image: Recent advancements in cancer immunotherapy have highlighted glypican-3 (GPC3) as a prominent target for treating hepatocellular carcinoma (HCC). However, approximately 10% to 30% of HCC patients exhibit low or absent GPC3 expression on the surface of tumor cells, which limits the feasibility of GPC3-targeted therapies. Consequently, it is essential for patients to undergo pre-diagnostic assessments of GPC3 expression in tumor cells to evaluate their suitability for GPC3-directed therapy. Although various methods have been developed to specifically detect GPC3 as a biomarker for treatment and prognosis, the diagnostic approaches currently employed in clinical studies remain relatively limited. Here, we provide a comprehensive overview of the clinical development of GPC3-targeted therapeutics, clinical trials in GPC3-positive HCC, and current methods for detecting GPC3 expression, highlighting their advantages and limitations. Furthermore, we explore the potential of integrating targeted therapy with various GPC3 detection modalities tailored to different pathological stages. This integration not only provides insights into the selection of effective methods for detecting GPC3 expression but also has the potential to significantly improve the clinical outcomes of patients with liver cancer. By simultaneously assessing the advantages and disadvantages of these methods, this review aims to establish a theoretical foundation for the clinical selection of appropriate GPC3 detection strategies for targeted therapy. Consequently, assessing GPC3 expression and distribution in HCC patients is essential for targeted treatment. For early-stage patients, various detection methods can be used to evaluate the GPC3 concentration in serum and on cell surfaces, as well as its tissue distribution, thereby enhancing diagnostic accuracy. Furthermore, rapid sampling and diagnosis using sensitive biosensors may reduce patient burden. Subsequently, targeted therapy can be initiated promptly based on GPC3 localization and expression levels to improve disease control rates. In contrast, advanced-stage patients should utilize combined methods, such as serum ELISA or flow cytometry, in combination with imaging methods, to accurately assess GPC3 expression levels and distribution. This approach facilitates the implementation of targeted therapies while maximizing clinical benefits.
Credit: Chuang Wang
Glypican-3 (GPC3) has emerged as a premier target for immunotherapy in hepatocellular carcinoma (HCC), owing to its high specificity and overexpression in tumor cells compared to healthy liver tissue. However, a significant challenge lies in the fact that 10-30% of HCC patients exhibit low or absent GPC3 expression, limiting the applicability of GPC3-directed therapies. This underscores the critical need for reliable pre-therapeutic diagnostic assessments to identify suitable candidates. While a variety of GPC3 detection methods have been developed, their clinical adoption remains limited. This review provides a comprehensive analysis of the clinical development of GPC3-targeted therapeutics and a detailed evaluation of current detection methodologies. By integrating insights on targeted therapy with tailored detection strategies for different disease stages, this work aims to establish a theoretical foundation for optimizing patient selection and improving clinical outcomes in liver cancer.
Introduction
Hepatocellular carcinoma is a global health burden with a high mortality rate, often diagnosed at advanced stages. While surgical interventions and molecular targeted agents are mainstays of treatment, high recurrence rates and drug resistance persist. Immunotherapy offers a promising alternative, with GPC3 standing out as an ideal target. GPC3 is an oncofetal proteoglycan specifically upregulated in over 70% of HCC cases, detectable on the tumor cell surface and in patient serum. Its expression is strongly associated with poor prognosis, making it a compelling focus for both diagnostic and therapeutic development. This review synthesizes the clinical landscape of GPC3-targeted therapies and the diagnostic tools essential for their effective implementation.
The Role of GPC3 in HCC
GPC3 is a glycosylphosphatidylinositol-anchored cell membrane protein that is cleaved into N- and C-terminal subunits. Its expression is regulated by transcription factors like c-Myc and ZHX2, as well as various miRNAs. Functionally, GPC3 is a key driver of HCC progression. It potently activates the Wnt/β-catenin signaling pathway by acting as a coreceptor, leading to the expression of pro-proliferative genes. It also facilitates metastasis by interacting with growth factors like HGF and FGF to activate MAPK and PI3K/AKT pathways, promoting epithelial-mesenchymal transition (EMT). Furthermore, GPC3 reshapes the tumor microenvironment by recruiting and polarizing tumor-associated macrophages (TAMs) towards the pro-tumor M2 phenotype. Critically, GPC3 is expressed more frequently than alpha-fetoprotein (AFP) in early-stage and AFP-negative HCC, solidifying its value as a diagnostic and prognostic biomarker.
Immunotherapy Targeting GPC3 in Clinical Application
The review categorizes GPC3-targeted therapies into two broad classes, summarizing ongoing clinical trials (Tables 1 and 2).
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Non-cellular Therapeutics: This category includes monoclonal antibodies (e.g., GC33, Codrituzumab), bispecific antibodies (e.g., ERY974, CW350) that engage T cells, therapeutic peptide vaccines, and novel modalities like antibody-drug conjugates (ADCs) and mRNA therapies. While early monoclonal antibody trials showed limited efficacy, next-generation bispecific and multi-specific antibodies are designed to enhance immune cell recruitment and tumor killing.
