Biomarkers and Management of Cholangiocarcinoma: Unveiling New Horizons for Precision Therapy

Abstract

Cholangiocarcinoma (CCA) is an aggressive malignancy with limited methods for early detection, necessitating the development of reliable biomarkers for diagnosis and management. However, conventional tumor markers, such as CA19-9 and CEA, exhibit insufficient diagnostic accuracy. Recent advancements in molecular genetics have identified several actionable mutations in CCA, enabling molecularly targeted therapies that improve survival in patients harboring these genetic alterations. Cancer panels, which facilitate multiplex genetic profiling, are critical for identifying these mutations. Studies indicate that several actionable mutations are detected in CCA cases, with patients receiving mutation-guided therapies achieving markedly better outcomes. Liquid biopsies, including cell-free DNA and circulating tumor DNA, offer real-time, non-invasive approaches to monitoring tumor dynamics, heterogeneity, and treatment responses. Furthermore, numerous studies have identified non-coding RNAs in serum and bile as promising biomarkers for the diagnosis and management of CCA. On the other hand, immunotherapy, particularly immune checkpoint inhibitors, has shown efficacy in subsets of CCA patients. However, the success of these therapies is often affected by the status of the tumor immune microenvironment (TME), underscoring the need for comprehensive TME analysis to predict responses to immune checkpoint inhibitors. Despite these advances, no single biomarker currently demonstrates sufficient sensitivity or specificity for clinical application. The integration of multi-omics approaches with cutting-edge technologies holds promise for enhancing diagnostic accuracy, optimizing treatment stratification, and advancing precision medicine in CCA. These developments highlight the transformative potential of biomarkers to improve early detection, prognostic assessment, and personalized therapeutic interventions for CCA.

Keywords: cholangiocarcinoma; liquid biopsy; mutations; non-coding RNAs; tumor immune microenvironment.

Figure 1

The candidate of biomarkers in the diagnosis, therapeutic selection, and monitoring of recurrence in cholangiocarcinoma. In addition to conventional serum biomarkers, novel biomarker candidates for the diagnosis, therapeutic selection, and monitoring of recurrence in cholangiocarcinoma (CCA) have been illustrated. Gene panel testing plays a critical role in determining the suitability of molecular targeted therapies for CCA. Moreover, biomarkers such as circulating tumor DNA (ctDNA), cell-free DNA (cfDNA), non-coding RNAs, extracellular vesicle-derived protein panels, and plasma metabolite panels have been reported for applications including diagnosis, evaluation of disease progression, and prognostic prediction. However, at present, these novel biomarkers, apart from gene panel testing, remain in the developmental stage.

Figure 2

Development of non-coding RNA as biomarkers for cholangiocarcinoma. Non-coding RNAs (ncRNAs) are functional RNAs that are not translated into proteins. Among the various types of ncRNAs, the shortest are microRNAs (miRNAs), which are approximately 20–25 nucleotides in length. miRNAs function by binding to target mRNAs and inhibiting their translation. Primary miRNAs (pri-miRNAs) are processed through several sequential cleavage steps to produce mature miRNAs. In contrast, ncRNAs longer than 500 nucleotides are collectively referred to as long non-coding RNAs (lncRNAs). These include intronic, exonic, promoter-associated, and enhancer-associated lncRNAs, which are generated through transcription and alternative splicing. Similarly, circular RNAs (circRNAs) are predominantly derived from precursor mRNAs (pre-mRNAs) via alternative splicing. CircRNAs can be classified into exonic, exonic-intronic, and intronic circRNAs based on their composition. These non-coding RNAs are closely associated with the initiation, progression, and chemoresistance of cholangiocarcinoma (CCA) and hold promise as potential biomarkers for clinical applications.

Figure 3

Schematic representation of the tumor immune microenvironment in cholangiocarcinoma. Several studies have classified the tumor microenvironment (TME) of cholangiocarcinoma (CCA). The red up arrows represent “activation” of the signal, and the blue down arrows show “inactivation”. In general, inflamed tumors exhibit the activation of anti-tumor immune responses, including interferon-gamma (IFN-γ) signaling, antigen presentation, and IL-6/JAK/STAT signaling. In such cases, immune checkpoint inhibitors (ICIs) may be effective (a). Conversely, a subset of CCA tumors displays an altered immune response characterized by increased TGF-β signaling, angiogenesis, and activation of hepatic stellate cells (b). In these tumors, various mesenchymal reactions—such as neovascularization, fibrosis, and epithelial–mesenchymal transition (EMT)—are induced, leading to restricted T cell infiltration. Additionally, the activation of TGF-β, vascular endothelial growth factor (VEGF), and Notch signaling promotes the infiltration of M2 macrophages and regulatory T cells (Tregs). In tumors lacking infiltrating immune cells, anti-tumor immune responses are largely absent, rendering ICIs potentially ineffective (c). The activation of the Wnt/β-catenin signaling pathway may contribute to this form of immune evasion.