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Where do we stand with hepatoblastoma? A review.Schnater JM, Kohler SE, Lamers WH, von Schweinitz D, Aronson DC.Pediatric Surgical Center of Amsterdam, Emma Children's Hospital AMC, Academic Medical Center, Amsterdam, The Netherlands.Hepatoblastoma (HB) is the most common pediatric liver malignancy, comprising approximately 1% of all pediatric cancers. The disparate clinical staging systems and histologic classifications that were developed during the last decades, nevertheless, reflect the remaining difficulties and uncertainties in characterizing HB. Furthermore, the combination of surgery and (neo)adjuvant chemotherapy has improved patient outcomes dramatically. A poor prognosis is associated with large tumor size, multifocality, extrahepatic disease, and metastatic spread. The exact etiology of HB remains unknown, but the cytogenetic alterations, phenotypic features, and biologic aspects that accompany this neoplasm yield more and more insight into its pathogenesis. New cell-biologic and molecular-biologic insights may lead to the development of new treatment modalities, especially for patients with a bad prognosis. This review summarizes the different aspects of this intriguing tumor and discusses the current status of research and treatment for patients with HB. Copyright 2003 American Cancer Society.DOI 10.1002/cncr.11585

Hepatoblastomas (HBs) represent the most frequent malignant liver tumors of childhood; yet little is known about the molecular pathogenesis and the alterations in expression patterns of these tumors. We used a suppression subtractive hybridization approach to identify new candidate genes that may play a role in HB tumorigenesis. cDNA species derived from corresponding liver and fetal liver were subtracted from HB cDNAs, and a series of interesting candidates were isolated that were differentially expressed. One of the transcripts overexpressed in HB was derived from the human Dickkopf-1 (hDkk-1) gene, which encodes a secreted protein acting as a potent inhibitor of the wingless/WNT signaling pathway. We examined the hDkk-1 expression levels in 32 HB biopsy specimens and in the corresponding liver samples, in 4 HB cell lines, and in a panel of other tumors and normal tissues using a differential PCR approach and Northern blotting. Eighty-one percent of the HBs but none of the normal pediatric or fetal liver tissues showed hDkk-1 expression. hDkk-1 transcripts were also present in 5 of 6 Wilms' tumors but only weakly detectable in 2 of 20 hepatocellular carcinoma samples and in 1 of 5 medulloblastoma cell lines; transcripts were absent in malignant gliomas and breast cancer. The central effector molecule in the WNT developmental control pathway is the beta-catenin protein. Interestingly, activating mutations of the beta-catenin gene have previously been identified in 48% of HBs, and more than 85% of HBs show accumulation of beta-catenin protein as the indicator for an activated pathway. The overexpression of the inhibitor Dkk-1 may therefore be related to uncontrolled wingless/WNT signaling and may represent a negative feedback mechanism. hDkk-1 expression represents a novel marker for HBs and Wilms' tumors.

BACKGROUND In the past 20 years, a dramatic improvement in the prognosis of patients with hepatoblastoma (HB) has been achieved by combining surgery with chemotherapy in several national and international trials. A worldwide, unsolved problem remains the treatment of patients with advanced or metastatic HB. METHODS The German Cooperative Pediatric Liver Tumor Study HB 94 was a prospective, multicenter, single-arm study. The study ran from January 1994 to December 1998. The protocol assessed the efficiency of chemotherapy consisting of cisplatin, ifosfamide, and doxorubicin (CDDP/IFO/DOXO) and/or etoposide and carboplatin (VP16/CARBO). The prognostic significance of the surgical strategy, pretreatment factors, and tumor characteristics for disease free survival (DFS) were analyzed. RESULTS Sixty-nine children with HB were treated in the HB 94 study. The median follow-up of survivors was 58 months (range, 32–93 months). Fifty-three of 69 patients (77%) remained alive, and 16 of 69 patients (23%) died. Long-term DFS was as follows: 26 of 27 patients had Stage I HB, 3 of 3 patients had Stage II HB, 19 of 25 patients had Stage III HB, and 5 of 14 patients had Stage IV. A complete resection of the primary tumor was achieved in 54 of 63 patients (86%). Six children (8%) had no surgical treatment. Twenty-two tumors were resected primarily, and 41 children underwent surgery after initial chemotherapy. Two children underwent liver transplantation. There was no perioperative death. Forty-eight children received primary chemotherapy with CDDP/IFO/DOXO. Forty-one of 48 children achieved partial remission after CDDP/IFO/DOXO. Eighteen children with advanced or recurrent HB underwent VP16/CARBO chemotherapy, with a response achieved by 12 children. The relevant pretreatment prognostic factors were growth pattern of the liver tumor (P = 0.0135), vascular tumor invasion (P = 0.0039), occurrence of distant metastases (P = 0.0001), initial α-fetoprotein level (P = 0.0034), and surgical radicality (P < 0.0001). CONCLUSIONS The current results underline the necessity of preoperative chemotherapy in all children with HB. Complete tumor resection is one of the main prognostic factors. Cancer 2002;95:172–82. © 2002 American Cancer Society. DOI 10.1002/cncr.10632

