Characterization of genomic alterations in hepatoblastomas. A role for gains on chromosomes 8q and 20 as predictors of poor outcome

A comprehensive analysis of minimally differentially methylated regions common to pediatric and adult solid tumors

Cancer is the second most common cause of death in children aged 1-14 years in the United States, with 11,000 new cases and 1200 deaths annually. Pediatric cancers typically have lower mutational burden compared to adult-onset cancers, however, the epigenomes in pediatric cancer are highly altered, with widespread DNA methylation changes. The rarity of pediatric cancers poses a significant challenge to developing cancer-type specific biomarkers for diagnosis, prognosis, or treatment monitoring. In the current study, we explored the potential of a DNA methylation profile common across various pediatric cancers. To do this, we conducted whole genome bisulfite sequencing (WGBS) on 31 recurrent pediatric tumor tissues, 13 normal tissues, and 20 plasma cell-free (cf)DNA samples, representing 11 different pediatric cancer types. We defined minimal focal regions that were differentially methylated across samples in the multiple cancer types which we termed minimally differentially methylated regions (mDMRs). These methylation changes were also observed in 506 pediatric and 5691 adult cancer samples accessed from publicly available databases, and in 44 pediatric cancer samples we analyzed using a targeted hybridization probe capture assay. Finally, we found that these methylation changes were detectable in cfDNA and could serve as potential cfDNA methylation biomarkers for early detection or minimal residual disease.

Mutational signature, cancer driver genes mutations and transcriptomic subgroups predict hepatoblastoma survival

BACKGROUND

Hepatoblastoma is the most frequent pediatric liver cancer. The current treatments lead to 80% of survival rate at 5 years. In this study, we evaluated the clinical relevance of molecular features to identify patients at risk of chemoresistance, relapse and death of disease.

METHODS

All the clinical data of 86 children with hepatoblastoma were retrospectively collected. Pathological slides were reviewed, tumor DNA sequencing (by whole exome, whole genome or target) and transcriptomic profiling with RNAseq or 300-genes panel were performed. Associations between the clinical, pathological, mutational and transcriptomic data were investigated.

RESULTS

High-risk patients represented 44% of our series and the median age at diagnosis was 21.9 months (range: 0-208). Alterations of the WNT/ß-catenin pathway and of the 11p15.5 imprinted locus were identified in 98% and 74% of the tumors, respectively. Other cancer driver genes mutations were only found in less than 11% of tumors. After neoadjuvant chemotherapy, disease-specific survival and poor response to neoadjuvant chemotherapy were associated with 'Liver Progenitor' (p = 0.00049, p < 0.0001) and 'Immune Cold' (p = 0.0011, p < 0.0001) transcriptomic tumor subtypes, SBS35 cisplatin mutational signature (p = 0.018, p = 0.001), mutations in rare cancer driver genes (p = 0.0039, p = 0.0017) and embryonal predominant histological type (p = 0.0013, p = 0.0077), respectively. Integration of the clinical and molecular features revealed a cluster of molecular markers associated with resistance to chemotherapy and survival, enlightening transcriptomic 'Immune Cold' and Liver Progenitor' as a predictor of survival independent of the clinical features.

CONCLUSIONS

Response to neoadjuvant chemotherapy and survival in children treated for hepatoblastoma are associated with genomic and pathological features independently of the clinical features.

Summary of biological research on hepatoblastoma: a scoping review

Background

Hepatoblastoma is the most prevalent primary hepatic malignancy in children, comprising 80% of pediatric hepatic malignancies and 1% of all pediatric malignancies. However, traditional treatments have proven inadequate in effectively curing hepatoblastoma, leading to a poor prognosis.

Methods

A literature search was conducted on multiple electronic databases (PubMed and Google Scholar). A total of 86 articles were eligible for inclusion in this review.

Result

This review aims to consolidate recent developments in hepatoblastoma research, focusing on the latest advances in cancer-associated genomics, epigenetic studies, transcriptional programs and molecular subtypes. We also discuss the current treatment approaches and forthcoming strategies to address cancer-associated biological challenges.

Conclusion

To provide a comprehensive summary of the molecular mechanisms associated with hepatoblastoma occurrence, this review highlights three key aspects: genomics, epigenetics, and transcriptomics. Our review aims to facilitate the exploration of novel molecular mechanisms and the development of innovative clinical treatment strategies for hepatoblastoma.

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.

Oncogenic Role of ADAM32 in Hepatoblastoma: A Potential Molecular Target for Therapy

Outcomes of pediatric hepatoblastoma (HBL) have improved, but refractory cases still occur. More effective and safer drugs are needed that are based on molecular mechanisms. A disintegrin and metalloproteases (ADAMs) are expressed with high frequency in various human carcinomas and play an important role in cancer progression. In this study, we analyzed expression of ADAMs in HBL with a cDNA microarray dataset and found that the expression level of ADAM32 is particularly high. To investigate the role of ADAM32 in cancer, forced expression or knockdown experiments were conducted with HepG2 and HBL primary cells. Colony formation, cell migration and invasion, and cell viability were increased in HepG2 expressing ADAM32, whereas knockdown of ADAM32 induced a decrease in these cellular functions. Quantitative RT-PCR demonstrated an association between ADAM32 expression and the expression of genes related to cancer stem cells and epithelial–mesenchymal transition (EMT), suggesting a role of ADAM32 in cancer stemness and EMT. Furthermore, knockdown of ADAM32 increased cisplatin-induced apoptosis, and this effect was attenuated by a caspase-8 inhibitor, suggesting that ADAM32 plays a role in extrinsic apoptosis signaling. We conclude that ADAM32 plays a crucial role in progression of HBL, so it might be a promising molecular target in anticancer therapy.

