Circulating tumor cells are associated with poor overall survival in patients with cholangiocarcinoma

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.

Bile liquid biopsy in biliary tract cancer

Biliary tract cancers are heterogeneous in etiology, morphology and molecular characteristics thus impacting disease management. Diagnosis is complex and prognosis poor. The advent of liquid biopsy has provided a unique approach to more thoroughly understand tumor biology in general and biliary tract cancers specifically. Due to their minimally invasive nature, liquid biopsy can be used to serially monitor disease progression and allow real-time monitoring of tumor genetic profiles as well as therapeutic response. Due to the unique anatomic location of biliary tract cancer, bile provides a promising biologic fluid for this purpose. This review focuses on the composition of bile and the use of these various components, ie, cells, extracellular vesicles, nucleic acids, proteins and metabolites as potential biomarkers. Based on the disease characteristics and research status of biliary tract cancer, considerable effort should be made to increase understanding of this disease, promote research and development into early diagnosis, develop efficient diagnostic, therapeutic and prognostic markers.

Current Role and Future Perspectives of Immunotherapy and Circulating Factors in Treatment of Biliary Tract Cancers

Biliary tract cancers (BTCs) are a heterogenous group of malignancies arising from the epithelial cells of the biliary tree and the gallbladder. They are often locally advanced or already metastatic at the time of the diagnosis and therefore prognosis remains dismal. Unfortunately, the management of BTCs has been limited by resistance and consequent low response rate to cytotoxic systemic therapy. New therapeutic approaches are needed to improve the survival outcomes for these patients. Immunotherapy, one of the newest therapeutic options, is changing the approach to the oncological treatment. Immune checkpoint inhibitors are by far the most promising group of immunotherapeutic agents: they work by blocking the tumor-induced inhibition of the immune cellular response. Immunotherapy in BTCs is currently approved as second-line treatment for patients whose tumors have a peculiar molecular profile, such as high levels of microsatellites instability, PD-L1 overexpression, or high levels of tumor mutational burden. However, emerging data from ongoing clinical trials seem to suggest that durable responses can be achieved in other subsets of patients. The BTCs are characterized by a highly desmoplastic microenvironment that fuels the growth of cancer tissue, but tissue biopsies are often difficult to obtain or not feasible in BTCs. Recent studies have hence proposed to use liquid biopsy approaches to search the blood circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) to use as biomarkers in BTCs. So far studies are insufficient to promote their use in clinical management, however trials are still in progress with promising preliminary results. Analysis of blood samples for ctDNA to research possible tumor-specific genetic or epigenetic alterations that could be linked to treatment response or prognosis was already feasible. Although there are still few data available, ctDNA analysis in BTC is fast, non-invasive, and could also represent a way to diagnose BTC earlier and monitor tumor response to chemotherapy. The prognostic capabilities of soluble factors in BTC are not yet precisely determined and more studies are needed. In this review, we will discuss the different approaches to immunotherapy and tumor circulating factors, the progress that has been made so far, and the possible future developments.

Optimizing Circulating Tumour DNA Use in the Perioperative Setting for Intrahepatic Cholangiocarcinoma: Diagnosis, Screening, Minimal Residual Disease Detection and Treatment Response Monitoring

In this review, we present the current evidence and future perspectives on the use of circulating tumour DNA (ctDNA) in the diagnosis, management and understanding the prognosis of patients with intrahepatic cholangiocarcinoma (iCCA) undergoing surgery. Liquid biopsies or ctDNA maybe utilized to: (1) determine the molecular profile of the tumour and therefore guide the selection of molecular targeted therapy in the neoadjuvant setting, (2) form a surveillance tool for the detection of minimal residual disease or cancer recurrence after surgery, and (3) diagnose and screen for early iCCA detection in high-risk populations. The potential for ctDNA can be tumour-informed or -uninformed depending on the goals of its use. Future studies will require ctDNA extraction technique validations, with standardizations of both the platforms and the timing of ctDNA collections.

The multidisciplinary management of cholangiocarcinoma

Cholangiocarcinoma is a lethal malignancy of the biliary epithelium that can arise anywhere along the biliary tract. Surgical resection confers the greatest likelihood of long-term survivability. However, its insidious onset, difficult diagnostics, and resultant advanced presentation render the majority of patients unresectable, highlighting the importance of early detection with novel biomarkers. Developing liver-directed therapies and emerging targeted therapeutics may offer improved survivability for patients with unresectable or advanced disease. In this article, the authors review the current multidisciplinary standards of care in resectable and unresectable cholangiocarcinoma, with an emphasis on novel biomarkers for early detection and nonsurgical locoregional therapy options.

Adjuvant therapy of biliary tract cancers

Biliary tract cancers (BTCs) are rare and heterogeneous malignant tumours including cholangiocarcinoma and gallbladder cancer. They are very aggressive, often refractory to chemotherapy and associated with an overall poor prognosis. Surgical resection remains the only potentially curative treatment option but less than 35% present with resectable disease. Adjuvant treatments have been widely used but until recently, supportive data were limited to non-randomised, non-controlled retrospective studies. Recent evidence from the BILCAP trial has established adjuvant capecitabine as the standard of care. But there are still unanswered questions as to the role of adjuvant therapy. Further prospective data and translational research with reproducible evidence of clinical benefit are needed. In this review of adjuvant therapy in resectable BTCs, we will summarise the latest evidence setting current treatment standards and highlight future prospects.

Circulating tumor cells as a preoperative risk marker for occult metastases in patients with resectable cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive tumor associated with a high rate of recurrence after resection. An important risk factor for recurrence is the presence of occult metasta-ses, which are not radiologically detectable at the time of diagnosis. There are currently no biomarkers for the preoperative assessment of micrometastases. A previous study demonstrated the prognostic relevance of circulating tumor cells (CTC) in patients with advanced CCA but the potential of CTCs as a preoperative marker for detecting occult metastases has not been investigated so far. In this two-phase study, we first recruited a cohort of 27 patients with histologically proven, metastatic CCA or gallbladder cancer (GBCA) to assess feasibility (feasibility cohort, FC). CTCs were measured in the peripheral blood using the CellSearch System (CSS) between October 2012 and January 2017. Subsequently, in 11 patients undergoing curative-intended resection for CCA (intrahepatic CCA: n =4; extrahepatic CCA n= 6; gallbladder cancer: n=1), peripheral and central venous blood specimens were obtained to improve detection rate by simultaneous measurement and to elucidate distribution of CTCs in different venous compartments. Presence of CTCs detection was correlated with postoperative TNM-status.

In the FC, CTCs (range 1-3 cells, median: 1) were detected in 40% (11/27) patients and were signifi-cantly associated with worse overall survival (hazard ratio: 3.59; 95% CI: 1.79- 7.1; p = 0.04). By combined peripheral and central measurement, CTC detection was increased to 54% (6/11) in the resection cohort (RC) and was associated with metastases that were only identified during the surgical procedure (peritoneal carcinoma: n = 1; infiltration of the duodenum: n = 1) or immediately after surgery (evidence of pulmonary metastases by CT scan two days after resection, not evident on initial tumor staging prior resection). Taken together, in this single center pilot study, we demonstrated that CTCs are detectable in CCA patients and are associated with significantly impaired survival in patients at metastatic stage. Detection rate prior to surgery was improved to >50% by combined peripheral and central measurement. Moreover, preoperative CTC detection may indicate existing metastases and could help to stratify patients more accurately.

