimal criteria for preclinical models to provide a uniform approach. These recommendations are based on two rounds of questionnaires completed by 35 (first round) and 45 (second round) experts to reach a consensus with 13 statements. An agreement was defined when at least 90% of the participants voting anonymously agreed with a statement. The ultimate goal was to transfer basic laboratory research to the clinics through increased disease understanding and to develop clinical biomarkers and innovative therapies for patients with CCA.

TNF receptor-related factor 3 inactivation promotes the development of intrahepatic cholangiocarcinoma through NF-κB-inducing kinase-mediated hepatocyte transdifferentiation

BACKGROUND AND AIMS

Intrahepatic cholangiocarcinoma (ICC) is a deadly but poorly understood disease, and its treatment options are very limited. The aim of this study was to identify the molecular drivers of ICC and search for therapeutic targets.

APPROACH AND RESULTS

We performed a Sleeping Beauty transposon-based in vivo insertional mutagenesis screen in liver-specific Pten -deficient mice and identified TNF receptor-related factor 3 ( Traf3 ) as the most significantly mutated gene in murine ICCs in a loss-of-function manner. Liver-specific Traf3 deletion caused marked cholangiocyte overgrowth and spontaneous development of ICC in Pten knockout and KrasG12D mutant mice. Hepatocyte-specific, but not cholangiocyte-specific, Traf3 -deficient and Pten -deficient mice recapitulated these phenotypes. Lineage tracing and single-cell RNA sequencing suggested that these ICCs were derived from hepatocytes through transdifferentiation. TRAF3 and PTEN inhibition induced a transdifferentiation-like phenotype of hepatocyte-lineage cells into proliferative cholangiocytes through NF-κB-inducing kinase (NIK) up-regulation in vitro. Intrahepatic NIK levels were elevated in liver-specific Traf3 -deficient and Pten -deficient mice, and NIK inhibition alleviated cholangiocyte overgrowth. In human ICCs, we identified an inverse correlation between TRAF3 and NIK expression, with low TRAF3 or high NIK expression associated with poor prognosis. Finally, we showed that NIK inhibition by a small molecule inhibitor or gene silencing suppressed the growth of multiple human ICC cells in vitro and ICC xenografts in vivo.

CONCLUSIONS

TRAF3 inactivation promotes ICC development through NIK-mediated hepatocyte transdifferentiation. The oncogenic TRAF3-NIK axis may be a potential therapeutic target for ICC.

MicroRNA-27a-3p targets FoxO signalling to induce tumour-like phenotypes in bile duct cells

BACKGROUND & AIMS

Cholangiocarcinoma (CCA) is a heterogeneous and lethal malignancy, the molecular origins of which remain poorly understood. MicroRNAs (miRs) target diverse signalling pathways, functioning as potent epigenetic regulators of transcriptional output. We aimed to characterise miRNome dysregulation in CCA, including its impact on transcriptome homeostasis and cell behaviour.

METHODS

Small RNA sequencing was performed on 119 resected CCAs, 63 surrounding liver tissues, and 22 normal livers. High-throughput miR mimic screens were performed in three primary human cholangiocyte cultures. Integration of patient transcriptomes and miRseq together with miR screening data identified an oncogenic miR for characterization. MiR-mRNA interactions were investigated by a luciferase assay. MiR-CRISPR knockout cells were generated and phenotypically characterized in vitro (proliferation, migration, colony, mitochondrial function, glycolysis) and in vivo using subcutaneous xenografts.

RESULTS

In total, 13% (140/1,049) of detected miRs were differentially expressed between CCA and surrounding liver tissues, including 135 that were upregulated in tumours. CCA tissues were characterised by higher miRNome heterogeneity and miR biogenesis pathway expression. Unsupervised hierarchical clustering of tumour miRNomes identified three subgroups, including distal CCA-enriched and IDH1 mutant-enriched subgroups. High-throughput screening of miR mimics uncovered 71 miRs that consistently increased proliferation of three primary cholangiocyte models and were upregulated in CCA tissues regardless of anatomical location, among which only miR-27a-3p had consistently increased expression and activity in several cohorts. FoxO signalling was predominantly downregulated by miR-27a-3p in CCA, partially through targeting of FOXO1. MiR-27a knockout increased FOXO1 levels in vitro and in vivo, impeding tumour behaviour and growth.

CONCLUSIONS

The miRNomes of CCA tissues are highly remodelled, impacting transcriptome homeostasis in part through regulation of transcription factors like FOXO1. MiR-27a-3p arises as an oncogenic vulnerability in CCA.

IMPACT AND IMPLICATIONS

Cholangiocarcinogenesis entails extensive cellular reprogramming driven by genetic and non-genetic alterations, but the functional roles of these non-genetic events remain poorly understood. By unveiling global miRNA upregulation in patient tumours and their functional ability to increase proliferation of cholangiocytes, these small non-coding RNAs are implicated as critical non-genetic alterations promoting biliary tumour initiation. These findings identify possible mechanisms for transcriptome rewiring during transformation, with potential implications for patient stratification.