Current Approaches in Hepatoblastoma-New Biological Insights to Inform Therapy

PURPOSE OF REVIEW

As the most common pediatric primary liver cancer with rising incidence, hepatoblastoma remains challenging to treat. Here, we review the current understanding of the biology of hepatoblastoma and discuss how recent advances may lead to new treatment modalities.

RECENT FINDINGS

Standard chemotherapy regimens including cisplatin, in addition to surgery, have led to high cure rates among patients with low stage hepatoblastoma; however, metastatic and relapsed disease continue to have poor outcomes. Recent genomics and functional studies in cell lines and mouse models have established a central role for the Wnt/β-catenin pathway in tumorigenesis. Targeted agents and immunotherapy approaches are emerging as potential treatment avenues. With recent gains in knowledge of the genomic and transcriptomic landscape of hepatoblastoma, new therapeutic mechanisms can now be explored to improve outcomes for metastatic and relapsed hepatoblastoma and to reduce the toxicity of current treatments.

Copy Number Alterations in Hepatoblastoma: Literature Review and a Brazilian Cohort Analysis Highlight New Biological Pathways

Hepatoblastoma (HB) is a rare embryonal tumor, although it is the most common pediatric liver cancer. The aim of this study was to provide an accurate cytogenomic profile of this type of cancer, for which information in cancer databases is lacking. We performed an extensive literature review of cytogenetic studies on HBs disclosing that the most frequent copy number alterations (CNAs) are gains of 1q, 2/2q, 8/8q, and 20; and losses at 1p and 4q. Furthermore, the CNA profile of a Brazilian cohort of 26 HBs was obtained by array-CGH; the most recurrent CNAs were the same as shown in the literature review. Importantly, HBs from female patients, high-risk stratification tumors, tumors who developed in older patients (> 3 years at diagnosis) or from patients with metastasis and/or deceased carried a higher diversity of chromosomal alterations, specifically chromosomal losses at 1p, 4, 11q and 18q. In addition, we distinguished three major CNA profiles: no detectable CNA, few CNAs and tumors with complex genomes. Tumors with simpler genomes exhibited a significant association with the epithelial fetal subtype of HBs; in contrast, the complex genome group included three cases with epithelial embryonal histology, as well as the only HB with HCC features. A significant association of complex HB genomes was observed with older patients who developed high-risk tumors, metastasis, and deceased. Moreover, two patients with HBs exhibiting complex genomes were born with congenital anomalies. Together, these findings suggest that a high load of CNAs, mainly chromosomal losses, particularly losses at 1p and 18, increases the tendency to HB aggressiveness. Additionally, we identified six hot-spot chromosome regions most frequently affected in the entire group: 1q31.3q42.3, 2q23.3q37.3, and 20p13p11.1 gains, besides a 5,3 Mb amplification at 2q24.2q24.3, and losses at 1p36.33p35.1, 4p14 and 4q21.22q25. An in-silico analysis using the genes mapped to these six regions revealed several enriched biological pathways such as ERK Signaling, MicroRNAs in Cancer, and the PI3K-Akt Signaling, in addition to the WNT Signaling pathway; further investigation is required to evaluate if disturbances of these pathways can contribute to HB tumorigenesis. The analyzed gene set was found to be associated with neoplasms, abnormalities of metabolism/homeostasis and liver morphology, as well as abnormal embryonic development and cytokine secretion. In conclusion, we have provided a comprehensive characterization of the spectrum of chromosomal alterations reported in HBs and identified specific genomic regions recurrently altered in a Brazilian HB group, pointing to new biological pathways, and relevant clinical associations.

Genetic and epigenetic basis of hepatoblastoma diversity

Hepatoblastoma (HB) is the most common pediatric liver malignancy; however, hereditary predisposition and acquired molecular aberrations related to HB clinicopathological diversity are not well understood. Here, we perform an integrative genomic profiling of 163 pediatric liver tumors (154 HBs and nine hepatocellular carcinomas) based on the data acquired from a cohort study (JPLT-2). The total number of somatic mutations is precious low (0.52/Mb on exonic regions) but correlated with age at diagnosis. Telomerase reverse transcriptase (TERT) promoter mutations are prevalent in the tween HBs, selective in the transitional liver cell tumor (TLCT, > 8 years old). DNA methylation profiling reveals that classical HBs are characterized by the specific hypomethylated enhancers, which are enriched with binding sites for ASCL2, a regulatory transcription factor for definitive endoderm in Wnt-pathway. Prolonged upregulation of ASCL2, as well as fetal-liver-like methylation patterns of IGF2 promoters, suggests their "cell of origin" derived from the premature hepatoblast, similar to intestinal epithelial cells, which are highly proliferative. Systematic molecular profiling of HB is a promising approach for understanding the epigenetic drivers of hepatoblast carcinogenesis and deriving clues for risk stratification.

