An Optimized Set of Fluorescence In Situ Hybridization Probes for Detection of Pancreatobiliary Tract Cancer in Cytology Brush Samples

The World Health Organization Reporting System for Pancreaticobiliary Cytopathology: Overview and Summary

The recently published WHO Reporting System for Pancreaticobiliary Cytopathology (World Health Organization [WHO] System) is an international approach to the standardized reporting of pancreaticobiliary cytopathology, updating the Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology (PSC System). Significant changes were made to the categorization of benign neoplasms, intraductal neoplasms, mucinous cystic neoplasms, and malignant neoplasms considered low grade. Benign neoplasms, such as serous cystadenoma, categorized as Neoplastic: benign in the PSC system, are categorized as Benign/negative for malignancy in the WHO system. Pancreatic neuroendocrine tumor, solid-pseudopapillary neoplasm, and gastrointestinal stromal tumor, categorized as Neoplastic: other in the PSC system, are categorized as Malignant in the WHO System in accord with their classification in the 5th edition WHO Classification of Digestive System Tumours (2019). The two new categories of Pancreaticobiliary Neoplasm Low-risk/grade and Pancreaticobiliary Neoplasm High-risk/grade are mostly limited to intraductal neoplasms and mucinous cystic neoplasms. Low-risk/grade lesions are mucinous cysts, with or without low-grade epithelial atypia. High-risk/grade lesions contain neoplastic epithelium with high-grade epithelial atypia. Correlation with clinical, imaging, and ancillary studies remains a key tenet. The sections for each entity are written to highlight key cytopathological features and cytopathological differential diagnoses with the pathologist working in low resource setting in mind. Each section also includes the most pertinent ancillary studies useful for the differential diagnosis. Sample reports are provided for each category. Finally, the book provides a separate section with risk of malignancy and management recommendations for each category to facilitate decision-making for clinicians.

Utility of methylated DNA markers for the diagnosis of malignant biliary strictures

BACKGROUND AND AIMS

Early identification of malignant biliary strictures (MBSs) is challenging, with up to 20% classified as indeterminants after preliminary testing and tissue sampling with endoscopic retrograde cholangiopancreatography. We aimed to evaluate the use of methylated DNA markers (MDMs) from biliary brushings to enhance MBS detection in a prospective cohort.

APPROACH

Candidate MDMs were evaluated for their utility in MBS diagnosis through a series of discovery and validation phases. DNA was extracted from biliary brushing samples, quantified, bisulfite-converted, and then subjected to methylation-specific droplet digital polymerase chain reaction.  Patients were considered to have no malignancy if the sampling was negative and there was no evidence of malignancy after 1 year or definitive negative surgical histopathology.

RESULTS

Fourteen candidate MDMs were evaluated in the discovery phase, with top-performing and new markers evaluated in the technical validation phase. The top 4 MDMs were TWIST1, HOXA1, VSTM2B, and CLEC11A, which individually achieved AUC values of 0.82, 0.81, 0.83, and 0.78, respectively, with sensitivities of 59.4%, 53.1%, 62.5%, and 50.0%, respectively, at high specificities for malignancy of 95.2%-95.3% for the final biologic validation phase. When combined as a panel, the AUC was 0.86, achieving 73.4% sensitivity and 92.9% specificity, which outperformed cytology and fluorescence in situ hybridization (FISH).

CONCLUSIONS

The selected MDMs demonstrated improved performance characteristics for the detection of MBS compared to cytology and FISH. Therefore, MDMs should be considered viable candidates for inclusion in diagnostic testing algorithms.

Cholangiocarcinoma: The Current Status of Surgical Options including Liver Transplantation

Cholangiocarcinoma (CCA) poses a substantial threat as it ranks as the second most prevalent primary liver tumor. The documented annual rise in intrahepatic CCA (iCCA) incidence in the United States is concerning, indicating its growing impact. Moreover, the five-year survival rate after tumor resection is only 25%, given that tumor recurrence is the leading cause of death in 53-79% of patients. Pre-operative assessments for iCCA focus on pinpointing tumor location, biliary tract involvement, vascular encasements, and metastasis detection. Numerous studies have revealed that portal vein embolization (PVE) is linked to enhanced survival rates, improved liver synthetic functions, and decreased overall mortality. The challenge in achieving clear resection margins contributes to the notable recurrence rate of iCCA, affecting approximately two-thirds of cases within one year, and results in a median survival of less than 12 months for recurrent cases. Nearly 50% of patients initially considered eligible for surgical resection in iCCA cases are ultimately deemed ineligible during surgical exploration. Therefore, staging laparoscopy has been proposed to reduce unnecessary laparotomy. Eligibility for orthotopic liver transplantation (OLT) requires certain criteria to be granted. OLT offers survival advantages for early-detected unresectable iCCA; it can be combined with other treatments, such as radiofrequency ablation and transarterial chemoembolization, in specific cases. We aim to comprehensively describe the surgical strategies available for treating CCA, including the preoperative measures and interventions, alongside the current options regarding liver resection and OLT.

How Molecular Discoveries Have Changed Liver Tumor Pathology: A Brief Review

CONTEXT

Recent molecular discoveries have led to improved understanding of tumor biology and the development of new diagnostic assays.

OBJECTIVE

To review primarily 3 examples of liver tumors and to briefly illustrate how recent molecular discoveries have altered clinical liver pathology practice.

DATA SOURCES

First, we will discuss fibrolamellar carcinoma, which will be the main focus of discussion, as an example for new diagnostic tests that have been developed as a result of molecular discoveries. Additional information on the role of molecular diagnostics in hepatocellular adenoma and hepatocellular carcinoma will be provided. Second, we will use the example of epithelioid hemangioendothelioma as an example of how new diagnostic tools, based on molecular discoveries, may support improved prognostication. Finally, we will use the example of intrahepatic cholangiocarcinoma as an example of a liver tumor where new molecular discoveries have identified tractable therapeutic targets and led to new effective therapies. This portion of the manuscript will also include a description of the anatomic and molecular differences between intrahepatic, hilar, and extrahepatic cholangiocarcinoma.

CONCLUSIONS

Fueled by molecular discoveries, new and better diagnostic tests and therapeutic targets have improved clinical care in patients affected by liver tumors.

The contribution of new methods in cytology for increasing sensitivity in the diagnosis of extrahepatic bile duct lesions

The aim of this review is to provide a comprehensive analysis of the existing literature pertaining to cytology of extrahepatic bile ducts. A search using the keywords "biliary brush cytology" was conducted in the PubMed database, with a focus on recent articles. The inclusion criteria primarily encompassed publications addressing problematic biliary stenosis. Emphasis was placed on identifying articles that explored innovative or less-utilized examination techniques aimed at enhancing the sensitivity of cytological examination. This review presents a comprehensive overview of the various types of materials used in sampling and the corresponding sampling methods. Additionally, it explores cytological and cytogenetic techniques, such as fluorescence in situ hybridization (FISH) and genetic methods (miRNA, NGS, cfDNA). These techniques possess the potential to improve the accuracy of diagnosing bile duct tumors, although their sensitivity varies. Furthermore, their utilization can facilitate early therapy, which plays a crucial role in patient prognosis. Each examination is always dependent on the quality and quantity of material delivered. A higher sensitivity of these examinations can be achieved by combining biliary cytology and other complementary methods.

Mutational Landscape and Precision Medicine in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth most common malignancy worldwide and exhibits a universal burden as the incidence of the disease continues to rise. In addition to curative-intent therapies such as liver resection and transplantation, locoregional and systemic therapy options also exist. However, existing treatments carry a dismal prognosis, often plagued with high recurrence and mortality. For this reason, understanding the tumor microenvironment and mutational pathophysiology has become the center of investigation for disease control. The use of precision medicine and genetic analysis can supplement current treatment modalities to promote individualized management of HCC. In the search for personalized medicine, tools such as next-generation sequencing have been used to identify unique tumor mutations and improve targeted therapies. Furthermore, investigations are underway for specific HCC biomarkers to augment the diagnosis of malignancy, the prediction of whether the tumor environment is amenable to available therapies, the surveillance of treatment response, the monitoring for disease recurrence, and even the identification of novel therapeutic opportunities. Understanding the mutational landscape and biomarkers of the disease is imperative for tailored management of the malignancy. In this review, we summarize the molecular targets of HCC and discuss the current role of precision medicine in the treatment of HCC.