Berberine targets the electron transport chain complex I and reveals the landscape of OXPHOS dependency in acute myeloid leukemia with IDH1 mutation

Metabolic reprogramming, a newly recognized trait of tumor biology, is an intensively studied prospect for oncology medicines. For numerous tumors and cancer cell subpopulations, oxidative phosphorylation (OXPHOS) is essential for their biosynthetic and bioenergetic functions. Cancer cells with mutations in isocitrate dehydrogenase 1 (IDH1) exhibit differentiation arrest, epigenetic and transcriptional reprogramming, and sensitivity to mitochondrial OXPHOS inhibitors. In this study, we report that berberine, which is widely used in China to treat intestinal infections, acted solely at the mitochondrial electron transport chain (ETC) complex I, and that its association with IDH1 mutant inhibitor (IDH1^mi) AG-120 decreased mitochondrial activity and enhanced antileukemic effect in vitro andin vivo. Our study gives a scientific rationale for the therapy of IDH1 mutant acute myeloid leukemia (AML) patients using combinatory mitochondrial targeted medicines, particularly those who are resistant to or relapsing from IDH1^mi.

Epigenetic dysregulation-mediated COL12A1 upregulation predicts worse outcome in intrahepatic cholangiocarcinoma patients

BACKGROUND

Collagen type XII alpha 1 chain (COL12A1) is associated with human cancer progression. Nevertheless, the expression pattern and the function of COL12A1 in intrahepatic cholangiocarcinoma (iCCA) remain unknown. The present study was performed to assess the role of COL12A1 in iCCA.

RESULTS

A total of 1669 genes, differentially expressed between iCCA and nontumor liver tissue samples, were identified as potential tumor-specific biomarkers for iCCA patients. Of these, COL12A1 was significantly upregulated in clinical iCCA tissue samples and correlated with epithelial-mesenchymal transition gene set enrichment score and advanced tumor stage in clinical iCCA. COL12A1-high expression was associated with the poor prognoses of iCCA patients (n = 421) from four independent cohorts. Promoter hypermethylation-induced downregulation of miR-424-5p resulted in COL12A1 upregulation in clinical iCCA. Experimental knockout of COL12A1 inhibited the proliferation, invasiveness and growth of iCCA cells. MiR-424-5p had a therapeutic potential in iCCA via directly targeting COL12A1.

CONCLUSIONS

Promoter hypermethylation-induced miR-424-5p downregulation contributes to COL12A1 upregulation in iCCA. COL12A1 is a promising druggable target for epigenetic therapy of iCCA.

Human Metastatic Cholangiocarcinoma Patient-Derived Xenografts and Tumoroids for Preclinical Drug Evaluation

PURPOSE

Cholangiocarcinoma (CCA) is usually diagnosed at advanced stages, with limited therapeutic options. Preclinical models focused on unresectable metastatic CCA are necessary to develop rational treatments. Pathogenic mutations in IDH1/2, ARID1A/B, BAP1, and BRCA1/2 have been identified in 30%-50% of patients with CCA. Several types of tumor cells harboring these mutations exhibit homologous recombination deficiency (HRD) phenotype with enhanced sensitivity to PARP inhibitors (PARPi). However, PARPi treatment has not yet been tested for effectiveness in patient-derived models of advanced CCA.

EXPERIMENTAL DESIGN

We have established a collection of patient-derived xenografts from patients with unresectable metastatic CCA (CCA_PDX). The CCA_PDXs were characterized at both histopathologic and genomic levels. We optimized a protocol to generate CCA tumoroids from CCA_PDXs. We tested the effects of PARPis in both CCA tumoroids and CCA_PDXs. Finally, we used the RAD51 assay to evaluate the HRD status of CCA tissues.

RESULTS

This collection of CCA_PDXs recapitulates the histopathologic and molecular features of their original tumors. PARPi treatments inhibited the growth of CCA tumoroids and CCA_PDXs with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1. In line with these findings, only CCA_PDX and CCA patient biopsy samples with mutations of BRCA2 showed RAD51 scores compatible with HRD.

CONCLUSIONS

Our results suggest that patients with advanced CCA with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1, are likely to benefit from PARPi therapy. This collection of CCA_PDXs provides new opportunities for evaluating drug response and prioritizing clinical trials.

Clinicopathological features and prognostic outcomes of molecularly defined entities in the new edition of the WHO classification of sinonasal carcinoma

Introduction

We investigated the clinicopathological features and prognoses of the new molecularly defined entities in latest edition of the World Health Organization (WHO) classification of sinonasal carcinoma (SNC).

Methods

Integrated data were combined into an individual patient data (IPD) meta-analysis.

