Circulating osteopontin per tumor volume as a prognostic biomarker for resectable intrahepatic cholangiocarcinoma

Molecular Biomarkers in Cholangiocarcinoma: Focus on Bile

Hepatobiliary system cancers have demonstrated an increasing incidence rate in the past years. Without the presence of early symptoms, the majority of such cancers manifest with a set of similar symptoms, such as cholestasis resulting in posthepatic icterus. Differential diagnosis of hepatobiliary cancers is required for the therapy selection, however, the similarity of the symptoms complicates diagnostics. Thus, the search for molecular markers is of high interest for such patients. Cholangiocarcinoma (CCA) is characterized by a poor prognosis due to a low resectability rate, which occurs because this disease is frequently beyond the limits of surgical therapy at the time of diagnosis. The CCA is diagnosed by the combination of clinical/biochemical features, radiological methods, and non-specific serum tumor biomarkers, although invasive examination is still needed. The main disadvantage is limited specificity and sensitivity, which complicates early diagnostics. Therefore, prognostic and predictive biomarkers are still lacking and urgently needed for early diagnosis. In contrast to serum, bile is more accessible to identify biliary disease due to its simpler composition. Moreover, bile can contain higher concentrations of tumor biomarkers due to its direct contact with the tumor. It is known that the composition of the main bile component - bile acids, may vary during different diseases of the biliary tract. This review summarizes the recent developments in the current research on the diagnostic biomarkers for CCA in serum and bile and provides an overview of the methods of bile acids analysis.

The Tumor Immune Microenvironment plays a Key Role in Driving the Progression of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is an epithelial cancer distinguished by bile duct cell differentiation and is also a fibroproliferative tumor. It is characterized by a dense mesenchyme and a complex tumor immune microenvironment (TME). The TME comprises both cellular and non-cellular components. The celluar component includes CCA cells, immune cells and mesenchymal cells represented by the cancer-associated fibroblasts (CAFs), while the non-cellular component is represented by mesenchymal elements such as the extracellular matrix (ECM). Recent studies have demonstrated the important role of the TME in the development, progression, and treatment resistance of CCA. These cell-associated prognostic markers as well as intercellular connections, may serve as potential therapeutic targets and could inspire new treatment approaches for CCA in the future. This paper aims to summarize the current understanding of CCA's immune microenvironment, focusing on immune cells, mesenchymal cells, ECM, intercellular interactions, and metabolism within the microenvironment.

RAB6A functions as a critical modulator of the stem-like subsets in cholangiocarcinoma

RAB6A is a member of RAB GTPase family and plays an important role in the targeted transport of neurotrophic receptors and inflammatory cytokines. RAB6A-mediated secretory pathway is involved in many physiological and pathological processes. Defects in RAB6A-mediated secretory pathway may lead to the development of many diseases, including cancer. However, its role in cholangiocarcinoma (CCA) has not yet been revealed. We explored the regulatory role of RAB6A in the stem-like subsets of CCA. We showed that RAB6A knockdown (KD) impedes cancer stem cells (CSCs) properties and epithelial-mesenchymal transition in vitro and that suppression of RAB6A inhibits tumor growth in vivo. We screened target cargos of RAB6A in CCA cells and identified a extracellular matrix component as the target cargo. RAB6A binds directly to OPN, and RAB6A KD suppressed OPN secretion and inhibited the interaction between OPN and αV integrin receptor. Moreover, RAB6A KD inhibited the AKT signaling pathway, which is a downstream effector of the integrin receptor signaling. In addition, shRNA targeting OPN blocked endogenous expression of OPN and consequently weakened CSCs properties in RAB6A-formed spheres. Similarly, inhibitor of AKT signaling, MK2206 also impedes oncogenic function of RAB6A in the stem-like subsets of CCA cells. In conclusion, our findings showed that RAB6A sustains CSCs phenotype maintenance by modulating the secretion of OPN and consequentially activating the downstream AKT signaling pathway. Targeting the RAB6A/OPN axis may be an effective strategy for CCA therapy.

Mechanism of postoperative recurrence and metastasis of intrahepatic cholangiocellular carcinoma and clinical prevention and treatment strategy

Intrahepatic cholangiocellular carcinoma is a primary adenocarcinoma originating from intrahepatic bile duct epithelial cells. The tumor has no capsule. At the early stage of the tumor, there are infiltration and metastasis along the lymphatic vessels, blood vessels, perineural space, and loose fibrous connective tissue, which are characterized by lymph node metastasis. Due to the absence of characteristic clinical manifestations and the lack of specific molecular markers for early diagnosis, the surgical resection rate is low and the postoperative tumor recurrence and metastasis rate is high. Low efficacy of chemoradiotherapy, molecular targeted drugs, and immunotherapy results in the poor prognosis. Further research of molecular pathology, gene function, and imaging technology can help elucidate the occurrence, recurrence, and metastasis mechanism of intrahepatic cholangiocellular carcinoma to improve its early diagnosis rate and precise clinical staging. Individualized precision treatment and prevention for the risk factors to reduce the recurrence and metastasis rate postoperatively are key to improving the patient prognosis.

