Expression of glypican 3 in hepatoblastoma: an immunohistochemical study of 65 cases

Glypican-3 deficiency in liver cancer upregulates MAPK/ERK pathway but decreases cell proliferation

Glypican-3 (GPC3) is overexpressed in hepatocellular carcinomas and hepatoblastomas and represents an important therapeutic target but the biologic importance of GPC3 in liver cancer is unclear. To date, there are limited data characterizing the biological implications of GPC3 knockout (KO) in liver cancers that intrinsically express this target. Here, we report on the development and characterization of GPC3-KO liver cancer cell lines and compare to them to parental lines. GPC3-KO variants were established in HepG2 and Hep3B liver cancer cell lines using a lentivirus-mediated CRISPR/Cas9 system. We assessed the effects of GPC3 deficiency on oncogenic properties in vitro and in murine xenograft models. Downstream cellular signaling pathway changes induced by GPC3 deficiency were examined by RNAseq and western blot. To confirm the usefulness of the models for GPC3-targeted drug development, we evaluated the target engagement of a GPC3-selective antibody, GC33, conjugated to the positron-emitting zirconium-89 (89Zr) in subcutaneous murine xenografts of wild type (WT) and KO liver cancer cell lines. Deletion of GPC3 significantly reduced liver cancer cell proliferation, migration, and invasion compared to the parental cell lines. Additionally, the tumor growth of GPC3-KO liver cancer xenografts was significantly slower compared with control xenografts. RNA sequencing analysis also showed GPC3-KO resulted in a reduction in the expression of genes associated with cell cycle regulation, invasion, and migration. Specifically, we observed the downregulation of components in the AKT/NFκB/WNT signaling pathways and of molecules related to cell cycle regulation with GPC3-KO. In contrast, pMAPK/ERK1/2 was upregulated, suggesting an adaptive compensatory response. KO lines demonstrated increased sensitivity to ERK (GDC09994), while AKT (MK2206) inhibition was more effective in WT lines. Using antibody-based positron emission tomography (immunoPET) imaging, we confirmed that 89Zr-GC33 accumulated exclusively in GPC3-expression xenografts but not in GPC3-KO xenografts with high tumor uptake and tumor-to-liver signal ratio. We show that GPC3-KO liver cancer cell lines exhibit decreased tumorigenicity and altered signaling pathways, including upregulated pMAPK/ERK1/2, compared to parental lines. Furthermore, we successfully distinguished between GPC3+ and GPC3- tumors using the GPC3-targeted immunoPET imaging agent, demonstrating the potential utility of these cell lines in facilitating GPC3-selective drug development.

An indocyanine green-based liquid biopsy test for circulating tumor cells for pediatric liver cancer

BACKGROUND

Hepatoblastoma and HCC are the most common malignant hepatocellular tumors seen in children. The aim of this study was to develop a liquid biopsy test for circulating tumor cells (CTCs) for these tumors that would be less invasive and provide real-time information about tumor response to therapy.

METHODS

For this test, we utilized indocyanine green (ICG), a far-red fluorescent dye used clinically to identify malignant liver cells during surgery. We assessed ICG accumulation in cell lines using fluorescence microscopy and flow cytometry. For our CTC test, we developed a panel of liver tumor-specific markers, including ICG, Glypican-3, and DAPI, and tested it with cell lines and noncancer control blood samples. We then used this panel to analyze whole-blood samples for CTC burden with a cohort of 15 patients with hepatoblastoma and HCC and correlated with patient characteristics and outcomes.

RESULTS

We showed that ICG accumulation is specific to liver cancer cells, compared to nonmalignant liver cells, non-liver solid tumor cells, and other nonmalignant cells, and can be used to identify liver tumor cells in a mixed population of cells. Experiments with the ICG/Glypican-3/DAPI panel showed that it specifically tagged malignant liver cells. Using patient samples, we found that CTC burden from sequential blood samples from the same patients mirrored the patients' responses to therapy.

CONCLUSIONS

Our novel ICG-based liquid biopsy test for CTCs can be used to specifically detect and quantify CTCs in the blood of pediatric patients with liver cancer.

Histopathologic and immunophenotypic characterization of patient-derived pediatric malignant hepatocellular tumor xenografts (PDXs)

Advances in targeted therapies for pediatric hepatocellular tumors have been limited due to a paucity of clinically relevant models. Establishment and validation of intrahepatic patient-derived xenograft (PDX) models would help bridging this gap. The aim of this study is to compare the histomorphologic and immunophenotypic fidelity of patient tumors and their corresponding intrahepatic PDX models. Murine PDX models were established by intrahepatic implantation of patient tumors. Pathology slides from both patients and their corresponding PDX models were reviewed and quantitatively assessed for various histologic components and immunophenotypic markers. Ten PDX models were successfully established from nine patients with pre- (n=3) and post- (n=6) chemotherapy samples; diagnosed of hepatoblastoma (n=8) and hepatocellular neoplasm, not otherwise specified (n=1). Two of nine (22.2%) patients showed ≥75% fetal component; however, the corresponding PDX models did not maintain this fetal differentiation. High grade histology was seen in three patients (33.3%) and overrepresented in six PDX models (60%). Within the subset of three PDXs that were further characterized, significant IHC concordance was seen in all 3 models for CK7, CK19, Ki-67, and p53; and 2 of 3 models for Sox9 and Beta-catenin. GPC-3 and GS showed variable to moderate concordance, while Hepar was the least concordant. Our study shows that in general, the PDX models appear to represent the higher-grade component of the original tumor and show significant concordance for Ki-67, making them appropriate tools for testing new therapies for the most aggressive, therapy-resistant tumors.

Genome-wide mapping of cancer dependency genes and genetic modifiers of chemotherapy in high-risk hepatoblastoma

A lack of relevant genetic models and cell lines hampers our understanding of hepatoblastoma pathogenesis and the development of new therapies for this neoplasm. Here, we report an improved MYC-driven hepatoblastoma-like murine model that recapitulates the pathological features of embryonal type of hepatoblastoma, with transcriptomics resembling the high-risk gene signatures of the human disease. Single-cell RNA-sequencing and spatial transcriptomics identify distinct subpopulations of hepatoblastoma cells. After deriving cell lines from the mouse model, we map cancer dependency genes using CRISPR-Cas9 screening and identify druggable targets shared with human hepatoblastoma (e.g., CDK7, CDK9, PRMT1, PRMT5). Our screen also reveals oncogenes and tumor suppressor genes in hepatoblastoma that engage multiple, druggable cancer signaling pathways. Chemotherapy is critical for human hepatoblastoma treatment. A genetic mapping of doxorubicin response by CRISPR-Cas9 screening identifies modifiers whose loss-of-function synergizes with (e.g., PRKDC) or antagonizes (e.g., apoptosis genes) the effect of chemotherapy. The combination of PRKDC inhibition and doxorubicin-based chemotherapy greatly enhances therapeutic efficacy. These studies provide a set of resources including disease models suitable for identifying and validating potential therapeutic targets in human high-risk hepatoblastoma.

An indocyanine green-based liquid biopsy test for circulating tumor cells for pediatric liver cancer

Background and Aims

Hepatoblastoma (HB) and hepatocellular carcinoma (HCC) are the most common malignant hepatocellular tumors seen in children. The aim of this work was to develop a liquid biopsy test for circulating tumor cells (CTCs) for these tumors that would be less invasive and provide information about the real-time state of tumors in response to therapies.

Methods

For this test, we utilized indocyanine green (ICG), a far-red fluorescent dye that is used clinically to identify malignant liver cells in the body during surgery. We assessed ICG accumulation in cell lines with fluorescence microscopy and flow cytometry. For our CTC test, we developed a panel of liver tumor-specific markers, ICG, Glypican-3 (GPC3), and DAPI and tested this panel with cell lines and non-cancer control blood samples. We then used this panel to analyze whole blood samples for CTC burden with a cohort of 14 HB and HCC patients and correlated with patient characteristics and outcomes.

