Biomarkers for the Diagnosis of Cholangiocarcinoma: A Systematic Review

Practice guidelines for managing extrahepatic biliary tract cancers

Backgrounds/Aims

Reported incidence of extrahepatic bile duct cancer is higher in Asians than in Western populations. Korea, in particular, is one of the countries with the highest incidence rates of extrahepatic bile duct cancer in the world. Although research and innovative therapeutic modalities for extrahepatic bile duct cancer are emerging, clinical guidelines are currently unavailable in Korea. The Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with related societies (Korean Pancreatic and Biliary Surgery Society, Korean Society of Abdominal Radiology, Korean Society of Medical Oncology, Korean Society of Radiation Oncology, Korean Society of Pathologists, and Korean Society of Nuclear Medicine) decided to establish clinical guideline for extrahepatic bile duct cancer in June 2021.

Methods

Contents of the guidelines were developed through subgroup meetings for each key question and a preliminary draft was finalized through a Clinical Guidelines Committee workshop.

Results

In November 2021, the finalized draft was presented for public scrutiny during a formal hearing.

Conclusions

The extrahepatic guideline committee believed that this guideline could be helpful in the treatment of patients.

The Diagnostic and Prognostic Potentials of Non-Coding RNA in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare biliary tract tumor with high malignancy. CCA is the second most common primary hepatobiliary cancer after hepatocarcinoma. Despite its rarity, the incidence of CCA is steadily increasing globally. Most patients with CCA are asymptomatic in the early stages, resulting in a late-stage diagnosis and poor prognosis. Finding reliable biomarkers is essential to improve CCA's early diagnosis and survival rate. Non-coding RNAs (ncRNAs) are non-protein coding RNAs produced by genomic transcription. This includes microRNAs, long non-coding RNAs, and circular RNAs. ncRNAs have multiple functions in regulating gene expression and are crucial for maintaining normal cell function and developing diseases. Many studies have shown that aberrantly expressed ncRNAs can regulate the occurrence and development of CCA. ncRNAs can be easily extracted and detected through tumor tissue and liquid biopsies, representing a potential tool for diagnosing and prognosis CCA. This review will provide a detailed update on the diagnostic and prognostic potentials of lncRNAs and cirRNAs as biomarkers in CCA.

Cholangiocarcinoma of the Common Bile Duct Presenting as Empyema of the Gallbladder: A Rare Case Report

Cholangiocarcinoma of the common bile duct (CBD) presenting as empyema of the gallbladder is a rare entity that poses a risk of septicemia, septic shock, peritonitis, and abscess formation. This case report describes an elderly female presenting with pain in the right hypochondrium, a positive Murphy's sign, and a history of regurgitation and constipation. It highlights the value of imaging in the early diagnosis of this rare presentation of underlying malignancy. The most common cause of empyema of the gallbladder is acute cholecystitis, followed by gallbladder neck obstruction by a calculus. This report discusses the important role of imaging supported by clinical history, examination, laboratory tests, and histopathological findings to diagnose this rare presentation of empyema of the gallbladder as a complication of underlying cholangiocarcinoma. Additionally, it briefly discusses the change in the management line for cholangiocarcinoma patients with complications such as gallbladder perforation and septicemia. The study concludes that the possibility of underlying bile duct malignancy cannot be overlooked in patients with similar symptoms, particularly among the elderly.

Clinical practice guidelines for molecular tumor marker, 2nd edition review part 2

In recent years, rapid advancement in gene/protein analysis technology has resulted in target molecule identification that may be useful in cancer treatment. Therefore, "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" was published in Japan in September 2021. These guidelines were established to align the clinical usefulness of external diagnostic products with the evaluation criteria of the Pharmaceuticals and Medical Devices Agency. The guidelines were scoped for each tumor, and a clinical questionnaire was developed based on a serious clinical problem. This guideline was based on a careful review of the evidence obtained through a literature search, and recommendations were identified following the recommended grades of the Medical Information Network Distribution Services (Minds). Therefore, this guideline can be a tool for cancer treatment in clinical practice. We have already reported the review portion of "Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition" as Part 1. Here, we present the English version of each part of the Clinical Practice Guidelines for Molecular Tumor Marker, Second Edition.

Liver transplantation as an alternative for the treatment of perihilar cholangiocarcinoma: A critical review

BACKGROUND

Perihilar cholangiocarcinoma (phCCC) is a dismal malignancy. There is no consensus regarding the best treatment for patients with unresectable phCCC. The present review aimed to gather the current pieces of evidence for liver transplantation and liver resection as a treatment for phCCC and to build better guidance for clinical practice.

DATA SOURCES

The search was conducted in PubMed, Embase, Cochrane, and LILACS. The related references were searched manually. Inclusion criteria were: reports in English or Portuguese literature that a) patients with confirmed diagnosis of phCCC; b) patients treated with a curative intent; c) patients with the outcomes of liver resection and liver transplantation. Case reports, reviews, letters, editorials, conference abstracts and papers with full-text unavailability were excluded from the analysis.

RESULTS

Most of the current literature is based on observational retrospective studies with low grades of evidence. Liver resection has better long-term outcomes than systemic chemotherapy or palliation therapy and liver transplantation is a good alternative for selected patients with unresectable phCCC. All candidates for resection or transplantation should be medically fit and free of intrahepatic or extrahepatic diseases. As a general rule, patients presenting with a tumor having a longitudinal size > 3 cm or extending below the cystic duct, lymph node disease, confirmed extrahepatic dissemination; intraoperatively diagnosed metastatic disease; a history of other malignancies within the last five years, and did not complete chemoradiation regimen and were medically unfit should not be considered for transplantation. Some of these criteria should be individually assessed. Liver transplantation or resection should only be considered in highly experienced hepatobiliary centers, and any decision-making must be based on a multidisciplinary evaluation.