Results

We included 61 studies with 278 SNCs including 25 IDH2-mutant, 41 NUT carcinoma, 187 SWI/SNF loss, and 25 triple negative SNCs (without IDH2 mutation, NUTM1 rearrangement, and SWI/SNF inactivation) for analyses. Compared to other molecular groups, NUT carcinoma was associated with a younger age at presentation and an inferior disease-specific survival. Among SNCs with SWI/SNF inactivation, SMARCB1-deficient tumors presented later in life and were associated with a higher rate of radiotherapy administration. SMARCA4-deficiency was mostly found in teratocarcinosarcoma while SMARCB1-deficient tumors were associated with undifferentiated carcinoma and non-keratinizing squamous cell carcinoma.

Conclusion

Our study facilitates our current understanding of this developing molecular-defined spectrum of tumors and their prognoses.

Hepatic Sarcomatoid Carcinoma Is an Aggressive Hepatic Neoplasm Sharing Common Molecular Features With Its Conventional Carcinomatous Counterparts

Hepatic sarcomatoid carcinoma is a rare hepatic tumor with an aggressive clinical behavior and dismal outcome. However, the molecular pathogenesis is incompletely defined. In this study, we analyzed 59 hepatic sarcomatoid carcinomas using targeted next-generation sequencing and immunohistochemistry. A panel of 14 genes commonly mutated in primary liver carcinomas was examined. PD-L1 and loss of expression for switch/sucrose nonfermenting complexes, including BAP1, ARID1A, ARID2, and PBRM1, were detected by immunohistochemistry. The 59 hepatic sarcomatoid carcinomas encompass various carcinomatous subtypes and tumors with complete sarcomatoid transformation. Mutations in TP53 and promoter of TERT (pTERT) were frequently identified in sarcomatoid hepatocellular carcinoma, sarcomatoid combined hepatocellular cholangiocarcinoma, and hepatic sarcomatoid carcinomas with complete sarcomatoid transformation but rarely in sarcomatoid cholangiocarcinoma. Alterations involving switch/sucrose nonfermenting complexes were uncommon in hepatic sarcomatoid carcinoma (n = 2). PD-L1 expressed in tumor-associated immune cells in 67% of the tumors and in tumor cells in 33% of the tumors. A multivariate survival analysis indicated that PD-L1 expression in immune cells served as an independent favorable predictive factor of patient survival (P = .036). In conclusion, hepatic sarcomatoid carcinoma displays molecular similarity with its conventional carcinomatous counterparts. This finding suggests persistent genetic characteristics during sarcomatous evolution. PD-L1 expression in immune cells is a favorable prognostic factor for patient outcomes and may be a potential biomarker for immunotherapeutic treatment.

Nestin as a diagnostic and prognostic marker for combined hepatocellular-cholangiocarcinoma

BACKGROUND & AIMS

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare primary liver cancer (PLC) associated with a poor prognosis. Given the challenges in its identification and its clinical implications, biomarkers are critically needed. We aimed to investigate the diagnostic and prognostic value of the immunohistochemical expression of Nestin, a progenitor cell marker, in a large multicentric series of PLCs.

METHODS

We collected 461 cHCC-CCA samples from 32 different clinical centers. Control cases included 368 hepatocellular carcinomas (HCCs) and 221 intrahepatic cholangiocarcinomas (iCCAs). Nestin immunohistochemistry was performed on whole tumor sections. Diagnostic and prognostic performances of Nestin expression were determined using receiver-operating characteristic curves and Cox regression modeling.

RESULTS

Nestin was able to distinguish cHCC-CCA from HCC with AUCs of 0.85 and 0.86 on surgical and biopsy samples, respectively. Performance was lower for the distinction of cHCC-CCA from iCCA (AUCs of 0.59 and 0.60). Nestin, however, showed a high prognostic value, allowing identification of the subset of cHCC-CCA ("Nestin High", >30% neoplastic cells with positive staining) associated with the worst clinical outcome (shorter disease-free and overall survival) after surgical resection and liver transplantation, as well as when assessment was performed on biopsies.

CONCLUSION

We show in different clinical settings that Nestin has diagnostic value and that it is a useful biomarker to identify the subset of cHCC-CCA associated with the worst clinical outcome. Nestin immunohistochemistry may be used to refine risk stratification and improve treatment allocation for patients with this highly aggressive malignancy.

LAY SUMMARY

There are different types of primary liver cancers (i.e. cancers that originate in the liver). Accurately identifying a specific subtype of primary liver cancer (and determining its associated prognosis) is important as it can have a major impact on treatment allocation. Herein, we show that a protein called Nestin could be used to refine risk stratification and improve treatment allocation for patients with combined hepatocellular carcinoma, a rare but highly aggressive subtype of primary liver cancer.

Impact of FGFR2 gene fusions on survival of patients with intrahepatic cholangiocarcinoma following curative intent resection

BACKGROUND

Intrahepatic Cholangiocarcinoma (iCCA) is an aggressive cancer with diverse mutational profiles. An important molecular subtype is fibroblast growth factor receptor 2 (FGFR2) fusion. The effect of FGFR2 fusions on prognosis is unknown. Our aim was to assess the outcomes in resected CCA patients in relation to FGFR2 status.