Results

We showed that ICG accumulation is specific to liver cancer cells, compared to non-malignant liver cells, non-liver solid tumor cells, and non-malignant cells and can be used to identify liver tumor cells in a mixed population of cells. Experiments with the ICG/GPC3/DAPI panel showed that it specifically tagged malignant liver cells. With patient samples, we found that CTC burden from sequential blood samples from the same patients mirrored the patients' responses to therapy.

Conclusions

Our novel ICG-based liquid biopsy test for CTCs can be used to specifically count CTCs in the blood of pediatric liver cancer patients.

Impact and implications

This manuscript represents the first report of circulating tumor cells in the blood of pediatric liver cancer patients. The novel and innovative assay for CTCs shown in this paper will facilitate future work examining the relationship between CTC numbers and patient outcomes, forming the foundation for incorporation of liquid biopsy into routine clinical care for these patients.

Graphical abstract

Overview of novel liquid biopsy test for circulating tumor cells for pediatric liver cancer. Figure made with Biorender.

UBE2C expression is elevated in hepatoblastoma and correlates with inferior patient survival

Hepatoblastoma (HB) is the most common malignant liver tumor among children. To gain insight into the pathobiology of HB, we performed RNA sequence analysis on 5 patient-derived xenograft lines (HB-243, HB-279, HB-282, HB-284, HB-295) and 1 immortalized cell line (HUH6). Using cultured hepatocytes as a control, we found 2,868 genes that were differentially expressed in all of the HB lines on mRNA level. The most upregulated genes were ODAM, TRIM71, and IGDCC3, and the most downregulated were SAA1, SAA2, and NNMT. Protein-protein interaction analysis identified ubiquitination as a key pathway dysregulated in HB. UBE2C, encoding an E2 ubiquitin ligase often overexpressed in cancer cells, was markedly upregulated in 5 of the 6 HB cell lines. Validation studies confirmed UBE2C immunostaining in 20 of 25 HB tumor specimens versus 1 of 6 normal liver samples. The silencing of UBE2C in two HB cell models resulted in decreased cell viability. RNA sequencing analysis showed alterations in cell cycle regulation after UBE2C knockdown. UBE2C expression in HB correlated with inferior patient survival. We conclude that UBE2C may hold prognostic utility in HB and that the ubiquitin pathway is a potential therapeutic target in this tumor.

Inhibition of Glypican-3 Cleavage Results in Reduced Cell Proliferation in a Liver Cancer Cell Line

INTRODUCTION

Glypican-3 (GPC3) is a surface-bound proteoglycan overexpressed in pediatric liver cancer and utilized clinically as an immunohistochemical tumor marker. Furin is a proprotein convertase that is ubiquitously expressed and shown to modify GPC3 post-translationally. In experimental models of epithelial-based cancers, furin inhibition decreased tumor cell migration and proliferation representing a potential therapeutic target.

METHODS

Using a synthetic furin inhibitor, we evaluated proliferation, migration, protein, and RNA expression in two liver cancer cell lines, HepG2 (GPC3-positive) and SKHep1 cells (GPC3-negative). Total furin protein and GPC3 protein expression were assessed to evaluate functional levels of furin.

RESULTS

There was a reduction in HepG2 proliferation with addition of furin inhibitor at the 48-h timepoint, however there was an increase in HepG2 migration.

CONCLUSIONS

GPC3 cleavage in hepatoblastoma (HB) has a role in cell proliferation with therapeutic potential, however furin inhibition is not an appropriate target for GPC3-expressing HB due to increased migration which may enhance metastatic potential.

Focal Nodular Hyperplasia-Like Lesions With Glypican-3 Positivity in Infancy

PURPOSE AND CONTEXT

Glypican-3 is often used to discriminate between neoplastic and nonneoplastic liver. In focal lesions, positivity may be considered suggestive of a malignancy such as hepatoblastoma. However, glypican-3 is also normally expressed in the immature liver. We present a series of 5 cases of focal nodular hyperplasia (FNH)-like lesions arising in very young patients with glypican-3 expression and highlight the challenges these lesions present in the differential diagnosis of hepatoblastoma.

METHODS

Cases were obtained from the files of 3 tertiary pediatric hospitals. Clinical data were obtained from the electronic medical record and histopathologic material including immunohistochemical stains were reviewed.

KEY RESULTS

Patients were aged 2 weeks to 6 months with peak AFP levels ranging from 88.6 to 204,696 ng/mL. Microscopically, all were variably demarcated hepatocellular lesions with cords of hepatocytes, marked sinusoidal dilatation, and occasional fibrous bands and areas reminiscent of central scar with bile ducts. No significant cytologic atypia or increased mitotic activity were present. All showed glypican-3 expression and were negative for nuclear beta-catenin with intact reticulin framework.

CONCLUSIONS

Our study highlights the pitfalls of evaluating focal liver lesions in infants when high AFP levels and glypican-3 expression may reflect immaturity rather than neoplasia.

Hepatoblastoma in molecularly defined, congenital diseases

Beckwith-Wiedemann spectrum, Simpson-Golabi-Behmel syndrome, familial adenomatous polyposis and trisomy 18 are the most common congenital conditions associated with an increased incidence of hepatoblastoma (HB). In patients with these genetic disorders, screening protocols for HB are proposed that include periodic abdominal ultrasound and measurement of alpha-fetoprotein levels. Surveillance in these children may contribute to the early detection of HB and possibly improve their chances of overall survival. Therefore, physicians must be aware of the high HB incidence in children with certain predisposing genetic diseases.

Teratoid Hepatoblastoma with Multi-Lineage Differentiation: An Uncommon Histological Variant and Review of Literature

Background

Teratoid hepatoblastoma is an uncommon but well-recognized variant of mixed hepatoblastoma.

Case report

A one-year female child presented with palpable and progressively increasing right abdominal mass for 3 months. The contrast-enhancing computed tomography (CECT) abdomen revealed a large heterogeneous hepatic mass measuring 12 × 6.6 × 6 cm. Histopathological examination of the resected specimen showed a mixed hepatoblastoma (epithelial and mesenchymal) with teratoid features and multi-lineage differentiation (all three germ cell layers). A focus showed embryonal rhabdomyosarcomatous element.

Conclusion

Teratoid hepatoblastoma can show a wide range of heterologous differentiation that may pose a significant diagnostic dilemma. Such a broad spectrum has not been described in the literature previously. An appropriate immunohistochemical panel may be needed to identify and delineate the various heterologous differentiation to clinch the correct diagnosis. Secondary somatic malignancy such as rhabdomyosarcoma can develop in a teratomatous element.

A functionalized magnetic nanoparticle regulated CRISPR-Cas12a sensor for the ultrasensitive detection of alpha-fetoprotein

Alpha-fetoprotein (AFP) is an important clinical tumor marker of hepatoblastoma, and the concentration of AFP in serum is closely related to the staging of hepatoblastoma. We report a magnetic bead separation platform based on a switching aptamer triggered hybridization chain reaction (SAT-HCR) and the CRISPR-Cas12a sensor for the in vitro detection of AFP. AFP aptamer, as an easily regulated nucleic acid strand, is responsible for binding to AFP into nucleic acid detection, while HCR-CRISPR-Cas12a, regulated by functionalized magnetic nanoparticles, is responsible for highly specific nucleic acid signal amplification. Under the optimal conditions, the fluorescence intensity was proportional to the concentration of AFP in the range of 0.5-10⁴ ng mL^-1 and the limit of detection was 0.170 ng mL^-1. In addition, we have successfully applied this biosensor to detect AFP in clinical samples from patients with hepatoblastoma, with greater sensitivity relative to ELISA. Our proposed method showed great potential application in clinical diagnosis and pharmaceutical-related fields with the properties of high sensitivity, low cost and high selectivity.