The Emerging Roles of Cancer Stem Cells and Wnt/Beta-Catenin Signaling in Hepatoblastoma

Hepatoblastoma (HB) is the most common form of primary liver malignancy found in pediatric populations. HB is considered to be clonal and arises from hepatoblasts, or embryonic liver progenitor cells. These less differentiated tumor-initiating progenitor cells, or cancer stem cells (CSCs), may contribute to tumor recurrence and resistance to therapies, and have high metastatic abilities. Phenotypic heterogeneity, undesired genetic and epigenetic alterations, and dysregulated signaling pathways provide CSCs with a survival advantage over current therapies. The molecular and cellular basis of HB and the mechanism of CSC induction are not fully understood. The Wnt/beta-catenin pathway is one of the major developmental pathways and is believed to play an important role in the pathogenesis of HB and CSC formation. This review summarizes the cellular and molecular characteristics of HB with a specific emphasis on CSCs and Wnt/beta-catenin signaling.

Targeting excessive MYCN expression using MLN8237 and JQ1 impairs the growth of hepatoblastoma cells

Hepatoblastoma (HB) is the most common liver tumor in children under the age of 3 years worldwide. While many patients achieve good outcomes with surgical resection and conventional chemotherapy, there is still a high‑risk population that exhibits a poor treatment response and unfavorable prognosis, which warrants the search for novel treatment options. In recent years, it has become clear that genetic events alone are not sufficient to explain the aggressive phenotype of this embryonal malignancy. Instead, epigenetic modifications and aberrant gene expression seem to be key drivers of HB. In the present study, expression analyses such as reverse transcription‑quantitative polymerase chain reaction revealed that the oncogene, MYCN proto‑oncogene basic‑helix‑loop‑helix transcription factor (MYCN) was upregulated in HB and other pediatric liver tumors, due to the transcriptional activity of its antisense transcript MYCN opposite strand (MYCNOS). Pyrosequencing demonstrated the hypomethylated regions in the promoter of MYCN and MYCNOS, suggesting that an epigenetic mechanism may underlie the induction of aberrant expression. Transient MYCN knockdown in HB cells resulted in growth inhibition over time. In addition, treating HB cells with the MYCN inhibitors JQ1 and MLN8237 led to the significant downregulation of MYCN either at the mRNA or protein levels, respectively. The underlying mechanism of action of the two inhibitors was revealed to be associated with the induction of dose‑dependent growth arrest, by arresting cells at either the G1/G0 or G2 phase. Furthermore, MLN8237 and JQ1 were able to cause spindle disturbances and/or apoptosis in HB cells. The present results suggest that MYCN may be a promising biomarker for HB and a potential therapeutic target in patients with tumors overexpressing MYCN.

The correlation between gain of chromosome 8q and survival in patients with clear and papillary renal cell carcinoma

Background

The proto-oncogene c-MYC, located on chromosome 8q, can be upregulated through gain of 8q, causing alteration in biology of renal cell carcinoma (RCC). The aim of this study was to evaluate the prevalence of c-MYC through chromosome 8q gain and to correlate findings with cancer-specific mortality (CSM), and overall survival (OS).

Methods

Cytogenetic analysis by conventional or Chromosomal Genomic Microarray Analysis (CMA) was performed on 414 renal tumors. Nonclear and nonpapillary RCC were excluded. Impact of gain in chromosome 8q status on CSM, OS, and its correlation with clinicopathological variables were evaluated. CSM and OS were assessed using log-rank test and the Cox proportional hazards model.

Results

A total of 297 RCC tumors with cytogenetic analysis were included. Gain of 8q was detected in 18 (6.1%) tumors (9 clear cell and 9 papillary RCC), using conventional method (n = 11) or CMA (n = 7). Gain of 8q was associated with higher T stage (p < 0.001), grade (p < 0.001), nodal involvement (p = 0.005), and distant metastasis (p < 0.001). No association between gain of 8q and age (p = 0.23), sex (p = 0.46), and Charlson comorbidity index (CCI, p = 0.59) were seen. Gain of 8q was associated with an 8.38-fold [95% confidence interval (CI), 3.83-18.34, p < 0.001] and 3.31-fold (95% CI, 1.56-7.04, p = 0.001) increase in CSM and decrease in OS, respectively, at a median follow up of 56 months.

Conclusion

Chromosome 8q harbors the proto-oncogene c-MYC, which can be upregulated by gain of 8q. Our findings suggest that gain of 8q, can predict aggressive tumor phenotype and inferior survival in RCC.

Long Non-Coding RNA SNHG6 as a Potential Biomarker for Hepatocellular Carcinoma

Long Non-coding RNAs (lncRNAs) refer to all non-protein coding transcripts longer than 200 nucleotides. Their critical roles in different biological pathways have been already well established. Altered expression of lncRNAs can be involved in the cancer initiation and/or progression. Since patients with hepatocellular carcinoma (HCC) are usually diagnosed in late stages, developing diagnostic methods seems to be essential. In this study, the expression levels of different lncRNAs were systematically analysed in different genomic and transcriptome datasets. The analyses showed that SNHG6 is among the lncRNAs with distinctive dysregulation of expression and copy number variation in HCC tumors compared with normal tissues. The results also suggest that the dysregulation of SNHG6 is highly cancer type specific. Through co-occurrence analyses, we found that SNHG6 and its related co-expressed genes on 8q are involved in the structural integrity of ribosome and translation. This comprehensive in silico analysis, provides a resource for investigating SNHG6 in hepatocellular carcinoma and lays the groundwork for design of next researches.