Recent Advances in the Management of Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by fibroinflammatory damage to the biliary tree, typically in the setting of inflammatory bowel disease, with an increased risk of liver failure and cholangiocarcinoma. A complex pathophysiology, heterogeneity in clinical features, and the rare nature of the disease have contributed to the lack of effective therapy to date. However, recent innovations in the characterization and prognostication of patients with PSC, in addition to new tools for medical management and emerging pharmacologic agents, give rise to the potential for meaningful progress in the next several years. This review summarizes current concepts in PSC and highlights particular areas in need of further study.

Cholangiocarcinoma - novel biological insights and therapeutic strategies

In the past 5 years, important advances have been made in the scientific understanding and clinical management of cholangiocarcinoma (CCA). The cellular immune landscape of CCA has been characterized and tumour subsets with distinct immune microenvironments have been defined using molecular approaches. Among these subsets, the identification of 'immune-desert' tumours that are relatively devoid of immune cells emphasizes the need to consider the tumour immune microenvironment in the development of immunotherapy approaches. Progress has also made in identifying the complex heterogeneity and diverse functions of cancer-associated fibroblasts in this desmoplastic cancer. Assays measuring circulating cell-free DNA and cell-free tumour DNA are emerging as clinical tools for detection and monitoring of the disease. Molecularly targeted therapy for CCA has now become a reality, with three drugs targeting oncogenic fibroblast growth factor receptor 2 (FGFR2) fusions and one targeting neomorphic, gain-of-function variants of isocitrate dehydrogenase 1 (IDH1) obtaining regulatory approval. By contrast, immunotherapy using immune-checkpoint inhibitors has produced disappointing results in patients with CCA, underscoring the requirement for novel immune-based treatment strategies. Finally, liver transplantation for early stage intrahepatic CCA under research protocols is emerging as a viable therapeutic option in selected patients. This Review highlights and provides in-depth information on these advances.

How Can Machine Perfusion Change the Paradigm of Liver Transplantation for Patients with Perihilar Cholangiocarcinoma?

Perihilar cholangiocarcinomas (pCCA) are rare yet aggressive tumors originating from the bile ducts. While surgery remains the mainstay of treatment, only a minority of patients are amenable to curative resection, and the prognosis of unresectable patients is dismal. The introduction of liver transplantation (LT) after neoadjuvant chemoradiation for unresectable pCCA in 1993 represented a major breakthrough, and it has been associated with 5-year survival rates consistently >50%. Despite these encouraging results, pCCA has remained a niche indication for LT, which is most likely due to the need for stringent candidate selection and the challenges in preoperative and surgical management. Machine perfusion (MP) has recently been reintroduced as an alternative to static cold storage to improve liver preservation from extended criteria donors. Aside from being associated with superior graft preservation, MP technology allows for the safe extension of preservation time and the testing of liver viability prior to implantation, which are characteristics that may be especially useful in the setting of LT for pCCA. This review summarizes current surgical strategies for pCCA treatment, with a focus on unmet needs that have contributed to the limited spread of LT for pCCA and how MP could be used in this setting, with a particular emphasis on the possibility of expanding the donor pool and improving transplant logistics.

Fluorescence In Situ Hybridization in Primary Diagnosis of Biliary Strictures: A Single-Center Prospective Interventional Study

Background and aims: Diagnosis of the biliary stricture remains a challenge. In view of the low sensitivity of brush cytology (BC), fluorescence in situ hybridization (FISH) has been reported as a useful adjunctive test in patients with biliary strictures. We aimed to determine performance characteristics of BC and FISH individually and in combination (BC + FISH) in the primary diagnosis of biliary strictures. Methods: This single-center prospective study was conducted between April 2019 and January 2021. Consecutive patients with unsampled biliary strictures undergoing first endoscopic retrograde cholangiopancreatography in our institution were included. Tissue specimens from two standardized transpapillary brushings from the strictures were examined by routine cytology and FISH. Histopathological confirmation after surgery or 12-month follow-up was regarded as the reference standard for final diagnosis. Results: Of 109 enrolled patients, six were excluded and one lost from the final analysis. In the remaining 102 patients (60.8% males, mean age 67.4, range 25–92 years), the proportions of benign and malignant strictures were 28 (27.5%) and 74 (72.5%), respectively. The proportions of proximal and distal strictures were 26 (25.5%) and 76 (74.5%), respectively. In comparison to BC alone, FISH increased the sensitivity from 36.1% to 50.7% (p = 0.076) while maintaining similar specificity (p = 0.311). Conclusions: Dual-modality tissue evaluation using BC + FISH showed an improving trend in sensitivity for the primary diagnosis of biliary strictures when compared with BC alone.

Advanced endoscopy meets molecular diagnosis of cholangiocarcinoma

Cholangiocarcinoma remains an aggressive and deadly malignancy that is often diagnosed late. Intrinsic tumour characteristics and the growth pattern of cancer cells contribute to the challenges of diagnosis and chemoresistance. However, establishing an early and accurate diagnosis, and in some instances identifying targetable changes, has the potential to impact survival. Primary sclerosing cholangitis, a chronic cholangiopathy prodromal to the development of a minority of cholangiocarcinomas, poses a particular diagnostic challenge. We present our diagnostic and theranostic approach to the initial evaluation of cholangiocarcinomas, focusing on extrahepatic cholangiocarcinoma. This involves a multipronged strategy incorporating advanced imaging, endoscopic methods, multiple approaches to tissue sampling, and molecular markers. We also provide an algorithm for the sequential use of these tools.

Molecular features of pancreaticobiliary neoplasms: Implications for diagnosis, prognostication, and therapy selection

BACKGROUND

Molecular diagnostics has impacted the diagnosis, prediction of prognosis, and selection of targeted therapy for many tumor types. While pulmonary adenocarcinomas and melanomas are among the neoplasms most associated with molecular diagnostics and targeted therapy, malignancies of the pancreaticobiliary system have also been impacted by precision medicine.

METHODS

We undertook an electronic search using PubMed and Embase to review the published literature to determine what forms of molecular testing, mutations and oncogenetic pathways are associated with neoplasms of the pancreaticobiliary system. Keywords utilized were pancreas, bile duct, mutations, ERCP, FNA, KRAS, SMAD4, TP53, next-generation sequencing, serous cystadenoma, pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasm, cystic mucinous neoplasm, solid pseudo-papillary neoplasm.

RESULTS

A search between 1999 and 2022 yielded 6874 manuscripts. Screening of these yielded 302 more focused manuscripts of which 55 were used for the study. Ductal adenocarcinoma of the pancreas is associated with a progression of mutations beginning wit KRAS mutations and ending with a set of mutations in the TP53, SMAD4, and DPC4 genes. Similar mutations are found in neoplastic mucinous cysts. Specific mutations characterize serous cystadenomas, solid, and pseudo papillary neoplasms and adenocarcinomas of the bile ducts.

CONCLUSIONS

Mutational analysis of cytologic specimens obtained by fine-needle aspiration, and duct brushings and washings are helpful in the diagnosis of pancreaticobiliary neoplasms and may supply prognostic information.

Molecular diagnosis of pancreatobiliary tract cancer by detecting mutations and methylation changes in bile samples

BACKGROUND

Patients with pancreatobiliary tract cancer usually have a poor clinical outcome, with a 5-year overall survival rate below 20%. This is mainly associated with the late diagnosis. In addition, the standard-of-care for patients with malignant biliary stenosis involves a major surgery, the Whipple procedure. An accurate preoperative diagnosis, including differentiation from benign diseases, is critical to avoid unnecessary treatment. Here we developed BileScreen, a sensitive detection modality for the diagnosis of pancreatobiliary tract cancer based on massively parallel sequencing mutation and methylation changes in bile samples.