Peptide-Based Vaccines for Hepatocellular Carcinoma: A Review of Recent Advances

Primary liver cancer is the sixth most commonly diagnosed cancer and the third leading cause of cancer-related deaths worldwide. After surgery, up to 70% of patients experience relapses. The current first-line therapy for advanced cases of hepatocellular carcinoma (HCC) comprises sorafenib and lenvatinib administered as single-drug therapies. Regorafenib, cabozantinib, and ramucirumab are administered as second-line therapies. Recently, it has been reported that using the immune checkpoint inhibitors atezolizumab (anti-PDL1 antibody) and bevacizumab (anti-VEGF antibody) leads to longer overall survival of unresectable cases, when compared with the use of sorafenib. The role of cancer immunity against HCC has attracted the attention of clinicians. In this review, we describe our phase I/II clinical trials of peptide vaccines targeting GPC3 in HCC and discuss the potential of peptide vaccines targeting common cancer antigens that are highly expressed in HCC, such as WT-I, AFP, ROBO1, and FOXM1. Further, we introduce recent cancer vaccines targeting neoantigens, which have attracted attention in recent times, as well as present our preclinical studies, the results of which might aid to initiate a neoantigen vaccine clinical trial, which would be the first of its kind in Japan.

Clinicopathological study of hepatic mesenchymal hamartoma and undifferentiated embryonal sarcoma of the liver: a single center study from Iran

Background

Undifferentiated embryonal sarcoma of liver (UESL) and hepatic mesenchymal hamartoma (HMH) are two rare entities which mainly affect the pediatric population. The aim of this investigation was to provide a comprehensive overview of the clinicopathologic characteristics of the patients diagnosed with these two conditions in a tertiary referral center in Iran.

Methods

In this retrospective study patients diagnosed with UESL or HMH between 2012 and 2020 were studied. A comprehensive histopathologic evaluation of the cases along with immunohistochemistry evaluation using a panel of antibodies was conducted. Furthermore, clinical, paraclinical, and treatment data and follow up information was collected.

Results

A total of 16 patients (8 UESL, 8 HMH) were studied in this investigation. Patients with UESL had a significantly (p = 0.002) higher age at diagnosis compared with those with HMH. Histologically, UESL cases were characterized by anaplastic cells with eosinophilic cytoplasm and bizarre nuclei and frequent atypical mitosis and spindling in a myxoid stroma while disordered arrangement of hepatic parenchyma, bile ducts, and primitive mesenchyme was seen in HMH. Furthermore, small round cells and extramedullary hematopoiesis were seen in 2 UESL and 3 HMH cases, respectively. Concurrent HMH was also seen in two UESL cases. Immunohistochemistry panel showed positive staining for Vimentin, Glypican-3, Desmin, CD56, CD10, and BCL2 in UESL cases and immunoreactivity for Vimentin, HepPar 1, Glypican-3, SMA, CD56, BCL2, and CD34 in various components of HMH.

Conclusions

In this study, the clinicopathologic features of UESL and HMH cases are presented. We also evaluated the utility of an immunohistochemistry panel in the diagnosis of these two rare entities and suggested novel markers. Our study corroborated the findings of previous investigations and expanded the clinicopathologic features of these two rare entities with diagnostic and potential therapeutic implications.

Application of Immunohistochemistry in the Pathological Diagnosis of Liver Tumors

Although radiological diagnostics have been progressing, pathological diagnosis remains the most reliable method for diagnosing liver tumors. In some cases, definite pathological diagnosis cannot be obtained by histological evaluation alone, especially when the sample is a small biopsy; in such cases, immunohistochemical staining is very useful. Immunohistochemistry is the most frequently used technique for molecular pathological diagnosis due to its broad application, ease of performance and evaluation, and reasonable cost. The results occasionally reflect specific genetic mutations. The immunohistochemical markers of hepatocellular carcinoma include those of hepatocellular differentiation—such as hepatocyte paraffin 1 and arginase-1—and those of malignant hepatocytes—such as glypican-3, heat shock protein 70, and glutamine synthetase (GS). To classify the subtypes of hepatocellular adenoma, examination of several immunohistochemical markers, such as liver fatty acid-binding protein, GS, and serum amyloid A, is indispensable. Immunohistochemical staining for GS is also important for the diagnosis of focal nodular hyperplasia. The representative immunohistochemical markers of intrahepatic cholangiocarcinoma include cytokeratin (CK) 7 and CK19. In this article, we provide an overview of the application of immunohistochemistry in the pathological diagnosis of liver tumors referring to the association with genetic alterations. Furthermore, we aimed to explain the practical points in the differential diagnosis of liver tumors by immunohistochemical staining.

The Role of Glypicans in Cancer Progression and Therapy

Glypicans are a family of heparan sulfate proteoglycans that are attached to the cell membrane via a glycosylphosphatidylinositol anchor. Glypicans interact with multiple ligands, including morphogens, growth factors, chemokines, ligands, receptors, and components of the extracellular matrix through their heparan sulfate chains and core protein. Therefore, glypicans can function as coreceptors to regulate cell proliferation, cell motility, and morphogenesis. In addition, some glypicans are abnormally expressed in cancers, possibly involved in tumorigenesis, and have the potential to be cancer-specific biomarkers. Here, we provide a brief review focusing on the expression of glypicans in various cancers and their potential to be targets for cancer therapy.

Immunotherapeutic Targeting of GPC3 in Pediatric Solid Embryonal Tumors

Glypican 3 (GPC3) is a heparan sulfate proteoglycan and cell surface oncofetal protein which is highly expressed on a variety of pediatric solid embryonal tumors including the majority of hepatoblastomas, Wilms tumors, rhabdoid tumors, certain germ cell tumor subtypes, and a minority of rhabdomyosarcomas. Via both its core protein and heparan sulfate side chains, GPC3 activates the canonical Wnt/β-catenin pathway, which is frequently overexpressed in these malignancies. Loss of function mutations in GPC3 lead to Simpson-Golabi-Behmel Syndrome, an X-linked overgrowth condition with a predisposition to GPC3-expressing cancers including hepatoblastoma and Wilms tumor. There are several immunotherapeutic approaches to targeting GPC3, including vaccines, monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, cytolytic T lymphocytes, and CAR T cells. These therapies offer a potentially novel means to target these pediatric solid embryonal tumors. A key pediatric-specific consideration of GPC3-targeted immunotherapeutics is that GPC3 can be physiologically expressed in normal tissues during the first year of life, particularly in the liver and kidney. In summary, this article reviews the current evidence for targeting childhood cancers with GPC3-directed immunotherapies.

Diffuse and canalicular patterns of glypican-3 expression reflect malignancy of hepatocellular carcinoma

Glypican-3 (GPC3) is expressed in most hepatocellular carcinomas (HCCs). To investigate the significance of various GPC3 staining patterns in HCC, we classified 134 HCC patients into three groups: those with diffuse GPC3 staining, canalicular GPC3 staining, and others (including negative staining). HCCs with diffuse staining were correlated with poor differentiation, high Ki-67 indices, high serum α-fetoprotein (AFP) levels, and early recurrence. In contrast, HCCs with canalicular staining were well differentiated with lower AFP levels. Overall survival in this group was better than that of the other two groups. Comparative analysis of GPC3 staining patterns with markers for HCC subclassification showed that diffuse staining was correlated with the expression of biliary/stem cell markers, whereas canalicular staining was correlated with expression of the markers of WNT-activated HCCs. Induction of leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), known as a target of the WNT signaling pathway, in HCC cells resulted in reduced GPC3 expression in vitro. The LGR5-induced cells formed tumors with canaliculus-like structures in mice and showed canalicular GPC3 staining. The current findings showed the significance of recognizing distinct GPC3 staining patterns, i.e., diffuse and canalicular, which may reflect different carcinogenetic mechanisms and indicate the level of malignancy of HCC.

New tumor suppressor microRNAs target glypican-3 in human liver cancer

Glypican-3 (GPC3) is an oncogene, frequently upregulated in liver malignancies such as hepatocellular carcinoma (HCC) and hepatoblastoma and constitutes a potential molecular target for therapy in liver cancer. Using a functional screening system, we identified 10 new microRNAs controlling GPC3 expression in malignant liver cells, five of them e.g. miR-4510, miR-203a-3p, miR-548aa, miR-376b-3p and miR-548v reduce GPC3 expression. These 5 microRNAs were significantly downregulated in tumoral compared to non-tumoral liver and inhibited tumor cell proliferation. Interestingly, miR-4510 inversely correlated with GPC3 mRNA and protein in HCC samples. This microRNA also induced apoptosis of hepatoma cells and blocked tumor growth in vivo in the chick chorioallantoic membrane model. We further show that the tumor suppressive effect of miR-4510 is mediated through direct targeting of GPC3 mRNA and inactivation of Wnt/β-catenin transcriptional activity and signaling pathway. Moreover, miR-4510 up-regulated the expression of several tumor suppressor genes while reducing the expression of other pro-oncogenes. In summary, we uncovered several new microRNAs targeting the oncogenic functions of GPC3. We provided strong molecular, cellular and in vivo evidences for the tumor suppressive activities of miR-4510 bringing to the fore the potential value of this microRNA in HCC therapy.