CONCLUSIONS

phCCC is a complex condition with high morbidity. Surgical therapies, including hepatectomy and liver transplantation, are the best option for better long-term disease-free survival.

Intrahepatic cholangiocarcinoma biomarkers: Towards early detection and personalized pharmacological treatments

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

Fish and Food-Fatale: Food-borne Trematode Opisthorchis viverrini and Cholangiocarcinoma

Neglected Tropical Diseases (NTDs) are a group of communicable diseases with a long history with human beings. NTDs are the proxy of poverty since they affect those in low-income and extreme-poverty populations, as those populations lack access to proper health care, clean water, sanitary conditions, and hygiene. NTDs create losses for a nation that come from the health and the economic sectors as well since the costs of diagnosis, prevention, and treatment strain the national purse strings. One of the 20 different forms of NTDs on the list is food-borne trematodes, comprises of Fasciola, Paragonimus, Clonorchis, and Opisthorchis. Currently, it is estimated that food-borne trematodes can cause a devastating effect on mortality and morbidity. All of them are zoonotic, as humans become infected by ingestion of a second intermediate host, such as freshwater snails, fish, or water vegetables. Opisthorchis viverrini, one of the food-borne trematodes that can be found mostly in South East Asia regions, especially in the Mekong basin, is regarded as a group 1 carcinogen leading to cholangiocarcinoma (CCA). This study aims to present the updated review of Opisthorchis viverrini and CCA.

Cost-Effectiveness Analysis of Ultrasound Surveillance for Cholangiocarcinoma in an Endemic Area of Thailand

OBJECTIVE

This research aimed to analyze the cost-effectiveness of ultrasound surveillance for Cholangiocarcinoma (CCA) in a high-risk population residing in the northern region of Thailand and compare these results with the non-surveillance patients who presented with CCA.

METHODS

This was a retrospective descriptive study of two groups monitored and treated for CCA in the same institute, but differing as to whether ultrasound was included in the surveillance. The ultrasound surveillance group comprised those who participated in the cohort study of CCA at Chulabhorn Hospital from 2011 to 2017. Whereas, the non-ultrasound surveillance group consisted of patients treated for CCA at Chulabhorn Hospital from 2009 to 2015 (and not part of the first group). Historical data and societal perspectives were analyzed and interpreted using a decision tree model. The results of one-way sensitivity analyses of probability and cost parameters affecting the change in incremental cost-effectiveness ratio (ICER) were analyzed and presented using tornado diagrams.

RESULT

The ultrasound surveillance group had the quality-adjusted life years gained (QALY gained) of 0.117 years, resulting in the incremental cost-effectiveness ratio (ICER) of 152,985 Thai Baht (THB) or equal to 4,222.6 US-dollars (USD) /QALY gained which is about when compared to the non-ultrasound surveillance group. Moreover, the ICER value was within the willingness to pay (WTP) calculated for Thailand of 4,416.2 USD (160,000 THB) /QALY gained.  The probability of non-diagnostic CCA in non-ultrasound surveillance group and the cost of abdominal ultrasound were found to be major factors affecting the ICER.

CONCLUSION

Ultrasound surveillance of CCA was cost-effective in Thailand. This information can be helpful for national policy planning in regard to Thai populations at high risk of CCA. Further study is recommended to assess cost-effectiveness in other areas with lower incidences of CCA.

The cancer glycocode as a family of diagnostic biomarkers, exemplified by tumor-associated gangliosides

One unexploited family of cancer biomarkers comprise glycoproteins, carbohydrates, and glycolipids (the Tumor Glycocode).A class of glycolipid cancer biomarkers, the tumor-marker gangliosides (TMGs) are presented here as potential diagnostics for detecting cancer, especially at early stages, as the biological function of TMGs makes them etiological. We propose that a quantitative matrix of the Cancer Biomarker Glycocode and artificial intelligence-driven algorithms will expand the menu of validated cancer biomarkers as a step to resolve some of the challenges in cancer diagnosis, and yield a combination that can identify a specific cancer, in a tissue-agnostic manner especially at early stages, to enable early intervention. Diagnosis is critical to reducing cancer mortality but many cancers lack efficient and effective diagnostic tests, especially for early stage disease. Ideal diagnostic biomarkers are etiological, samples are preferably obtained via non-invasive methods (e.g. liquid biopsy of blood or urine), and are quantitated using assays that yield high diagnostic sensitivity and specificity for efficient diagnosis, prognosis, or predicting response to therapy. Validated biomarkers with these features are rare. While the advent of proteomics and genomics has led to the identification of a multitude of proteins and nucleic acid sequences as cancer biomarkers, relatively few have been approved for clinical use. The use of multiplex arrays and artificial intelligence-driven algorithms offer the option of combining data of known biomarkers; however, for most, the sensitivity and the specificity are below acceptable criteria, and clinical validation has proven difficult. One strategic solution to this problem is to expand the biomarker families beyond those currently exploited. One unexploited family of cancer biomarkers comprise glycoproteins, carbohydrates, and glycolipids (the Tumor Glycocode). Here, we focus on a family of glycolipid cancer biomarkers, the tumor-marker gangliosides (TMGs). We discuss the diagnostic potential of TMGs for detecting cancer, especially at early stages. We include prior studies from the literature to summarize findings for ganglioside quantification, expression, detection, and biological function and its role in various cancers. We highlight the examples of TMGs exhibiting ideal properties of cancer diagnostic biomarkers, and the application of GD2 and GD3 for diagnosis of early stage cancers with high sensitivity and specificity. We propose that a quantitative matrix of the Cancer Biomarker Glycocode and artificial intelligence-driven algorithms will expand the menu of validated cancer biomarkers as a step to resolve some of the challenges in cancer diagnosis, and yield a combination that can identify a specific cancer, in a tissue-agnostic manner especially at early stages, to enable early intervention.