Loss of EGFR-ASAP1 signaling in metastatic and unresectable hepatoblastoma

Hepatoblastoma (HBL), the most common childhood liver cancer is cured with surgical resection after chemotherapy or with liver transplantation if local invasion and multifocality preclude resection. However, variable survival rates of 60-80% and debilitating chemotherapy sequelae argue for more informed treatment selection, which is not possible by grading the Wnt-β-catenin over activity present in most HBL tumors. A hypothesis-generating whole transcriptome analysis shows that HBL tumors removed at transplantation are enriched most for cancer signaling pathways which depend predominantly on epidermal growth factor (EGF) signaling, and to a lesser extent, on aberrant Wnt-β-catenin signaling. We therefore evaluated whether EGFR, ASAP1, ERBB2 and ERBB4, which signal downstream after ligation of EGF, and which show aberrant expression in several other invasive cancers, would also predict HBL tumor invasiveness. Immunohistochemistry of HBL tumors (n = 60), which are histologically heterogeneous, shows that compared with well-differentiated fetal cells, less differentiated embryonal and undifferentiated small cells (SCU) progressively lose EGFR and ASAP1 expression. This trend is exaggerated in unresectable, locally invasive or metastatic tumors, in which embryonal tumor cells are EGFR-negative, while SCU cells are EGFR-negative and ASAP1-negative. Loss of EGFR-ASAP1 signaling characterizes undifferentiated and invasive HBL. EGFR-expressing HBL tumors present novel therapeutic targeting opportunities.

Patient-derived mouse xenografts from pediatric liver cancer predict tumor recurrence and advise clinical management

Identification of new treatments for relapsing pediatric cancer is an unmet clinical need and a societal challenge. Liver cancer occurrence in infancy, 1.5 for million children per year, falls far below the threshold of interest for dedicated drug development programs, and this disease is so rare that it is very difficult to gather enough children into a phase II clinical trial. Here, we present the establishment of an unprecedented preclinical platform of 24 pediatric liver cancer patient-derived xenografts (PLC-PDXs) from 20 hepatoblastomas (HBs), 1 transitional liver cell tumor (TCLT), 1 hepatocellular carcinoma, and 2 malignant rhabdoid tumors. Cytogenetic array and mutational analysis of the parental tumors and the corresponding PLC-PDXs show high conservation of the molecular features of the parental tumors. The histology of PLC-PDXs is strikingly similar to that observed in primary tumors and recapitulates the heterogeneity of recurrent disease observed in the clinic. Tumor growth in the mouse is strongly associated with elevated circulating alpha-fetoprotein (AFP), low rate of necrosis/fibrosis after treatment, and gain of chromosome 20, all indicators of resistance to chemotherapy and poor outcome. Accordingly, the ability of a tumor to generate PLC-PDX is predictive of poor prognosis. Exposure of PLC-PDXs to standards of care or therapeutic options already in use for other pediatric malignancies revealed unique response profiles in these models. Among these, the irinotecan/temozolomide combination induced strong tumor regression in the TCLT and in a model derived from an AFP-negative relapsing HB.

CONCLUSION

These results provide evidence that PLC-PDX preclinical platform can strongly contribute to accelerate the identification and diversification of anticancer treatment for aggressive subtypes of pediatric liver cancer. (Hepatology 2016;64:1121-1135).

Novel patient-derived xenograft and cell line models for therapeutic testing of pediatric liver cancer

BACKGROUND & AIMS

Pediatric liver cancer is a rare but serious disease whose incidence is rising, and for which the therapeutic options are limited. Development of more targeted, less toxic therapies is hindered by the lack of an experimental animal model that captures the heterogeneity and metastatic capability of these tumors.

METHODS

Here we established an orthotopic engraftment technique to model a series of patient-derived tumor xenograft (PDTX) from pediatric liver cancers of all major histologic subtypes: hepatoblastoma, hepatocellular cancer and hepatocellular malignant neoplasm. We utilized standard (immuno) staining methods for histological characterization, RNA sequencing for gene expression profiling and genome sequencing for identification of druggable targets. We also adapted stem cell culturing techniques to derive two new pediatric cancer cell lines from the xenografted mice.

RESULTS

The patient-derived tumor xenografts recapitulated the histologic, genetic, and biological characteristics-including the metastatic behavior-of the corresponding primary tumors. Furthermore, the gene expression profiles of the two new liver cancer cell lines closely resemble those of the primary tumors. Targeted therapy of PDTX from an aggressive hepatocellular malignant neoplasm with the MEK1 inhibitor trametinib and pan-class I PI3 kinase inhibitor NVP-BKM120 resulted in significant growth inhibition, thus confirming this PDTX model as a valuable tool to study tumor biology and patient-specific therapeutic responses.

CONCLUSIONS

The novel metastatic xenograft model and the isogenic xenograft-derived cell lines described in this study provide reliable tools for developing mutation- and patient-specific therapies for pediatric liver cancer.

LAY SUMMARY

Pediatric liver cancer is a rare but serious disease and no experimental animal model currently captures the complexity and metastatic capability of these tumors. We have established a novel animal model using human tumor tissue that recapitulates the genetic and biological characteristics of this cancer. We demonstrate that our patient-derived animal model, as well as two new cell lines, are useful tools for experimental therapies.