METHODS

A total of 338 patients, from five hospitals in China, with pancreatobiliary system disorders were enrolled in this study between November 2018 and October 2020, and 259 were included for the analysis of BileScreen. We profiled 23 gene mutations and 44 genes with methylation modifications in parallel from bile samples, and set up a model for the detection of malignancy based on multi-level biomarkers.

FINDINGS

We applied the BileScreen assay in a training cohort (n = 104) to set up the model and algorithm. The model was further evaluated in a validation cohort (n = 105), resulting in 92% sensitivity and 98% specificity. The performance of BileScreen was further assessed in a prospective test cohort (n = 50) of patients diagnosed with suspicious or negative pathology by endoscopic retrograde cholangiopancreatography and were confirmed in follow-up. BileScreen yielded 90% sensitivity and 80% specificity, and outcompeted serum carbohydrate antigen 19-9 in detecting pancreatobiliary tract cancer in all three cohorts, especially in terms of specificity.

INTERPRETATION

Taken together, BileScreen has the ability to interrogate mutations and methylation changes in bile samples in parallel, thus rendering it a potentially sensitive detection method to help in the diagnosis of pancreatobiliary tract cancer in a safe, convenient and less-invasive manner.

FUNDING

This study was supported by the Capital's Funds for Health Improvement and Research (2020-2-4025 to S.H.), the National Natural Science Foundation of China (81972311 to H.Z.), CAMS Innovation Fund for Medical Sciences (CIFMS) (2017-12M-4-002 to H.Z.), the CAMS Innovation Fund for Medical Sciences(CIFMS) (2021-I2M-1-066 to CJQ), the Non-profit Central Research Institution Fund of Chinese Academy of Medical Sciences (2019PT310026 to H.Z.) and Sanming Project of Medicine in Shenzhen (SZSM202011010 to H.Z.).

Genetic alterations during the neoplastic cascade towards cholangiocarcinoma in primary sclerosing cholangitis

Carcinogenesis of primary sclerosing cholangitis (PSC)-associated cholangiocarcinoma (CCA) is largely unexplored. Improved understanding of the molecular events involved may guide development of novel avenues for rational clinical management. We aimed to assess the genetic alterations during progression of the neoplastic cascade from biliary dysplasia towards CCA in PSC. Forty-four resection specimens or biopsies of PSC patients with biliary dysplasia (n = 2) and/or CCA (n = 42) were included. DNA was extracted from sections of formalin-fixed paraffin-embedded tissue blocks with dysplasia (n = 23), CCA (n = 69), and nonneoplastic tissue (n = 28). A custom-made next-generation sequencing (NGS) panel of 28 genes was used for mutation and copy number variation (CNV) detection. In addition, CNVs of CDKN2A, EGFR, MCL1, and MYC were examined by fluorescence in situ hybridization. Alterations in 16 low-grade dysplasia samples included loss of FGFR1 (19%), CDKN2A (13%), and SMAD4 (6%), amplification of FGFR3 (6%), EGFR (6%), and ERBB2 (6%), and mutations in SMAD4 (13%). High-grade dysplasia (n = 7) is characterized by MYC amplification (43%), and mutations in ERBB2 (71%) and TP53 (86%). TP53 mutations are the most common aberrations in PSC-CCA (30%), whereas mutations in KRAS (16%), GNAS (14%), and PIK3CA (9%) are also common. In conclusion, PSC-CCA exhibits a variety of genetic alterations during progression of the neoplastic cascade, with mainly CNVs being present early, whereas mutations in ERBB2, TP53, and KRAS appear later in the development of CCA. These findings are promising for the development of NGS-guided diagnostic strategies in PSC-CCA. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pathological and molecular diagnoses of early cancer with bile and pancreatic juice

The dismal prognosis of pancreaticobiliary malignancies is mainly attributed to the extremely difficult detection of early-stage lesions, including intraepithelial neoplasia. To improve prognosis, several studies on the early detection of cancer have been conducted using bile and pancreatic juices for pathological or molecular analyses. One approach is liquid biopsy that includes information about the tumor, such as circulating tumor cells, circulating tumor DNA, microRNAs, and exosomes released by the tumor. Another approach is proteomics/metabolomics that reflects specific conditions in the tumor. These two approaches lead to artificial intelligence-based multiomics analyses that comprises genomics, proteomics/metabolomics, and transcriptomics. Based on the findings of molecular analysis, pathological analysis using immunohistochemical staining/fluorescence in situ hybridization has also been developed. Moreover, there have been reports of new methods/ingenuities for obtaining appropriate samples for the diagnosis of early-stage cancer. Here we review the knowledge on cutting-edge pathological and molecular analyses of bile and pancreatic juices, introduce some ingenuities in sampling and sample processing to promote effective clinical practice, and provide a basis for future studies.

Evaluating the Significance of Pancreatobiliary Fluorescence In Situ Hybridization Polysomy on Prognosis in De Novo Cholangiocarcinoma

INTRODUCTION

We recently developed a fluorescence in situ hybridization probe set for evaluating suspicious biliary and pancreatic duct strictures (PB-FISH). We aimed to determine whether PB-FISH results in biliary brush cytology specimens are associated with outcomes of patients with cholangiocarcinoma (CCA).

METHODS

We performed a retrospective study of patients with CCA tested by PB-FISH from January 2015 to August 2018. CCA was stratified by primary sclerosing cholangitis (PSC) into those with (PSC CCA) or without PSC ( de novo CCA). PB-FISH results were categorized as polysomy (gain of multiple loci), nonpolysomy (single locus gain, single locus gain with 9p21 loss, homozygous 9p21 loss, tetrasomy), and disomy (no abnormalities). Overall survival (OS) was estimated using Kaplan-Meier methods and compared between the PB-FISH results using log-rank tests. Cox models were adjusted for age, sex, CA 19-9, cytology results, source of brushing sample, and treatments.

RESULTS

Characteristics of 264 eligible patients (median age 60.4; range 18-92) were comparable for patients with PB-FISH polysomy vs nonpolysomy vs disomy. The median OS was similar between disomy, nonpolysomy, and polysomy in the overall population (22.7 vs 22.7 vs 20.3 months, respectively). For de novo CCA, both polysomy and nonpolysomy were associated with worse OS compared with disomy (polysomy: hazard ratio [HR] = 2.09, 95% confidence interval [CI] = 1.14-3.83; nonpolysomy: HR = 2.4, 95% CI = 0.54-2.46; P = 0.027). For PSC CCA, neither polysomy nor nonpolysomy were significantly associated with worse OS (polysomy: 0.90, 95% CI = 0.47-1.75; nonpolysomy: HR = 1.78, CI = 0.71-4.49; P = 0.27).

DISCUSSION

PB-FISH alterations are associated with worse survival in de novo CCA, though statistical significance was lost when adjusting for confounding variables.

Histological assessment of new cholangioscopy-guided forceps in ERCP biliary stricture sampling: a blinded comparative study

Background and study aims  Obtaining quality tissue during ERCP biliary stricture sampling is of paramount importance for a timely diagnosis. While single-operator cholangioscopy (SOC)-guided biopsies have been suggested to be the superior biliary tissue acquisition modality given direct tissue visualization, less is known about the specimen histological quality. We aimed to analyze the specimen quality of SOC biopsies and compare the new generation forceps with prior "legacy" forceps. Patients and methods  Patients who underwent SOC from January 2017-August 2021 for biliary sampling were reviewed. In February 2020, the SOC-guided biopsy forceps were changed from legacy SpyBite to the SpyBite Max forceps (max). Specimens were assessed by blinded pathologists for crush artifact (none, mild, or severe) and gross size (greatest dimension in mm). Crush artifact and gross size were compared between the two groups. The diagnostic performance characteristics for cholangiocarcinoma (CCA), were assessed in an exploratory fashion. Results  Eighty-one patients (max = 27, legacy = 54) with similar baseline characteristics were included in this study. On blinded pathological assessment, 58 % had crush artifact, without significant differences between the two groups (Max 63 % vs. Legacy 56 %; P  = 0.64). A similar mean specimen size was found (max 3 mm vs. legacy 3.2 mm; P  = 0.24). The overall prevalence of CCA was 40 %. The sensitivity, specificity, positive predictive value, and negative predictive value of the entire cohort using a combination of cytology, fluorescence in situ hybridization, and SOC-guided biopsies were 78.1 %, 91.8 %, 86.2 %, and 86.5 %, respectively. No difference between legacy or max groups was found. Conclusions  A high rate of crush artifact was found in SOC-guided biopsy specimens. Further investigation regarding proper biopsy technique and handling is necessary to increase the diagnostic yield with SOC-guided biopsies.