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.

Current Perspectives on the Surgical Management of Perihilar Cholangiocarcinoma

Cholangiocarcinoma (CCA) represents nearly 15% of all primary liver cancers and 2% of all cancer-related deaths worldwide. Perihilar cholangiocarcinoma (pCCA) accounts for 50-60% of all CCA. First described in 1965, pCCAs arise between the second-order bile ducts and the insertion of the cystic duct into the common bile duct. CCA typically has an insidious onset and commonly presents with advanced, unresectable disease. Complete surgical resection is technically challenging, as tumor proximity to the structures of the central liver often necessitates an extended hepatectomy to achieve negative margins. Intraoperative frozen section can aid in assuring negative margins and complete resection. Portal lymphadenectomy provides important prognostic and staging information. In specialized centers, vascular resection and reconstruction can be performed to achieve negative margins in appropriately selected patients. In addition, minimally invasive surgical techniques (e.g., robotic surgery) are safe, feasible, and provide equivalent short-term oncologic outcomes. Neoadjuvant chemoradiation therapy followed by liver transplantation provides a potentially curative option for patients with unresectable disease. New trials are needed to investigate novel chemotherapies, immunotherapies, and targeted therapies to better control systemic disease in the adjuvant setting and, potentially, downstage disease in the neoadjuvant setting.

Pathological, molecular, and clinical characteristics of cholangiocarcinoma: A comprehensive review

Cholangiocarcinomas are a heterogeneous group of highly aggressive cancers that may arise anywhere within the biliary tree. There is a wide geographical variation with regards to its incidence, and risk-factor associations which may include liver fluke infection, primary sclerosing cholangitis, and hepatolithiasis amongst others. These tumours are classified into intrahepatic, perihilar and distal based on their anatomical location. Morphologically, intrahepatic cholangiocarcinomas are further sub-classified into small and large duct variants. Perihilar and distal cholangiocarcinomas are usually mucin-producing tubular adenocarcinomas. Cholangiocarcinomas develop through a multistep carcinogenesis and are preceded by dysplastic and in situ lesions. While clinical characteristics and management of these tumours have been extensively elucidated in literature, their ultra-structure and tumour biology remain relatively unknown. This review focuses on the current knowledge of pathological characteristics, molecular alterations of cholangiocarcinoma, and its precursor lesions (including biliary intraepithelial neoplasia, intraductal papillary neoplasms of the bile duct, intraductal tubulopapillary neoplasms and mucinous cystic neoplasm).

The longitudinal change of circulating tumor cell during chemotherapy and its correlation with disease features, treatment response and survival profile of advanced gallbladder carcinoma

The current study aimed to investigate the relation of circulating tumor cell (CTC) with clinicopathological features. In addition, its longitudinal change during chemotherapy and its correlation with prognosis in advanced gallbladder carcinoma (GBC) patients were explored. Totally 45 unresectable, locally advanced or metastatic GBC patients who underwent chemotherapy were enrolled in this prospective study. The CTC in 7.5 ml blood was detected at pre-treatment and 3 months post-treatment. CTC was almost detectable in all advanced GBC patients before treatment, whose count was positively correlated with metastatic disease (vs. local advanced disease) (P=0.002), number of organs with metastases (P=0.006), and CA199 level (P=0.002). After treatment, CTC count declined from 4.0 (range: 0.0-83.0) at pre-treatment to 2.0 (range: 0.0-36.0) at post-treatment (P=0.003). Interestingly, pre-treatment CTC count (P=0.270) was of no difference, while post-treatment CTC count was lower (P=0.038) in objective-response patients compared to that in non-objective-response patients; meanwhile, both pre-treatment CTC count (P=0.017) and post-treatment CTC count (P<0.001) were lower in disease-control patients compared with those in non-disease-control patients. Importantly, pre-treatment CTC count ≥2 (versus <2) was only correlated with worse progression-free survival (PFS) (P=0.014) but not overall survival (OS) (P=0.057); while pre-treatment CTC count ≥5 (versus <5), post-treatment CTC count ≥2 (versus <2), post-treatment CTC count ≥5 (versus <5), CTC count up (versus equal/down) were all correlated with poor PFS and OS (all P<0.050). In conclusion, higher CTC count during chemotherapy correlates with worse treatment response, PFS and OS in advanced GBC patients, which implies that CTC measurement may optimize the prognostication and individualized treatment in these patients.

Survivin-positive circulating tumor cells as a marker for metastasis of hepatocellular carcinoma

BACKGROUND

Circulating tumor cells (CTCs) and survivin are indicators for tumor stage and metastasis, as well as epitheliomesenchymal transition, in various cancers, including hepatocellular cancer (HCC).

AIM

To explore the potential of survivin-positive CTCs, specifically, as a marker for tumor progression in HCC patients.

METHODS

We examined the survivin expression pattern in CTCs obtained from 179 HCC patients, and investigated the in vitro effects of survivin silencing and overexpression on the proliferation and invasion of HCC cells. CTC count and survivin expression in patient samples were examined using RNA in situ hybridization.

RESULTS

All 179 patients were positive for CTC markers, and 94.41% of the CTCs were positive for survivin. The CTC and survivin-positive CTC counts were significantly higher in the HCC patients than in the normal controls, and were significantly associated with tumor stage and degree of differentiation. Further, survivin overexpression was found to induce HepG2 cell proliferation, reduce apoptosis, and improve invasive ability.

CONCLUSION

Survivin shows upregulated expression (indicative of anti-apoptotic effects) in HCC. Thus, survivin-positive CTCs are promising as a predictor of HCC prognosis and metastasis, and their accurate measurement may be useful for the management of this cancer.

Biliary Tract Cancers: Treatment Updates and Future Directions in the Era of Precision Medicine and Immuno-Oncology

The effective management of biliary tract cancers (BTCs) has been hampered by limited options for systemic therapy. In recent years, the focus on precision medicine has made technologies such as next-generation sequencing (NGS) accessible to clinicians to identify targetable mutations in BTCs in tumor tissue (primarily) as well as blood, and to treat them with targeted therapies when possible. It has also expanded our understanding of functional pathways associated with genetic alterations and opened doors for identifying novel targets for treatment. Recent advances in the precision medicine approach allowed us to identify new molecular markers in BTCs, such as epigenetic changes (methylation and histone modification) and non-DNA markers such as messenger RNA, microRNA, and long non-coding RNA. It also made detecting these markers from non-traditional sources such as blood, urine, bile, and cytology (from fine-needle aspiration and biliary brushings) possible. As these tests become more accessible, we can see the integration of different molecular markers from all available sources to aid physicians in diagnosing, assessing prognosis, predicting tumor response, and screening BTCs. Currently, there are a handful of approved targeted therapies and only one class of immunotherapy agents (immune checkpoint inhibitors or ICIs) to treat BTCs. Early success with new targets, vascular endothelial growth factor receptor (VEGFR), HER2, protein kinase receptor, and Dickkopf-1 (DKK1); new drugs for known targets, fibroblast growth factor receptors (FGFRs) such as futabatinib, derazantinib, and erdafitinib; and ICIs such as durvalumab and tremelimumab is encouraging. Novel immunotherapy agents such as bispecific antibodies (bintrafusp alfa), arginase inhibitors, vaccines, and cellular therapy (chimeric antigen receptor-T cell or CAR-T, natural killer cells, tumor-infiltrating lymphocytes) have the potential to improve outcomes of BTCs in the coming years.