METHODS

Surgically treated CCA patients from a single institution were retrospectively reviewed between 2008 and 2014. FGFR rearrangements were detected by fluorescence in situ hybridization (FISH). Data included patient demographics, tumor pathology, disease-free survival (DFS) and overall survival (OS).

RESULTS

Ninety-five patients underwent surgical resection for iCCA. Twelve (13%) of these were found to have FGFR2 fusion, none of which were treated with FGFR targeted therapy. Patients with FGFR2 fusions were found to have a longer 5-year (83 vs. 32%, p = 0.01) and 10-year (46 vs. 22%, p = 0.04) OS. Five and 10-year DFS was also increased (68 vs. 33% p = 0.04) and (68 vs. 25 %, p = 0.02,). FGFR2 fusion status was the strongest independent factor associated with improved OS (HR 0.23, 0.09-0.62, p=0.003) and DFS (HR 0.18, 0.05-0.67, p=0.01).

CONCLUSION

Patients with CCA FGFR2 fusion have improved OS and DFS following surgical resection.

Effect of FGFR2 Alterations on Overall and Progression-Free Survival in Patients Receiving Systemic Therapy for Intrahepatic Cholangiocarcinoma

Background

First-line standard-of-care therapy for advanced cholangiocarcinoma is gemcitabine plus cisplatin; there is no established second-line systemic therapy. Fibroblast growth factor receptor (FGFR)-2 fusions/rearrangements can be oncogenic drivers, occurring almost exclusively in intrahepatic cholangiocarcinoma, but little is known about whether FGFR2 status affects the response to systemic chemotherapy.

Objective

We aimed to evaluate the effects of FGFR2 status on survival outcomes in patients receiving systemic therapy for intrahepatic cholangiocarcinoma.

Methods

In this retrospective analysis, patients treated with systemic therapy at Memorial Sloan Kettering Cancer Center for intrahepatic cholangiocarcinoma were categorized into three cohorts: FGFR2 fusions; other FGFR2 alterations; no FGFR2 alterations. Endpoints were overall survival and progression-free survival per therapy line.

Results

In total, 132 patients with intrahepatic cholangiocarcinoma were included (FGFR2 fusions, n = 15; other FGFR2 alterations, n = 2 [data not reported]; no FGFR2 alterations, n = 115). First-line therapy was platinum based in 93% of patients; 80% received platinum/pyrimidine-based second-line therapy. For patients with FGFR2 fusions and no FGFR2 alterations, respectively, median overall survival from diagnosis was 31.3 months (95% confidence interval [CI] 5.8–not estimable months) [n = 9] and 21.7 months (95% CI 16.1–26.6) [n = 109]; median progression-free survival in first-line therapy was 6.2 months (95% CI 2.0–16.8) [n = 15] and 7.2 months (95% CI 5.0–8.3) [n = 107], and median progression-free survival in second-line therapy was 5.6 months (95% CI 2.8–10.3) [n = 8] and 3.7 months (95% CI 2.6–5.6) [n = 81].

Conclusions

Patients with intrahepatic cholangiocarcinoma and FGFR2 fusions may have a better prognosis than those without FGFR2 alterations in terms of overall survival, and progression-free survival on second-line, but not first-line systemic therapy. Progression-free survival improvement on second-line chemotherapy may imply an important impact of prior chemotherapy as first line.

Intrahepatic cholangiocarcinoma (iCCA) can be caused by changes in many different genes. One type of change in iCCA is a fibroblast growth factor receptor 2 gene (FGFR2) fusion. In fusions, the FGFR2 gene has fused to another gene. Our study examined people with iCCA to compare the overall survival following diagnosis for people with FGFR2 changes and people without. We also measured progression-free survival, which is the time from their first chemotherapy dose until their cancer got worse. All participants had iCCA and their first or second treatment was chemotherapy. Fifteen participants had FGFR2 fusions and 115 had no FGFR2 changes. We found that participants with FGFR2 fusions lived longer (median 31 months) than those without these fusions (median 22 months). During their first treatment, median progression-free survival was similar for participants with and without FGFR2 fusions. After the second chemotherapy, median progression-free survival was about 2 months longer for participants with FGFR2 fusions than those without. Results will vary from person to person and will depend on other factors. However, people with iCCA with FGFR2 fusions may stay slightly longer on their second treatment without their cancer getting worse. With chemotherapy, they may also live somewhat longer than those without FGFR2 fusions.