The roles of epigenetic regulation in cholangiocarcinogenesis

Cholangiocarcinoma (CCA), a heterogeneous malignancy of bile duct epithelial cells, is characterized by aggressiveness, difficult diagnosis, and poor prognosis due to limited understanding and lack of effective therapeutic strategies. Genetic and epigenetic alterations accumulated in CCA cells can cause the aberrant regulation of oncogenes and tumor suppressors. Epigenetic alterations with histone modification, DNA methylation, and noncoding RNA modulation are associated with the carcinogenesis of CCA. Mutation or silencing of genes by various mechanisms can be a frequent event during CCA development. Alterations in histone acetylation/deacetylation at the posttranslational level, DNA methylation at promoters, and noncoding RNA regulation contribute to the heterogeneity of CCA and drive tumor development. In this review article, we mainly focus on the roles of epigenetic regulation in cholangiocarcinogenesis. Alterations in epigenetic modification can be potential targets for the therapeutic management of CCA, and epigenetic targets may become diagnostic biomarkers of CCA.

Peptidylarginine Deiminase Type 2 Predicts Tumor Progression and Poor Prognosis in Patients with Curatively Resected Biliary Tract Cancer

(1) Background: PADI2 is a post-translational modification (PTM) enzyme that catalyzes citrullination, which then triggers autoimmune disease and cancer. This study aimed to evaluate the prognostic value of peptidylarginine deiminase 2 (PADI2) protein expression in biliary tract cancer (BTC) patients. (2) Methods: Using immunohistochemistry, the PADI2 protein expression in BTC tissues was analyzed. The correlations between PADI2 protein expression and clinicopathologic characteristics were analyzed using Chi-square tests. The Kaplan-Meier procedure was used for comparing survival distributions. We used Cox proportional hazards regression for univariate and multivariate analyses. From 2014 to 2020, 30 resected BTC patients were enrolled in this study. (3) Results: Patients with high PADI2 protein expression were associated with shorter progress-free survival (PFS; p = 0.041), disease-specific survival (DSS; p = 0.025), and overall survival (OS; p = 0.017) than patients with low PADI2 protein expression. (4) Conclusions: The results indicated that PADI2 protein expression was an independent poor prognostic factor for BTC patients regarding PFS, DSS, and OS.

Raman Scattering-Based Optical Sensing Of Chronic Liver Diseases

Chronic liver diseases (CLDs) are a major public health problem. Despite the progress achieved in fighting against viral hepatitis, the emergence of non-alcoholic fatty liver disease might pose a serious challenge to the public's health in the coming decades. Medical management of CLDs represents a substantial burden on the public health infrastructures. The health care cost of these diseases is an additional burden that weighs heavily on the economies of developing countries. Effective management of CLDs requires the adoption of reliable and cost-effective screening and diagnosing methods to ensure early detection and accurate clinical assessment of these diseases. Vibrational spectroscopies have emerged as universal analytical methods with promising applications in various industrial and biomedical fields. These revolutionary analytical techniques rely on analyzing the interaction between a light beam and the test sample to generate a spectral fingerprint. This latter is defined by the analyte's chemical structure and the molecular vibrations of its functional groups. Raman spectroscopy and surface-enhanced Raman spectroscopy have been used in combination with various chemometric tests to diagnose a wide range of malignant, metabolic and infectious diseases. The aim of the current review is to cast light on the use of these optical sensing methods in the diagnosis of CLDs. The vast majority of research works that investigated the potential application of these spectroscopic techniques in screening and detecting CLDs were discussed here. The advantages and limitations of these modern analytical methods, as compared with the routine and gold standard diagnostic approaches, were also reviewed in details.

Understanding the Clinical Significance of MUC5AC in Biliary Tract Cancers

Biliary tract cancers (BTC) arise from biliary epithelium and include cholangiocarcinomas or CCA (including intrahepatic (ICC) and extrahepatic (ECC)) and gallbladder cancers (GBC). They often have poor outcomes owing to limited treatment options, advanced presentations, frequent recurrence, and poor response to available systemic therapy. Mucin 5AC (MUC5AC) is rarely expressed in normal biliary epithelium, but can be upregulated in tissues of benign biliary disease, premalignant conditions (e.g., biliary intraepithelial neoplasia), and BTCs. This mucin's numerous glycoforms can be divided into less-glycosylated immature and heavily-glycosylated mature forms. Reported MUC5AC tissue expression in BTC varies widely, with some associations based on cancer location (e.g., perihilar vs. peripheral ICC). Study methods were variable regarding cancer subtypes, expression positivity thresholds, and MUC5AC glycoforms. MUC5AC can be detected in serum of BTC patients at high concentrations. The hesitancy in developing MUC5AC into a clinically useful biomarker in BTC management is due to variable evidence on the diagnostic and prognostic value. Concrete conclusions on tissue MUC5AC are difficult, but serum detection might be relevant for diagnosis and is associated with poor prognosis. Future studies are needed to further the understanding of the potential clinical value of MUC5AC in BTC, especially regarding predictive and therapeutic value.

High Level of Serum Coiled-coil Domain Containing 25 (CCDC25) as a Diagnostic Marker for Cholangiocarcinoma But Not for Other Cancers

BACKGROUND/AIM

Recently, we reported that coiled-coil domain containing 25 (CCDC25) protein is elevated in the sera of patients with cholangiocarcinoma (CCA) and is suggested to be a diagnostic biomarker for CCA. This study aimed to examine whether serum CCDC25 level can be a unique biomarker for CCA. Bioinformatic analyses using Human Protein Atlas (HPA) database and Gene Expression Profiling Interactive Analysis 2 (GEPIA2) indicated that CCDC25 protein and mRNA are expressed not only in CCA but also in other cancers, such as colorectal cancer (CRC), breast cancer (BC), and hepatocellular carcinoma (HCC), all of which are the top 5 cancers highly prevalent in Thailand.