A Novel Cell Line Based Orthotopic Xenograft Mouse Model That Recapitulates Human Hepatoblastoma

Currently, preclinical testing of therapies for hepatoblastoma (HB) is limited to subcutaneous and intrasplenic xenograft models that do not recapitulate the hepatic tumors seen in patients. We hypothesized that injection of HB cell lines into the livers of mice would result in liver tumors that resemble their clinical counterparts. HepG2 and Huh-6 HB cell lines were injected, and tumor growth was monitored with bioluminescence imaging (BLI) and magnetic resonance imaging (MRI). Levels of human α-fetoprotein (AFP) were monitored in the serum of animals. Immunohistochemical and gene expression analyses were also completed on xenograft tumor samples. BLI signal indicative of tumor growth was seen in 55% of HepG2- and Huh-6-injected animals after a period of four to seven weeks. Increased AFP levels correlated with tumor growth. MRI showed large intrahepatic tumors with active neovascularization. HepG2 and Huh-6 xenografts showed expression of β-catenin, AFP, and Glypican-3 (GPC3). HepG2 samples displayed a consistent gene expression profile most similar to human HB tumors. Intrahepatic injection of HB cell lines leads to liver tumors in mice with growth patterns and biologic, histologic, and genetic features similar to human HB tumors. This orthotopic xenograft mouse model will enable clinically relevant testing of novel agents for HB.

Practical Immunohistochemistry in Neoplastic Pathology of the Gastrointestinal Tract, Liver, Biliary Tract, and Pancreas

CONTEXT

- Immunomarkers with diagnostic, therapeutic, or prognostic values have been increasingly used to maximize the benefits of clinical management of patients with neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas.

OBJECTIVES

- To review the characteristics of immunomarkers that are commonly used in surgical pathology practice for neoplasms of the gastrointestinal tract, liver, biliary tract, and pancreas, and to summarize the clinical usefulness of immunomarkers that have been discovered in recent years in these fields.

DATA SOURCES

- Data sources include literature review, authors' research data, and personal practice experience.

CONCLUSIONS

- Immunohistochemistry is an indispensable tool for the accurate diagnosis of neoplastic diseases of the gastrointestinal tract, liver, biliary tract, and pancreas. Useful immunomarkers are available to help distinguish malignant neoplasms from benign conditions, determine organ origins, and subclassify neoplasms that are morphologically and biologically heterogeneous. Specific immunomarkers are also available to help guide patient treatment and assess disease aggressiveness, which are keys to the success of personalized medicine. Pathologists will continue to play a critical role in the discovery, validation, and application of new biomarkers, which will ultimately improve patient care.

Phase I study of glypican-3-derived peptide vaccine therapy for patients with refractory pediatric solid tumors

The carcinoembryonic antigen glypican-3 (GPC3) is a good target of anticancer immunotherapy against pediatric solid tumors expressing GPC3. In this non-randomized, open-label, phase I clinical trial, we analyzed the safety and efficacy of GPC3-peptide vaccination in patients with pediatric solid tumors. Eighteen patients with pediatric solid tumors expressing GPC3 underwent GPC3-peptide vaccination (intradermal injections every 2 weeks), with the primary endpoint being the safety of GPC3-peptide vaccination and the secondary endpoints being immune response, as measured by interferon (IFN)-γ enzyme-linked immunospot assay and Dextramer staining, and the clinical outcomes of tumor response, progression free survival (PFS), and overall survival (OS). Our findings indicated that GPC3 vaccination was well tolerated. We observed disease-control rates [complete response (CR)+partial response+stable disease] of 66.7% after 2 months, and although patients in the progression group unable to induce GPC3-peptide-specific cytotoxic T lymphocytes (CTLs) received poor prognoses, patients in the partial-remission and remission groups or those with hepatoblastoma received good prognoses. The GPC3-peptide vaccine induced a GPC3-specific CTL response in seven patients, with PFS and OS significantly longer in patients with high GPC3-specific CTL frequencies than in those with low frequencies. Furthermore, we established GPC3-peptide-specific CTL clones from a resected-recurrent tumor from one patient, with these cells exhibiting GPC3-peptide-specific cytokine secretion. The results of this trial demonstrated that the GPC3-peptide-specific CTLs induced by the GPC3-peptide vaccine infiltrated tumor tissue, and use of the GPC3-peptide vaccine might prevent the recurrence of pediatric solid tumors, especially hepatoblastomas, after a second CR.

Hepatocellular malignant neoplasm, NOS: a clinicopathological study of 11 cases from a single institution

AIMS

The primary aim of this study is to characterize hepatocellular malignant neoplasm, NOS (HEMNOS), a new provisional entity describing a subset of paediatric hepatocellular tumours, which have histological features of neither typical hepatoblastoma (HB) nor hepatocellular carcinoma (HCC).

METHODS AND RESULTS

The clinicopathological features of 11 patients with HEMNOS were analysed retrospectively. The median age and serum alpha-fetoprotein level at diagnosis was 7 years and 182 000 ng/ml, respectively. Ten patients presented with pretreatment extent of disease (PRETEXT) stages III/IV multifocal tumours, eight with major vascular involvement, three with lung metastases and three with extrahepatic extension. The original pathology diagnoses were: HB in seven patients, HCC in two and HEMNOS in two. Our pathology review of pre-chemotherapy specimens showed that six tumours had equivocal/overlapping histological features of HB and HCC, four had predominant HB histology along with focal HCC-like histology and one had HB histology. Seven of nine post-chemotherapy resection specimens showed predominant HCC-like histology. Beta-catenin, glypican 3 and spalt-like transcription factor 4 immunostaining showed that all the tumours had a mixed HB/HCC immunophenotype. Telomerase reverse transcriptase immunostaining showed nuclear staining in nine of the 11 tumours. All patients received chemotherapy and achieved gross total primary tumour resection. Nine of the 11 patients were treated with established HB chemotherapy regimens. After a median follow-up of 6.1 years (range: 1.2-11.8 years), all patients were in remission.

CONCLUSIONS

HEMNOS is a subtype of HB with focal HCC-like histology, a high-risk clinical profile but favourable outcome following chemotherapy and complete tumour resection.

Glypican 3 as a Serum Marker for Hepatoblastoma

Hepatoblastoma (HB) is the most common primary liver cancer in children. The conventional serum marker for HB, alpha-fetoprotein (AFP), has its limitations. Novel serum markers need to be explored. Glypican 3 (GPC3) has been reported to be an excellent histological immunomarker for HB. However, the clinical value of serum GPC3 in patients with HB is unknown. A total of 184 serum samples were tested for both GPC3 by ELISA, and AFP by immunometric assay. Of these, 134 were from 32 patients with HB at three treatment stages, 30 from age-matched patients with benign hepatobiliary disorders (BHD) and 20 from age-matched “normal controls”(NC). We found that the GPC3 levels in HB pretreatment group were significantly higher than those in NC group and HB remission group but not statistically different from those in BHD group and HB during treatment group. In contrast, AFP showed significant differences among different groups. The areas under the receiver operating curve (AUROC) value, sensitivity and specificity of GPC3 for HB pretreatment group versus all controls were all significantly lower than those of AFP. Serum GPC3 levels were not associated with prognostic parameters. We concluded that GPC3 is inferior to AFP as a serum marker for HB.