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.

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.

Vimentin-Positive Circulating Tumor Cells as Diagnostic and Prognostic Biomarkers in Patients with Biliary Tract Cancer

Biliary tract cancer (BTC) has poor prognosis; thus, early diagnosis is important to decrease mortality. Although vimentin-positive circulating tumor cells (V-CTCs) are a good candidate for diagnostic and prognostic biomarkers, studies on the topic are limited. We aimed to evaluate the diagnostic efficacy of V-CTCs between BTC and benign biliary disease (BBD) and determine the prognostic value of V-CTCs in BTC patients. We recruited 69 participants who had BTCs and BBDs from a single tertiary referral center. We analyzed CTCs and V-CTCs in peripheral blood using the CD-PRIME^TM system. Seven patients were excluded due to a technical failure of CTC detection. CTCs were detected in all 62 patients. CTC count > 40/mL blood (55.8% vs. 20%, p = 0.039), V-CTC count > 15/mL blood (57.7% vs. 10%, p = 0.005), and V-CTC/CTC ratio > 40% (48.1% vs. 10%, p = 0.025) were significantly different between BTCs and BBDs. Two or more of these three parameters (61.5% vs. 10%, p = 0.002) increased the accuracy. A combination of CTC markers with CA19-9 and biopsy increased the accuracy (90.4% vs. 10%, p = 0.000). V-CTC > 50/mL blood was a significant factor affecting survival (140 (66.6–213.3) vs. 253 (163.9–342.1) days, p = 0.008). V-CTC could be a potential biomarker for early diagnosis and predicting prognosis in patients with BTC.

Potential utility of liquid biopsies in the management of patients with biliary tract cancers: A review

Biliary tract cancer, comprising gallbladder cancer, cholangiocarcinoma and ampullary cancer, represents a more uncommon entity outside high-endemic areas, though global incidence is rising. The majority of patients present at a late stage, and 5-year survival remains poor. Advanced stage disease is incurable, and though palliative chemotherapy has been shown to improve survival, further diagnostic and therapeutic options are required in order to improve patient outcomes. Although certain subtypes of biliary tract cancer are relatively rich in targetable mutations, attaining tumour tissue for histological diagnosis and treatment monitoring is challenging due to locoregional anatomical constraints and patient fitness. Liquid biopsies offer a safe and convenient alternative to invasive procedures and have great potential as diagnostic, predictive and prognostic biomarkers. In this review, the current standard of care for patients with biliary tract cancer, future treatment horizons and the possible utility of liquid biopsies within a variety of contexts will be discussed. Circulating tumour DNA, circulating microRNA and circulating tumour cells are discussed with an overview of their potential applications in management of biliary tract cancer. A summary is also provided of currently recruiting clinical trials incorporating liquid biopsies within biliary tract cancer research.

[Influence of molecular pathology on oncological surgery of liver and bile duct tumors]

BACKGROUND

Molecular pathology is increasingly being used to guide treatment in oncology. Approximately 25% of all hepatocellular carcinomas (HCC) and 50% of cholangiocarcinomas (CCA) present with known cancer-relevant mutations; however, the impact of the mutations on the treatment of these tumors is not yet sufficiently understood.

PURPOSE

To evaluate the current literature on molecular pathological advances in HCC/CCA and the potential impact on oncological surgery.

MATERIAL AND METHODS

A comprehensive search of the available literature on currently known molecular biomarkers in HCC/CCA was performed in PubMed and clinitrials.gov. Following review, the potential impact of these biomarkers on oncological surgery was analyzed and is discussed.

CONCLUSION

Molecular pathological investigations can be used to support the classification of tumors and to determine the dignity of HCC/CCA. Predictive molecular biomarkers are not yet established in routine diagnostics but can be used to individualize advanced oncological treatment.

Next-Generation Biomarkers for Cholangiocarcinoma

Simple Summary

Early and non-invasive diagnosis of cholangiocarcinoma (CCA) is still challenging, thus largely contributing to the increased mortality rates observed worldwide. Consequently, several efforts have been made in order to report novel biomarkers for CCA, that would aid on diagnosis and also to predict prognosis and therapy response. We herein aim to provide an in-depth and critical revision on the next-generation biomarkers for CCA that have been recently proposed.

Abstract

The increasing mortality rates of cholangiocarcinoma (CCA) registered during the last decades are, at least in part, a result of the lack of accurate non-invasive biomarkers for early disease diagnosis, making the identification of patients who might benefit from potentially curative approaches (i.e., surgery) extremely challenging. The obscure CCA pathogenesis and associated etiological factors, as well as the lack of symptoms in patients with early tumor stages, highly compromises CCA identification and to predict tumor development in at-risk populations. Currently, CCA diagnosis is accomplished by the combination of clinical/biochemical features, radiological imaging and non-specific serum tumor biomarkers, although a tumor biopsy is still needed to confirm disease diagnosis. Furthermore, prognostic and predictive biomarkers are still lacking and urgently needed. During the recent years, high-throughput omics-based approaches have identified novel circulating biomarkers (diagnostic and prognostic) that might be included in large, international validation studies in the near future. In this review, we summarize and discuss the most recent advances in the field of biomarker discovery in CCA, providing new insights and future research directions.

Detection Methods and Clinical Applications of Circulating Tumor Cells in Breast Cancer

Circulating Tumor Cells (CTCs) are cancer cells that split away from the primary tumor and appear in the circulatory system as singular units or clusters, which was first reported by Dr. Thomas Ashworth in 1869. CTCs migrate and implantation occurs at a new site, in a process commonly known as tumor metastasis. In the case of breast cancer, the tumor cells often migrate into locations such as the lungs, brain, and bones, even during the early stages, and this is a notable characteristic of breast cancer. Survival rates have increased significantly over the past few decades because of progress made in radiology and tissue biopsy, making early detection and diagnosis of breast cancer possible. However, liquid biopsy, particularly that involving the collection of CTCs, is a non-invasive method to detect tumor cells in the circulatory system, which can be easily isolated from human plasma, serum, and other body fluids. Compared to traditional tissue biopsies, fluid sample collection has the advantages of being readily available and more acceptable to the patient. It can also detect tumor cells in blood earlier and in smaller numbers, possibly allowing for diagnosis prior to any tumor detection using imaging methods. Because of the scarcity of CTCs circulating in blood vessels (only a few CTCs among billions of erythrocytes and leukocytes), thorough but accurate detection methods are particularly important for further clinical applications.

Biomarkers in Hepatobiliary Cancers: What is Useful in Clinical Practice?