MATERIALS AND METHODS

Using a quantitative dot blot assay, serum CCDC25 levels were measured for 30 healthy controls (HC), 34 CRC, 42 BC, 43 HCC, and 83 CCA.

RESULTS

The serum CCDC25 levels of CCA patients (0.193±0.039 ng/μl) were significantly higher than those of CRC (0.019±0.006 ng/μl), BC (0.036±0.015 ng/μl), HCC (0.035±0.016 ng/μl), and higher than those of HC (0.012±0.003 ng/μl). The serum CCDC25 level can discriminate CCA from the HC, CRC, BC, and HCC with a sensitivity of 100, 99, 94, and 94%, respectively, and specificity of 100, 100, 98, and 95%, respectively.

CONCLUSION

CCDC25 is a candidate diagnostic biomarker for CCA.

Translational Proteomic Approach for Cholangiocarcinoma Biomarker Discovery, Validation, and Multiplex Assay Development: A Pilot Study

Cholangiocarcinoma (CCA) is a highly lethal disease because most patients are asymptomatic until they progress to advanced stages. Current CCA diagnosis relies on clinical imaging tests and tissue biopsy, while specific CCA biomarkers are still lacking. This study employed a translational proteomic approach for the discovery, validation, and development of a multiplex CCA biomarker assay. In the discovery phase, label-free proteomic quantitation was performed on nine pooled plasma specimens derived from nine CCA patients, nine disease controls (DC), and nine normal individuals. Seven proteins (S100A9, AACT, AFM, and TAOK3 from proteomic analysis, and NGAL, PSMA3, and AMBP from previous literature) were selected as the biomarker candidates. In the validation phase, enzyme-linked immunosorbent assays (ELISAs) were applied to measure the plasma levels of the seven candidate proteins from 63 participants: 26 CCA patients, 17 DC, and 20 normal individuals. Four proteins, S100A9, AACT, NGAL, and PSMA3, were significantly increased in the CCA group. To generate the multiplex biomarker assays, nine machine learning models were trained on the plasma dynamics of all seven candidates (All-7 panel) or the four significant markers (Sig-4 panel) from 45 of the 63 participants (70%). The best-performing models were tested on the unseen values from the remaining 18 (30%) of the 63 participants. Very strong predictive performances for CCA diagnosis were obtained from the All-7 panel using a support vector machine with linear classification (AUC = 0.96; 95% CI 0.88–1.00) and the Sig-4 panel using partial least square analysis (AUC = 0.94; 95% CI 0.82–1.00). This study supports the use of the composite plasma biomarkers measured by clinically compatible ELISAs coupled with machine learning models to identify individuals at risk of CCA. The All-7 and Sig-4 assays for CCA diagnosis should be further validated in an independent prospective blinded clinical study.

High expression of protein tyrosine phosphatase receptor S (PTPRS) is an independent prognostic marker for cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive tumor of the bile duct with a high rate of mortality. Lymph node metastasis is an important factor facilitating the progression of CCA. A reliable biomarker for diagnosis, progression status, or prognosis of CCA is still lacking. To identify a novel and reliable biomarker for diagnosis/prognosis of CCA, liquid chromatography-mass spectrometry and tandem mass spectrometry (LC-MS/MS) in combination with bioinformatics analysis were applied for the representative serum samples of patients with CCA. The proteome results showed that protein tyrosine phosphatase receptor S (PTPRS) had the highest potential candidate. Then, a dot blot assay was used to measure the level of serum PTPRS in patients with CCA (n = 80), benign biliary disease patients (BBD; n = 39), and healthy controls (HC; n = 55). PTPRS level of CCA sera (14.38 ± 9.42 ng/ml) was significantly higher than that of BBD (10.7 ± 5.05 ng/ml) or HC (6 ± 3.73 ng/ml) (P < 0.0001). PTPRS was associated with serum albumin (P = 0.028), lymph node metastasis (P = 0.038), and the survival time of patients (P = 0.011). Using a log-rank test, higher serum PTPRS level was significantly (P = 0.031) correlated with a longer overall survival time of patients with CCA, and PTPRS was an independent prognostic marker for CCA superior to carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA) or alkaline phosphatase (ALP). High expression of PTPRS could be a good independent prognostic marker for CCA.

Precision Medicine in Biliary Tract Cancer

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

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

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

Long Non-Coding RNAs as Molecular Biomarkers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a biliary system cancer that has the characteristics of strong invasiveness, poor prognosis, and few therapy choices. Furthermore, the absence of precise biomarkers for early identification and prognosis makes it hard to intervene in the early phase of initial diagnosis or recurring cholangiocarcinoma following surgery. Encouragingly, previous studies found that long non-coding RNA (lncRNA), a subgroup of RNA that is more than 200 nucleotides long, can affect cell proliferation, migration, apoptosis, and even drug resistance by altering numerous signaling pathways, thus reaching pro-cancer or anti-cancer outcomes. This review will take a retrospective view of the recent investigations on the work of lncRNAs in cholangiocarcinoma progression and the potential of lncRNAs serving as promising clinical biomarkers and therapeutic targets for CCA.

Prediction of Multiple Serum Tumor Markers in Hepatolithiasis Complicated with Intrahepatic Cholangiocarcinoma

Objective

To evaluate the predictive value of multiple serum tumor markers in hepatolithiasis complicated with intrahepatic cholangiocarcinoma (hepatolithiasis-associated cholangiocarcinoma, HL-CCA).

Methods

From January 2010 to December 2020, three hundred eighty-five hepatolithiasis patients in Zhoukou Central Hospital were retrospectively analyzed, among them thirty patients complicated with intrahepatic cholangiocarcinoma. The levels of serum AFP, CA125, CA19-9, CA242, and CEA in hepatolithiasis or HL-CCA were measured. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic effects of single or combined detection of the five tumor markers for HL-CCA.