Up-regulated expression of phospholipase C, β1 is associated with tumor cell proliferation and poor prognosis in hepatocellular carcinoma

Background

Phospholipase C, β1 (PLCB1) plays critical roles in intracellular transduction and regulating signal activation which are important to tumorigenesis. However, the mechanism of PLCB1 in hepatocellular carcinoma (HCC) is still unknown. This study aims to investigate whether its expression is associated with the clinicopathological parameters and prognosis of the patients with HCC.

Methods

Immunohistochemistry on two tissue microarrays containing 141 cases of HCC tissues and adjacent non-tumorous tissues were performed to analyze the correlation between PLCB1 expression and clinicopathological features. Kaplan–Meier analysis and Cox multivariate analysis were performed to determine the PLCB1 expression in HCC prognosis. Furthermore, effects of PLCB1 on proliferation of HCC cells were explored using a colony formation assay and apoptosis assay.

Results

We identified that PLCB1 expression was significantly higher in tumor tissues than that in adjacent non-tumorous tissues and associated with advanced tumor stage. Kaplan–Meier survival analysis showed that patients with PLCB1-positive tumors had poorer survival than the patients with PLCB1-negative tumors. In multivariate analyses, PLCB1 expression was an independent prognostic factor. Moreover, overexpression of PLCB1 in HCC cells promoted cell proliferation and inhibited apoptosis, while knocking down PLCB1 reduced cell viability in vitro. Further investigation found that activation of ERK signaling might involve in PLCB1-mediated cell growth.

Conclusion

Our study suggests that PLCB1 promotes the progression of HCC and can be served as an independent prognostic factor and a promising therapeutic target in HCC.

Induction of apoptosis by IGFBP3 overexpression in hepatocellular carcinoma cells

BACKGROUND

The insulin-like growth factor (IGF) system comprises a group of proteins that play key roles in regulating cell growth, differentiation, and apoptosis in a variety of cellular systems. The aim of this study was to investigate the role of insulin-like growth factor binding protein 3 (IGFBP3) in hepatocellular carcinoma.

MATERIALS AND METHODS

Expression of IGF2, IGFBP3, and PTEN was analyzed by qRT-PCR. Lentivirus vectors were used to overexpress IGFBP3 in hepatocellular carcinoma cell (HCC) lines. The effect of IGFBP3 on proliferation was investigated by MTT and colony formation assays.

RESULTS

Expression of IGF2, IGFBP3, and PTEN in several HCC cell lines was lower than in normal cell lines. After 5-aza-2'-deoxycytidine/trichostatin A treatment, significant demethylation of the promoter region of IGFBP3 was observed in HCC cells. Overexpression of IGFBP3 induced apoptosis and reduced colony formation in HUH7 cells.

CONCLUSIONS

Expression of IGF2, IGFBP3, and PTEN in several HCC cell lines was lower than in normal cell lines. After 5-aza-2'-deoxycytidine/ trichostatin A treatment, significant demethylation of the promoter region of IGFBP3 was observed in HCC cells. Overexpression of IGFBP3 induced apoptosis and reduced colony formation in HUH7 cells.

Upregulated genes at 2q24 gains as candidate oncogenes in hepatoblastomas

AIM

Cytogenetic data of hepatoblastomas, a rare embryonal tumor of the liver, mostly consist of descriptions of whole-chromosome aneuploidies and large chromosome alterations. High-resolution cytogenetics may provide clues to hepatoblastoma tumorigenesis and indicate markers with clinical significance.

PATIENTS & METHODS

We used array-CGH (180K) to screen for genomic imbalances in nine hepatoblastomas. Additionally, we investigated the expression pattern of selected genes exhibiting copy number changes.

RESULTS

Analysis showed mainly whole-chromosome or chromosome-arm aneuploidies, but some focal aberrations were also mapped. Expression analysis of 48 genes mapped at one 10 Mb amplification at 2q24 revealed upregulation of DAPL1, ERMN, GALNT5, SCN1A and SCN3A in the set of tumors compared with differentiated livers.

CONCLUSION

These genes appear as candidates for hepatoblastoma tumorigenesis.

The genomic landscape of hepatoblastoma and their progenies with HCC-like features

BACKGROUND & AIMS

Hepatoblastoma (HB) is the most common childhood liver cancer and occasionally presents with histological and clinical features reminiscent of hepatocellular carcinoma (HCC). Identification of molecular mechanisms that drive the neoplastic continuation towards more aggressive HCC phenotypes may help to guide the new stage of targeted therapies.

METHODS

We performed comprehensive studies on genetic and chromosomal alterations as well as candidate gene function and their clinical relevance.