Novel cell subtypes of SPP1 + S100P+, MS4A1-SPP1 + S100P+ were key subpopulations in intrahepatic cholangiocarcinoma

BACKGROUND

In this study, we integrated single-cell RNA sequencing (scRNA-seq) data to investigate cell heterogeneity and utilized MSigDB and CIBERSORTx to explore the pathways of major cell types and the relationships between different cell subtypes. Subsequently, we explored the correlation of cell subtypes with survival and used Gene Set Enrichment Analysis (GSEA) analyses to assess the pathways associated with the infiltration of specific cell subtypes. Finally, multiplex immunohistochemistry in tissue microarray cohort were performed to validate differences in protein level and their correlation with survival.

RESULTS

iCCA presented a unique immune ecosystem, with increased proportions of Epi (epithelial)-SPP1-2, Epi-S100P-1, Epi-DN (double negative for SPP1 and S100P expression)-1, Epi-DN-2, Epi-DP (double positive for SPP1 and S100P expression)-1, Plasma B-3, Plasma B-2, B-HSPA1A-1, B-HSPA1A-2 cells, and decreased proportions of B-MS4A1. High level of Epi-DN-2, Epi-SPP1-1, Epi-SPP1-2, B-MS4A1, and low level of Epi-DB-1, Epi-S100P-1, and Epi-S100P-2 was significantly associated with longer overall survival (OS), and high level of B-MS4A1_Low_Epi-DN-2_Low was associated with the shortest OS. Moreover, the results of MsigDB and GSEA suggest that bile acid metabolism is a crucial process in iCCA. Finally, we found that S100P+, SPP1+, SPP1 + S100P+, and MS4A1-SPP1 + S100P+ were highly expressed, whereas MS4A1 was lowly expressed in iCCA, and patients with high level of S100P+, SPP1 + S100P+, and MS4A1-SPP1 + S100P+ exhibited shorter survival.

CONCLUSIONS

We identified the cell heterogeneity of iCCA, found that iCCA is a unique immune ecosystem with many cell subtypes, and showed that the novel cell subtypes of SPP1 + S100P+ and MS4A1-SPP1 + S100P+ were key subpopulations in iCCA.

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.

Liver transplantation and intrahepatic cholangiocarcinoma: time to go forward again?

PURPOSE OF REVIEW

Liver transplantation for intrahepatic cholangiocarcinoma (iCCA) has been mired in controversy. High rates of recurrence posttransplant combined with donor organ scarcity resulted in most transplant centers treating iCCA as a contraindication for liver transplantation.

RECENT FINDINGS

Recent studies have shown that carefully selected patients with unresectable iCCA can have good outcomes after liver transplantation. Better outcomes have been seen in patients with smaller tumors and favorable tumor biology.

SUMMARY

Because many patients are diagnosed with iCCA at later stages, tumor biology and genetics are useful tools to identify patients who will have excellent overall and recurrence-free survival after liver transplantation. Further larger multicenter prospective studies are needed to identify patients who would benefit from liver transplantation with good outcomes. Additional advances will come through early diagnosis and utilizing a combination of chemotherapy and locoregional modalities as a bridge to transplant. There is also a need to recognize and develop additional neo- and adjuvant therapies for patients whose tumor biology currently precludes their inclusion on the liver transplantation waitlist.

The Role of Osteopontin in Tumor Progression Through Tumor-Associated Macrophages

Osteopontin (OPN) is a multifunctional phosphorylated protein. It is widely involved in solid tumor progression, such as intensification of macrophage recruitment, inhibition of T-cell activity, aggravation of tumor interstitial fibrosis, promotion of tumor metastasis, chemotherapy resistance, and angiogenesis. Most of these pathologies are affected by tumor-associated macrophages (TAMs), an important component of the tumor microenvironment (TME). TAMs have been extensively characterized, including their subsets, phenotypes, activation status, and functions, and are considered a promising therapeutic target for cancer treatment. This review focuses on the interaction between OPN and TAMs in mediating tumor progression. We discuss the strategies for targeting OPN and TAMs to treat cancer and factors that may affect the therapeutic outcomes of blocking OPN or depleting TAMs. We also discuss the role of cancer cell- vs. TAM-derived OPN in tumorigenesis, the mechanisms of how OPN affects TAM recruitment and polarization, and why OPN could mediate anti-tumor and pro-tumor effects, as well as previously reported discrepancies.