Role of genetic testing in hepatic, pancreatic, and biliary cancers

Hepatic, pancreatic, and biliary (HPB) cancers, including hepatocellular carcinoma (HCC), pancreatic ductal adenocarcinoma (PDAC), and cholangiocarcinoma (CCA) cause a disproportionate amount of the global cancer-related mortality. Despite advances in surgical technique and improved systemic therapies, overall 5-year survival remains dismal, especially for patients with pancreatic and biliary cancer. Historically, systemic therapies for patients with HPB cancers were administered in a "one-size-fits-all" approach due to limited reliable data on efficacy for specific patient populations. However, recent advances in genetic testing techniques have greatly improved our understanding of HPB oncogenesis, shedding light on specific genetic mutations responsible for progression from physiologic cellular regulation to uninhibited cellular replication and invasive cancer. Investigations into the oncogenesis of HPB cancers have revealed multiple actionable genetic variants, as well as increased susceptibilities to currently available systemic therapies. For example, patients with PDAC and a known BRCA mutation are more likely to benefit from FOLFIRINOX or gemcitabine plus cisplatin. While patients with CCA and a IDH1 mutation may benefit from ivosidenib. As a result, many national and societal guidelines now recommend some form of genetic testing in the workup of patients with HPB cancers. We herein review the role of genetic testing in these aggressive cancers including DNA sequencing techniques, clinically relevant mutations, therapeutic implications, and current clinical recommendations.

Comprehensive genomic and epigenomic analysis in cancer of unknown primary guides molecularly-informed therapies despite heterogeneity

The benefit of molecularly-informed therapies in cancer of unknown primary (CUP) is unclear. Here, we use comprehensive molecular characterization by whole genome/exome, transcriptome and methylome analysis in 70 CUP patients to reveal substantial mutational heterogeneity with TP53, MUC16, KRAS, LRP1B and CSMD3 being the most frequently mutated known cancer-related genes. The most common fusion partner is FGFR2, the most common focal homozygous deletion affects CDKN2A. 56/70 (80%) patients receive genomics-based treatment recommendations which are applied in 20/56 (36%) cases. Transcriptome and methylome data provide evidence for the underlying entity in 62/70 (89%) cases. Germline analysis reveals five (likely) pathogenic mutations in five patients. Recommended off-label therapies translate into a mean PFS ratio of 3.6 with a median PFS1 of 2.9 months (17 patients) and a median PFS2 of 7.8 months (20 patients). Our data emphasize the clinical value of molecular analysis and underline the need for innovative, mechanism-based clinical trials.

The identification of molecular biomarkers in cancer of unknown primary site (CUP) cases may enable the improvement of prognosis in these patients. Here, the authors integrate whole genome/exome, transcriptome and methylome data in 70 CUP patients, recommend therapies based on their analysis and report clinical outcome data.

FGFR2-IIIb Expression by Immunohistochemistry Has High Specificity in Cholangiocarcinoma with FGFR2 Genomic Alterations

BACKGROUND

FGFR2 genomic alterations are observed in 10-20% of cholangiocarcinoma (CCA). Although FGFR2 fusions are an important actionable target, FGFR2 protein expression has not been thoroughly characterized.

AIMS

To evaluate FGFR2 protein expression in cholangiocarcinoma harboring FGFR2 genomic alterations.

METHODS

FGFR2 protein expression was evaluated in 99 CCA cases with two different antibodies. FGFR2 genomic alterations were confirmed via next-generating sequencing (NGS) or FISH. Primary objective was to determine the specificity and sensitivity of FGFR2 immunohistochemistry staining for detecting FGFR2 genomic alterations. Secondary objectives included overall FGFR2 immunohistochemistry staining in CCA patients, and evaluation of whether FGFR2 expression correlates with clinical outcomes including overall survival (OS), progression-free survival (PFS), and time-to-tumor recurrence (TTR).

RESULTS

Immunohistochemistry staining with two antibodies against FGFR2, FPR2-D, and clone 98706 showed high accuracy (78.7% and 91.9%) and specificity (82.9% and 97.7%), and moderate sensitivity (53.9% and 57.1%), respectively, when compared with the standard methods for detecting FGFR2 genomic alterations. In a median follow-up of 72 months, there were no statistically significant differences in OS, PFS, and TTR, for patients with positive or negative FGFR2 staining.

CONCLUSION

FGFR2 protein expression by immunohistochemistry has high specificity and therefore could be used to imply the presence of FGFR2 genomic alterations in the context of a positive test. In the case of a negative test, NGS or FISH would be necessary to ascertain cases with FGFR2 genomic alterations.

Ferroptosis in Intrahepatic Cholangiocarcinoma: IDH1105GGT Single Nucleotide Polymorphism Is Associated With Its Activation and Better Prognosis

Objectives

Intrahepatic cholangiocarcinoma (ICC) has a dismal prognosis and often demonstrates an anti-apoptotic landscape, which is a key step to chemotherapy resistance. Isocitrate dehydrogenase 1 or 2 (IDH1-2)-mutated ICCs have been described and associated with better prognosis. Ferroptosis is a regulated iron-mediated cell death induced by glutathione peroxidase 4 (GPX4) inhibition, and may be triggered pharmacologically. GPX4 is overexpressed in aggressive cancers, while its expression is inhibited by IDH1^R132C mutation in cell lines. We investigated tissue expression of ferroptosis activation markers in ICC and its correlation with clinical-pathological features and IDH1-2 status.