Background During recent years, we identified characteristic genetic alterations in sporadic hepatoblastoma (HB). These include loss of heterozygosity (LOH) at the chromosomal region 11p15.5, LOH on chromosome arms 1p and 1q, activating mutations in exon 3 of the β-catenin gene, as well as overexpression of the c-met oncogene, which encodes the hepatocyte growth factor receptor. We now wanted to evaluate the prognostic relevance of these abnormalities concerning the outcome in a large group of patients. Procedure All but 7 of 56 patients with HB were treated either with primary resection for small tumors, or neo-adjuvant chemotherapy with ifosfamide, cisplatin and doxorubicin (IPA) before delayed surgery in case of extended disease and additional adjuvant IPA therapy in all cases. Seven tumors were primarily resected and adjuvantly treated with different cytotoxic drugs. LOH 11p15.5, LOH 1p, and LOH 1q were detected in tumor tissue in comparison to normal liver and/or peripheral blood leukocytes by PCR based microsatellite analysis. Beta-catenin mutations were analysed with SSCP, deletion screening and direct sequencing. RT-PCR was used for identification of c-met mRNA overexpression. The results were correlated with the tumors' stage, histological type and epithelial differentiation, as well as with the patients' outcome. Results Overall disease-free survival after median follow-up of 5 years was 43/56 patients (77%). LOH 11p15.5 was found in 15/56, LOH1p in 11/53, LOH1q in 7/53 and β-catenin mutations in 25/55 HB. 13/23 HB had a c-met overexpression. LOH 11p15.5 and LOH 1p were significantly more often found in embryonal HB, while there was no correlation of other genetic alterations with histological type or differentiation. Furthermore, statistical analysis revealed no correlation of any of these disorders with initial tumor stage, nor with the patients' outcome. Conclusion None of the investigated molecular genetic alterations are suited to serve as a prognostic indicator in HB. Further investigations, especially genetic screening of tumor tissue may reveal prognostic markers for this neoplasm. Med Pediatr Oncol 2002;38:104–108. © 2002 Wiley-Liss, Inc.

The human insulin-like growth factor-II (IGF2) is a regulatory peptide which is critical in normal fetal growth. IGF2 gene transcription is controlled by the usage of four promoters P1–P4 of which promoters P2–P4 are genomically imprinted. Disruption of imprinting and the resulting increase of gene dosage have been shown to be implicated in tumor progression in a variety of human tumors. Due to the need for high amounts of tissue material for conventional methods such as Northern blotting or ribonuclease protection assay (RPA), studies on IGF2 expression have most often been limited to the detection of total IGF2 transcript, though different dysregulatory events can be responsible for the abundance of IGF2 mRNA found in many tumors. We established a highly sensitive competitive RT-PCR assay for the four different transcripts of the IGF2 gene with transcript-specific external RNA competitors in which we take advantage of fluorescence-based quantification on a semiautomated sequencer. The amount of total RNA needed is approximately 100 times lower than the amounts required for Northern blotting or RPA, so that even cytological samples can be analyzed. We applied the assay to a series of eleven hepatoblastomas (HB) in which normal adjacent liver tissue could also be analyzed.