Molecular diagnostics and biomarkers in cholangiocarcinoma

Regardless of anatomic origin, cholangiocarcinoma is generally an aggressive malignancy with a relatively high case fatality. Surgical resection with curative intent remains the best opportunity to achieve meaningful long-term survival. Most patients present, however, with advanced disease and less than 20% of patients are candidates for surgical resection. Unfortunately, even patients who undergo resection have a 5-year survival that ranges from 20 to 40%. Biomarkers are indicators of normal, pathologic, or biologic responses to an intervention and can range from a characteristic (i.e., blood pressure reading which can detect hypertension) to specific genetic mutations or proteins (i.e., carcinoembryonic antigen level). Novel biomarkers and improved molecular diagnostics represent an attractive opportunity to improve detection as well as to identify novel therapeutic targets for patients with cholangiocarcinoma. We herein review the latest advances in molecular diagnostics and biomarkers related to the early detection and treatment of patients with cholangiocarcinoma.

Endoscopic Evaluation and Management of Cholangiocarcinoma

Cholangiocarcinoma is a rare malignancy of the biliary tract with a relatively poor prognosis. As a gastroenterologist, our main role is to differentiate between benign and malignant biliary disease, help achieve a diagnosis, and palliate jaundice related to biliary obstruction. This article focuses on summarizing the various tools currently available for endoscopic evaluation and management of cholangiocarcinoma.

Multidisciplinary Approach to Indeterminate Biliary Strictures

Biliary strictures that remain unclassified after cross-sectional imaging and endoscopic retrograde cholangiopancreatography-based tissue sampling are defined as indeterminate biliary strictures (IDBS). A substantial proportion of biliary strictures fall into this category due to low sensitivity of brush cytology and intraductal biopsy. Over last few decades, several modalities have emerged for the evaluation of IDBS. Of these, cholangioscopy and endosonography are the frontrunners and have cemented their place for the evaluation of IDBS. Both of these modalities are widely available, and therefore, biliary strictures that remain uncharacterized after their utilization represent IDBS in the current era.

Impact of trimodality sampling on detection of malignant biliary strictures compared with patients with primary sclerosing cholangitis

BACKGROUND AND AIMS

Malignant biliary strictures can be difficult to diagnose, with up to 20% considered indeterminate after initial tissue sampling. This study aimed to determine the performance characteristics of transpapillary biopsy sampling (TPB) and fluorescence in situ hybridization (FISH) in isolation or in combination with standard brush cytology (BC) in patients who received trimodality sampling for biliary strictures.

METHODS

This single-center retrospective cohort study included patients with biliary strictures undergoing ERCP with trimodality sampling between September 2014 and April 2019. Performance characteristics for each diagnostic test alone and in combination were calculated.

RESULTS

Two hundred four patients underwent trimodality biliary sampling, including 104 (51.0%) with malignancy. The diagnostic sensitivity for malignancy with BC (17.3%) significantly improved with dual modality (BC+FISH, 58.7%; BC+TPB, 40.4%) or trimodality sampling (68.3%; P < .001 for all comparisons). Trimodality sampling improved diagnostic sensitivity for malignancy compared with BC+FISH (P = .002) and BC+TPB (P < .001). There was no statistically significant difference in the sensitivity of trimodality sampling in detecting cholangiocarcinoma (79.7%) compared with pancreatic cancer (62.5%; P = .1). Among 57 patients with primary sclerosing cholangitis (PSC), the sensitivity of detecting biliary malignancy (n = 20) was 20% for BC and significantly improved with the addition of FISH (80%; P < .001) but not with TPB (35.0%; P = .25). Trimodality sampling did not further improve diagnostic sensitivity (85%) over BC+FISH (80%) for malignancy in the setting of PSC (P = 1).

CONCLUSIONS

Trimodality sampling improves the diagnostic sensitivity for the detection of malignant biliary strictures with no significant difference in sensitivity for cholangiocarcinoma compared with pancreatic cancer. However, in patients with PSC, trimodality sampling was not superior to BC+FISH.

A Predictive Model Based on the Gut Microbiota Improves the Diagnostic Effect in Patients With Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a malignant hepatic tumor with a poor prognosis, which needs early diagnosis urgently. The gut microbiota has been shown to play a crucial role in the progression of liver cancer. Here, we explored a gut microbiota model covering genera Burkholderia-Caballeronia-Paraburkholderia, Faecalibacterium, and Ruminococcus_1 (B-F-R) for CCA early diagnosis. A case-control study was conducted to enroll 53 CCA patients, 47 cholelithiasis patients, and 40 healthy controls. The feces samples and clinical information of participants were collected in the same period. The gut microbiota and its diversity of individuals were accessed with 16S rDNA sequencing, and the gut microbiota profile was evaluated according to microbiota diversity. Finally, four enriched genera in the CCA group (genera Bacteroides, Muribaculaceae_unclassified, Muribaculum, and Alistipes) and eight enriched genera in the cholelithiasis group (genera Bifidobacterium, Streptococcus, Agathobacter, Ruminococcus_gnavus_group, Faecalibacterium, Subdoligranulum, Collinsella, Escherichia-Shigella) constitute an overall different microbial community composition (P = 0.001). The B-F-R genera model with better diagnostic value than carbohydrate antigen 19-9 (CA19-9) was identified by random forest and Statistical Analysis of Metagenomic Profiles (STAMP) to distinguish CCA patients from healthy controls [area under the curve (AUC) = 0.973, 95% CI = 0.932–1.0]. Moreover, the correlative analysis found that genera Burkholderia-Caballeronia-Paraburkholderia were positively correlated with body mass index (BMI). The significantly different microbiomes between cholelithiasis and CCA were found via principal coordinates analysis (PCoA) and linear discriminant analysis effect size (LEfSe), and Venn diagram and LEfSe were utilized to identify four genera by comparing microbial compositions among patients with malignant obstructive jaundice (MOJ-Y) or not (MOJ-N). In brief, our findings suggest that gut microbiota vary from benign and malignant hepatobiliary diseases to healthy people and provide evidence supporting gut microbiota to be a non-invasive biomarker for the early diagnosis of CCA.

Next-generation sequencing in the evaluation of biliary strictures in patients with primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a well-described risk factor for the development of cholangiocarcinoma (CCA). Early detection of CCA in these patients is of great importance because it expands options for therapeutic interventions, including liver transplantation. Current diagnostic tests for the evaluation of biliary strictures are limited to biliary brushing (BB) cytology and fluorescence in situ hybridization (FISH). Next-generation sequencing (NGS) has become an important diagnostic tool in oncology and may be a useful tool for diagnosing CCA on BBs. It is not clear how NGS performs when it is added to BB cytology and FISH in patients with PSC.

METHODS

This study reports the authors' experience with NGS performed as a prospective cotest with cytology and FISH on BBs obtained from 60 patients with PSC followed at Massachusetts General Hospital. A duct with malignancy was defined as a high-risk (HR) stricture with either high-grade dysplasia or CCA.

RESULTS

NGS was better than FISH and cytology in detecting HR strictures, which showed multiple genetic mutations in all cases. NGS provided specific mutational information, and NGS results were reproducible in longitudinal samples.

CONCLUSIONS

Adding NGS to BB cytology and FISH in the evaluation of biliary strictures for patients with PSC may provide additional information that could help to inform clinical management.