Novel approaches in search for biomarkers of cholangiocarcinoma

Cholangiocarcinoma (CCA) arises from the ductular epithelium of the biliary tree, either within the liver (intrahepatic CCA) or more commonly from the extrahepatic bile ducts (extrahepatic CCA). This disease has a poor prognosis and a growing worldwide prevalence. The poor outcomes of CCA are partially explained by the fact that a final diagnosis is challenging, especially the differential diagnosis between hepatocellular carcinoma and intrahepatic CCA, or distal CCA and pancreatic head adenocarcinoma. Most patients present with an advanced disease, unresectable disease, and there is a lack in non-surgical therapeutic modalities. Not least, there is an acute lack of prognostic biomarkers which further complicates disease management. Therefore, there is a dire need to find alternative diagnostic and follow-up pathways that can lead to an accurate result, either singlehandedly or combined with other methods. In the "-omics" era, this goal can be attained by various means, as it has been successfully demonstrated in other primary tumors. Numerous variants can reach a biomarker status ranging from circulating nucleic acids to proteins, metabolites, extracellular vesicles, and ultimately circulating tumor cells. However, given the relatively heterogeneous data, extracting clinical meaning from the inconsequential noise might become a tall task. The current review aims to navigate the nascent waters of the non-invasive approach to CCA and provide an evidence-based input to aid clinical decisions and provide grounds for future research.

Single-cell transcriptomic analysis suggests two molecularly subtypes of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is a highly heterogeneous cancer with limited understanding of its classification and tumor microenvironment. Here, by performing single-cell RNA sequencing on 144,878 cells from 14 pairs of iCCA tumors and non-tumor liver tissues, we find that S100P and SPP1 are two markers for iCCA perihilar large duct type (iCCA^phl) and peripheral small duct type (iCCA^pps). S100P + SPP1− iCCA^phl has significantly reduced levels of infiltrating CD4⁺ T cells, CD56⁺ NK cells, and increased CCL18⁺ macrophages and PD1⁺CD8⁺ T cells compared to S100P-SPP1 + iCCA^pps. The transcription factor CREB3L1 is identified to regulate the S100P expression and promote tumor cell invasion. S100P-SPP1 + iCCA^pps has significantly more SPP1⁺ macrophage infiltration, less aggressiveness and better survival than S100P + SPP1− iCCA^phl. Moreover, S100P-SPP1 + iCCA^pps harbors tumor cells at different status of differentiation, such as ALB + hepatocyte differentiation and ID3+ stemness. Our study extends the understanding of the diversity of tumor cells in iCCA.

The molecular classification and tumour microenvironment in intrahepatic cholangiocarcinoma (iCCA) need further characterisation. Here, the authors perform single cell RNA-sequencing from 14 pairs of iCCA tumours and non-tumour liver tissues and propose S100P and SPP1 as markers for patient classification.

Biomarkers and Genetic Markers of Hepatocellular Carcinoma and Cholangiocarcinoma-What Do We Already Know

Simple Summary

Hepatocellular carcinoma and cholangiocarcinoma continue to remain a serious threat. In this review, we describe the most common biomarkers and genetic markers currently used in the diagnosis of hepatocellular carcinoma and cholangiocarcinoma. It can be observed that biomarkers and genetic markers might be applied in various parts of diagnosis including screening tests in a high-risk group, non-invasive detection, control of therapy, treatment selection, and control of recurrence. Also, it can be seen that nowadays there is a need for more specific markers that would improve the detection in early or very early stages of both types of cancers and further research should be focused on it.

Abstract

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with an increasing worldwide mortality rate. Cholangiocarcinoma (CCA) is the second most common primary liver cancer. In both types of cancers, early detection is very important. Biomarkers are a relevant part of diagnosis, enabling non-invasive detection and control of cancer recurrence, as well as in the application of screening tests in high-risk groups. Furthermore, some of these biomarkers are useful in controlling therapy and treatment selection. Detection of some markers presents higher sensitivity and specificity in combination with other markers when compared with a single detection. Some gene aberrations are also prognostic markers in the two types of cancers. In the following review, we discuss the most common biomarkers and genetic markers currently being used in the diagnosis of hepatocellular carcinoma and cholangiocarcinoma.