Hepatoblastoma (HB) is the most common malignant liver tumor in children with a histology that resembles various stages of the developing liver. To explore the genetic origin of this cancer, we performed whole-exome sequencing of 8 tumors and matched germline tissue. In average, we detected only three sequence variants per tumor, which is the lowest mutation rate ever reported for any cancer. Mutations of ß-catenin (CTNNB1) displayed the only recurrent event occurring in all tumors, thereby underscoring the significance of activated Wnt signaling in the genesis of HB. Gene ontology analysis revealed a predominance of candidate genes involved in the regulation of gene expression and transcription, including the nuclear factor (erythroid-derived 2)-like 2 (NFE2L2). Targeted resequencing of a cohort of 50 HB cases and cell lines revealed NFE2L2 mutations in 10% of all tumors. Interestingly, all mutations were located in or adjacent to the DLG and ETGE motifs of the NFE2L2 protein that are known to be recognized from the KEAP1/CUL3 complex for proteasomal degradation. In line with this, cells transfected with mutant NFE2L2 were insensitive to KEAP1-mediated downregulation of NFE2L2 signaling. Clinically, overexpression of the NFE2L2 target gene NQO1 in tumor tissues was significantly associated with high tumor stage, metastasis, and poor outcome. These data suggest that activation of NFE2L2-KEAP1 signaling through mutations in NFE2L2 is a prominent characteristic in pediatric liver tumors, thereby advocating inhibition of aberrant NFE2L2 activity as a therapeutic option, especially in high-risk patients with advanced disease. Citation Format: Roland Kappler, Melanie Eichenmüller, Franziska Trippel, Tim M. Strom, Dietrich von Schweinitz. The genetic landscape of the childhood liver cancer hepatoblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3086. doi:10.1158/1538-7445.AM2014-3086

Hepatoblastomas (HBs), representing malignant liver tumors of childhood, show frequent loss of heterozygosity (LOH) in the chromosomal region 11p15.5. This loss is of maternal origin suggesting the presence of a monoallelically expressed tumor suppressor gene in this region. p57 KIP2 (KIP2) located at 11p15.5 is predominantly expressed from the maternal allele and encodes a cyclin-dependent kinase inhibitor. We screened a series of 56 HB tumors and five HB cell lines for allelic loss (LOH) of the KIP2 locus by microsatellite analysis and KIP2 coding sequence mutations by single-strand conformation polymorphism analysis. Although LOH at the KIP2 locus occurred in 25% of the cases, no mutations were found. Analysis of KIP2 mRNA expression by competitive reverse transcriptase-polymerase chain reaction revealed up-regulation in nine of 12 HBs compared to matching liver samples. In contrast, mRNA levels of the putative suppressor gene H19 on 11p15.5 were decreased in 10 of 12 tumors, indicating that KIP2 and H19 are not co-regulated in HBs. IGF2 mRNA expression was increased in 11 of 12 HB samples. All HBs showed monoallelic KIP2 expression. However, the overexpression of KIP2 in HBs with maternal loss of 11p15.5 suggests a reactivation of the paternal allele in these cases. Overexpression of KIP2 in HBs argues against a role as a HB suppressor gene.