Biliary Strictures and Cholangiocarcinoma - Untangling a Diagnostic Conundrum

Cholangiocarcinoma is an uncommon and highly aggressive biliary tract malignancy with few manifestations until late disease stages. Diagnosis is currently achieved through a combination of clinical, biochemical, radiological and histological techniques. A number of reported cancer biomarkers have the potential to be incorporated into diagnostic pathways, but all lack sufficient sensitivity and specificity limiting their possible use in screening and early diagnosis. The limitations of standard serum markers such as CA19-9, CA125 and CEA have driven researchers to identify multiple novel biomarkers, yet their clinical translation has been slow with a general requirement for further validation in larger patient cohorts. We review recent advances in the diagnostic pathway for suspected CCA as well as emerging diagnostic biomarkers for early detection, with a particular focus on non-invasive approaches.

Primary Sclerosing Cholangitis-Associated Cholangiocarcinoma Demonstrates High Intertumor and Intratumor Heterogeneity

INTRODUCTION

Intertumor and intratumor heterogeneity may explain the diagnostic challenge and limited efficacy of chemotherapy for primary sclerosing cholangitis-associated cholangiocarcinoma (PSC-CCA). In this study, tumor heterogeneity was assessed through p53 and p16 protein expression analysis and next-generation sequencing (NGS) of TP53 and CDKN2A genetic alterations in PSC-associated CCA.

METHODS

Formalin-fixed paraffin-embedded tissue samples from resection material of patients with PSC-CCA or patients with PSC diagnosed with biliary dysplasia were selected. Sections with CCA and foci with dysplastic epithelium were identified by 2 independent gastrointestinal pathologists. Immunohistochemical evaluation of p53 and p16 protein expression and NGS of TP53 and CDKN2A genetic alterations were performed.

RESULTS

A total of 49 CCA and 21 dysplasia samples were identified in the resection specimens of 26 patients. P53 protein expression showed loss of expression, wild type, and overexpression in 14%, 63%, and 23% CCA and in 19%, 62%, and 19% dysplasia samples, respectively. P16 protein expression showed negative, heterogeneous, and positive results in 31%, 57%, and 12% CCA and in 33%, 53%, and 14% dysplasia samples, respectively. NGS showed high intertumor and intratumor heterogeneity of TP53 mutations and CDKN2A loss. Nearly 70% of the samples with a TP53 missense mutation demonstrated p53 overexpression, whereas all samples with a TP53 nonsense mutation demonstrated loss of p53 protein expression.

DISCUSSION

PSC-associated CCA is characterized by high intertumor and intratumor heterogeneity of both p53/p16 protein expression and genetic alterations in TP53/CDKN2A, indicating that these tumors consist of multiple subclones with substantially different genetic makeup. The high intertumor and intratumor heterogeneity in PSC-CCA should be acknowledged during the development of diagnostic and therapeutic strategies.

Clinical utility of methionyl-tRNA synthetase 1 immunostaining in cytologic brushings of indeterminate biliary strictures: a multicenter prospective study

BACKGROUND AND AIMS

Endobiliary brushings are routinely used in the diagnosis, treatment, and prognostication of biliary strictures. However, standard Papanicolaou (Pap) staining has a low sensitivity in this setting, and the accuracy of brush cytology has not been established for indeterminate strictures. We therefore evaluated the diagnostic merit of methionyl-transfer RNA synthetase 1 (MARS1) immunofluorescence (IF) staining in such cytologic specimens.

METHODS

During ERCP, endobiliary brushings were obtained from patients with extrahepatic biliary strictures prospectively enrolled at 6 tertiary hospitals. Using liquid-based cytologic preparations of these samples, we performed Pap and MARS1 IF staining.

RESULTS

In total, 240 patients were eligible; of these, we compared the Pap and MARS1 IF staining results of 218 (malignant, 157; benign, 61). By conventional Pap staining, the diagnoses were distributed as follows: malignant, 55; suspicious of malignancy, 60; atypical, 45; negative for malignancy, 58. MARS1 IF staining was strongly positive in malignant biliary stricture but not so in specimens negative for malignancy. The diagnostic parameters (sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of the MARS1 IF (93.6%, 96.7%, 98.7%, 85.5%, and 94.5%, respectively) and conventional Pap (73.2%, 100%, 100%, 59.2%, and 80.7%, respectively) staining methods differed significantly (P < .0001).

CONCLUSIONS

The high sensitivity and accuracy of MARS1 IF staining enabled the detection of malignancy in patients with biliary strictures. Further prospective studies are needed to validate our findings. (Clinical trial registration number: NCT03708445.).

Advances in the management of cholangiocarcinoma

Cholangiocarcinoma (CCA) is a primary malignancy of the bile ducts with three anatomically and molecularly distinct entities: Intrahepatic CCA (iCCA), perihilar CCA (pCCA), and distal CCA. As a result of phenotypic and anatomic differences they differ significantly with respect to management. For each type of CCA there have been significant changes in management over the last several years which will be discussed in this review. Although resection remains the standard of care for all types of CCA, liver transplantation has been established as curative treatment for selected patients with pCCA and is being evaluated for iCCA with early success. With respect to systemic therapy capecitabine is now first line adjuvant therapy for all biliary tract malignancies after curative intent resection. Progress in exploiting the pathologic mutations and molecular abnormalities has also yielded regulatory approval of targeted therapy for CCA in patients with acquired alterations in the fibroblast growth factor receptor. There is also increased consensus in managing malignant biliary obstruction associated with CCA where pre-operative biliary stenting is not beneficial while self-expanding metal stents have been shown to be superior to plastic stents in patients who are not surgical candidates.

Cholangiocarcinoma and liver transplantation: What we know so far?

Cholangiocarcinoma (CCA) is a type of cancer with increasing prevalence around the world that originates from cholangiocytes, the epithelial cells of the bile duct. The tumor begins insidiously and is distinguished by high grade neoplasm, poor outcome, and high risk for recurrence. Liver transplantation has become broadly accepted as a treatment option for CCA. Liver transplantation is expected to play a crucial role as palliative and curative therapy for unresectable hilar CCA and intrahepatic CCA. The purpose of this study was to determine which cases with CCA should be subjected to liver transplantation instead of resection, although reported post-transplant recurrence rate averages approximately 20%. This review also aims to highlight the molecular current frontiers of CCA and directions of liver transplantation for CCA.

Antibody array-based proteomic screening of novel biomarkers in malignant biliary stricture

BACKGROUND

Distinguishing between benign and malignant bile duct strictures has long been a diagnostic challenge in clinical practice.

OBJECTIVE

This study aimed to discover novel biomarkers in bile to improve the diagnostic accuracy of malignant biliary strictures.

METHODS

Bile samples were collected from 6 patients with malignant or benign biliary stricture, respectively. Protein profiles of the bile were analyzed with a semi-quantitative human antibody array of 440 proteins. Then the differential expressed proteins were screened by Venn diagram analysis. Following this, the accuracy of these potential biomarkers for discriminating between malignant and non-malignant biliary strictures was validated in a larger (n= 40) group of patients using lasso analysis.

RESULTS

Twenty proteins were found differentially expressed in malignant versus benign biliary strictures, 6 of which were identified by Venn diagram analysis to be up-regulated regardless of the location of biliary strictures. Among the 6 biomarkers, bile lipocalin-2, P-cadherin, and adipsin showed better diagnostic utility than that of bile CA19-9. Lasso analysis identified that lipocalin-2, P-cadherin and CA19-9 as a group of makers best distinguished malignant from benign strictures.

CONCLUSIONS

Lipocalin-2 and P-cadherin measurements in bile could be clinically useful for the detection of malignant biliary strictures.

Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a highly lethal adenocarcinoma of the hepatobiliary system, which can be classified as intrahepatic, perihilar and distal. Each anatomic subtype has distinct genetic aberrations, clinical presentations and therapeutic approaches. In endemic regions, liver fluke infection is associated with CCA, owing to the oncogenic effect of the associated chronic biliary tract inflammation. In other regions, CCA can be associated with chronic biliary tract inflammation owing to choledocholithiasis, cholelithiasis, or primary sclerosing cholangitis, but most CCAs have no identifiable cause. Administration of the anthelmintic drug praziquantel decreases the risk of CCA from liver flukes, but reinfection is common and future vaccination strategies may be more effective. Some patients with CCA are eligible for potentially curative surgical options, such as resection or liver transplantation. Genetic studies have provided new insights into the pathogenesis of CCA, and two aberrations that drive the pathogenesis of non-fluke-associated intrahepatic CCA, fibroblast growth factor receptor 2 fusions and isocitrate dehydrogenase gain-of-function mutations, can be therapeutically targeted. CCA is a highly desmoplastic cancer and targeting the tumour immune microenvironment might be a promising therapeutic approach. CCA remains a highly lethal disease and further scientific and clinical insights are needed to improve patient outcomes.

Refined pancreatobiliary UroVysion criteria and an approach for further optimization

Pancreatobiliary strictures are a common source of false negatives for malignancy detection. UroVysion is more sensitive than any other method but remains underutilized because of conflicting sensitivities and specificities due to a lack of standardized cutoff criteria and confusion in interpreting results in the context of primary sclerosing cholangitis. We set out to determine the sensitivities and specificities of UroVysion, brushing cytology, forceps biopsies, and fine needle aspiration (FNAs) for pancreatobiliary stricture malignancy detection. A retrospective review was performed of all biopsied pancreatobiliary strictures at our institution over 5 years. UroVysion was unquestionably the most sensitive method and all methods were highly specific. Sensitivity was highest while maintaining specificity when a malignant interpretation was limited to cases with 5+ cells with the same polysomic signal pattern and/or loss of one or both 9p21 signals. Only UroVysion detected the metastases and a neuroendocrine tumor. In reviewing and analyzing the signal patterns, we noticed trends according to location and diagnosis. Herein we describe our method for analyzing signal patterns and propose cutoff criteria based upon observations gleaned from such analysis.

Atypical cells in fine needle aspiration biopsies of pancreas: Causes, work-up, and recommendations for management

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a sensitive and specific method for diagnosing cancer in solid pancreatic masses. However, some cases receive indeterminate atypical diagnoses, which creates management dilemmas. In the 2014 Papanicolaou Society of Cytopathology (PSC) standardized guidelines for pancreatobiliary cytology, specimens in the "Atypical" category show a spectrum of architectural and/or cellular changes beyond normal or reactive, but, quantitatively or qualitatively, insufficient for classification as neoplastic (benign/other), suspicious or positive for malignancy. Implementation of the PSC system decreased atypical diagnoses, particularly for cystic lesions, and redistributed many cases into benign and neoplastic categories. Because no set cytologic criteria exist for the "Atypical" category there is wide variability in its use, and its frequency ranges from 0%-16% (mean 6%). It consists of a heterogeneous mix of cases that occur because of preanalytic, lesion-specific (low cellularity, necrosis, cystic, reactive and premalignant changes), to pathologist-dependent factors (experience, expertise, training and institutional case volume). Outcomes of atypical diagnoses in solid pancreatic masses range from benign to premalignant and malignant and include reactive atypia in pancreatitis, well differentiated adenocarcinoma, and non-ductal malignancies. The associated risk of malignancy (ROM) ranges from 28%-100%, with an overall intermediate ROM in large-scale studies. Cytopathologists and institutions should monitor and keep their personal and/or laboratory's atypical rates low by judiciously using rapid onsite evaluation, ancillary studies, consensus or expert review, as well as correlation with clinical and radiologic findings. Early repeat EUS-FNA is indicated for unresolved cases.

DNA Methylation Markers for Detection of Cholangiocarcinoma: Discovery, Validation, and Clinical Testing in Biliary Brushings and Plasma

Cholangiocarcinoma (CCA) has poor prognosis due to late-stage, symptomatic presentation. Altered DNA methylation markers may improve diagnosis of CCA. Reduced-representation bisulfite sequencing was performed on DNA extracted from frozen CCA tissues and matched to adjacent benign biliary epithelia or liver parenchyma. Methylated DNA markers (MDMs) identified from sequenced differentially methylated regions were selected for biological validation on DNA from independent formalin-fixed, paraffin-embedded CCA tumors and adjacent hepatobiliary control tissues using methylation-specific polymerase chain reaction. Selected MDMs were then blindly assayed on DNA extracted from independent archival biliary brushing specimens, including 12 perihilar cholangiocarcinoma, 4 distal cholangiocarcinoma cases, and 18 controls. Next, MDMs were blindly assayed on plasma DNA from patients with extrahepatic CCA (eCCA), including 54 perihilar CCA and 5 distal CCA cases and 95 healthy and 22 primary sclerosing cholangitis controls, balanced for age and sex. From more than 3,600 MDMs discovered in frozen tissues, 39 were tested in independent samples. In the clinical pilot of 16 MDMs on cytology brushings, methylated EMX1 (empty spiracles homeobox 1) had an area under the curve (AUC) of 0.98 (95% confidence interval [CI], 0.95-1.0). In the clinical pilot on plasma, a cross-validated recursive partitioning tree prediction model from nine MDMs was accurate for de novo eCCA (AUC, 0.88 [0.81-0.95]) but not for primary sclerosing cholangitis-associated eCCA (AUC, 0.54 [0.35-0.73]). Conclusion: Next-generation DNA sequencing yielded highly discriminant methylation markers for CCA. Confirmation of these findings in independent tissues, cytology brushings, and plasma supports further development of DNA methylation to augment diagnosis of CCA.

Current Surgical Management of Peri-Hilar and Intra-Hepatic Cholangiocarcinoma

Cholangiocarcinoma accounts for approximately 10% of all hepatobiliary tumors and represents 3% of all new-diagnosed malignancies worldwide. Intrahepatic cholangiocarcinoma (i-CCA) accounts for 10% of all cases, perihilar (h-CCA) cholangiocarcinoma represents two-thirds of the cases, while distal cholangiocarcinoma accounts for the remaining quarter. Originally described by Klatskin in 1965, h-CCA represents one of the most challenging tumors for hepatobiliary surgeons, mainly because of the anatomical vascular relationships of the biliary confluence at the hepatic hilum. Surgery is the only curative option, with the goal of a radical, margin-negative (R0) tumor resection. Continuous efforts have been made by hepatobiliary surgeons in order to achieve R0 resections, leading to the progressive development of aggressive approaches that include extended hepatectomies, associating liver partition, and portal vein ligation for staged hepatectomy, pre-operative portal vein embolization, and vascular resections. i-CCA is an aggressive biliary cancer that arises from the biliary epithelium proximal to the second-degree bile ducts. The incidence of i-CCA is dramatically increasing worldwide, and surgical resection is the only potentially curative therapy. An aggressive surgical approach, including extended liver resection and vascular reconstruction, and a greater application of systemic therapy and locoregional treatments could lead to an increase in the resection rate and the overall survival in selected i-CCA patients. Improvements achieved over the last two decades and the encouraging results recently reported have led to liver transplantation now being considered an appropriate indication for CCA patients.

Liquid biopsy in cholangiocarcinoma: Current status and future perspectives

Cholangiocarcinoma (CCA) are a heterogeneous group of tumors in terms of aetiology, natural history, morphological subtypes, molecular alterations and management, but all sharing complex diagnosis, management, and poor prognosis. Several mutated genes and epigenetic changes have been detected in CCA, with the potential to identify diagnostic and prognostic biomarkers and therapeutic targets. Accessing tumoral components and genetic material is therefore crucial for the diagnosis, management and selection of targeted therapies; but sampling tumor tissue, when possible, is often risky and difficult to be repeated at different time points. Liquid biopsy (LB) represents a way to overcome these issues and comprises a diverse group of methodologies centering around detection of tumor biomarkers from fluid samples. Compared to the traditional tissue sampling methods LB is less invasive and can be serially repeated, allowing a real-time monitoring of the tumor genetic profile or the response to therapy. In this review, we analysis the current evidence on the possible roles of LB (circulating DNA, circulating RNA, exosomes, cytokines) in the diagnosis and management of patients affected by CCA.