Results

The level of AFP was insignificantly different between the hepatolithiasis and HL-CCA (P=0.730). CA125, CA19-9, CA242 and CEA were elevated in HL-CCA. The area under ROC curves (AUCs) of the single detection of serum CA125, CA19-9, CA242 and CEA were all more than 0.5. The maximum AUC occurred in CA19-9. The AUC of AFP was slightly higher than 0.5, but the level of serum AFP was insignificantly different between hepatolithiasis and HL-CCA. The single detection of AFP was not of great significance to the differential diagnosis. The optimal cut-off values of CA125, CA19-9, CA242, and CEA were 104.09 kU/L, 383.28 U/mL, 152.56 kU/L, 6.29 ng/mL. The diagnostic effect of CA19-9 was the highest one for differential diagnosis between hepatolithiasis and HL-CCA. With reference to CA19-9 >383.28 U/mL, the sensitivity and specificity of the single detection were 80.00% and 82.61% respectively, and the AUC was 0.883. The diagnostic effect of CEA was secondary toward CA19-9. With reference to CEA >6.29 ng/mL, the sensitivity and specificity of the single detection were 66.67% and 83.76% respectively, and the AUC was 0.814.

Conclusion

Serum CA19-9 maybe the effective tumor marker in the diagnosis of HL-CCA, and measurement of combined serum tumor markers can help in the detection of HL-CCA.

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.

Detection of Human Cholangiocarcinoma Markers in Serum Using Infrared Spectroscopy

Simple Summary

Cholangiocarcinoma is a form of liver cancer that is found, predominantly, in Thailand. Due to the non-specific symptoms and laboratory investigation, it is difficult to rule out cholangiocarcinoma from other liver conditions. Here, we demonstrate the development of a diagnostic tool for cholangiocarcinoma, based on the ATR-FTIR analyses of sera, coupled with multivariate analyses and machine learning tools to obtain a better specificity. The innovative approach that shows highly promising results for this otherwise difficult to diagnose cancer.

Abstract

Cholangiocarcinoma (CCA) is a malignancy of the bile duct epithelium. Opisthorchis viverrini infection is a known high-risk factor for CCA and in found, predominantly, in Northeast Thailand. The silent disease development and ineffective diagnosis have led to late-stage detection and reduction in the survival rate. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) is currently being explored as a diagnostic tool in medicine. In this study, we apply ATR-FTIR to discriminate CCA sera from hepatocellular carcinoma (HCC), biliary disease (BD) and healthy donors using a multivariate analysis. Spectral markers differing from healthy ones are observed in the collagen band at 1284, 1339 and 1035 cm⁻¹, the phosphate band (vsPO2−) at 1073 cm⁻¹, the polysaccharides band at 1152 cm⁻¹ and 1747 cm⁻¹ of lipid ester carbonyl. A Principal Component Analysis (PCA) shows discrimination between CCA and healthy sera using the 1400–1000 cm⁻¹ region and the combined 1800—1700 + 1400–1000 cm⁻¹ region. Partial Least Square-Discriminant Analysis (PLS-DA) scores plots in four of five regions investigated, namely, the 1400–1000 cm⁻¹, 1800–1000 cm⁻¹, 3000–2800 + 1800–1000 cm⁻¹ and 1800–1700 + 1400–1000 cm⁻¹ regions, show discrimination between sera from CCA and healthy volunteers. It was not possible to separate CCA from HCC and BD by PCA and PLS-DA. CCA spectral modelling is established using the PLS-DA, Support Vector Machine (SVM), Random Forest (RF) and Neural Network (NN). The best model is the NN, which achieved a sensitivity of 80–100% and a specificity between 83 and 100% for CCA, depending on the spectral window used to model the spectra. This study demonstrates the potential of ATR-FTIR spectroscopy and spectral modelling as an additional tool to discriminate CCA from other conditions.

Role of microRNAs in the anticancer effects of the flavonoid luteolin: a systematic review

Flavonoids, a broad class of polyphenolic compounds, can potentially have several therapeutic properties in human diseases, including protective effects against oxidative stress, inflammation, cardiovascular disease, diabetes, neurodegenerative disorders, and cancers. Luteolin as a member of flavonoids has been found to exhibit several anticancer properties mainly through cell apoptosis induction, inhibition of invasion, cell proliferation, network formation, and migration. Recent studies have revealed that phytochemicals such as luteolin may exert therapeutic properties through microRNAs (miRNAs or miRs), which have been emerged as important molecules in cancer biology in recent years. miRNAs, as a class of noncoding RNAs, have several important roles in cancer progression or regression. In this review, we aimed to summarize and discuss the role of miRNAs in the luteolin effects on different cancers. This review can be in line with the studies, which have shown that miRNAs may be potential therapeutic targets in cancer treatment.

Prognostic biomarkers for cholangiocarcinoma (CCA): state of the art

Introduction:Although advances in understanding the molecular basis of cholangiocarcinoma (CCA) have been made, surgery is the only curative therapy option and the overall prognosis of patients suffering from the disease remains poor. Therefore, estimation of prognosis based on known and novel biomarkers is essential for therapy guidance of CCA in both, curative and palliative settings.Areas covered:An extensive literature search on biomarkers for CCA with special emphasis on prognosis was performed. Based on this, prognostic biomarkers from serum, tumor tissue and other compartments that are currently in use or under evaluation for CCA were summarized in this review. Furthermore, an overview of new biomarkers was provided including those determined from extracellular vesicles (EVs), metabolites and nucleic acids. Finally, prognostic markers associated with potential new therapy options for the treatment of CCA were summed up.Expert opinion:So far, an optimal prognostic biomarker for CCA has not been described. However, based on the increasing knowledge about the molecular basis of CCA but also due to novel, innovative technologies, a plethora of novel prognostic biomarkers is currently under evaluation and will be available for CCA in future.