Hepatocellular carcinoma (HCC) and biliary tract cancers (BTC) exhibit a poor prognosis with 5-year overall survival rates around 15%, all stages combined. Most of these primary liver malignancies are metastatic at diagnostic, with only limited therapeutic options, relying mainly on systemic therapies. Treatment modalities are different yet partially overlapping between HCC and BTC. The complex molecular profile of BTC yields to several actionable therapeutic targets, contrary to HCC that remains the field of antiangiogenic drugs in non-molecularly selected patients. Immunotherapy is now validated in the first line in HCC in combination with bevacizumab, while clinical activity of single agent immunotherapy appears limited to a subset of patients in BTC, still poorly characterized, and combinations are currently under investigation. In this review, we provide a critical evaluation and grading of clinical relevance on (i) the main prognostic biomarkers in HCC and BTC, (ii) the main theragnostic biomarkers in both tumors, and lastly (iii) what is recommended in clinical practice.

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.

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.

3D Culture of Circulating Tumor Cells for Evaluating Early Recurrence and Metastasis in Patients with Hepatocellular Carcinoma

Purpose

Circulating tumor cells (CTCs) are considered to be a key factor involved in tumor metastasis. However, the isolation and culture of CTCs in vitro remains challenging, and their clinical application for predicting prognosis and survival is still limited. The development of accurate evaluating system for CTCs will benefit for clinical assessment of HCC.

Methods

Density gradient centrifugation and magnetic separation based on CD45 antibody were used to isolate CTCs. 3D culture was used to maintain and amplify CTCs and HCC cells. Cellular immunofluorescence was used to identify CTCs and spheroids. The cutoff value of CTC spheroid was calculated using X-tile software. The relationship between clinicopathological variables and CTC spheroids in HCC patients is analyzed. In vivo models were used to evaluate tumor growth and metastasis of CTC spheroids.

Results

Patient-derived CTCs/HCC cells were isolated and expanded to form spheroids using 3D culture. CTC spheroids could be used to predict short-term recurrence of CTCs compared with conventional CTC enumeration. Different cell lines exhibited different formation rates and grew to different sizes. Identification of CTC spheroids revealed that EpCAM and β-catenin were expressed in spheroids derived from HCC cells and in the HCC/CTCs. EpCAM-positive HCC cells exhibited improved spheroid formation in 3D culture and were more tumorigenic and likely to metastasize to the lung in vivo. Abnormal activation of the Wnt/β-catenin signaling pathway was observed in EpCAM positive cells.

Conclusion

CTC spheroids could predict prognosis of HCC more precisely compared with conventional CTC enumeration. EpCAM may participate in the formation and survival of CTC spheroids which dependent on Wnt/β-catenin signaling pathway.

Targeted therapies for extrahepatic cholangiocarcinoma: preclinical and clinical development and prospects for the clinic

Introduction: Until recently, cholangiocarcinoma (CCA) was a largely overlooked disease, and among CCAs, extrahepatic CCA (eCCA) was even more neglected. Despite the growing impact of molecularly targeted therapies and immunotherapy, prognosis of eCCA is dismal. Therefore, unraveling the complex molecular landscape of eCCA has become an urgent need. Deep phenotyping studies have revealed that eCCA is a heterogeneous tumor, harboring specific alterations categorizable into four classes, 'Mesenchymal', 'Proliferation', 'Immune', 'Metabolic'. Molecular alterations convey the activation of several pro-oncogenic pathways, where either actionable drivers or outcome predictors can be identified.Areas covered: We offer insights on perturbed pathways, molecular profiling, and actionable targets in eCCA and present a perspective on the potential stepping-stones to future progress. A systematic literature search in PubMed/ClinicalTrials.gov websites was performed by authors from different disciplines according to their specific topic knowledge to identify the newest and most relevant advances in precision medicine of eCCA.Expert opinion: eCCA is a distinct entity with unique features in terms of molecular classes, oncogenic drivers, and tumor microenvironment. Since more prevalent mutations are currently undruggable, and immunotherapy can be offered only to a minority of patients, international collaborations are instrumental to improve the understanding of the molecular underpins of this disease.

Adjuvant and neoadjuvant therapy for biliary tract cancer: a review of clinical trials

Cancer originating in the biliary tract can be classified as bile duct cancer (cholangiocarcinoma), gallbladder cancer, or ampullary cancer. Bile duct cancer is further divided to intrahepatic, perihilar and distal bile duct subtypes according to the anatomical location of the tumor. The biological characteristics of each tumor are heterogeneous. However, because of the rarity of each disease, the efficacy of new drugs has been tested in groups of patients with different biliary tract cancers. In patients with metastatic or recurrent biliary tract cancer, recent randomized clinical trials revealed the non-inferiority of gemcitabine + S-1 and the superiority of gemcitabine + cisplatin + S-1 compared with gemcitabine + cisplatin in terms of overall survival, thereby establishing a new standard treatment. In the field of adjuvant therapy for biliary tract cancer, the British BILCAP (capecitabine compared with observation in resected biliary tract cancer) study revealed longer median overall survival in the capecitabine group than in the observation group in the per-protocol analysis (but not in the intention-to-treat analysis), bringing a shift toward postoperative management. Several other studies of adjuvant therapy are ongoing, and they may lead to reforms in treatment strategy for resectable biliary tract cancer in the future. The use of neoadjuvant therapy for biliary tract cancer is in its infancy, but it is expected to overcome the limitations of adjuvant therapy for this malignancy. In this review, we summarized the evidence available from clinical trials of adjuvant and neoadjuvant therapy for biliary tract cancer and described ongoing clinical trials.

Clinical utility of a newly developed microfluidic device for detecting circulating tumor cells in the blood of patients with pancreatico-biliary malignancies

BACKGROUND

The development of an optimal screening method is required to improve the prognosis of pancreatico-biliary (PB) cancers. A recently developed microfluidic device achieved a high diagnostic yield by detecting circulating tumor cells (CTCs) in the blood of cancer patients. We conducted this study to investigate the clinical utility of measuring CTCs in peripheral venous blood to diagnose PB cancer.

METHODS

Sixty-three subjects were enrolled in this study (29 with pancreatic cancer [PC], 19 with biliary cancer [BC] and 16 non-tumor controls). Using a microfluidic chip device and image analyzer, circulating blood cells were selected based on their size and immunocytochemistry staining pattern. The primary endpoint was the diagnostic accuracy of CTCs with regard to distinguishing between PB cancer patients and controls. We divided all cases into the training set (n = 32) and validation set (n = 31). The diagnostic accuracy of CTCs, carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9) were analyzed.

RESULTS

In both the training set and validation set, CTCs showed the highest diagnostic accuracy (training set: CTCs 90.6%, CA19-9 90.6%, CEA 65.6%, validation set: CTCs 87.5%, CA19-9 78.1%, CEA 81.2). Regarding non-metastatic PC (cStage I-III, n = 11), CTCs also had the highest diagnostic accuracy among the three markers tested (CTCs: 84.6%, CA19-9:80.7%, CEA 73.0%).

CONCLUSIONS

A newly developed microfluidic device could diagnose PB cancers by detecting CTCs. This trial was registered with the UMIN Clinical Trials Registry, no. UMIN000029808.

Preoperative circulating tumor cells to predict microvascular invasion and dynamical detection indicate the prognosis of hepatocellular carcinoma

Background

This study explored the diagnostic power of preoperative circulating tumor cells (CTCs) for the presence of microvascular invasion (MVI) and the relationship between dynamic changes in postoperative CTCs and prognosis.