Analysis of transcriptome in the relationship between expression of PRC1 protein and prognosis of patients with cholangiocarcinoma

OBJECTIVE

To investigate whether protein regulator of cytokinesis 1 (PRC1), which is involved in the regulation of human carcinogenesis, contributes to poor prognosis in patients with cholangiocarcinoma (CCA).

METHODS

Data and tissues from patients with CCA were retrospectively studied. Immunohistochemical staining and western blotting were used to evaluate and contrast the PRC1 expression profile at the protein level in CCA tumour and pericarcinomatous tissues from the same study population. Relationships between clinical characteristics and patient survival were observed using univariate and multivariate analyses. Correlations between PRC1 expression and clinical characteristics were analysed by logistic regression.

RESULTS

A total of 45 patients were included. PRC1 expression was found to be upregulated in CCA cancer tissues versus pericarcinomatous tissues. Overexpression of PRC1 was shown to be related to tumour differentiation, tumour node metastasis staging and lymph node metastasis, and was also revealed to be an independent marker of poor CCA prognosis.

CONCLUSIONS

The present results suggest that PRC1 may be a prognostic and therapeutic biomarker for patients with CCA.

Optimal tissue sampling during ERCP and emerging molecular techniques for the differentiation of benign and malignant biliary strictures

Patients with cholangiocarcinoma have poor survival since the majority of patients are diagnosed at a stage precluding surgical resection, due to locally irresectable tumors and/or metastases. Optimization of diagnostic strategies, with a principal role for tissue diagnosis, is essential to detect cancers at an earlier stage amenable to curative treatment. Current barriers for a tissue diagnosis include both insufficient tissue sampling and a difficult cyto- or histopathological assessment. During endoscopic retrograde cholangiopancreatography, optimal brush sampling includes obtaining more than one brush within an individual patient to increase its diagnostic value. Currently, no significant increase of the diagnostic accuracy for the new cytology brush devices aiming to enhance the cellularity of brushings versus standard biliary brush devices has been demonstrated. Peroral cholangioscopy with bile duct biopsies appears to be a valuable tool in the diagnostic work-up of indeterminate biliary strictures, and may overcome current technical difficulties of fluoroscopic-guided biopsies. Over the past years, molecular techniques to detect chromosomal instability, mutations and methylation profiling of tumors have revolutionized, and implementation of these techniques on biliary tissue during diagnostic work-up of biliary strictures may be awaited in the near future. Fluorescence in situ hybridization has already been implemented in routine diagnostic evaluation of biliary strictures in several centers. Next-generation sequencing is promising for standard diagnostic care in biliary strictures, and recent studies have shown adequate detection of prevalent genomic alterations in KRAS, TP53, CDKN2A, SMAD4, PIK3CA, and GNAS on biliary brush material. Detection of DNA methylation of tumor suppressor genes and microRNAs may evolve over the coming years to a valuable diagnostic tool for cholangiocarcinoma. This review summarizes optimal strategies for biliary tissue sampling during endoscopic retrograde cholangiopancreatography and focuses on the evolving molecular techniques on biliary tissue to improve the differentiation of benign and malignant biliary strictures.

Application of enhancer of zeste homolog 2 immunocytochemistry to bile cytology

BACKGROUND

Bile cytology has low diagnostic sensitivity and requires ancillary techniques. This study assessed the utility of enhancer of zeste homolog 2 (EZH2) immunocytochemistry (ICC) in bile cytology.

METHODS

A total of 141 bile cytology specimens from 141 patients were evaluated retrospectively. Papanicolaou-stained slides were immunostained with an antibody to EZH2. After calculation of the EZH2 labeling index (LI), the cutoff value was determined via receiver operating characteristic curve analysis. Cytological performance with and without EZH2 ICC was evaluated with reference to the final diagnosis.

RESULTS

The area under the curve for the EZH2 LI was 0.955, and the cutoff value for identifying benign bile samples versus malignant ones was 24.0%. The sensitivity and specificity values for malignancy were 53.4% and 100% for routine cytology only, 89.0% and 95.7% for EZH2 ICC only, and 89.8% and 95.7% for a combination of routine cytology and EZH2 ICC. The sensitivities of EZH2 ICC only and a combination of routine cytology and EZH2 ICC were significantly improved in comparison with routine cytology only (P < .001). EZH2 ICC alone had a sensitivity of 68.0% and a specificity of 85.7% in bile samples with atypical cytology, a sensitivity of 87.0% in samples that were suspicious for malignancy, and a sensitivity of 85.7% and a specificity of 100% in samples that were negative for malignancy.

CONCLUSIONS

EZH2 ICC improved the diagnostic sensitivity for pancreatobiliary adenocarcinoma in bile cytology. This method is particularly meaningful in samples of indeterminate cytology and may be useful as an initial assessment to ensure that no cancer cells are missed.

Extrahepatic cholangiocarcinoma: Current status of endoscopic approach and additional therapies

The prognosis of patients with advanced or unresectable extrahepatic cholangiocarcinoma is poor. More than 50% of patients with jaundice are inoperable at the time of first diagnosis. Endoscopic treatment in patients with obstructive jaundice ensures bile duct drainage in preoperative or palliative settings. Relief of symptoms (pain, pruritus, jaundice) and improvement in quality of life are the aims of palliative therapy. Stent implantation by endoscopic retrograde cholangiopancreatography is generally preferred for long-term palliation. There is a vast variety of plastic and metal stents, covered or uncovered. The stent choice depends on the expected length of survival, quality of life, costs and physician expertise. This review will provide the framework for the endoscopic minimally invasive therapy in extrahepatic cholangiocarcinoma. Moreover, additional therapies, such as brachytherapy, photodynamic therapy, radiofrequency ablation, chemotherapy, molecular-targeted therapy and/or immunotherapy by the endoscopic approach, are the nonsurgical methods associated with survival improvement rate and/or local symptom palliation.

Biomarkers for Hepatobiliary Cancers

The clinical management of primary liver cancers such as hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) has significantly changed in the last 3 years. The introduction of systemic therapies, including immune-based therapies and biomarker-driven therapies, has significantly improved survival, particularly in patients at advanced stages of disease. Survival is still poor, and projections from the World Health Organization underscore the need to improve outcomes in these patients. Biomarkers have emerged as powerful tools for the diagnosis, prognosis, and prediction of treatment responses to improve patient stratification and maximize clinical benefits. Recent advances in understanding the molecular alterations of HCC have not yet translated into biomarkers. Some reasons for the lack of progress are the absence of druggable mutations in the majority of liver cancers and the significant heterogeneity of the disease. In contrast, several therapeutic targets have been identified in CCA, and biomarker-driven therapies are currently under evaluation in phase 2/3 clinical trials. Here, we summarize the status on biomarker development for HCC and CCA.

Single Topic Conference on Autoimmune Liver Disease from the Canadian Association for the Study of the Liver

Autoimmune liver disease (AILD) spans a spectrum of chronic disorders affecting the liver parenchyma and biliary system. Three main categories of AILD are autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and primary sclerosing cholangitis (PSC). This review condenses the presentation and discussions of the Single Topic Conference (STC) on AILD that was held in Ottawa, Ontario, in November 2019. We cover generalities regarding disease presentation and clinical diagnosis; mechanistic themes; treatment paradigms; clinical trials, including approaches and challenges to new therapies; and looking beyond traditional disease boundaries. Although these diseases are considered autoimmune, the etiology and role of environmental triggers are poorly understood. AILDs are progressive and chronic conditions that affect survival and quality of life. Advances have been made in PBC treatment because second-line treatments are now available (obeticholic acid, bezafibrate); however, a significant proportion still present suboptimal response. AIH treatment has remained unchanged for several decades, and data suggest that fewer than 50% of patients achieve a complete response and as many as 80% develop treatment-related side effects. B-cell depletion therapy to treat AIH is in an early stage of development and has shown promising results. An effective treatment for PSC is urgently needed. Liver transplant remains the best option for patients who develop decompensated cirrhosis or hepatocellular carcinoma within specific criteria, but recurrent AILD might occur. Continued efforts are warranted to develop networks for AILD aimed at assessing geo-epidemiological, clinical, and biochemical differences to capture the new treatment era in Canada.