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Cellular Therapeutics: Chimeric Antigen Receptor T-cell (CAR-T) therapy targeting GPC3 represents a major research focus, with numerous clinical trials underway. Early-phase trials have demonstrated preliminary safety and antitumor activity. For instance, a phase I study (NCT02395250) showed an overall survival rate of 50.3% at six months, with some patients achieving long-term disease control. To overcome challenges in the solid tumor microenvironment, researchers are engineering "armored" CAR-T cells that secrete cytokines (e.g., IL-15, IL-21) or using gene editing (e.g., knocking out PD-1) to enhance persistence and efficacy. The development of "off-the-shelf" therapies using CAR-NK and CAR-γδT cells is also progressing.
Methods and Applications of Patient-Specific GPC3 Identification
Accurate detection of GPC3 is the cornerstone of patient stratification for targeted therapy. The review systematically compares three categories of detection methods (Table 3).
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Chemical Immunoassays: These are the most established methods.
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Immunohistochemistry (IHC) is the current gold standard in clinical trials for assessing GPC3 expression in tumor tissue biopsies, providing visual and spatial information.
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Enzyme-Linked Immunosorbent Assay (ELISA) is highly effective for quantifying soluble GPC3 in serum, demonstrating high specificity in distinguishing HCC from liver cirrhosis. It is recommended for routine serum screening due to its high throughput and technical maturity.
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Flow Cytometry can detect GPC3 on circulating tumor cells, offering high sensitivity and specificity.
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Imaging Methods: Advanced radiomic models using Magnetic Resonance Imaging (MRI) can non-invasively predict GPC3 expression status in tumors with high accuracy (AUC > 0.90 in some studies). Immuno-Positron Emission Tomography (Immuno-PET) with radiolabeled anti-GPC3 tracers allows for real-time, in vivo assessment of GPC3 expression and distribution, overcoming the issue of tumor heterogeneity.
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Biosensors: This emerging field offers highly sensitive and rapid detection. Electrochemical and fluorescence-based aptasensors, which use GPC3-specific aptamers and nanomaterials for signal amplification, have achieved detection limits in the ng/mL to pg/mL range. While not yet widely used in clinics, biosensors hold great potential for point-of-care testing and early diagnosis due to their simplicity and minimal sample requirements.
Achievements and Limitations
Significant progress has been made in developing GPC3 as a theranostic target. The integration of GPC3 with other biomarkers (e.g., AFP, GP73) can enhance diagnostic accuracy. A major achievement is the establishment of strict patient selection criteria in clinical trials, where IHC is used to enroll only patients with strong GPC3 positivity (≥ ++), thereby ensuring trial integrity and maximizing therapeutic benefit.
However, challenges remain. The relationship between membrane-bound and soluble GPC3, and its dynamic changes during disease progression, requires further elucidation. While biosensors are promising, they lack standardization for clinical use. Imaging techniques, though powerful, must contend with issues of radioactivity and heterogeneous antigen distribution.
Conclusions
In conclusion, GPC3 represents a paradigm for a theranostic target in HCC. For clinical success, a precision medicine approach is essential. We recommend the routine integration of serum GPC3 detection (via ELISA) and tissue GPC3 assessment (via IHC) into the diagnostic workflow for HCC patients. This strategy enables the identification of ideal candidates for GPC3-targeted immunotherapies, such as CAR-T cells or bispecific antibodies. For advanced-stage patients, a combination of serum assays and non-invasive imaging can provide a comprehensive view of GPC3 expression to guide treatment. Future efforts should focus on standardizing detection methods, validating novel biosensors, and further elucidating the biology of GPC3 to fully unlock its potential in improving outcomes for liver cancer patients.
Full text
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The study was recently published in the Journal of Clinical and Translational Hepatology.
The Journal of Clinical and Translational Hepatology (JCTH) is owned by the Second Affiliated Hospital of Chongqing Medical University and published by XIA & HE Publishing Inc. JCTH publishes high quality, peer reviewed studies in the translational and clinical human health sciences of liver diseases. JCTH has established high standards for publication of original research, which are characterized by a study’s novelty, quality, and ethical conduct in the scientific process as well as in the communication of the research findings. Each issue includes articles by leading authorities on topics in hepatology that are germane to the most current challenges in the field. Special features include reports on the latest advances in drug development and technology that are relevant to liver diseases. Regular features of JCTH also include editorials, correspondences and invited commentaries on rapidly progressing areas in hepatology. All articles published by JCTH, both solicited and unsolicited, must pass our rigorous peer review process.
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Journal
Journal of Clinical and Translational Hepatology
Article Title
Targeting Glypican-3 for Liver Cancer Therapy: Clinical Applications and Detection Methods
Article Publication Date
7-Aug-2025