Methods

A total of 137 patients were recruited for the study. Preoperative blood samples were collected from all patients to detect CTCs. The time points for blood collection were before the operation, during the operation, and at 1 week, 1 month, 2 months, 3 months, 6 months, and 1 year after surgery. The predictive power of CTC count for the presence of MVI was analyzed by receiver operating characteristic (ROC) curve analysis. According to recurrence status, 137 patients were divided into three groups: no recurrence, early recurrence, and non-early recurrence groups.

Results

A threshold CTC count of 5 showed the most significant power for predicting the existence of MVI. In multivariate analysis, the parameters of preoperative CTC count, alpha-fetoprotein (AFP) and tumor diameter were independent predictors of MVI (P <  0.05). A CTC count greater than or equal to 5 had better predictive value than AFP > 400 μg/L and tumor diameter > 5 cm. The number of intraoperative CTCs in the three groups did not increase compared to that before surgery (P > 0.05). The number of CTCs in the nonrecurrence group and the non-early recurrence group decreased significantly 1 week after surgery compared with the intraoperative values (P <  0.001), although there was no significant difference in the early recurrence group (P = 0.95). Patients with mean CTC count ≥5 had significantly worse long-term outcomes than those with mean CTC count < 5 (P <  0.001).

Conclusion

The preoperative CTC counts in the peripheral blood of patients with HCC are closely correlated with MVI. The intraoperative manipulation of the lesion by the surgeon does not increase the number of CTCs in peripheral blood. Surgical removal of the tumor decreases the number of CTCs. The persistence of CTCs at a high level (≥ 5) after surgery suggests a risk of early recurrence.

Clinical trial registration

Registration number is ChiCTR-OOC-16010183, date of registration is 2016-12-18.

Cholangiocarcinoma 2020: the next horizon in mechanisms and management

Cholangiocarcinoma (CCA) includes a cluster of highly heterogeneous biliary malignant tumours that can arise at any point of the biliary tree. Their incidence is increasing globally, currently accounting for ~15% of all primary liver cancers and ~3% of gastrointestinal malignancies. The silent presentation of these tumours combined with their highly aggressive nature and refractoriness to chemotherapy contribute to their alarming mortality, representing ~2% of all cancer-related deaths worldwide yearly. The current diagnosis of CCA by non-invasive approaches is not accurate enough, and histological confirmation is necessary. Furthermore, the high heterogeneity of CCAs at the genomic, epigenetic and molecular levels severely compromises the efficacy of the available therapies. In the past decade, increasing efforts have been made to understand the complexity of these tumours and to develop new diagnostic tools and therapies that might help to improve patient outcomes. In this expert Consensus Statement, which is endorsed by the European Network for the Study of Cholangiocarcinoma, we aim to summarize and critically discuss the latest advances in CCA, mostly focusing on classification, cells of origin, genetic and epigenetic abnormalities, molecular alterations, biomarker discovery and treatments. Furthermore, the horizon of CCA for the next decade from 2020 onwards is highlighted.

Current and novel therapeutic opportunities for systemic therapy in biliary cancer

Biliary tract cancers (BTCs) are a group of rare and aggressive malignancies that arise in the biliary tree within and outside the liver. Beyond surgical resection, which is beneficial for only a small proportion of patients, current strategies for treating patients with BTCs include chemotherapy, as a single agent or combination regimens, in the adjuvant and palliative setting. Increased characterisation of the molecular landscape of these tumours has facilitated the identification of molecular vulnerabilities, such as IDH mutations and FGFR fusions, that can be exploited for the treatment of BTC patients. Beyond targeted therapies, active research avenues explore the development of novel therapeutics that target the crosstalk between cancer and stroma, the cellular pathways involved in the regulation of cell death, the chemoresistance phenotype and the dysregulation of RNA. In this review, we discuss the therapeutic opportunities currently available in the management of BTC patients, and explore the strategies that can support the implementation of precision oncology in BTCs, including novel molecular targets, liquid biopsies and patient-derived predictive tools.

Ligand-targeted polymerase chain reaction for the detection of folate receptor-positive circulating tumour cells as a potential diagnostic biomarker for pancreatic cancer

OBJECTIVES

To detect folate receptor (FR)-positive circulating tumour cells (FR+ CTCs) by using ligand-targeted polymerase chain reaction (LT-PCR) in periampullary cancer patients and to investigate the diagnostic value of FR+ CTCs in distinguishing pancreatic cancer (PC) from benign pancreatic disease.

MATERIALS AND METHODS

CTCs were enriched from 3 mL of peripheral blood and portal vein blood by immunomagnetic depletion of leucocytes and were then detected by LT-PCR. The diagnostic performance of FR+ CTCs in PC was investigated by receiver-operating characteristic curve analysis.

RESULTS

In total, 57 consecutive patients, including 46 patients with PC, five patients with non-pancreatic periampullary cancer (non-PC) and six patients with benign pancreatic diseases, were enrolled. FR+ CTC levels were significantly higher in patients with malignant diseases (PC and non-PC) than in patients with benign pancreatic diseases (P < .01). There was no notable difference in CTC levels between patients with PC and those with non-PC (P > .05). The combination of FR+ CTCs with carbohydrate antigen 19-9 (CA19-9) had better diagnostic efficiency than each of these two markers alone, with high sensitivity (97.8%) and specificity (83.3%).

CONCLUSIONS

LT-PCR is feasible and reliable for detecting FR+ CTCs in patients with periampullary cancer. FR+ CTCs, especially when used in combination with CA19-9, have potential as a biomarker for the diagnosis of PC.

The Role of Proteoglycans in Cancer Metastasis and Circulating Tumor Cell Analysis

Circulating tumor cells (CTCs) are accessible by liquid biopsies via an easy blood draw. They represent not only the primary tumor site, but also potential metastatic lesions, and could thus be an attractive supplement for cancer diagnostics. However, the analysis of rare CTCs in billions of normal blood cells is still technically challenging and novel specific CTC markers are needed. The formation of metastasis is a complex process supported by numerous molecular alterations, and thus novel CTC markers might be found by focusing on this process. One example of this is specific changes in the cancer cell glycocalyx, which is a network on the cell surface composed of carbohydrate structures. Proteoglycans are important glycocalyx components and consist of a protein core and covalently attached long glycosaminoglycan chains. A few CTC assays have already utilized proteoglycans for both enrichment and analysis of CTCs. Nonetheless, the biological function of proteoglycans on clinical CTCs has not been studied in detail so far. Therefore, the present review describes proteoglycan functions during the metastatic cascade to highlight their importance to CTCs. We also outline current approaches for CTC assays based on targeting proteoglycans by their protein cores or their glycosaminoglycan chains. Lastly, we briefly discuss important technical aspects, which should be considered for studying proteoglycans.

Meta-analysis of randomized clinical trials of adjuvant chemotherapy for resected biliary tract cancers

BACKGROUND

This meta-analysis was performed by analyzing randomized controlled trials (RCTs) to assess the potential prognostic value of adjuvant chemotherapy (ACT) for patients with resected biliary tract cancers (BTCs).

METHODS

PubMed, EMBASE, and the Cochrane Library were searched for relevant articles published. Only RCTs affected by tumors of gallbladder, intrahepatic, perihilar, and distal bile ducts were considered. Data were pooled using a random-effects model. The primary endpoint of the study was overall survival (OS).