Materials and Methods

We enrolled 112 patients who underwent hepatic resection or diagnostic liver biopsy for ICC. Immunostaining for transferrin-receptor 1 and GPX4, and Pearls’ stain for iron deposits were performed to evaluate ferroptosis activation. Immunostaining for STAT3 was performed to study pro-inflammatory and anti-apoptotic landscape. Main IDH1-2 mutations were investigated in 90 cases by real-time polymerase chain reaction.

Results

GPX4 overexpression was seen in 79.5% of cases and related to poor histological prognostic factors (grading and perineural and vascular invasion; p < 0.005 for all) and worse prognosis (OS p = 0.03; DFS p = 0.01). STAT3 was expressed in 95.5% of cases, confirming the inflammation-related anti-apoptotic milieu in ICC, and directly related to GPX4 expression (p < 0.0001). A high STAT3 expression correlated to a worse prognosis (OS p = 0.02; DFS p = 0.001). Nearly 12% of cases showed IDH1^105GGT single nucleotide polymorphism, which was never described in ICC up to now, and was related to lower tumor grade (p < 0.0001), longer overall survival (p = 0.04), and lower GPX4 levels (p = 0.001).

Conclusion

Our study demonstrates for the first time that in most inflammatory ICCs ferroptosis is not active, and its triggering is related to IDH1-2 status. This supports the possible therapeutic role of ferroptosis-inducer drugs in ICC patients, especially in drug-resistant cases.

Germline variants of ATG7 in familial cholangiocarcinoma alter autophagy and p62

Autophagy is a housekeeping mechanism tasked with eliminating misfolded proteins and damaged organelles to maintain cellular homeostasis. Autophagy deficiency results in increased oxidative stress, DNA damage and chronic cellular injury. Among the core genes in the autophagy machinery, ATG7 is required for autophagy initiation and autophagosome formation. Based on the analysis of an extended pedigree of familial cholangiocarcinoma, we determined that all affected family members had a novel germline mutation (c.2000C>T p.Arg659* (p.R659*)) in ATG7. Somatic deletions of ATG7 were identified in the tumors of affected individuals. We applied linked-read sequencing to one tumor sample and demonstrated that the ATG7 somatic deletion and germline mutation were located on distinct alleles, resulting in two hits to ATG7. From a parallel population genetic study, we identified a germline polymorphism of ATG7 (c.1591C>G p.Asp522Glu (p.D522E)) associated with increased risk of cholangiocarcinoma. To characterize the impact of these germline ATG7 variants on autophagy activity, we developed an ATG7-null cell line derived from the human bile duct. The mutant p.R659* ATG7 protein lacked the ability to lipidate its LC3 substrate, leading to complete loss of autophagy and increased p62 levels. Our findings indicate that germline ATG7 variants have the potential to impact autophagy function with implications for cholangiocarcinoma development.

Pathogenesis of Choledochal Cyst: Insights from Genomics and Transcriptomics

Choledochal cysts (CC) is characterized by extra- and/or intra-hepatic b\ile duct dilations. There are two main theories, “pancreaticobiliary maljunction” and “congenital stenosis of bile ducts” proposed for the pathogenesis of CC. Although family cases or CC associated with other anomalies have been reported, the molecular pathogenesis of CC is still poorly understood. Recent advances in transcriptomics and genomics analysis platforms have unveiled key expression signatures/genes/signaling pathways in the pathogenesis of human diseases including CC. This review summarizes insights from genomics and transcriptomics studies into the pathogenesis of CC, with the aim to improve (i) our understanding of its underlying complex pathomechanisms, and (ii) clinical management of different subtypes of CC, in particular their associated hepatic fibrotic change and their risk of malignancy transformation.

Next-generation sequencing of bile cell-free DNA for the early detection of patients with malignant biliary strictures

OBJECTIVE

Despite significant progresses in imaging and pathological evaluation, early differentiation between benign and malignant biliary strictures remains challenging. Endoscopic retrograde cholangiopancreatography (ERCP) is used to investigate biliary strictures, enabling the collection of bile. We tested the diagnostic potential of next-generation sequencing (NGS) mutational analysis of bile cell-free DNA (cfDNA).

DESIGN

A prospective cohort of patients with suspicious biliary strictures (n=68) was studied. The performance of initial pathological diagnosis was compared with that of the mutational analysis of bile cfDNA collected at the time of first ERCP using an NGS panel open to clinical laboratory implementation, the Oncomine Pan-Cancer Cell-Free assay.

RESULTS

An initial pathological diagnosis classified these strictures as of benign (n=26), indeterminate (n=9) or malignant (n=33) origin. Sensitivity and specificity of this diagnosis were 60% and 100%, respectively, as on follow-up 14 of the 26 and eight of the nine initially benign or indeterminate strictures resulted malignant. Sensitivity and specificity for malignancy of our NGS assay, herein named Bilemut, were 96.4% and 69.2%, respectively. Importantly, one of the four Bilemut false positives developed pancreatic cancer after extended follow-up. Remarkably, the sensitivity for malignancy of Bilemut was 100% in patients with an initial diagnosis of benign or indeterminate strictures. Analysis of 30 paired bile and tissue samples also demonstrated the superior performance of Bilemut.