Rapid growth of residual tumor after partial hepatectomy has been observed during the period of liver regeneration in children with malignant embryonal hepatoblastoma. The aim of this study was to elucidate the role of hepatocyte growth-factor-scatter factor (HGF-SF) in this phenomenon. Markedly increased serum levels of HGF-SF up to 15 ng/ml were found in 13/18 patients after liver resection and in 6/16 patients with regressive tumors after chemotherapy, in comparison with 15 patients with non-pre-treated hepatoblastoma and 20 healthy children of the same age group. In the tumors, epithelial tumor cells highly expressed the HGF-SF receptor c-met, as shown by immunohistochemistry and m-RNA RT-PCR. The hepatoblastoma cell lines HepT1, HepT3 and HUH6 reacted with significantly increased proliferation to rhHGF-SF in these concentrations (1-15 ng/ml). In the tumors, HGF-SF was found to be expressed in the stromal fibroblasts. In culture, hepatoblastoma cells (HepT3, HUH6) stimulated secretion of the factor by human fibroblasts, indicating the paracrine fashion of intratumoral HGF-SF production. Cultured hepatoblastoma cells ceased to proliferate at 20-50 ng/ml HGF-SF, and they underwent cell death at ≥100 ng/ml. In contrast, the hepatocellular-carcinoma cell line HepG2 decreased growth under HGF-SF in a dose-dependent manner. We conclude that post-operatively secreted and intratumorally produced HGF-SF can function as a growth factor for hepatoblastoma, while the same agent has a cytostatic effect in unphysiologically high concentrations. Int. J. Cancer 85:151–159, 2000. ©2000 Wiley-Liss, Inc.

Background Hepatoblastoma (HB) is the most common liver tumor of childhood, and comprises approximately 1% of all pediatric malignancies. Although recent data from multicenter trials of GPOH, SIOP, CCG and POG indicate a remarkable improvement of therapy results, the prognosis of advanced or recurrent HB is still not satisfying. Patients and methods During 1989 and 1997, the German Cooperative Pediatric Liver Tumor Studies HB 89 and HB 94 registered 141 patients with HB, who were treated according to the study protocols. These patients received standard chemotherapy with ifosfamide, cisplatin and doxorubicin (IPA) pre-operatively and/or post-operatively. Fourteen children with recurrent or advanced HB were additionally treated with carboplatin and etoposide (CARBO/VP 16), the reason being observations of drug resistance in children with HB after four or more courses of IPA-therapy in the HB 89 study. The clinical data and course of these patients were evaluated to investigate the efficiency of CARBO/VP 16 chemotherapy and for analyzing the role of surgery. Results Mean follow-up for survivors was 4.3 years (range 13 months-8 years). Tumor resection was attempted in 13 children but, in only 3 cases, was a complete tumor resection achieved in one operation. There was no perioperative death, and 7 of the patients (50%) are in remission. Two patients underwent adjuvant chemotherapy with CARBO/VP 16 for advanced HB at first operation: all are alive and well. Five patients with local relapse and/or distant metastases responded partially to CARBO/VP 16 therapy, and a complete remission was achieved in one patient. In five patients, progressive disease was observed during therapy with CARBO/VP 16. One patient, stable while on chemotherapy, had a successful resection. Acute toxicity of chemotherapy was observed in 7 patients (50%). Conclusion An aggressive approach using IPA and CARBO/VP 16 chemotherapy and highly developed surgical techniques may improve the prognosis of advanced or recurrent HBs.

Background. Hepatoblastoma is an uncommon liver tumor of infancy and early childhood. Though most patients with nonmetastatic hepatoblastomas can be cured by defining surgical strategies and chemotherapy regimes, new drugs are needed for children with advanced hepatoblastomas. The activity of paclitaxel as a new antineoplastic agent with limited experience in pediatric oncology was studied in a xenograft model. Procedure. Hepatoblastoma cell suspensions from three children were transplanted subcutaneously into nude mice NMRI (nu/nu). One of the primary tumors was an embryonal multifocal hepatoblastoma, whereas the other tumors were embryonal/fetal hepatoblastomas localized on a liver lobe. After 4 weeks, xenografted tumor sizes reached 50-100 mm 3 , The xenografted tumors resembled their originals histologically and produced high levels of α-fetoprotein. The efficiency of paclitaxel at equitoxic doses was analyzed. Results. Paclitaxel produced an effect in all three hepatoblastomas. There was a significant reduction of tumor volume (P < 0.001) and α-fetoprotein levels after chemotherapy (P < 0.0001). The proliferation activity of the tumor cells corresponded with these results. Histologically, after treatment with paclitaxel the tumor regression was 35%-49%. The mechanism of paclitaxel action could be demonstrated by light microscopy immunohistochemistry and electron microscopy. Conclusions. The preliminary results in phase I trials of solid tumors in children and the results of this study suggest that paclitaxel in phase II studies can now be entertained for patients with hepatoblastoma.