RESULTS

The study identified 1192 patients who met the inclusion and exclusion criteria. ACT had nearly reached a significant better OS (HR, 0.88; 95% CI, 0.77-1.01; P = 0.07) and achieved a significant better RFS (HR, 0.83; 95% CI, 0.69-0.99; P = 0.04). The effectiveness of ACT for OS was significantly modified by fluorouracil-based ACT (HR, 0.83; 95% CI, 0.70-0.99; P = 0.04), but not by gemcitabine-based ACT (HR, 0.91; 95% CI, 0.74-1.12; P = 0.36). The survival benefit was also not modified by primary disease site, resection margin status, and lymph node status.

CONCLUSIONS

ACT is correlated with favorable relapse-free survival compared with non-ACT for resected BTCs patients. Fluorouracil-based ACT could be viewed as a standard practice for resected BTCs patients regardless of the primary cancer site, lymph node or margin status.

An Immune-Magnetophoretic Device for the Selective and Precise Enrichment of Circulating Tumor Cells from Whole Blood

Here, we validated the clinical utility of our previously developed microfluidic device, GenoCTC, which is based on bottom magnetophoresis, for the isolation of circulating tumor cells (CTCs) from patient whole blood. GenoCTC allowed 90% purity, 77% separation rate, and 80% recovery of circulating tumor cells at a 90 μL/min flow rate when tested on blood spiked with epithelial cell adhesion molecule (EpCAM)-positive Michigan Cancer Foundation-7 (MCF7) cells. Clinical studies were performed using blood samples from non-small cell lung cancer (NSCLC) patients. Varying numbers (2 to 114) of CTCs were found in each NSCLC patient, and serial assessment of CTCs showed that the CTC count correlated with the clinical progression of the disease. The applicability of GenoCTC to different cell surface biomarkers was also validated in a cholangiocarcinoma patient using anti-EPCAM, anti-vimentin, or anti-tyrosine protein kinase MET (c-MET) antibodies. After EPCAM-, vimentin-, or c-MET-positive cells were isolated, CTCs were identified and enumerated by immunocytochemistry using anti-cytokeratin 18 (CK18) and anti-CD45 antibodies. Furthermore, we checked the protein expression of PDL1 and c-MET in CTCs. A study in a cholangiocarcinoma patient showed that the number of CTCs varied depending on the biomarker used, indicating the importance of using multiple biomarkers for CTC isolation and enumeration.

Intravenous 5-fluoro-2'-deoxycytidine administered with tetrahydrouridine increases the proportion of p16-expressing circulating tumor cells in patients with advanced solid tumors

PURPOSE

Following promising responses to the DNA methyltransferase (DNMT) inhibitor 5-fluoro-2'-deoxycytidine (FdCyd) combined with tetrahydrouridine (THU) in phase 1 testing, we initiated a non-randomized phase 2 study to assess response to this combination in patients with advanced solid tumor types for which tumor suppressor gene methylation is potentially prognostic. To obtain pharmacodynamic evidence for DNMT inhibition by FdCyd, we developed a novel method for detecting expression of tumor suppressor protein p16/INK4A in circulating tumor cells (CTCs).

METHODS

Patients in histology-specific strata (breast, head and neck [H&N], or non-small cell lung cancers [NSCLC] or urothelial transitional cell carcinoma) were administered FdCyd (100 mg/m2) and THU (350 mg/m2) intravenously 5 days/week for 2 weeks, in 28-day cycles, and progression-free survival (PFS) rate and objective response rate (ORR) were evaluated. Blood specimens were collected for CTC analysis.

RESULTS

Ninety-three eligible patients were enrolled (29 breast, 21 H&N, 25 NSCLC, and 18 urothelial). There were three partial responses. All strata were terminated early due to insufficient responses (H&N, NSCLC) or slow accrual (breast, urothelial). However, the preliminary 4-month PFS rate (42%) in the urothelial stratum exceeded the predefined goal-though the ORR (5.6%) did not. An increase in the proportion of p16-expressing cytokeratin-positive CTCs was detected in 69% of patients evaluable for clinical and CTC response, but was not significantly associated with clinical response.

CONCLUSION

Further study of FdCyd + THU is potentially warranted in urothelial carcinoma but not NSCLC or breast or H&N cancer. Increase in the proportion of p16-expressing cytokeratin-positive CTCs is a pharmacodynamic marker of FdCyd target engagement.

Exploring Circulating Tumor Cells in Cholangiocarcinoma Using a Novel Glycosaminoglycan Probe on a Microfluidic Platform

The search of alternative approaches to epithelial cell adhesion molecule (EpCAM), for the isolation of circulating tumor cells (CTC), is on the rise. This work attempts at evaluating the feasibility of using a new glycosaminoglycan, SCH45, as a probe to isolate CTCs from the peripheral blood of 65 advanced/metastatic cholangiocarcinoma (CCA) patients. The positive enrichment of CTCs from 1 mL of blood using SCH45-bound magnetic beads and subsequent staining on an integrated microfluidic platform is demonstrated. Results detailing CTC concentrations averaging ≥1 CTCs mL^-1 of blood are shown, and a conventional protein biomarker, EpCAM, has been used to corroborate the finding that 100% of the patients possess CTCs in their blood. Studies detailing the use of CTCs in the prognostic monitoring and treatment effectiveness of advanced/metastatic CCA are scarce, and the isolation of CTCs from all CCA patients tested has not been reported yet. A strong correlation between CTC counts and disease progression at the time of and/or in advance of radiographic imaging in patients receiving chemotherapy is also reported. This study is one of its kind with the new probe and reduced sample volume and has potential for use in CCA diagnosis and prognosis in the near future.

The combination of preoperative D-dimer and CA19-9 predicts lymph node metastasis and survival in intrahepatic cholangiocarcinoma patients after curative resection

Background

To investigate the predictive role of D-dimer and its combination of preoperative CA19-9 for lymph node metastasis (LNM) and prognosis in intrahepatic cholangiocarcinoma (ICC) patients who underwent curative-intent resection.

Methods

One hundred and seventy-three patients admitted to our hospital between April 2012 and December 2018 were included. The combination of preoperative D-dimer and CA19-9 (CPDC) was scored as 0 (decreased D-dimer levels with decreased CA19-9 levels), 2 (elevated D-dimer levels with elevated CA19-9 levels), or 1 (all other combinations). Multivariate logistic regression analysis was performed to identify independent factors. Cox proportional hazard regression was adopted for the multivariate survival analysis.

Results

The CPDC score was an independent predictor of LNM and overall survival (OS) in the multivariate analyses. For the prediction of LNM, the area under the curve (AUC) for the CPDC score was 0.722 (95% CI: 0.613–0.831, P<0.001), and for the prediction of survival, the AUC for the CPDC score was 0.756 (95% CI: 0.658–0.854, P<0.001). The predictive capacity of the CPDC score was higher than that of D-dimer or CA19-9. Kaplan-Meier curve analysis revealed that a CPDC =2 was significantly associated with a worse OS (P<0.001, median OS: 8.00 versus 19.00 months versus not reached) and shorter progression-free survival (PFS) (P<0.001, median PFS: 4.00 versus 11.00 versus 15.00 months) than a CPDC =1 or CPDC =0 in ICC patients. There were significant differences in the OS comparisons between any two groups. Decreased preoperative CPDC was associated with worse OS and PFS in all subgroups except in the HBsAg (+) group. In the cirrhosis, HBsAg (−) and tumour size ≥5 cm subgroups, there were significant differences in the OS and PFS comparisons between any two groups.