CONCLUSION

Implementation of Bilemut at the initial diagnostic stage for biliary strictures can significantly improve detection of malignancy, reduce delays in the clinical management of patients and assist in selecting patients for targeted therapies.

The genomic landscape of cholangiocarcinoma reveals the disruption of post-transcriptional modifiers

Molecular variation between geographical populations and subtypes indicate potential genomic heterogeneity and novel genomic features within CCA. Here, we analyze exome-sequencing data of 87 perihilar cholangiocarcinoma (pCCA) and 261 intrahepatic cholangiocarcinoma (iCCA) cases from 3 Asian centers (including 43 pCCAs and 24 iCCAs from our center). iCCA tumours demonstrate a higher tumor mutation burden and copy number alteration burden (CNAB) than pCCA tumours, and high CNAB indicates a poorer pCCA prognosis. We identify 12 significantly mutated genes and 5 focal CNA regions, and demonstrate common mutations in post-transcriptional modification-related potential driver genes METTL14 and RBM10 in pCCA tumours. Finally we demonstrate the tumour-suppressive role of METTL14, a major RNA N6-adenosine methyltransferase (m6A), and illustrate that its loss-of-function mutation R298H may act through m6A modification on potential driver gene MACF1. Our results may be valuable for better understanding of how post-transcriptional modification can affect CCA development, and highlight both similarities and differences between pCCA and iCCA.

Cholangiocarcinoma is a heterogenous group of cancers, with large genetic variation seen within subtypes. Here, the authors find 12 significantly mutated genes and 5 focal CNA regions were found in perihilar cholangiocarcinoma, and identified METTL14 to have a potential tumour suppressive role.

MGMT inactivation as a new biomarker in patients with advanced biliary tract cancers

Biliary tract cancers (BTCs) have poor prognosis and limited therapeutic options. The impact of O⁶ -methylguanine-DNA methyltransferase (MGMT) inactivation in advanced BTC patients is not established. We investigated the prevalence, prognostic and predictive impact of MGMT inactivation in two multicenter cohorts. MGMT inactivation was assessed through PCR and immunohistochemistry (IHC) in an Italian cohort; the results were then externally validated using RNA sequencing (RNA-seq) data from the BTC subcohort of the MASTER (Molecularly Aided Stratification for Tumor Eradication Research) precision oncology program of the National Center for Tumor Diseases Heidelberg and the German Cancer Consortium. Among 164 Italian cases, 18% presented MGMT promoter hypermethylation (>14%) and 73% had negative MGMT protein expression. Both were associated with worse overall survival (OS) (HR 2.31; p<.001 and HR 1.99, p=0.012, respectively). In the MASTER cohort, patients with lower MGMT mRNA expression showed significantly poorer OS (mOS 20.4 vs 31.7 months, unadjusted HR 1.89; p=0.043). Our results suggest that MGMT inactivation is a frequent epigenetic alteration in BTC, with a significant prognostic impact, and provide the rationale to explore DNA-damaging agents in MGMT-inactivated BTCs.

Homologous Recombination Repair in Biliary Tract Cancers: A Prime Target for PARP Inhibition?

Biliary tract cancers (BTCs) are a heterogeneous group of malignancies that make up ~7% of all gastrointestinal tumors. It is notably aggressive and difficult to treat; in fact, >70% of patients with BTC are diagnosed at an advanced, unresectable stage and are not amenable to curative therapy. For these patients, chemotherapy has been the mainstay treatment, providing an inadequate overall survival of less than one year. Despite the boom in targeted therapies over the past decade, only a few targeted agents have been approved in BTCs (i.e., IDH1 and FGFR inhibitors), perhaps in part due to its relatively low incidence. This review will explore current data on PARP inhibitors (PARPi) used in homologous recombination deficiency (HRD), particularly with respect to BTCs. Greater than 28% of BTC cases harbor mutations in genes involved in homologous recombination repair (HRR). We will summarize the mechanisms for PARPi and its role in synthetic lethality and describe select genes in the HRR pathway contributing to HRD. We will provide our rationale for expanding patient eligibility for PARPi use based on literature and anecdotal evidence pertaining to mutations in HRR genes, such as RAD51C, and the potential use of reliable surrogate markers of HRD.

In Vivo Modeling of Patient Genetic Heterogeneity Identifies New Ways to Target Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy of the bile ducts within the liver characterized by high levels of genetic heterogeneity. In the context of such genetic variability, determining which oncogenic mutations drive ICC growth has been difficult, and developing modes of patient stratification and targeted therapies remains challenging. Here we model the interactions between rare mutations with more common driver genes and combine in silico analysis of patient data with highly multiplexed in vivo CRISPR-spCas9 screens to perform a functional in vivo study into the role genetic heterogeneity plays in driving ICC. Novel tumor suppressors were uncovered, which, when lost, cooperate with the RAS oncoprotein to drive ICC growth. Focusing on a set of driver mutations that interact with KRAS to initiate aggressive, sarcomatoid-type ICC revealed that tumor growth relies on Wnt and PI3K signaling. Pharmacologic coinhibition of Wnt and PI3K in vivo impeded ICC growth regardless of mutational profile. Therefore, Wnt and PI3K activity should be considered as a signature by which patients can be stratified for treatment independent of tumor genotype, and inhibitors of these pathways should be levied to treat ICC.