BACKGROUND Hepatoblastoma is the most common primary malignant liver tumor affecting infants and young children. Recent clinical experience with advanced hepatoblastoma shows that a reliable in vivo model to study the tumor's response to drugs is needed urgently. METHODS Hepatoblastoma cell suspensions from three children were transplanted subcutaneously into NMRI nude mice (nu/nu). One of the primary tumors was a embryonal multifocal hepatoblastoma, whereas the other tumors were embryonal/fetal hepatoblastomas localized to one liver lobe. The xenograft tumors resembled their original tumors histologically and produced high levels of α-fetoprotein. The mice who received the tumors were given ifosfamide, cisplatin, doxorubicin, carboplatin, and etoposide as single agents. Thereafter, the tumor growth rate and α-fetoprotein levels in the animal sera were measured before and after chemotherapy and compared with the control group. After chemotherapy, the tumors were studied by conventional histology. RESULTS The tumors in the nude mice derived from the multifocal hepatoblastoma reacted minimally against four of the five cytotoxic agents, whereas cisplatin reduced the tumor volume significantly. There was a marked reduction in tumor volume in the other tumors after application of cisplatin and doxorubicin, respectively. The tumors displayed a moderate reduction in size after treatment with ifosfamide, etoposide, and carboplatin. The responses to the different cytostatic agents also corresponded with serum α-fetoprotein levels and mitotic rates in the tumor cells. CONCLUSIONS To the authors' knowledge, this is the first time an in vivo model for analyzing the effects of chemotherapy on hepatoblastoma has been established. The animal model may be suited for the evaluation of new drugs for the treatment of hepatoblastoma and for the investigation of multidrug resistance mechanisms in hepatoblastoma. Cancer 1998;83:2400-2407. © 1998 American Cancer Society.

The objectives of this study were to investigate clinical and patho-histological characteristics of childhood hepatoblastoma on their value as prognostic factors, and to evaluate the predictive impact of different staging systems for liver tumors on 72 patients treated in the German Pediatric Liver-Tumor Study HB89. Statistical analysis was performed by comparing patients' disease-free survival with characteristics and stages. Multivariate analysis was done by the Cox proportional-hazards model, the recursive partitioning and amalgamation model (RECPAM) and the model of clustering by response (CBR). The following characteristics were significantly related with prognosis: tumor involvement of one vs. both liver lobes, multifocal disseminated vs. unifocal growth pattern in the liver, distant metastases, vascular invasion, fetal vs. embryonal differentiation, and serum alpha-fetoprotein; patients with values ofor = 100 ng/ml oror = 1,000,000 ng/ml had a worse outcome than those with 100 to 1,000,000 ng/ml. Multivariate analysis with the 3 models revealed that tumor-growth pattern, serum alpha-fetoprotein and, in the Cox and CBR models, vascular invasion also are independent prognostic factors, permitting the allocation of hepatoblastoma patients to 1 of 2 prognostic groups for differential therapy. Post-surgical staging and the conventional TNM system for liver carcinoma had a high predictive value, in contrast to a TNM system proposed by the UICC for testing on childhood liver tumors. We therefore propose that the TNM system for liver carcinoma be applied for comparison of treatment results in hepatoblastoma.