Establishment of a Potential Serum Biomarker Panel for the Diagnosis and Prognosis of Cholangiocarcinoma Using Decision Tree Algorithms

Potential biomarkers which include S100 calcium binding protein A9 (S100A9), mucin 5AC (MUC5AC), transforming growth factor β1 (TGF-β1), and angiopoietin-2 have previously been shown to be effective for cholangiocarcinoma (CCA) diagnosis. This study attempted to measure the sera levels of these biomarkers compared with carbohydrate antigen 19-9 (CA19-9). A total of 40 serum cases of CCA, gastrointestinal cancers (non-CCA), and healthy subjects were examined by using an enzyme-linked immunosorbent assay. The panel of biomarkers was evaluated for their accuracy in diagnosing CCA and subsequently used as inputs to construct the decision tree (DT) model as a basis for binary classification. The findings showed that serum levels of S100A9, MUC5AC, and TGF-β1 were dramatically enhanced in CCA patients. In addition, 95% sensitivity and 90% specificity for CCA differentiation from healthy cases, and 70% sensitivity and 83% specificity for CCA versus non-CCA cases was obtained by a panel incorporating all five candidate biomarkers. In CCA patients with low CA19-9 levels, S100A9 might well be a complementary marker for improved diagnostic accuracy. The high levels of TGF-β1 and angiopoietin-2 were both associated with severe tumor stages and metastasis, indicating that they could be used as a reliable prognostic biomarkers panel for CCA patients. Furthermore, the outcome of the CCA burden from the Classification and Regression Tree (CART) algorithm using serial CA19-9 and S100A9 showed high diagnostic efficiency. In conclusion, results have shown the efficacy of CCA diagnosis and prognosis of the novel CCA-biomarkers panel examined herein, which may prove be useful in clinical settings.

BIRC7 and STC2 Expression Are Associated With Tumorigenesis and Poor Outcome in Extrahepatic Cholangiocarcinoma

Background:

Extrahepatic cholangiocarcinoma (EHCC) is a highly aggressive epithelial malignancy and has a poor prognosis for the insensitivity to therapies and difficulty in detection. Novel targets and biomarkers are urgently needed to develop for functional, diagnostic and prognostic application on EHCC.

Methods:

Immunohistochemical staining technique using the EnVision antibody complex was performed on the samples obtained from 100 EHCC, 30 peritumoral extrahepatic biliary tract (EHBT), 10 EHBT adenomas and 15 normal EHBT tissues.

Results:

The positive rates of BIRC7 and STC2 expression in tissues obtained from peritumoral EHBT, EHBT adenomas and normal EHBT were significantly lower than those in EHCC tissues. BIRC7 and STC2 proteins were expressed at significantly higher levels in patients with lymph node metastasis, invasion of adjacent tissues, and higher TNM stage (III and/or IV) and unable to undergo resection (biopsy only). Kaplan-Meier survival curves indicated that significantly decreased overall survival rate in patients with positive-BIRC7 or positive-STC2 expression compared with patients of negative-BIRC7 or negative-STC2 expression, respectively. Cox-proportional regression analysis demonstrated that positive-BIRC7 and positive-STC2 expression, along with poor differentiation of EHCC, tumor size >3 cm, lymph node metastasis, invasion of adjacent tissues and unable to undergo resection are independent prognostic factors of EHCC patients.

Conclusions:

The levels of BIRC7 and STC2 expression were correlated with clinicopathological characteristics of EHCC, and positive expression of BIRC7 and STC2 are associated with progression and poor clinical outcomes of EHCC. BIRC7 and STC2 might be a potential biomarker for EHCC in clinic.

Neoadjuvant treatment strategies for intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver malignancy and is increasing in incidence. Long-term outcomes are optimized when patients undergo margin-negative resection followed by adjuvant chemotherapy. Unfortunately, a significant proportion of patients present with locally advanced, unresectable disease. Furthermore, recurrence rates are high even among patients who undergo surgical resection. The delivery of systemic and/or liver-directed therapies prior to surgery may increase the proportion of patients who are eligible for surgery and reduce recurrence rates by prioritizing early systemic therapy for this aggressive cancer. Nevertheless, the available evidence for neoadjuvant therapy in ICC is currently limited yet recent advances in liver directed therapies, chemotherapy regimens, and targeted therapies have generated increasing interest its role. In this article, we review the rationale for, current evidence for, and ongoing research efforts in the use of neoadjuvant therapy for ICC.

PCAT1 induced by transcription factor YY1 promotes cholangiocarcinoma proliferation, migration and invasion by sponging miR-216a-3p to up-regulate oncogene BCL3

This study was designed to illustrate the function and role of PCAT1 in CCA. The relative expression was confirmed by RT-qPCR and western blot. The biological function of PCAT1 was evaluated by CCK8, EdU, colony formation, wound healing, transwell, and subcutaneous tumor formation assays. Protein levels of EMT markers were measured by western blot. The binding relationship was predicted by JASPAR and starBase. The binding of YY1 to PCAT1 promoter was assessed by ChIP and luciferase reporter. The binding capacity between miR-216a-3p and PCAT1 as well as BCL3 was assessed by luciferase reporter and AGO2-RIP assays. In this study, we found that PCAT1 was up-regulated in CCA tissues and cells, and the PCAT1 overexpression was associated with poor prognosis. Moreover, PCAT1 was assessed as an independent risk factor of prognosis for CCA patients. Amplified PCAT1 was found to promote tumor proliferation, migration, invasion and EMT process, whereas PCAT1 knockdown inhibited these malignant phenotypes. Mechanistically, PCAT1 was predominantly localized in the cytoplasm and competitively bound miR-216a-3p to increase BCL3 expression. In addition, PCAT1 was activated by transcription factor YY1. This study revealed that PCAT1 acted as an oncogene in CCA, and the YY1/PCAT1/miR-216a-3p/BCL3 axis exhibited critical functions in CCA progression.