An assessment of chromosomal alterations detected by fluorescence in situ hybridisation in pancreatobiliary tract malignancy

Background

Using fluorescence in situ hybridisation (FISH) to detect any gain of chromosomes 3, 7, or 17 and loss of the 9p21 locus has been proven to be sensitive in the diagnosis of pancreatobiliary tumors. However, both genetic and environmental factors contribute to the pathogenesis of pancreatobiliary tumors. Therefore, it is unknown whether this method is suitable for Chinese patients with pancreatobiliary tumors. This study aims to compare the sensitivity, specificity, predictive values and accuracy of cytology, ERCP/MRCP and FISH based on Chinese patients with pancreatobiliary tumors,and to analyze differences between brushing-based and formalin-fixed paraffin-embedded (FFPE)-based FISH.

Methods

A total of 66 brush cytology specimens obtained during ERCP were detected by FISH and cytology test respectively to compare the sensitivity, specificity, predictive values and accuracy. Besides, FFPE-based FISH was performed on 46 corresponding paraffin sections of pancreatobiliary tumors obtained by surgical resection.

Results

Our findings demonstrate that FISH greatly improves diagnostic sensitivity and negative predictive value compared to ERCP/MRCP and cytology without much reduction in specificity and positive predictive value. However, our results also indicate that FFPE-based FISH could not effectively identify the false-negative of brushing-based FISH.

Conclusions

We believe that FISH can effectively distinguish true positive and false positive results of cytological or radiological suspicions of malignancy. However, FFPE-based FISH still does not precisely recognize the false-negative of brushing-based FISH. Both cytology-based and PPFE-based FISH had limitation in some specimens.

Bioimprint Mediated Label-Free Isolation of Pancreatic Tumor Cells from a Healthy Peripheral Blood Cell Population

New techniques are required for earlier diagnosis and response to treatment of pancreatic cancer. Here, a label-free approach is reported in which circulating pancreatic tumor cells are isolated from healthy peripheral blood cells via cell bioimprinting technology. The method involves pre-fabrication of pancreatic cell layers and sequential casting of cell surfaces with a series of custom-made resins to produce negative cell imprints. The imprint is functionalized with a combination of polymers to engineer weak attraction to the cells which is further amplified by the increased area of contact with the matching cells. A flow-through bioimprint chip is designed and tested for selectivity toward two pancreatic tumor cell lines, ASPC-1 and Mia-PaCa-2. Healthy human peripheral blood mononuclear cells (PBMCs) are spiked with pancreatic tumor cells at various concentrations. Bioimprints are designed for preferential retention of the matching pancreatic tumor cells and with respect to PBMCs. Tumor bioimprints are capable of capturing and concentrating pancreatic tumor cells from a mixed cell population with increased retention observed with the number of seedings. ASPC-1 bioimprints preferentially retain both types of pancreatic tumor cells. This technology could be relevant for the collection and interrogation of liquid biopsies, early detection, and relapse monitoring of pancreatic cancer patients.

Transpapillary tissue sampling of biliary strictures: balloon dilatation prior to forceps biopsy improves sensitivity and accuracy

The early and definitive diagnosis of malignant bile duct stenoses is essential for a timely and adequate therapy. However, tissue sampling with transpapillary brush cytology (BC) or forceps biopsy (FB) remains challenging. With this study, we aimed to compare the effectiveness and safety of different tissue sampling modalities (BC, FB without/after previous balloon dilatation). Standardized database research identified all patients, who underwent endoscopic retrograde cholangiography with BC and/or FB for indeterminate bile duct stenosis between January 2010 and April 2018 and with a definitive diagnosis. 218 patients were enrolled (149 cases with malignant and 69 with benign disease). FB had a significant higher sensitivity than BC (43% vs. 16%, p < 0.01). Prior balloon dilatation of the stenosis improved the sensitivity of FB from 41 to 71% (p = 0.03), the NPV from 36 to 81% (p < 0.01) and the accuracy from 55 to 87% (p < 0.01). The complication rates did not differ significantly between the modalities. In our center FB turned out to be the diagnostically more effective procedure. Balloon dilatation of the stenosis before FB had a significant diagnostic benefit and was not associated with a higher complication rate.

Tiny but mighty: use of next generation sequencing on discarded cytocentrifuged bile duct brushing specimens to increase sensitivity of cytological diagnosis

Bile duct brushing (BDB) is used to evaluate pancreatobiliary lesions as it widely samples lesions with a low complication rate. Cytological evaluation of BDB is a specific but insensitive test. There is limited literature on the use of post-cytocentrifuged (PCC) samples, which are usually discarded, for next-generation sequencing (NGS) as an adjunct to cytological diagnosis of BDB. In this study we investigate whether molecular analysis by NGS of PCC specimens improves the sensitivity of diagnosis. PCC samples from 100 consecutive BDB specimens spanning 93 unique patients were retained. DNA was extracted and mutational analysis was performed agnostic of morphologic or clinical findings. Each BDB specimen was characterized as negative, atypical or positive based on morphological analysis by trained cytopathologists. Performance characteristics for mutational profiling and morphological analysis were calculated on the basis of clinicopathologic follow-up. There was sufficient clinicopathologic follow-up to classify 94 of 100 cases as either malignant (n = 43) or benign (n = 51). Based on morphologic analysis of cytology, these 94 cases were classified as either benign (n = 55), atypical (n = 18), or as at least suspicious or positive for malignancy (n = 21). Morphologic analysis of cytology showed a sensitivity of 49% and a specificity of 100% if atypical cases were considered negative. NGS revealed oncogenic alterations in 40/43 (93%) of malignant cases based on clinicopathologic follow-up. The most common alterations were in KRAS and TP53, observed in 77% and 49% of malignant cases respectively. No alterations were observed in the 51 benign cases classified based on clinicopathologic follow-up. Supplementing cytomorphologic analysis with molecular profiling of PCC by targeted NGS analysis increased the sensitivity to 93% and maintained specificity at 100%. This study provides evidence for the utility of NGS molecular profiling of PCC specimens to increase the sensitivity of BDB cytology samples, although studies with larger cohorts are needed to verify these findings.

Cholangiocarcinoma in Patients with Primary Sclerosing Cholangitis (PSC): a Comprehensive Review

Cholangiocarcinoma (CCA) is the most common malignancy in patients with primary sclerosing cholangitis (PSC) and carries a high rate of mortality. Although the pathogenesis of CCA in PSC is largely unknown, inflammation-driven carcinogenesis concomitant with various genetic and epigenetic abnormalities are underlying factors. The majority of CCA cases develop from a dominant stricture (DS), which is defined as a stricture with a diameter < 1.5 mm in the common bile duct or < 1.0 mm in the hepatic duct. In PSC patients presenting with an abrupt aggravation of jaundice, pain, fatigue, pruritus, weight loss, or worsening liver biochemistries, CCA should be suspected and evaluated utilizing a variety of diagnostic modalities. However, early recognition of CCA in PSC remains a major challenge. Importantly, 30-50% of CCA in PSC patients are observed within the first year following the diagnosis of PSC followed by an annual incidence ranging from 0.5 to 1.5 per 100 persons, which is nearly 10 to 1000 times higher than that in the general population. Cumulative 5-year, 10-year, and lifetime incidences are 7%, 8-11%, and 9-20%, respectively. When PSC-associated CCA is diagnosed, most tumors are unresectable, and no effective medications are available. Given the poor therapeutic outcome, the surveillance and management of PSC patients who are at an increased risk of developing CCA are of importance. Such patients include older males with large-duct PSC and possibly concurrent ulcerative colitis. Thus, more attention should be paid to patients with these clinical features, in particular within the first year after PSC diagnosis. In contrast, CCA is less frequently observed in pediatric or female PSC patients or in those with small-duct PSC or concurrent Crohn's disease. Recently, new biomarkers such as antibodies to glycoprotein 2 have been found to be associated with an increased risk of developing CCA in PSC. Herein, we review the literature on the pathogenesis, incidence, clinical features, and risk factors, with a focus on various diagnostic modalities of PSC-associated CCA.