Redirecting T Cells to Glypican-3 with 4-1BB Zeta Chimeric Antigen Receptors Results in Th1 Polarization and Potent Antitumor Activity

T cells engineered to express CD19-specific chimeric antigen receptors (CARs) have shown breakthrough clinical successes in patients with B-cell lymphoid malignancies. However, similar therapeutic efficacy of CAR T cells in solid tumors is yet to be achieved. In this study we systematically evaluated a series of CAR constructs targeting glypican-3 (GPC3), which is selectively expressed on several solid tumors. We compared GPC3-specific CARs that encoded CD3ζ (Gz) alone or with costimulatory domains derived from CD28 (G28z), 4-1BB (GBBz), or CD28 and 4-1BB (G28BBz). All GPC3-CARs rendered T cells highly cytotoxic to GPC3-positive hepatocellular carcinoma, hepatoblastoma, and malignant rhabdoid tumor cell lines in vitro. GBBz induced the preferential production of Th1 cytokines (interferon γ/granulocyte macrophage colony-stimulating factor) while G28z preferentially induced Th2 cytokines (interleukin-4/interleukin-10). Inclusion of 4-1BB in G28BBz could only partially ameliorate the Th2-polarizing effect of CD28. 4-1BB induced superior expansion of CAR T cells in vitro and in vivo. T cells expressing GPC3-CARs incorporating CD28, 4-1BB, or both induced sustained tumor regressions in two xenogeneic tumor models. Thus, GBBz CAR endows T cells with superior proliferative potential, potent antitumor activity, and a Th1-biased cytokine profile, justifying further clinical development of GBBz CAR for immunotherapy of GPC3-positive solid tumors.

Expression of glypican-3 is highly associated with pediatric hepatoblastoma: a systemic analysis

OBJECTIVE

Glypican-3 (GPC3) is reported to be an oncofetal protein that is a useful diagnostic immunomarker for hepatoblastoma. However, the results are not inclusive. This study systemically investigated the association between expression of GPC3 and pediatric hepatoblastoma.

METHODS

Clinical studies evaluating the association were identified using a predefined search strategy. GPC3 immunohistochemistry was applied in the pathological diagnosis of hepatoblastoma using the monoclonal antibodies with formalin-fixed and paraffin-embedded specimens. Positive predictive rates for the association between expression of GPC3 and pediatric hepatoblastoma were calculated.

RESULTS

Specimens from four clinical studies which including 134 patients with pediatric hepatoblastoma tested by GPC3 immunohistochemistry were considered eligible for inclusion. Systemic analysis showed that, in all patients, pooled positive predictive rate of the association between expression of GPC3 and pediatric hepatoblastoma was 95.5% (128/134).

CONCLUSION

This systemic analysis suggests that the expression of glypican-3 is highly associated with the diagnosis of pediatric hepatoblastoma.

Spalt-like transcription factor 4 immunopositivity is associated with epithelial cell adhesion molecule expression in combined hepatocellular carcinoma and cholangiocarcinoma

AIM

Combined hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) (cHCC-CC) is a rare biphasic liver cancer. Recent studies have demonstrated that cHCC-CC originates from hepatic progenitor cells (HPCs). Spalt-like transcription factor 4 (SALL4) is a marker for a progenitor subclass of HCC with an aggressive phenotype. However, little has been revealed about SALL4 expression in cHCC-CC. The aims of this study were to report SALL4 immunopositivity and the results of clinicopathological analysis in cHCC-CC, and to examine the two different nuclear immunostaining patterns for SALL4.

METHODS AND RESULTS

We defined the diffuse finely granular nuclear immunostaining pattern as immunopositive for SALL4; this was observed in eight (8.9%) of 90 cHCC-CCs. SALL4 immunopositivity was significantly associated with immunopositivity for α-fetoprotein, glypican 3, and epithelial cell adhesion molecule (EpCAM). There was no relationship between SALL4 immunopositivity and prognosis. We confirmed SALL4 mRNA expression in samples with a punctuate/clumped immunostaining pattern, which showed a significantly lower rate of immunopositivity for EpCAM than those with a diffuse finely granular pattern.

CONCLUSIONS

SALL4 immunopositivity is not a prognostic factor in cHCC-CC; however, it is associated with α-fetoprotein, glypican 3 and EpCAM immunopositivity, indicating the mechanism of carcinogenesis. Further study is necessary to interpret the immunostaining pattern for SALL4.

Glypican-3 is a biomarker and a therapeutic target of hepatocellular carcinoma

BACKGROUND

The carcinogenesis of hepatocellular carcinoma (HCC) is a multi-factorial, multi-step and complex process. Early diagnosis and effective treatments are of utmost importance. This review summarized the recent studies of oncofetal glypican-3 (GPC-3), a membrane-associated heparan sulfate proteoglycan, in the diagnosis and treatment of HCC.

DATA SOURCES

English-language reports published from June 2001 to September 2014 were searched from MEDLINE. The key words searched included: GPC-3, biomarker, target and HCC. The sensitivity, specificity, positive and negative predictive values were extracted, and the effect of GPC-3 targeted therapy on HCC was also evaluated.

RESULTS

GPC-3 plays a crucial role in HCC cell proliferation and metastasis. It mediates oncogenesis involving signaling pathways during hepatocyte malignant transformation. GPC-3 expression is increased in atypical hyperplasia and cancerous tissues. GPC-3 levels in HCC patients are related to HBV infection, TNM stage, periportal cancerous embolus, and extrahepatic metastasis. The diagnostic accuracy of the combination of serum GPC-3 and alpha-fetoprotein in HCC is up to 94.3%. Down-regulation of GPC-3 with specific siRNA or anti-GPC-3 antibody alters cell migration, metastasis and invasion behaviors. The nude mice xenograft tumor growth is inhibited by silencing GPC-3 gene transcription.

CONCLUSION

Oncofetal GPC-3 is a highly specific biomarker for the diagnosis of HCC and a promising target molecule for HCC gene therapy.

Quantification of glypican 3, β-catenin and claudin-1 protein expression in hepatoblastoma and paediatric hepatocellular carcinoma by colour deconvolution

AIMS

To identify an immunohistochemical panel for paediatric malignant epithelial liver tumours.

METHODS AND RESULTS

Forty-five hepatoblastomas (HBs), 13 paediatric hepatocellular carcinomas (HCCs) and two hepatocellular malignant neoplasms not otherwise specified (NOS) were chosen for immunohistochemical staining of glypican 3 (GPC3), β-catenin, claudin-1, delta-like protein (DLK), and forkhead box protein G1 (FOXG1). Immunostaining was quantitatively analysed with NIH imagej software coupled with colour deconvolution. Different subtypes of HB and HCC showed distinct staining patterns of GPC3, β-catenin, and claudin-1. Moreover, GPC3, β-catenin and claudin-1 all showed higher expression in classic HCC and embryonal HB than in fetal HB; GPC3 showed complete negativity in small-cell undifferentiated (SCU) HB and fibrolamellar HCC (FLC); β-catenin showed the strongest expression in SCU HB but the weakest expression in FLC. A panel of these three immunomarkers was useful for the diagnosis of hepatocellular malignant neoplasms NOS. The expression of DLK and FOXG1 was inconstant among fetal and embryonal HB and classic HCC.

CONCLUSIONS

A panel of GPC3, β-catenin and claudin-1 is helpful for differentiating HB subtypes and distinguishing HB from HCC.

Detection of Serum Protein Biomarkers for the Diagnosis and Staging of Hepatoblastoma

The present study aimed to identify serum biomarkers for the detection of hepatoblastoma (HB). Serum samples were collected from 71 HB patients (stage I, n = 19; stage II, n = 19, stage III, n = 19; and stage IV, n = 14) and 23 age- and sex-matched healthy children. Differential expression of serum protein markers were screened using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS), and the target proteins were isolated and purified using HPLC and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), SEQUEST, and bioinformatics analysis. Differential protein expression was confirmed by enzyme-linked immunosorbent analysis (ELISA). SELDI-TOF-MS screening identified a differentially expressed protein with an m/z of 9348 Da, which was subsequently identified as Apo A–I; its expression was significantly lower in the HB group as compared to the normal control group (1546.67 ± 757.81 vs. 3359.21 ± 999.36, respectively; p < 0.01). Although the expression level decreased with increasing disease stage, pair-wise comparison revealed significant differences in Apo A–I expression between the normal group and the HB subgroups (p < 0.01). ELISA verified the reduced expression of Apo A–I in the HB group. Taken together, these results suggest that Apo A–I may represent a serum protein biomarker of HB. Further studies will assess the value of using Apo A–I expression for HB diagnosis and staging.