Interleukin 25 (IL-25) expression in cholangiocarcinoma

Various cytokines are involved in carcinogenesis and tumor progression. Some tumor cells produce cytokines by themselves. Using secretome analysis, a high expression of APEX-1 was found in cholangiocarcinoma (CCA) cell lines. During this secretome analysis, it was found that CCA cell lines overexpressed some cytokines and related molecules, including interleukin 25 (IL-25). In the present study, we first performed precise secretome analysis on cytokines and related molecules in CCA cell lines and identified that IL-25 was overexpressed in CCA cell lines. Then, using immunohistochemical methods, we investigated the expression of IL-25 in the cancer tissues from 20 CCA patients in Northeast Thailand. Correlation between IL-25 expression levels and patients' clinical parameters were analyzed. The results showed that IL-25 expression was significantly (P<0.0001) higher in cancerous tissues than in the normal bile ducts and in the adjacent tissues. Overexpression of IL-25 protein in CCA tissue was confirmed using western blot analysis. Moreover, IL-25 expression in cancerous tissues was significantly (P<0.0015) higher in CCA patients with metastasis than in CCA patients without metastasis. Survival analysis revealed that a high expression of IL-25 was correlated with shorter survival time of CCA patients (P=0.0260). Aberrant expression of IL-25 in CCA tissue was associated with tumor metastasis and poor prognosis, suggesting that IL-25 is a potential prognostic biomarker. Biological roles of IL-25 in CCA genesis and progression should be explored in future.

The role of extracellular vesicles in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare tumor that arises from cholangiocytes, the epithelial cells of the bile duct. The tumor is characterized by insidious onset, high degree of malignancy, poor prognosis and high recurrence rate. Due to the lack of specific biomarkers, it is difficult to diagnose CCA early and evaluate prognosis. Extracellular vesicles (EVs), which include apoptotic bodies, microvesicles and exosomes, have emerged as having important roles in cell-to-cell communication in both normal physiology and pathological conditions. Some research has found that EVs play a crucial role in the occurrence and development of CCA. EVs can carry specific molecular substances such as nucleic acids and proteins, which have potential for the diagnosis and therapy of CCA. This article reviews the current knowledge on the role of EVs in CCA. We highlight EVs and their functions in the physiology and pathophysiology of CCA, and discuss their therapeutic potential and their role as biomarkers.

MicroRNAs in the anticancer effects of celecoxib: A systematic review

Cyclooxygenase-2 (COX-2) is known as an important enzyme in the inflammation process that has tumorigenesis function in various cancers through the induction of epithelial-to-mesenchymal transition (EMT), cell proliferation, migration, and invasion that lead to metastasis. Celecoxib is a nonsteroidal anti-inflammatory drug (NSAID) that can selectively target COX-2, suppress downstream pathways, and finally lead to anticancer potentiality. microRNAs (miRNAs), as a class of small noncoding RNAs, play pivotal roles in cancers through the tumor-suppressive or oncogenic effects, by post-transcriptional regulation of their target genes. In this regard, shreds of evidence have shown that, COX-2 reveals its action through miRNA regulation. So, in this systematic review, we aimed to highlight the tumorigenic role of COX-2 in cancer development and the therapeutic effects of celecoxib, as a selective COX-2 drug, through the regulation of miRNAs.

PIMREG, a Marker of Proliferation, Facilitates Aggressive Development of Cholangiocarcinoma Cells Partly Through Regulating Cell Cycle-Related Markers

BACKGROUND

Phosphatidylinositol binding clathrin assembly protein interacting mitotic regulator (PIMREG) is a protein associated with cell proliferation. Its aberrant expression was reported to be correlated with the development in multiple tumors. However, its role in cholangiocarcinoma (CAA) has not yet been evaluated in detail.

METHODS

Data were acquired from the public TCGA database for evaluating the expression pattern of PIMREG and assessing its clinical relevance as well as its correlation with overall survival. RBE and HUH28 cell lines were selected to perform loss- and gain-of-function of PIMREG assays respectively. Quantitative real-time PCR (RT-qPCR) and western blot analyses were used to measure the mRNA and protein levels of PIMREG. Cell Counting Kit-8, colony formation tests, and Transwell assays served to measure the effect of PIMREG on the proliferative, invasive and migratory capacities of CAA cells, appropriately. Gene set enrichment analysis (GSEA) was conducted to identify PIMREG associated gene set, which was further confirmed by western blot.

RESULTS

PIMREG was found to be highly expressed in CAA tissues and cell lines according to the public dataset and RT-qPCR analysis, and negatively related to the prognosis of patients with CAA. Moreover, knockdown of PIMREG suppressed and overexpression of PIMREG promoted the proliferation, invasion and migration of CAA cells. Furthermore, GSEA revealed that high PIMREG expression was positively associated with cell cycle signaling. And the next western blot analysis demonstrated that silencing PIMREG resulted in a reduction on the levels of p-CDK1, CCNE1, and CCNB1, whereas PIMREG overexpression led to an opposite result.

CONCLUSION

The results suggested that PIMREG facilitates the growth, invasion and migration of CAA cells partly by regulating the cell cycle relative biomarkers, revealing that PIMREG may be a crucial molecule in the progression of CAA.