RESULTS

Whole-exome sequencing identified HB as a genetically very simple tumour (2.9 mutations per tumour) with recurrent mutations in ß-catenin (CTNNB1) (12/15 cases) and the transcription factor NFE2L2 (2/15 cases). Their HCC-like progenies share the common CTNNB1 mutation, but additionally exhibit a significantly increased mutation number and chromosomal instability due to deletions of the genome guardians RAD17 and TP53, accompanied by telomerase reverse-transcriptase (TERT) promoter mutations. Targeted genotyping of 33 primary tumours and cell lines revealed CTNNB1, NFE2L2, and TERT mutations in 72.5%, 9.8%, and 5.9% of cases, respectively. All NFE2L2 mutations affected residues of the NFE2L2 protein that are recognized by the KEAP1/CUL3 complex for proteasomal degradation. Consequently, cells transfected with mutant NFE2L2 were insensitive to KEAP1-mediated downregulation of NFE2L2 signalling. Clinically, overexpression of the NFE2L2 target gene NQO1 in tumours was significantly associated with metastasis, vascular invasion, the adverse prognostic C2 gene signature, as well as poor outcome.

CONCLUSIONS

Our study demonstrates the importance of CTNNB1 mutations and NFE2L2-KEAP1 pathway activation in HB development and defines loss of genomic stability and TERT promoter mutations as prominent characteristics of aggressive HB with HCC features.

Exome sequencing of hepatoblastoma reveals novel mutations and cancer genes in the Wnt pathway and ubiquitin ligase complex

Hepatoblastoma (HB) is the most common primary liver tumor in children. Mutations in the β-catenin gene that lead to constitutive activation of the Wnt pathway have been detected in a large proportion of HB tumors. To identify novel mutations in HB, we performed whole-exome sequencing of six paired HB tumors and their corresponding lymphocytes. This identified 24 somatic nonsynonymous mutations in 21 genes, many of which were novel, including three novel mutations targeting the CTNNB1 (G512V) and CAPRIN2 (R968H/S969C) genes in the Wnt pathway, and genes previously shown to be involved in the ubiquitin ligase complex (SPOP, KLHL22, TRPC4AP, and RNF169). Functionally, both the CTNNB1 (G512V) and CAPRIN2 (R968H/S969C) were observed to be gain-of-functional mutations, and the CAPRIN2 (R968H/S969C) was also shown to activate the Wnt pathway in HB cells. These findings suggested the activation of the Wnt pathway in HB, which was confirmed by immunohistochemical staining of the β-catenin in 42 HB tumors. We further used short hairpin RNA (shRNA)-mediated interference to assess the effect of 21 mutated genes on HB cell survival. The results suggested that one novel oncogene (CAPRIN2) and three tumor suppressors (SPOP, OR5I1, and CDC20B) influence HB cell growth. Moreover, we found that SPOP S119N is a loss-of-function mutation in HB cells. We finally demonstrated that one of the mechanisms by which SPOP inhibits HB cell proliferation is through regulating CDKN2B expression.

CONCLUSION

These results extend the landscape of genetic alterations in HB and highlight the dysregulation of Wnt and ubiquitin pathways in HB tumorigenesis.

[Cytogenetics profiles of renal carcinoma]

Renal carcinomas are histologically and prognostically heterogeneous. Genomic as well as chromosomal studies of these tumors have permitted a better comprehension of molecular mechanisms implicated in their development and progression. The most frequent histological subtypes are characterized by recurrent cytogenetic abnormalities, such as the loss of the chromosome 3 short arm involving a VHL gene copy in clear cell renal carcinomas, or trisomies 7 and 17 in papillary renal cell carcinomas. New histological subtypes like renal carcinomas associated with Xp11.2 translocations have also been individualized. Besides diagnosis, some chromosomal aberrations like the loss of a short arm of chromosome 9 in different renal carcinoma histological subtypes have a worse prognostic impact. The identification of chromosomal shuffles contributes in backing histological diagnosis and in precising the individual prognosis of patients. This review describes chromosomal abnormalities associated to renal carcinomas and their impact for an accurate classification of these tumors and the evaluation of their prognosis.

Current and future management strategies for relapsed or progressive hepatoblastoma

Hepatoblastoma is the most common primary malignant neoplasm of the liver in children. Improvements in chemotherapy and surgical techniques have increased survival rates for those with localized disease. The prognosis for patients with progressive or relapsed disease continues to be dismal. Complete resection by surgery or liver transplantation is necessary for cure. Few conventional chemotherapy agents have demonstrated activity in progressive or relapsed hepatoblastoma. Irinotecan has shown activity in relapsed and progressive hepatoblastoma. The efficacy of high-dose chemotherapy in this setting is unknown. Newer targeted agents that 'selectively' interfere with pathway targets involved in tumor growth and progression such as insulin-like growth factor, phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR) are currently under development. Because of the rarity of hepatoblastoma, only a small minority of these agents will ever be evaluated in children with this disorder. Gene-directed therapy and immunotherapy have shown promising results in the preclinical setting, and should be investigated as future treatment options for advanced hepatoblastoma.

Gain of chromosome 8q is associated with metastases and poor survival of patients with clear cell renal cell carcinoma

BACKGROUND

The aim of this study was to evaluate the prevalence of chromosome 8q gain in clear cell renal cell carcinoma (CCRCC) and to correlate the findings with tumor phenotype and disease-specific survival (DSS).

METHODS

The tumor karyotypes of 336 consecutive patients with CCRCC were prospectively evaluated with classical cytogenetic analysis. Chromosome 8q status was correlated with clinicopathological variables, and its impact on DSS was evaluated.