Prognostic and Predictive Molecular Markers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common primary liver cancer and subsumes a heterogeneous group of malignant tumors arising from the intra- or extrahepatic biliary tract epithelium. A rising mortality from CCA has been reported worldwide during the last decade, despite significant improvement of surgical and palliative treatment. Over 50% of CCAs originate from proximal extrahepatic bile ducts and constitute the most common CCA entity in the Western world. Clinicopathological characteristics such as lymph node status and poor differentiation remain the best-studied, but imperfect prognostic factors. The identification of prognostic molecular markers as an adjunct to traditional staging systems may not only facilitate the selection of patients who would benefit the most from surgical, adjuvant or palliative treatment strategies, but may also be helpful in defining the aggressiveness of the disease and identifying patients at high-risk for tumor recurrence. The purpose of this review is to provide an overview of currently known molecular prognostic and predictive markers and their role in CCA.

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.

The Tumor Microenvironment in Cholangiocarcinoma Progression

Cholangiocarcinoma (CCA) is an aggressive and heterogeneous malignancy of the biliary tree. A typical hallmark of CCA is that cancer cells are embedded into a dense stroma containing fibrogenic cells, lymphatics and a variety of immune cells. Functional roles of the reactive tumor stroma are not fully elucidated; however, recent studies suggest that the tumor microenvironment plays a key role in the progression and invasiveness of CCA. CCA cells exchange autocrine/paracrine signals with other cancer cells and the infiltrating cell types that populate the microenvironment. This crosstalk is under the control of signals mediated by various cytokines, chemokines, and growth factors. In addition, extracellular vesicles (EVs), exosomes and microvesicles, containing cargo mediators, such as proteins and RNAs, play a key role in cell-to-cell communication, and particularly in epigenetic regulation thanks to their content in miRNAs. Both cytokine- and EV-mediated communications between CCA cells and other liver cells provide a potential novel target for the management of CCA. This review summarizes current understandings of the tumor microenvironment and intercellular communications in CCA and their role in tumor progression.

Effect of surgical margin on recurrence based on preoperative circulating tumor cell status in hepatocellular carcinoma

Background

High rates of recurrence after resection severely worsen hepatocellular carcinoma (HCC) prognosis. This study aims to explore whether circulating tumor cell (CTC) is helpful in determine the appropriate liver resection margins for HCC patients.

Methods

HCC patients who underwent liver resection were enrolled into training (n=117) or validation (n=192) cohorts, then classified as CTC-positive (CTC≥1) or CTC-negative (CTC=0). A standardized pathologic sampling method was used in the training cohort to quantify microvascular invasion (mVI) and the farthest mVI from the tumor (FMT).

Findings

CTC number positively correlated with mVI counts (r=0.655, P<0.001) and FMT (r=0.495, P<0.001). The CTC-positive group had higher mVI counts (P=0.032) and greater FMT P=0.008) than the CTC-negative group. In the CTC-positive group, surgical margins of >1 cm independently protected against early recurrence (training cohort, P=0.004; validation cohort, P=0.001) with lower early recurrence rates (training cohort, 20.0% vs. 65.1%, P=0.005; validation cohort, 36.4% vs. 65.1%, P=0.003) compared to surgical margins of ≤1 cm. No differences in postoperative liver function were observed between patients with margins >1 cm vs. ≤1 cm. Surgical margin size minimally impacted early postoperative HCC recurrence in CTC-negative patients when using 0.5 cm or 1 cm as the threshold.

Interpretations

Preoperative CTC status predicts mVI severity in HCC patients and is a potential factor for determining optimal surgical margin size to ensure disease eradication and conserve liver function. A surgical margin of >1 cm should be achieved for patients with positive CTC.

Funding

A full list of funding bodies that contributed to this study can be found in the Acknowledgement section.

Role of Chemokines in the Biology of Cholangiocarcinoma

Cholangiocarcinoma (CCA), a heterogeneous tumor with poor prognosis, can arise at any level in the biliary tree. It may derive from epithelial cells in the biliary tracts and peribiliary glands and possibly from progenitor cells or even hepatocytes. Several risk factors are responsible for CCA onset, however an inflammatory milieu nearby the biliary tree represents the most common condition favoring CCA development. Chemokines play a key role in driving the immunological response upon liver injury and may sustain tumor initiation and development. Chemokine receptor-dependent pathways influence the interplay among various cellular components, resulting in remodeling of the hepatic microenvironment towards a pro-inflammatory, pro-fibrogenic, pro-angiogenic and pre-neoplastic setting. Moreover, once tumor develops, chemokine signaling may influence its progression. Here we review the role of chemokines in the regulation of CCA development and progression, and the modulation of angiogenesis, metastasis and immune control. The potential role of chemokines and their receptors as possible biomarkers and/or therapeutic targets for hepatobiliary cancer is also discussed.