Conclusions

The preoperative CPDC score is a convenient and powerful prognostic biomarker to predict LNM and OS for ICC patients after curative resection. Especially for radiologically-negative metastatic lymph node in ICC patients, CPDC could be helpful to assess the extent of lymph node dissection and make follow-up plans.

Liver Transplantation for Cholangiocarcinoma: Insights into the Prognosis and the Evolving Indications

PURPOSE OF REVIEW

Cholangiocarcinoma (CCA) is a rare malignancy of the biliary ducts that can be classified as intrahepatic, perihilar, or distal based on anatomic location. Although surgical resection can be curative, complete excision with negative margins is often difficult to achieve. In patients with unresectable disease, long-term survival is rarely seen with medical therapy alone. A multimodal treatment approach, including liver transplantation (LT) for select patients with unresectable CCA, should be considered.

RECENT FINDINGS

While currently only an approved indication for early, liver-limited, perihilar cholangiocarcinoma, promising results have been achieved for LT in localized intrahepatic disease. The absolute indication for transplant for intrahepatic tumors is currently the subject of multiple investigations. Continued advances in neoadjuvant/adjuvant therapy and better understanding of tumor biology may further augment the number of candidates for surgical therapies, with liver transplant acting as a promising tool to improve patient outcomes. Thorough consideration for any expansion in the indication for liver transplant in malignancy is necessary in order to balance patient outcomes with utilization of the scarce donor organ resources.

Cholangiocarcinoma Disease Modelling Through Patients Derived Organoids

Cancer organoids are 3D phenotypic cultures that can be established from resected or biopsy tumour samples and can be grown as mini tumours in the dish. Flourishing evidence supports the feasibility of patient derived organoids (PDO) from a number of solid tumours. Evidence for cholangiocarcinoma (CCA) PDO is still sparse but growing. CCA PDO lines have been established from resected early stage disease, advanced cancers and highly chemorefractory tumours. Cancer PDO was shown to recapitulate the 3D morphology, genomic landscape and transcriptomic profile of the source counterpart. They proved to be a valued model for drug discovery and sensitivity testing, and they showed to mimic the drug response observed in vivo in the patients. However, PDO lack representation of the intratumour heterogeneity and the tumour-stroma interaction. The efficiency rate of CCA PDO within the three different subtypes, intrahepatic, perihilar and distal, is still to be explored. In this manuscript we will review evidence for CCA PDO highlighting advantages and limitations of this novel disease model.

A novel circulating tumor cell subpopulation for treatment monitoring and molecular characterization in biliary tract cancer

In biliary tract cancer (BTC), tissue biopsies to guide treatment are rarely feasible, thus implementing liquid biopsy approaches to improve patient management represents a priority. So far, studies on circulating tumor cells (CTCs) in BTC are insufficient to promote their use in patient clinical management and are limited to EpCAM‐enriched CTCs evaluated with the CellSearch. We applied a single‐cell protocol allowing identification not only of epithelial CTCs (eCTCs), but also of nonconventional CTCs (ncCTCs) lacking epithelial and leukocyte markers, but presenting aberrant genomes as confirmed by copy number alterations and therefore representing a distinct subpopulation of bona fide CTCs. In 41 blood samples longitudinally collected from 21 patients with advanced‐stage BTC, addition of ncCTC to classic eCTC led to a CTC‐positivity increase from 19% to 83%. Patients presenting with at least 1 eCTC/10 ml of blood at baseline prior to treatment start had a significantly shorter median disease‐specific survival (DSS) compared to those lacking eCTCs (9 months vs. 19 months, p = 0.03 by log‐rank test). No differences in DSS were observed according to ncCTC‐positivity, conversely, variations in ncCTC counts during, and at the end of treatment, were associated with the RECIST response supporting their role in treatment monitoring. Moreover, in 88 ncCTCs collected at different times during treatment, unsupervised clustering evidenced segregation of cells by patient's best response, allowing identification of genomic regions possibly involved in resistance mechanisms. The presence of ncCTCs beside eCTCs opens the way to exploiting liquid biopsy for optimizing clinical management in BTC.

What's new?

Late diagnosis of advanced biliary tract cancer (BTC) limits tissue biopsy for molecular analyses, resulting in missed opportunities for personalized therapy. Meanwhile, circulating tumor cells (CTCs) are promising tissue surrogates, but current CTC‐based methods detect only a fraction of BTC patients. Here, using unbiased CTC‐enrichment, coupled with identification and recovery of single cells, the authors identify a novel CTC subpopulation detectable in all BTC patient samples prior to treatment. The presence of even a single epithelial CTC was associated with reduced disease‐specific survival. This novel approach to CTC detection could be useful for treatment‐response monitoring and molecular characterization in BTC.

Advances in the Diagnosis and Treatment of Patients with Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is an aggressive biliary tract cancer (BTC) that arises from the biliary tract epithelium distal to the secondary biliary radicals. Over the past decade, significant advances have been made in the diagnosis, staging, and treatment of ICC. Emerging data have highlighted the importance of lymphadenectomy for elucidating patient prognosis as well as the at-risk nodal basins based on tumor location (de Jong et al. in J Clin Oncol 29(23):3140-3145, 2011). Several large randomized controlled trials have recently been published clarifying the role of adjuvant therapy for BTCs (Cloyd and Pawlik in J Oncol Pract 14(12):723-724, 2018). In addition, the molecular understanding of ICC pathogenesis has increased over time, leading to new potential molecular biomarkers and opening opportunities for novel targeted and immunologic therapies (Rizvi et al. in Nat Rev Clin Oncol 15(2):95-111, 2018). These recent advances serve to only improve our understanding of the optimal multidisciplinary treatment of this difficult disease.

The biology and clinical potential of circulating tumor cells

Background

Tumor cells can shed from the tumor, enter the circulation and travel to distant organs, where they can seed metastases. These cells are called circulating tumor cells (CTCs). The ability of CTCs to populate distant tissues and organs has led us to believe they are the primary cause of cancer metastasis. The biological properties and interaction of CTCs with other cell types during intravasation, circulation in the bloodstream, extravasation and colonization are multifaceted and include changes of CTC phenotypes that are regulated by many signaling molecules, including cytokines and chemokines. Considering a sample is readily accessible by a simple blood draw, monitoring CTC levels in the blood has exceptional implications in oncology field. A method called the liquid biopsy allows the extraction of not only CTC, but also CTC products, such as cell free DNA (cfDNA), cell free RNA (cfRNA), microRNA (miRNA) and exosomes.

Conclusions

The clinical utility of CTCs and their products is increasing with advances in liquid biopsy technology. Clinical applications of liquid biopsy to detect CTCs and their products are numerous and could be used for screening of the presence of the cancer in the general population, as well as for prognostic and predictive biomarkers in cancer patients. With the development of better CTC isolation technologies and clinical testing in large prospective trials, increasing clinical utility of CTCs can be expected. The understanding of their biology and interactions with other cell types, particularly with those of the immune system and the rise of immunotherapy also hold great promise for novel therapeutic possibilities.