RESULTS

Gain of 8q occurred in 28 tumors (8.3%). Gain of 8q was associated with a higher risk of regional lymph node (21.4% vs 6.2%, P = .011) and distant metastases (50.0% vs 24.4%, P = .006), and greater tumor sizes (P = .030). Patients with gain of 8q had a 3.22-fold increased risk of death from CCRCC (P < .001). In multivariable analysis, gain of 8q was identified as an independent prognostic factor (hazard ratio, 2.37; P = .006). The concordance index of a multivariable base model increased significantly following inclusion of 8q gain (P = .0015).

CONCLUSIONS

Gain of chromosome 8q occurs in a subset of CCRCCs and is associated with an increased risk of metastases and death from CCRCC. Because the proto-oncogene c-MYC is among the list of candidate genes located on 8q, our data suggest that these tumors may have unique pathways activated, which are associated with an aggressive tumor phenotype. If confirmed, defining tumors with gain of 8q may assist in identifying patients who would benefit for specific c-MYC inhibitors or agents that target the MAPK/ERK (mitogen-activated protein kinase) pathway.

Copy-number variations in hepatoblastoma associate with unique clinical features

PURPOSE

Hepatoblastoma is a rare childhood liver malignancy with limited relevant cytogenetic data. This study aimed to discover common genomic copy-number variations (CNVs) in subjects with hepatobalstoma and its relevance to the clinical course.

METHODS

Gene copy-number was systemically rated by high-resolution comparative genomic hybridization (CGH) DNA oligonucleotide microarray. The study group consisted of 12 children (7 males and 5 females) with hepatoblastoma and another 20 healthy individuals (10 males and 10 females) as controls. The influence of recurrent CNVs on clinical outcomes was analyzed.

RESULTS

Four highly recurrent CNVs were identified in these 12 hepatoblastoma children after comparison with controls, including a gain on 1p13.3 (n = 3, 25%) and losses on 5p15.33 (n = 4, 33.3%), 16q12.2 (n = 4, 33.3%), and 19q13.42 (n = 3, 25%). The most prevalent sites of genomic deletion were 5p15.33 and 16q12.2. Zinc finger, DHHC-type containing 11 (ZDHHC11) and DHHC-type containing 11B (ZDHHC11B) were mapped to 5p15.33, which was associated with a lower rate of survival with native liver (p = 0.03). The carboxylesterase 4-like (CES4) gene that mapped to 16q12.2 was associated with smaller tumor size at presentation.

CONCLUSIONS

Deletions of 5p15.33 (33.3%) and 16q12.2 (33.3%) are the most frequent hepatoblastoma-related events in our patient group with 5p15.33 microdeletion as a potential biomarker for the fate of survival with native liver.

Prognostic value of hedgehog signal component expressions in hepatoblastoma patients

OBJECTIVE

Activation of hedgehog (Hh) pathway has been implicated in the development of human malignancies. Hh as well as related downstream target genes has been extensively studied in many kinds of malignant tumours for clinical diagnostic or prognostic utilities. This study aimed at investigating whether Hh molecules provides a molecular marker of hepatoblastoma malignancy.

METHODS

We obtained tissue sections from 32 patients with hepatoblastoma as well as cholestasis and normal control. Immunohistochemical analysis were performed to determine Hh signal components in human hepatoblastoma. The prognostic significance of single expression of Hh signal components were evaluated using Cox proportional hazards regression models and Kaplan-Meier survival analysis for statistical analysis.

RESULTS

Expression of Hh signal components showed an increase in hepatoblastoma compared with cholestasis and normal tissues. There was a positive correlation between Smo or Gli1 expression and tumor clinicopathological features, such as histological type, tumor grade, tumor size and clinical stage. Both Smo or Gli1 protein high expression was significantly associated with poor prognosis by univariate analyses and multivariate analyses.

CONCLUSIONS

Abnormal Hh signaling activation plays important roles in the malignant potential of hepatoblastoma. Gli1 expression is an independent prognostic marker.

Genome-wide analysis of allelic imbalances reveals 4q deletions as a poor prognostic factor and MDM4 amplification at 1q32.1 in hepatoblastoma

In a single-nucleotide polymorphism array-based analysis of 56 hepatoblastoma (HB) tumors, allelic imbalances were detected in 37 tumors (66%). Chromosome gains were found in 1q (28 tumors), 2q (24), 6p (8), 8q (8), 17q (6), and 20pq (10), and losses in 1p (6), 4q (9), and 16q (4). Fine mapping delineated the shortest overlapping region (SOR) of gains at 1q32.1 (1.3 Mb) and 2q24.2-q24.3 (4.8 Mb), and losses at 4q34.3-q35.2 (8.7 Mb) and 4q32.3 (1.6 Mb). Uniparental disomy of 11pter-11p15.4 (IGF2) and loss of 11pter-p14.1 were found in 11 and 2 tumors, respectively. Expression of HTATIP2 (11p15.1) was absent in 9 of 20 tumors. Amplification was identified in four tumors at 1q32.1, where the candidate oncogene MDM4 is located. In the 4q32.3-SRO, ANXA10S, a variant of the candidate tumor suppressor ANXA10, showed no expression in 19 of 24 tumors. Sequence analysis of ANXA10S identified a missense mutation (E36K, c.106G>A) in a HB cell line. Multivariate analysis revealed that both 4q deletion and RASSF1A methylation (relative risks: 4.21 and 7.55, respectively) are independent prognostic factors. Our results indicate that allelic imbalances and gene expression patterns provide possible diagnostic and prognostic markers, as well as therapeutic targets in a subset of HB.