10037 Background: Congenital hepatoblastoma, defined as diagnosis in the first month of life (Ammann RA, Plaschkes JLeibundgut K. Congenital hepatoblastoma: A distinct entity? Med Pediatr Oncol 1999:32:466-468.), has been reported to have a poor prognosis; however, a comprehensive evaluation of this entity is lacking. Methods: We performed a retrospective review including three patients from the senior authors’ personal series and 23 cases identified in the databases of several multicenter group studies (INT-0098, P9645, 881, P9346, HB 89, HB94 and HB 99). We then compared this series with the data of all cases of congenital hepatoblastoma previously published in the literature. Results: The overall 2-year survival in our case series was 86% (18/21) with a median followup of 85.5 months (range 44 to 230 months). Presentation and treatment were not substantially different from hepatoblastoma cohorts unselected for age. The infants in our study exhibited a comparable survival rate to the reported disease free survival for a similar cohort of hepatoblastoma patients unselected for age between 1986 and 2002 (82.5%) [Tiao GM, Bobey N, Allen S, et al. The current management of hepatoblastoma: A combination of chemotherapy, conventional resection, and liver transplantation. J Pediatr 2005:146:204-211.]. The overall 2-year survival rate of cases previously reported in the literature was 0% (0/11) for patients reported before 1992, and 47% (8/17) for those reported after 1992. The improved survival of our current series of patients, collected from the past 20 years of German and American multicenter trials and personal series, suggests that the outcome of HB at this young age is much better than has been historically reported. Conclusions: Congenital hepatoblastoma does not appear to confer a worse prognosis. The overall survival in our series does not appear to be worse than in older children; more rigorous analysis should be conducted in future multicenter trials. It is possible that congenital HB should be treated like all other patients with hepatoblastoma provided that the child is stable enough to proceed with surgery and chemotherapy and complete staging is performed.

63 Background: Hepatoblastoma (HB) is the most common malignant liver tumor in childhood. Although combination of neoadjuvant chemotherapy and surgery has improved the outcome of standard-risk HB-patients up to 94% the outcome of high-risk HB-patients with metastatic tumors or invasion of large hepatic veins is still dismal and only 60% of these patients survive. Therefore, the identification of biomarkers that could help early detection of high-risk HB-patients and lead to risk-adapted therapies is of utmost importance. Methods: Genomic DNA of tumor and normal liver samples from 21 HB patients was extracted with standard procedures and bisulfite-treated using EpiTect Bisulfite Kit (Qiagen). Methylation status of the Ras association (RalGDS/AF-6) domain family member 1 (RASSF1) gene was analyzed by methylation-specific-PCR. cDNA of tumor and normal liver samples was used to determine the 16-gene expression signature according to Cairo et al. (2008, Cancer Cell) using real-time PCR. Association studies of molecular and clinical data were performed with GraphPad Prism Version 3.0 using two-tailed Chi square test. Results: We identified 9/21 HB cases hypermethylated in the RASSF1 promoter region. Interestingly, RASSF1 promoter methylation was significantly associated with metastases (p=0.0166) and occurrence of this epigenetic marker was associated with a reduced overall survival of patients (p=0.0008). Moreover, we discriminated HB tumors in C1 and C2 subclasses by using the 16-gene signature and correlation of these subtypes with the methylation status of RASSF1 showed a significant association (p=0.0037) for aggressive C2 tumors (8/11), but not C1 tumors (1/10). Conclusions: RASSF1 promoter hypermethylation is a strong prognostic marker for metastasis and worse outcome and correlates with an aggressive C2 HB-tumor profile. Since the detection of tumor-derived methylated DNA in the blood stream of cancer patients is nowadays practical, our data advise RASSF1 methylation assays to be used for risk assessment in HB-patients in the future.