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.

Effect of surgical liver resection on circulating tumor cells in patients with hepatocellular carcinoma

BACKGROUND

This study explored the effect of liver resection on perioperative circulating tumor cells (CTCs) and found that the prognostic significance of surgery was associated with changes in CTC counts in patients with hepatocellular carcinoma (HCC).

METHODS

One hundred thirty-nine patients with HCC were consecutively enrolled. The time-points for collecting blood were one day before operation and three days after operation. CTCs in the peripheral blood were detected by the CellSearch™ System.

RESULTS

Both CTC detection incidence and mean CTC counts showed greater increases postoperatively (54%, mean 1.54 cells) than preoperatively (43%, mean 1.13 cells). The postoperative CTC counts increased in 41.7% of patients, decreased in 25.2% of patients and did not change in 33.1% of patients. The increase in postoperative CTC counts was significantly associated with the macroscopic tumor thrombus status. Patients with increased postoperative CTC counts (from preoperative CTC < 2 to postoperative CTC ≥ 2) had significantly shorter disease-free survival (DFS) and overall survival (OS) than did patients with persistent CTC < 2. Patients with persistent CTC levels of ≥2 had the worst prognoses.

CONCLUSIONS

Surgical liver resection is associated with an increase in CTC counts, and increased postoperative CTC numbers are associated with a worse prognosis in patients with HCC.

Circulating Biomarkers for Cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) represents the second most common primary liver malignancy. The incidence rate has constantly increased over the last decades and CCA patients face a dismal prognosis with a 5-year survival rate of less than 5% for advanced stage of disease. Surgical tumor resection has remained the only potentially curative treatment option in daily practice but is often not feasible due to advanced disease stage at initial diagnosis.

SUMMARY

The early detection of cholangiocarcinoma is essential to provide patients with a potentially curative treatment. Furthermore, prognostic biomarkers represent a valuable tool to offer patients a tailored therapeutic approach in accordance to their life expectancy. The clinically most established biomarker carbohydrate antigen 19-9 shows only a limited diagnostic and prognostic power, encouraging the evaluation of novel biomarkers for cholangiocarcinoma in the last years. Key Massage: In this review, we assess currently available and potential future biomarkers for the diagnosis and prognosis of cholangicarcinoma.

Emerging Technologies for the Diagnosis of Perihilar Cholangiocarcinoma

The diagnosis of malignant biliary strictures remains problematic, especially in the perihilar region and in primary sclerosing cholangitis (PSC). Conventional cytology obtained during endoscopic retrograde cholangiography (ERC)-guided brushings of biliary strictures is suboptimal due to limited sensitivity, albeit it remains the gold standard with a high specificity. Emerging technologies are being developed and validated to address this pressing unmet patient need. Such technologies include enhanced visualization of the biliary tree by cholangioscopy, intraductal ultrasound, and confocal laser endomicroscopy. Conventional cytology can be aided by employing complementary and advanced cytologic techniques such as fluorescent in situ hybridization (FISH), and this technique should be widely adapted. Interrogation of bile and serum by examining extracellular vesicle number and cargo, and exploiting next-generation sequencing and proteomic technologies, is also being explored. Examination of circulating cell-free deoxyribonucleic acid (cfDNA) for differentially methylated regions is a promising test which is being rigorously validated. The special expertise required for these analyses has to date hampered their validation and adaptation. Herein, we will review these emerging technologies to inform the reader of the progress made and encourage further studies, as well as adaptation of validated approaches.

Stem-like plasticity and heterogeneity of circulating tumor cells: current status and prospect challenges in liver cancer

Poor prognosis and high recurrence remain leading causes of primary liver cancerassociated mortality. The spread of circulating tumor cells (CTCs) in the blood plays a major role in the initiation of metastasis and tumor recurrence after surgery. Nevertheless, only a subset of CTCs can survive, migrate to distant sites and establish secondary tumors. Consistent with cancer stem cell (CSC) hypothesis, stem-like CTCs might represent a potential source for cancer relapse and distant metastasis. Thus, identification of stem-like metastasis-initiating CTC-subset may provide useful clinically prognostic information. This review will emphasize the most relevant findings of CTCs in the context of stem-like biology associated to liver carcinogenesis. In this view, the emerging field of stem-like CTCs may deliver substantial contribution in liver cancer field in order to move to personalized approaches for diagnosis, prognosis and therapy.

Impact of serum carbohydrate antigen 19-9 level on prognosis and prediction of lymph node metastasis in patients with intrahepatic cholangiocarcinoma

BACKGROUND AND AIM

Lymph node metastasis is an important prognostic factor for intrahepatic cholangiocarcinoma (ICC), but accurate preoperative diagnosis is difficult. The aim of this study was to measure the concentration of serum carbohydrate antigen 19-9 (s-CA19-9) as a preoperative predictor of lymph node metastasis.

METHODS

In our department, curative-intent hepatectomy for ICC has been performed only once the absence of metastases in para-aortic lymph nodes (PALN) has been confirmed from intraoperative frozen-section pathological examinations. The present study included 13 non-resected ICC patients with PALN metastasis (PALN group) and 44 resected ICC patients without PALN metastasis (non-PALN group). S-CA19-9 was examined to evaluate predictive performance for PALN metastasis and regional lymph node metastasis (pN1) from analysis of the receiver operating characteristic curve. In the non-PALN group, univariate and multivariate analyses for survival were performed on clinicopathological variables.

RESULTS

From receiver operating characteristic curve analysis, s-CA19-9 showed good diagnostic accuracy for PALN metastasis (68%; cut-off, 200 U/mL) and pN1 (77%; cut-off, 100 U/mL). In univariate analysis, age (<65 years), s-CA19-9 (≥100 U/mL), portal vein resection, pN1, and positive resection margin (R1) were all identified as significant negative prognostic factors. Five-year survival rates of patients with high s-CA19-9 and pN1 were 6.9% and 7.3%, respectively. In multivariate analysis, high s-CA19-9 and R1 represented independent predictors of poor prognosis.

CONCLUSIONS

Preoperative s-CA19-9 appears useful as a biomarker in patients with ICC, for predicting not only lymph node metastasis but also prognosis after surgical resection with curative intent.

Clinical applications of the CellSearch platform in cancer patients

The CellSearch® system (CS) enables standardized enrichment and enumeration of circulating tumor cells (CTCs) that are repeatedly assessable via non-invasive "liquid biopsy". While the association of CTCs with poor clinical outcome for cancer patients has clearly been demonstrated in numerous clinical studies, utilizing CTCs for the identification of therapeutic targets, stratification of patients for targeted therapies and uncovering mechanisms of resistance is still under investigation. Here, we comprehensively review the current benefits and drawbacks of clinical CTC analyses for patients with metastatic and non-metastatic tumors. Furthermore, the review focuses on approaches beyond CTC enumeration that aim to uncover therapeutically relevant antigens, genomic aberrations, transcriptional profiles and epigenetic alterations of CTCs at a single cell level. This characterization of CTCs may shed light on the heterogeneity and genomic landscapes of malignant tumors, an understanding of which is highly important for the development of new therapeutic strategies.