Screening and identification of apolipoprotein A-I as a potential hepatoblastoma biomarker in children, excluding inflammatory factors

The aim of the present study was to identify a child hepatoblastoma serum biomarker that is unaffected by inflammatory factors, with the ultimate aim of finding an effective method for the early diagnosis of hepatoblastoma. The magnetic bead-based weak cation exchange chromatography technique was used to process serum harvested from 30 children with hepatoblastoma, 20 children with systemic inflammatory response syndrome (SIRS) and 20 healthy children. Proteins differentially expressed in SIRS were excluded from consideration as biomarkers for hepatoblastoma. Proteins differentially expressed in hepatoblastoma and healthy controls were screened using surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS). Target proteins were purified by SDS-PAGE, and matrix-assisted laser desorption/ionization (MALDI)-TOF-MS was used to determine their amino acid sequences. Protein matches were searched in the SwissProt database. Quantitative polymerase chain reaction (qPCR) and ELISA were employed to confirm the expression of target proteins. Following screening to exclude inflammatory factors, SELDI-TOF-MS revealed a protein with a mass-to-charge ratio of 9,348 Da that was expressed at significantly lower levels in the serum of children with hepatoblastoma compared with healthy controls (P<0.01). Sequence analysis identified this protein as apolipoprotein A-1 (Apo A-I). qPCR and ELISA confirmed that the expression of Apo A-I mRNA and protein were significantly lower in children with hepatoblastoma compared with healthy controls (P<0.05). These results indicate that Apo A-I is a non-inflammatory protein marker for hepatoblastoma with the potential for use in early diagnosis of hepatoblastoma. In addition, the present study demonstrates the feasibility of proteomic screening for the identification of proteins that can serve as markers for a specific tumor.

An infant with a diagnostically challenging hepatic teratoma, hypofibrinogenemia, and adrenal neuroblastoma: case report

Teratomas of the liver are exceedingly rare. Neuroblastoma is the most common, extracranial solid tumor of infancy. We describe the case of a 2-month-old, female infant who presented with an abdominal mass arising in the right lobe of the liver, and a severe coagulopathy, which necessitated cryoprecipitate infusion. Biopsy was interpreted as hepatoblastoma. Following resection, difficulty classifying the mass led to several consultations, and an eventual diagnosis of teratoma. During follow-up, the patient was diagnosed with right adrenal neuroblastoma, which, in retrospect, had been present before the hepatic resection. To our knowledge, these 2 tumors have never been reported together, or in combination with isolated hypofibrinogenemia.

Glypican 3 overexpression in primary and metastatic Wilms tumors

Glypican 3 (GPC3), a heparan sulfate proteoglycan, plays a role in cell growth and differentiation. Mutations of the GPC3 gene are responsible for Simpson-Golabi-Behmel syndrome, which is characterized by anomalies of postnatal overgrowth and an increased risk of developing pediatric malignancies, mostly Wilms tumor and liver cancer. In order to understand the possible role of GPC3 in renal development and Wilms tumor formation, we analyzed messenger RNA (mRNA) and protein levels of GPC3 in sporadic Wilms tumors and compared it to normal kidneys and other common renal epithelial tumors. By using Affymetrix HGU133 oligonucleotide gene expression microarray data from 191 renal tumors and 12 normal kidneys, we found significant overexpression of GPC3 in Wilms tumors (p < 0.01), with 3.5-fold higher expression in comparison to normal kidneys and 6.5-fold higher than any type of renal tumors. The GPC3 gene product in Wilms tumor was further evaluated by immunohistochemistry and quantified by an automated image analysis. Cytoplasmic and membranous GPC3 immunoreactivity was present in 77 % of primary Wilms tumors (23/30), 93 % of metastatic Wilms tumors (13/14), 50 % of metanephric adenomas (4/8), 33 % of congenital mesoblastic nephromas (2/6), 100 % of nephrogenic rests (11/11), and 100 % of fetal kidneys (5/5). GPC3 staining was predominantly identified in blastemal and epithelial components of Wilms tumors, similar to that of fetal non-neoplastic kidney. All adult renal tumors (n = 60) and normal kidneys (n = 15) were GPC3 negative. These findings suggest the utility of GPC3 in differential diagnosis and follow-up of Wilms tumors. Our data also indicate that GPC3 is an oncofetal protein with a potential therapeutic value.

Discovery and diagnostic value of a novel oncofetal protein: glypican 3

Glypican 3 is a membrane-bound heparan sulfate proteoglycan, which has recently been identified as a marker for liver cancer and germ cell malignancies. Individuals with loss-of-function mutations for the glypican 3 gene exhibit Simpson-Golabi-Behmel syndrome, a rare X-linked overgrowth disorder. Expression of glypican 3 mRNA and protein is normally silenced in most adult organs and may reappear during malignant transformation. In the past few years, immunohistochemical and molecular characteristics of glypican 3 in hepatocellular carcinoma have been elucidated. More recently, glypican 3 has been emerging as a new diagnostic marker for germ cell tumors and especially testicular and ovarian yolk sac tumors. However, in other tumors such as renal cell carcinomas, squamous cell carcinomas, and melanomas, studies disagree on the level of glypican 3 expression. Finally, there is the controversial notion of glypican 3 as a tumor suppressor gene. In this review article, we update current knowledge on glypican 3 expression in normal and neoplastic tissues, evaluate its utility as a tumor marker in clinical practice, and explore its role as a novel oncofetal protein with clinical implications. Our focus is on the diagnostic value of glypican 3 in germ cell tumors and other neoplasms in addition to hepatocellular carcinoma. In conclusion, glypican 3 has been proven to be a useful immunohistochemical marker in distinguishing yolk sac tumors, choriocarcinomas, and Wilms tumors from other malignancies histologically mimicking these primitive tumors. Clinically, we recommend that glypican 3 be used as part of a panel of markers in subtyping testicular germ cell tumors.

Critical analysis of the potential of targeting GPC3 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. The treatment options for patients with advanced HCC are limited, and novel treatment strategies are required urgently. Glypican-3 (GPC3), a member of the glypican family of heparan sulfate proteoglycans, is overexpressed in 72%−81% of HCC cases, and is correlated with a poor prognosis. GPC3 regulates both stimulatory and inhibitory signals, and plays a key role in regulating cancer cell growth. GPC3 is released into the serum, and so might be a useful diagnostic marker for HCC. GPC3 is also used as an immunotherapeutic target in HCC. A Phase I study of a humanized anti-GPC3 monoclonal antibody, GC33, revealed a good safety profile and potential antitumor activity, and a Phase II trial is currently ongoing. In addition, the authors’ investigator-initiated Phase I study of a GPC3-derived peptide vaccine showed good safety and tolerability, and demonstrated that the GPC3 peptide-specific cytotoxic T-lymphocyte frequency in peripheral blood correlated with overall survival in HCC patients. A sponsor-initiated Phase I clinical trial of a three-peptide cocktail vaccine, which includes a GPC3-derived peptide, is also underway. GPC3 is currently recognized as a promising therapeutic target and diagnostic marker for HCC. This review introduces the recent progress in GPC3 research, from biology to clinical impact.