In contrast to remarkable improvements in the survival and cure rates that have been encountered for many childhood malignancies, the prognosis of children with advanced stage neuroblastoma remains poor. Searching for novel strategies to modulate apoptosis in neuroblastoma we investigated the potential of the proteasome inhibitor Bortezomib to modulate TRAIL-induced apoptosis in neuroblastoma cell lines, primary neuroblastoma cultures and in an in vivo model of neuroblastoma. Here, we provide first evidence that Bortezomib at subtoxic concentrations synergistically cooperates with TRAIL to induce apoptosis (combination index 0.5). In addition, Bortezomib acts in concert with TRAIL to reduce colony formation of neuroblastoma cells, demonstrating an effect also on longterm survival. Mechanistic studies reveal that Bortezomib profoundly enhances TRAIL-induced cleavage of Bid into tBid, accumulation of tBid in the cytosol and its insertion into mitochondrial membranes, pointing to a concerted effect on Bid cleavage (TRAIL) and stabilization of tBid (Bortezomib), which links the death receptor to the mitochondrial pathway. Additionally, Bortezomib increases expression of p53 and Noxa. All these changes lead to increased activation of Bax and Bak, loss of the mitochondrial membrane potential, cytochrome c release, caspase activation and caspase-dependent apoptosis upon treatment with Bortezomib and TRAIL. Knockdown of either Bid, Noxa or p53 significantly delays the kinetic of Bortezomib- and TRAIL-induced apoptosis, whereas it does not confer longterm protection. By comparison, overexpression of Bcl-2, which simultaneously antagonizes tBid, Noxa and p53, significantly inhibits Bortezomib- and TRAIL-induced apoptosis and even rescues clonogenic survival. Of note, Bortezomib and TRAIL act in concert to trigger apoptosis in several patients’ derived primary neuroblastoma cultures, underscoring the clinical relevance. Importantly, Bortezomib cooperates with TRAIL to suppress tumor growth in an in vivo model of neuroblastoma. In conclusion, these findings demonstrate for the first time that Bortezomib at subtoxic concentrations represents a promising new approach to prime neuroblastoma cells towards TRAIL-induced apoptosis by linking the death receptor to the mitochondrial pathway. Thus, this study provides the rational for future (pre)clinical evaluation of the combination strategy with Bortezomib and TRAIL in neuroblastoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4341. doi:10.1158/1538-7445.AM2011-4341

The receptor tyrosine kinase erbB2 is known to play a role in the development of hepatic progenitor cells and is often found to be expressed and mutated in different solid tumors. Activated erbB2 is a marker of poor prognosis in several malignancies and to date, successful strategies have been developed to target erbb2 receptor. The aim of this study was to determine the expression of erbb2 in human hepatoblastoma, the most common primary hepatic malignancy in early childhood, and its functional role in hepatoblastoma cell biology. Expression of erbB2 on the protein level was analyzed by Western Blot, immunofluorescence and RT-PCR of lysates of primary tumors and cell lines HuH6, HepT1, HepT3 and HepG2. Immunohistochemical staining was performed to determine phosphorylated erbB2 and subsequent kinases. Single strand conformation polymorphism (SSCP) analysis was used to scan known hotspots for mutations (exons 6, 8, 18–23 of erbB2) in a panel of 56 tumor samples. Cells were stimulated with rhHRG1-β. Activation of subsequent kinases was determined via Western Blot and MTT assay was used to determine proliferation after stimulation and overexpression of erbb2 via transient transfection. The influence of rhHRG1-β on the activity of the Wnt/ß-catenin pathway was measured by transfection with the TOP-/FOP-Flash reporter assay. The effects of erbB2 kinase knockdown by transient transfection with siRNA against erbB2 on apoptosis and proliferation were also evaluated. Expression of erbB2 was detected in all four cell lines and most of the primary tumors. Immunohistochemistry indicated expression of phosphorylated (activated) Erbb2 proteins in 90% and activation of subsequent kinases, which are downstream targets of erbb2. Mutations were not present in the erbB2 gene. Stimulation with HRG1-β induced phosphorylation of Akt, Erk1/2 and p70S6K and resulted in increased cell proliferation. This effect was not mediated by an increase of activity of the Wnt/ß-catenin signaling pathway because TOP-Flash reporter activity was not further increased in the presence of rhHRG1-β. Overexpression of erbB2 resulted in enhanced proliferation after stimulation with HRG1-β in all four cell lines, whereas knockdown of erbB2 decreased the proliferative effect of HRG1-β on hepatoblastoma cell lines. Knockdown of erbB2 did not induce apoptosis in hepatoblastoma cell lines. These results indicate that erbB2 might play an important functional role in hepatoblastoma cell biology. Further experiments are needed to evaluate the clinical significance. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-372. doi:10.1158/1538-7445.AM2011-LB-372