Serum coiled-coil domain containing 25 protein as a potential screening/diagnostic biomarker for cholangiocarcinoma

Coiled-coil domain containing 25 (CCDC25) was previously reported to be upregulated in cholangiocarcinoma (CCA) tissues compared with adjacent normal tissues. The present study investigated whether serum CCDC25 level may be used as a potential marker for the diagnosis of CCA. Bioinformatics tools were used to reveal that CCDC25 is secreted into plasma/serum via a non-conventional pathway, which secretes proteins independently from the endoplasmic reticulum/golgi complex, but is yet to be fully elucidated. Subsequently, the CCDC25 levels in the sera of patients with CCA (n=141), patients with benign biliary disease (BBD; n=53) and healthy controls (HC; n=72) were measured using a quantitative dot blot assay based on the standard curve created using recombinant CCDC25 protein. The results demonstrated that the serum CCDC25 level in the CCA group (0.28±0.06 ng/µl) was significantly higher compared with that in the BBD (0.15±0.03 ng/µl) or HC (0.0017±0.0008 ng/µl) groups. Serum CCDC25 level provided an improved resolution (P=0.0001) compared with carcinoembryonic antigen (P=0.098) or carbohydrate antigen 19-9 (P=0.271) for the differential diagnosis between BBD and CCA. Receiver operating characteristic curve analysis revealed high sensitivity and specificity of serum CCDC25 level to differentiate between patients with CCA and HC (93.0 and 100%, respectively), and also to differentiate between patients with CCA and patients with BBD (75.0 and 84.0%, respectively). CCDC25 expression was further investigated in 23 CCA tissues, and CCDC25 expression in cancer tissues was moderately correlated with the serum CCDC25 level (r²=0.52, P=0.01). Among patients with CCA, serum CCDC25 level was significantly higher in patients with non-metastatic CCA compared with patients with metastatic CCA. Correspondingly, a higher serum CCDC25 level was associated with a longer overall survival time in patients with CCA. In conclusion, serum CCDC25 level may be a promising screening and diagnostic marker for the differential diagnosis of CCA.

Weighted gene coexpression network analysis reveals hub genes involved in cholangiocarcinoma progression and prognosis

AIM

Cholangiocarcinoma (CCA) is a highly malignant tumor found in the bile duct epithelial cells, and the second most common primary tumor of the liver. However, the pivotal roles of molecular biomarkers in oncogenesis of CCA are unclear. Therefore, we aim to explore the underlying mechanisms of progression and screen for novel prognostic biomarkers and treatment targets.

METHOD

The data of mRNA sequencing and clinical information of CCA patients in The Cancer Genome Atlas was analyzed by weighted gene coexpression network analysis (WGCNA). Modules and clinical traits were constructed according to Pearson's correlation analysis, and Gene Ontology and pathway enrichment analysis were applied. Hub genes of these modules were screened by intramodule analysis; Cytoscape with Search Tool for the Retrieval of Interacting Genes was utilized to visualize protein-protein interaction of these modules; hub genes of these modules were validated afterwards. Furthermore, the significance of these genes was confirmed by survival analysis.

RESULTS

Genes MRPS18A, CST1, and SCP2 were identified as candidate genes in the module, which was associated with clinical traits including pathological stage, histological grade, and liver function and which also affected overall survival of CCA patients. Nineteen hub genes were analyzed together and were associated with progression and prognosis of CCA. Survival analyses found that several of the multiple genes could serve as biomarkers to stratify CCA patients into low- and high-risk groups.

CONCLUSION

These candidate genes could be involved in progression of CCA, which could serve as novel prognostic markers and treatment targets. Moreover, most of them were first reported in CCA and deserve further research.

Diagnostic and prognostic biomarkers in cholangiocarcinoma

The high mortality rate of cholangiocarcinoma (CCA) is due, in part, to the lack of non-invasive approaches able to accurately detect this silent tumour at early stages, when therapeutic options can be potentially curative or may at least increase the overall survival of patients. The fact that the majority of CCA tumours are not linked to any known aetiological factor highly compromises the monitoring of patients at risk for tumour development and also their early diagnosis. Combination of clinical/biochemical features, imaging techniques and analysis of non-specific tumour biomarkers in serum are commonly used to help in the diagnosis of CCA, but tumour biopsy is usually required to confirm the diagnosis. Moreover, no prognostic biomarkers are currently used in the clinical setting, deserving more innovative research, and international validation and consensus. Important efforts have been made in the last few years to identify accurate non-invasive biomarkers, by using innovative techniques and high-throughput omics technologies. This review summarizes and discusses the advances in the investigation of novel diagnostic and prognostic biomarkers in CCA and envisions the future directions in this field of research.

Cholangiocarcinoma: Classification, Histopathology and Molecular Carcinogenesis

Cholangiocarcinoma (CC) is the second most common tumor of the liver, originating from the biliary system with increasing incidence and mortality worldwide. Several new classifications review the significance of tumor localization, site of origin, proliferation and biomarkers in the intrahepatic, perihilar and distal forms of the lesion. Based on growth pattern mass-forming, periductal-infiltrating, intraductal, undefined and mixed types are differentiated. There are further subclassifications which are applied for the histological features, in particular for intrahepatic CC. Recognition of the precursors and early lesions of CC including biliary intraepithelial neoplasia (BilIN), intraductal papillary neoplasm of the bile ducts (IPNB), biliary mucinous cystic neoplasm (MCNB) and the candidate precursors, such as bile duct adenoma and von Meyenburg complex is of increasing significance. In addition to the previously used biliary markers detected by immunohistochemistry, several new markers have been added to the differentiation of both the benign and malignant lesions, which can be used to aid in the subclassification in association with the outcome of CC. Major aspects of biliary carcinogenesis have been revealed, yet, the exact way of this diverse process is still unclear. The factors contributing to molecular cholangiocarcinogenesis include various risk factors, different anatomical localizations, multiple cellular origins, genetic and epigenetic alterations, tumor microenvironment, heterogeneity and clonal evolution. Driver mutations have been identified, implying that they are optimal candidates for targeted therapy. The most promising therapeutic candidates have entered clinical trials.