Towards an international pediatric liver tumor consensus classification: proceedings of the Los Angeles COG liver tumors symposium

Liver tumors are rare in children, and their diagnoses may be challenging particularly because of the lack of a current consensus classification system. Systematic central histopathological review of these tumors performed as part of the pediatric collaborative therapeutic protocols has allowed the identification of histologic subtypes with distinct clinical associations. As a result, histopathology has been incorporated within the Children's Oncology Group (COG) protocols, and only in the United States, as a risk-stratification parameter and for patient management. Therefore, the COG Liver Tumor Committee sponsored an International Pathology Symposium in March 2011 to discuss the histopathology and classification of pediatric liver tumors, and hepatoblastoma in particular, and work towards an International Pediatric Liver Tumors Consensus Classification that would be required for international collaborative projects. Twenty-two pathologists and experts in pediatric liver tumors, including those serving as central reviewers for the COG, European Société Internationale d'Oncologie Pédiatrique, Gesellschaft für Pädiatrische Onkologie und Hämatologie, and Japanese Study Group for Pediatric Liver Tumors protocols, as well as pediatric oncologists and surgeons specialized in this field, reviewed more than 50 pediatric liver tumor cases and discussed classic and newly reported entities, as well as criteria for their classification. This symposium represented the first collaborative step to develop a classification that may lead to a common treatment-stratification system incorporating tumor histopathology. A standardized, clinically meaningful classification will also be necessary to allow the integration of new biological parameters and to move towards clinical algorithms based on patient characteristics and tumor genetics, which should improve future patient management and outcome.

A patient with Simpson-Golabi-Behmel syndrome, biliary cirrhosis and successful liver transplantation

Simpson-Golabi-Behmel syndrome type 1 (SGBS1) -OMIM 312870- is a rare X-linked inherited overgrowth syndrome caused by a loss of function mutation in the GPC3 gene. Affected patients present a variable phenotype with pre- and post-natal macrosomia, distinctive facial dysmorphism, organomegaly, and multiple congenital anomalies. Intellectual disability is not constant. About 10% of patients have an increased risk of developing embryonic tumors in early childhood. Only one case of biliary disease has been described so far. GPC3 is localized on Xq26. It encodes for glypican 3, a heparan sulfate proteoglycan, which among its different known roles, negatively regulates liver regeneration and hepatocyte proliferation. This report concerns a male with a SGBS1, carrier of a GPC3 pathogenic mutation, and neonatal liver disease, who developed an early biliary cirrhosis. Together with the associated risk of cancer and developmental delay, liver transplantation was discussed and then successfully performed at the age of 19 months. A hypothesis on the role of GPC3 in the patient's liver disease is also proposed.

Immunohistochemistry for the novel markers glypican 3, PAX8, and p40 (ΔNp63) in squamous cell and urothelial carcinoma

OBJECTIVES

To examine squamous cell carcinomas (SCCs) from diverse anatomic sites and invasive urothelial carcinomas (UCs) for expression of the oncofetal antigen glypican 3 (GPC3), the paired box transcription factor PAX8, and the ΔN isoform of p63 (p40).

METHODS

Immunohistochemistry for GPC3, PAX8, and p40 was performed on whole sections of 107 SCCs from 11 anatomic sites and 49 UCs; evaluation included extent and intensity of staining.

RESULTS

GPC3 was detected in 20% of SCCs and 12% of UCs and PAX8 in 3% of SCCs, limited to the uterine cervix, and 10% of UCs. p40 Was found in 99% of SCCs and 96% of UCs.

CONCLUSIONS

GPC3 expression is frequent in SCC/UC, awareness of which should guard against an incorrect diagnosis of hepatocellular carcinoma, while PAX8, limited in distribution, may have some use in suggesting a cervical or urothelial tract origin in a metastatic squamotransitional carcinoma of unknown primary. There is no drop-off in sensitivity for the diagnoses of SCC or UC with ΔNp63-specific immunohistochemistry, and if this performance can be extended to other applications, p40 may supplant the dominant "pan-p63" antibody clone.

Teratoid hepatoblastoma with abundant cholangioblastic component in a child with full trisomy 13

Teratoid hepatoblastoma is a rare histological subtype of hepatoblastoma. A 15-month-old girl with full trisomy 13 presented with a liver mass (6 × 4.4 × 3.4 cm). Histological examination showed a teratoid hepatoblastoma with very different differentiation patterns intermixed with each other. Approximately 30% of the tumor demonstrated a primitive glandular epithelium component, which had a moderate to well-differentiated adenocarcinoma-like morphology, and features of mucinous epithelium with a biliary immunophenotype. We designated it as cholangioblastic component. The child received 4 cycles of monotherapy with doxorubicin after complete resection and showed no evidence of residual tumor 8 months after surgery. Our case is not only the 1st report of hepatoblastoma in trisomy 13 but also represents a unique example with a large glandular epithelium component with cholangioblastic features. Increased awareness of this entity and further molecular studies are needed for better understanding of the pathogenesis of teratoid hepatoblastoma.

Glypican-3 antibodies: a new therapeutic target for liver cancer

Glypican-3 (GPC3) is an emerging therapeutic target in hepatocellular carcinoma (HCC), even though the biological function of GPC3 remains elusive. Currently human (MDX-1414 and HN3) and humanized mouse (GC33 and YP7) antibodies that target GPC3 for HCC treatment are under different stages of preclinical or clinical development. Humanized mouse antibody GC33 is being evaluated in a phase II clinical trial. Human antibodies MDX-1414 and HN3 are under different stages of preclinical evaluation. Here, we summarize current evidence for GPC3 as a new target in liver cancer, discuss both its oncogenic function and its mode of actions for current antibodies, and evaluate potential challenges for GPC3-targeted anti-cancer therapies.

Clinicopathologic implication of hepatic progenitor cell marker expression in hepatoblastoma

Hepatic progenitor cells (HPCs) are thought to play a role in hepatoblastoma, as hepatoblastomas are characterized by an immature histology and a wide variety of cell lineages. We aimed to investigate the extent of expression of HPCs marker and its clinical implication in hepatoblastoma. We collected 61 hepatoblastomas and 9 childhood hepatocellular carcinomas (HCCs) and performed immunohistochemistry for HPC markers, including cytokeratin 19 (CK19), octamer-binding transcription factor 3/4 (Oct-3/4), epithelial cell adhesion molecule (EpCAM), and delta-like 1 homolog (DLK1). Of the hepatoblastoma samples, 27/61 (44.3%), 21/61 (34.4%), 51/61 (83.6%) and 56/61 (91.8%) exhibited positivity for CK19, Oct-3/4, EpCAM and DLK-1, respectively. For HCCs, the rates of expression were 22.2% (CK19), 77.8% (EpCAM) and 77.8% (DLK-1). Oct-3/4 was not expressed in HCC cells. Hepatoblastomas with a poorly differentiated epithelial component had a higher incidence of CK19 and Oct-3/4 expression than those with a well differentiated epithelial component (p=0.005 and 0.037, respectively). Higher disease stage of hepatoblastoma was correlated with CK19 expression (p=0.043). Oct-3/4-positive hepatoblastomas were associated with short disease-free survival (p=0.035). Both hepatoblastomas and childhood HCCs, therefore, exhibit characteristics of HPCs, and the poor prognosis of patients with Oct-3/4-positive hepatoblastoma suggests that stem-like properties affect hepatoblastoma pathogenicity.

Immunohistochemical expression of glypican-3 in pediatric tumors: an analysis of 414 cases

Glypican-3 (GPC3) is a proteoglycan thought to play an important role during development. Germline GPC3 mutations are seen in the rare Simpson-Golabi-Behmel syndrome (SGBS), which predisposes patients to Wilms tumor, hepatoblastoma, and neuroblastoma. While numerous adult tumors have been evaluated by immunohistochemistry for GPC3, no comprehensive assessment has been done in pediatric tumors. We therefore investigated GPC3 expression in 143 pediatric central nervous system (CNS) tumors and 271 non-CNS tumors. Among non-CNS tumors, GPC3 expression was seen in 9/9 (100%) hepatoblastomas, 4/6 (67%) malignant rhabdoid tumors, 5/13 (38%) Wilms tumors, 11/37 (30%) alveolar rhabdomyosarcomas, and 8/45 (18%) embryonal rhabdomyosarcomas. All 136 neuroblastomas, 14 Ewing sarcoma/primitive neuroectodermal tumors, and 11 synovial sarcomas were immunonegative for GPC3. Among CNS tumors, GPC3 had restricted expression, with positivity in 6/6 (100%) atypical teratoid rhabdoid tumors and 1/4 (25%) craniopharyngiomas. The remaining 136 CNS tumors-23 medulloblastomas, 21 pilocytic astrocytomas, 13 gangliogliomas, 12 ependymomas, 12 glioblastomas, 11 choroid plexus neoplasms, 10 diffuse astrocytomas (grade II/III), 10 meningiomas, 8 dysembryoplastic neuroepithelial tumors, 8 oligodendrogliomas, 3 craniopharyngiomas, 3 germinomas, and 2 neurocytomas-were entirely negative for GPC3. These results showed GPC3 positivity in a number of non-CNS tumors, with no consistent discrimination between tumors that were or were not associated with SGBS. Within the CNS, GPC3 positivity was limited to a small subset of CNS neoplasms and may thus serve as a useful positive diagnostic biomarker (P < 0.0001) in addition to negative INI1/BAF47/SMARCB1 staining to differentiate atypical teratoid rhabdoid tumors from other high-grade pediatric brain tumors.