Background. In several types of tumors, including hepatocellular carcinoma, prognosis could be correlated with DNA ploidy. Few studies have been performed on hepatoblastoma with contradictory results. Methods. Twenty-nine cases of nonpretreated hepatoblastoma were studied with flow cytometry and image cytometry for DNA index and proliferation index using paraffin-embedded tissue. Results. Twenty-three (79.9%) tumors were diploid, and 6 (20.7%) were aneuploid (hyperdiploid). Patients with diploid tumors were younger than those with aneuploid tumors. With regard to stage, diploid tumors were almost equally distributed among stages (tumor, lymph node metastases, distant metastases), whereas aneuploid tumors tended to occur in higher stages (tumor, lymph node metastases, distant metastases). Diploid tumors had clearly a better prognosis than aneuploid tumors, although the difference was not statistically significant (flow cytometry, P = 0.06; image cytometry, P = 0.16). A more favorable prognosis was also noted for hepatoblastomas with low-proliferation index (≤ 7%), but the difference from tumors with high-proliferation index ( > 7%) again was not statistically significant (P = 0.16). Conclusions. Although no statistically significant differences in prognosis between hepatoblastomas with diploid and aneuploid DNA content, respectively, were found, there is a clear tendency that diploid hepatoblastomas behave more favorably. The same is true for hepatoblastomas with low-proliferation index.

Infantile choriocarcinoma of the liver is an extremely rare entity, and outcome has been fatal in almost all published cases. To the authors' knowledge, this is the first report on successful treatment with preoperative chemotherapy. A 10-week-old girl presented with a large liver tumor, ovarian cysts, cardiac insufficiency, progressive hemolytic anemia, and thrombocytopenia. Ultrasound scan and magnetic resonance tomography (MRT) showed the typical pattern of infantile hemangioendothelioma. An emergency laparotomy was performed because of increasing cardiac insufficiency with ligation of the right hepatic artery, tumor biopsy, and subtotal resection of the ovarian cysts. Histology findings showed a choriocarcinoma of the liver and corpus luteum cysts of the ovaries. Serum β-human chorionic gonadotropin (β-HCG) was elevated to 1.600.00 U/L. Chemotherapy was initiated with etoposide and cisplatin. When x-ray examination showed development of lung metastases, chemotherapy was intensified with etoposide, cisplatin, and ifosfamid according to the German Study Group of Extracranial Nontesticular Malignant Germ Cell Tumors in Childhood and Adolescence (MAKEI-96). Serum β-HCG levels decreased further, ultrasound examination showed significant tumor reduction, and pulmonal metastasis could no longer be found in chest x-rays. After the fourth course, a complete tumor resection was achieved by an extended right hemihepatectomy with adjuvant chemotherapy being administered after the operation. The child has been in complete remission for 22 months. The authors' experience shows that chemotherapy is effective for preoperative tumor reduction. J Pediatr Surg 35:1134-1135. Copyright © 2000 by W.B. Saunders Company.

An unusual case of fibrolamellar carcinoma of the liver developed 5 years after removal of a hepatocellular adenoma in a 14-year-old girl belonging to a family with Carney syndrome. Both tumors were studied by light and electron microscopy, flow cytometry, and comparative genomic hybridization. The first tumor, removed at the age of 9, was a bulky well-circumscribed liver mass composed of large eosinophilic cells with a focal pseudoglandular pattern but without cytologic atypia or sclerosis. A diagnosis of hepatocellular adenoma was rendered. Five years later, another hepatic tumor was removed from the right lobe. Microscopic examination revealed polygonal cells, each with a large amount of eosinophilic cytoplasm and a round nucleus with a conspicuous nucleolus. These cells were arranged in nests and strands and separated by bands of dense fibrous tissue, leading to a diagnosis of fibrolamellar carcinoma. Comparative genomic hybridization analysis revealed no genetic alteration in the adenoma; however, several chromosomal aberrations (loss of chromosome regions 1p and 4p and gains of chromosome regions 6q, 13q, and Xq) were detected in the fibrolamellar carcinoma. To our knowledge, this is the first report of an association between hepatocellular adenoma and fibrolamellar carcinoma.