SIGNIFICANCE

This work shows that, despite significant genetic heterogeneity, intrahepatic cholangiocarcinoma relies on a limited number of signaling pathways to grow, suggesting common therapeutic vulnerabilities across patients.

Chemoresistance and resistance to targeted therapies in biliary tract cancer: What have we learned?

INTRODUCTION

Biliary tract cancer (BTC), including intra- and extrahepatic cholangiocarcinoma and gallbladder cancer, is a rare and highly difficult to manage human malignancy. Besides late diagnosis and associated unresectability, frequently observed unresponsiveness towards and recurrence following chemotherapy or targeted therapy essentially contribute to the dismal prognosis of BTC patients.

AREAS COVERED

The review provides an update on individual mechanisms involved resistance of BTC towards conventional chemotherapy as well as targeted therapies. We review the distinct mechanisms of pharmacoresistance (MPRs) which have been defined in BTC cells on a molecular basis and examine the specific consequences for the various approaches of chemo-, targeted or immunomodulatory therapies.

EXPERT OPINION

Based on currently available experimental and clinical data, the present knowledge about these MPRs in BTCs are summarized. While some possible tactics for overcoming these mechanisms of resistance have been investigated, a BTC-specific and efficient approach based on comprehensive in vitro and in vivo experimental systems is not yet available. Additionally, a reliable monitoring of therapy-relevant cellular changes needs to be established which allows for choosing the optimal drug (combination) before and/or during pharmacological therapy.

Novel and emerging targets for cholangiocarcinoma progression: therapeutic implications

INTRODUCTION

Cholangiocarcinoma (CCA) is a heterogeneous group of aggressive biliary malignancies. While surgery and liver transplantation are the only potentially curative modalities for early-stage disease, limited options are available for most patients with incurable-stage disease. Survival outcomes remain dismal. Recent molecular profiling efforts have led to improved understanding of the genomic landscape of CCA and to the identification of subgroups with distinct diagnostic, prognostic, and therapeutic implications.

AREAS COVERED

: We provide an updated review and future perspectives on features of cholangiocarcinogenesis that can be translated into therapeutic biomarkers and targets. We highlight the critical studies that have established current systemic chemotherapy and targeted therapeutics, while elaborating on novel targeted and immunotherapeutic approaches in development. Relevant literature and clinical studies were identified by searching PubMed and www.ClinicalTrials.gov.

EXPERT OPINION

: While therapies targeting the various molecular subgroups of CCA are rapidly emerging and changing treatment paradigms, their success has been limited by the genetic heterogeneity of CCA and the plasticity of the targets. Novel strategies aiming to combine immunotherapy, chemotherapy, and molecularly-targeted therapeutics will be required to offer durable clinical benefit and maximize survival.

Driver mutations of intrahepatic cholangiocarcinoma shape clinically relevant genomic clusters with distinct molecular features and therapeutic vulnerabilities

Purpose: To establish a clinically applicable genomic clustering system, we investigated the interactive landscape of driver mutations in intrahepatic cholangiocarcinoma (ICC).

Methods: The genomic data of 1481 ICCs from diverse populations was analyzed to investigate the pair-wise co-occurrences or mutual exclusivities among recurrent driver mutations. Clinicopathological features and outcomes were compared among different clusters. Gene expression and DNA methylation profiling datasets were analyzed to investigate the molecular distinctions among mutational clusters. ICC cell lines with different gene mutation backgrounds were used to evaluate the cluster specific biological behaviors and drug sensitivities.

Results: Statistically significant mutation-pairs were identified across 21 combinations of genes. Seven most recurrent driver mutations (TP53, KRAS, SMAD4, IDH1/2, FGFR2-fus and BAP1) showed pair-wise co-occurrences or mutual exclusivities and could aggregate into three genetic clusters: Cluster1: represented by tripartite interaction of KRAS, TP53 and SMAD4 mutations, exhibited large bile duct histological phenotype with high CA19-9 level and dismal prognosis; Cluster2: co-association of IDH/BAP1 or FGFR2-fus/BAP1 mutation, was characterized by small bile duct phenotype, low CA19-9 level and optimal prognosis; Cluster3: mutation-free ICC cases with intermediate clinicopathological features. These clusters showed distinct molecular traits, biological behaviors and responses to therapeutic drugs. Finally, we identified S100P and KRT17 as “cluster-specific”, “lineage-dictating” and “prognosis-related” biomarkers, which in combination with CA19-9 could well stratify Cluster3 ICCs into two biologically and clinically distinct subtypes.

Conclusions: This clinically applicable clustering system can be instructive to ICC prognostic stratification, molecular classification, and therapeutic optimization.