Current issues and controversies in the classification of pediatric hepatocellular tumors

Systematic histopathologic examination of hepatoblastoma specimens from patients enrolled in therapeutic protocols has allowed the identification of clinically relevant histologic subtypes that are being incorporated into risk stratification systems. Genetic and molecular studies have documented recurrent chromosomal abnormalities and aberrant activation of developmental, and oncogenic signaling pathways in hepatoblastoma. Molecular profiling has also identified molecular subclasses and gene signatures that could be used to stratify hepatoblastoma patients. Future international collaboration is needed to develop consensus pathology classifications, and to progressively incorporate genetic and molecular biomarkers into therapeutic pediatric liver tumors protocols.

Genetics and epigenetics of hepatoblastoma

A number of unique genetic features are observed in hepatoblastoma that have provided insights into the origins of hepatoblastoma. Hallmark cytogenetic changes in hepatoblastoma include the acquisition of additional copies of whole chromosomes and a recurring unbalanced translocation involving 1q. Genetic syndromes are associated with approximately 15% of hepatoblastoma and the understanding and recognition of these syndromes will be important in determining future surveillance studies needed to prevent additional cancers in survivors as well as in some case guide the care of family members. This article will review the genetic changes, both germ line and acquired, that are recurring events in hepatoblastoma, with emphasis on how these genetic changes could work together with other developmental factors and influence cancer predisposition, tumor growth, as well as aid in prognosis. Tumor-specific signatures based on transcriptional or epigenetic alterations will be reviewed that might be used in the future to better diagnose and subtype the disease as well as predict prognosis and response to therapy.

Expression of glypican-3 in undifferentiated embryonal sarcoma and mesenchymal hamartoma of the liver

Glypican-3 (GPC3) is an oncofetal protein that has been demonstrated to be a useful diagnostic immunomarker for hepatocellular carcinoma and hepatoblastoma. Its expression in mesenchymal tumors of the liver, particularly undifferentiated embryonal sarcoma (UES) and mesenchymal hamartoma (MH), has not been investigated. In this study, a total of 24 UESs and 18 MHs were immunohistochemically stained for GPC3 expression. The results showed cytoplasmic staining for GPC3 in 14 (58%) UESs, of which 6 exhibited diffuse immunoreactivity and the remaining 8 showed focal positivity. The patients with GPC3-positive UES tended to be younger (mean 18 years; median 11 years) than those with GPC3-negative tumors (mean 39.4 years; median 27 years), although the difference did not reach statistical significance (P = .06). Eight MHs also exhibited GPC3 immunoreactivity (44%; 4 diffuse and 4 focal). Positive staining in all 8 cases was primarily seen in entrapped nonlesional hepatocytes with a canalicular and cytoplasmic staining pattern. In only 4 cases (22%) was GPC3 immunoreactivity also observed in the mesenchymal component. The patients with positive staining also tended to be younger (mean 2.6 years; median 1.1 years) compared with those with negative staining (mean 16.3 years; median 4.5 years), but the difference was not statistically significant (P = .15). Our data demonstrate that GPC3 is expressed in a subset of UES and MH of the liver. Caution should thus be exercised when evaluating a GPC3-expressing hepatic neoplasm, particularly on a needle biopsy when the differential diagnosis includes poorly differentiated hepatocellular carcinoma or hepatoblastoma.

Glypican-3, a novel prognostic marker of hepatocellular cancer, is related with postoperative metastasis and recurrence in hepatocellular cancer patients

Metastasis/recurrence has been the most fundamental characteristic of hepatocellular cancer (HCC) and the ultimate cause of most HCC-related deaths. However, there are still a limited number of reliable tumor markers that can be used to predict the possibility of metastasis/recurrence in an HCC patient after operation. Recently, much evidence has shown that glypican-3 (GPC3) can be a useful tool to identify the early development of HCC, but little research has been done to test its usefulness as a prognostic marker related to post-operative metastasis/recurrence in HCC patients. In this study, the expression of GPC3 and its relationship with clinicopathological factors were determined by immunohistochemical analysis in 61 primary HCC patients. The potential prognostic value of GPC3 was investigated by comparing the survival time between HCC patients with high and low GPC3 expression. The results demonstrated that GPC3 expression was closely related with metastasis/recurrence in an HCC patient who can receive the operation. The risk of metastasis/recurrence after surgery in an HCC patient with high GPC3 expression was increased to 3.214 as compared to that of an HCC patient with low GPC3 expression. Survival analysis showed that HCC patients with high GPC3 expression had a significantly shorter overall survival time than HCC patients with low GPC3 expression (P=0.003). Further, multivariate analysis showed that GPC3 expression was a significant, independent prognostic parameter (P=0.030) for HCC patients. Overall, the study indicates that GPC3 might be a valuable marker closely related with prognosis and post-operative metastasis/recurrence in HCC patients.

Glypican-3: a new target for cancer immunotherapy

Hepatocellular carcinoma (HCC) remains a common malignant cancer worldwide. There is an urgent need to identify new molecular targets for the development of novel therapeutic approaches. Herein, we review the structure, function and biology of glypican-3 (GPC3) and its role in human cancer with a focus on its potential as a therapeutic target for immunotherapy. GPC3 is a cell-surface protein that is over-expressed in HCC. Loss-of-function mutations of GPC3 cause Simpson-Golabi-Behmel syndrome (SGBS), a rare X-linked overgrowth condition. GPC3 binds Wnt and Hedgehog (Hh) signalling proteins. GPC3 is also able to bind basic growth factors such as fibroblast growth factor 2 through its heparan sulphate glycan chains. GPC3 is a promising candidate for liver cancer therapy given that it shows high expression in HCC. An anti-GPC3 monoclonal antibody has shown anti-cancer activity in mice and its humanised IgG molecule is currently undergoing clinical evaluation in patients with HCC. There is also evidence that soluble GPC3 may be a useful serum biomarker for HCC.

Glypican 3 has a higher sensitivity than alpha-fetoprotein for testicular and ovarian yolk sac tumour: immunohistochemical investigation with analysis of histological growth patterns

AIMS

Glypican 3 (GPC3) has been reported to be overexpressed in yolk sac tumour (YST), but the sensitivity has not been compared with alpha-fetoprotein (AFP). YST can form numerous growth patterns and the expression of GPC3 in these patterns has not been studied. The aim was to address these aspects.

METHODS AND RESULTS

Sections from testicular or ovarian YST were subjected to immunohistochemistry using GPC3 (n = 39) and AFP (n = 24). Overall immunoreactivity for each case and specific histological patterns were semiquantitatively evaluated (0-3+) and intensity of reactivity was scored (0-3). All cases expressed GPC3 (1+, 5%; 2+, 8%; 3+, 87%) with strong intensity (2.9). The majority expressed AFP (58%) but immunoreactivity was often focal (0, 42%; 1+, 33%; 2+, 25%) and intensity was low (1.0). Using GPC3, >75% of the microcystic (n = 38), macrocystic (n = 26), solid (n = 21), glandular-alveolar (n = 8), endodermal sinus (n = 7), polyvesicular vitelline (n = 5), enteric (n = 4) and micropapillary (n = 2) growth patterns displayed 2+ or 3+ positivity.

CONCLUSIONS

YST can display a variety of growth patterns that can be confused with other germ cell tumour components. GPC3 detects all growth patterns tested and has a higher sensitivity for detecting YST than AFP.