Establishment and characterization of a cancer cell line derived from an aggressive childhood liver tumor

BACKGROUND

Hepatoblastoma is a rare malignancy of childhood. The scarcity of adequate cell models has limited our understanding of this tumor. Here we describe and characterize a new human liver tumor cell line, Hep293TT, derived from an aggressive childhood hepatoblastoma.

PROCEDURES

Hep293TT cells were established using primary tumor tissues from a 5-year-old Caucasian female child. This cell line has been maintained for more than 34 months and over 20 subcultures, and was characterized by histopathology, ELISA, genotype, cytogenetics, CGH array, immunohistochemistry, and molecular sequence analyses.

RESULTS

Cells were confirmed to originate from parental tumor cells, secrete alpha-fetoprotein, and express hepatic markers and beta-catenin. Hep293TT cells were able to form colonies in soft agar. Tumorigenicity was demonstrated by induction of solid tumors after subrenal capsule injection in immunodeficient mice. Hep293TT cells demonstrated a highly aneuploid karyotype, and a whole genome CGH analysis revealed chromosomal imbalances in every chromosome. Allelotype analysis demonstrated loss of alleles at distal 11p15.5 as is typical of embryonal tumors. Both Hep293TT cells and the primary tumor contain a deletion of 351 nucleotides in beta-catenin, as has been seen in other hepatoblastoma tumors. The cell line expressed beta-catenin protein in both full-length and partially deleted forms, and expressed NOTCH2 protein characteristic of hepatoblasts. No mutation was detected in the APC, MYH, MLH1, or MSH2 genes.

CONCLUSION

This cell line, Hep293TT, is a valuable resource for the study of childhood liver cancer and may potentially provide a tool in the development of new agents.

Cytogenetic and array comparative genomic hybridization analysis of a series of hepatoblastomas

Hepatoblastoma is the most common primary hepatic tumor in children, and only a limited number of detailed karyotypic analyses have been reported to date. In the present study, cytogenetic abnormalities were identified in nine cases of hepatoblastoma from a single institution. Among characteristic chromosomal changes detected were simple numerical aberrations, structural alterations of chromosomes 1, 2, and 8, and the recurrent unbalanced rearrangements der(4)t(1;4)(q25.2;q35.1) and der(6)t(1;6)(q21;q26). Array comparative genomic hybridization was applied in four of the cases. The combined cytogenetic, molecular cytogenetic, and histopathologic analyses are presented here, together with clinical data. The results substantially confirm previous findings of aberrations involving chromosomal loci on 1q, 2 or 2q, 4q, 6q, 8 or 8q, and 20 as significant in the development and clinical course of this disease.

Clinical and cytogenetic analysis of an intracranial inflammatory myofibroblastic tumor induced by a ventriculoperitoneal shunt

The authors report the first case of an intracranial inflammatory myofibroblastic tumor (IMT) associated with the placement of a ventriculoperitoneal shunt, which occurred in a 7-year-old boy. Neuroradiological features showed a mass surrounding the ventricular catheter. The lesion was completely resected. Histological study revealed the mass to be an IMT. The patient's postoperative course was complicated by a local recurrence requiring a second surgery. Cytogenetic analysis of the sample by comparative genome hybridization revealed several chromosomal amplifications and regional losses. The occurrence of IMT in the CNS has rarely been reported. For treatment of this condition, the authors recommend a total removal of the shunt with a mass excision to prevent local recurrence.

Blocking the hedgehog pathway inhibits hepatoblastoma growth

Recent evidence has indicated that Hedgehog (Hh) signaling significantly contributes to liver development and regeneration and that activation of the pathway may contribute to growth of hepatocellular carcinoma (HCC) in adults. However, the role of Hh signaling in pediatric liver tumors remains to be elucidated. In this study, we show that Hh signaling is activated in hepatoblastoma (HB), the most common liver tumor in childhood, with most occurrences before the age of 3 years. The Hh target genes glioma-associated oncogene homolog 1 (GLI1) and Patched (PTCH1) showed increased transcript levels in 65% and 30% of HB samples, respectively, compared with normal liver tissues. Most interestingly, the gene encoding the hedgehog interacting protein (HHIP) is transcriptionally silenced by cytosine-phospho-guanosine (CpG) island promoter hypermethylation in 26% of HB cases and treatment with the DNA-demethylating agent 5-aza-2'-deoxycytidine partially restored HHIP expression. Blocking Hh signaling with the antagonist cyclopamine had a strong inhibitory effect on cell proliferation of HB cell lines with an activated pathway. We further demonstrate that this decrease in cell viability is caused by a massive induction of apoptosis, as shown by morphological changes and phosphatidylserine membrane asymmetry. In cyclopamine-exposed HB cells, caspase 3 and poly(adenosine diphosphate-ribose) polymerase proteins were specifically activated by their proteolytic cleavage.

CONCLUSION

This study demonstrates, for the first time, the frequent occurrence of GLI1 and PTCH1 overexpression and HHIP promoter methylation in early childhood HB, thus indicating a key role for Hh signaling activation in the malignant transformation of embryonal liver cells.

Hepatic stem-like phenotype and interplay of Wnt/beta-catenin and Myc signaling in aggressive childhood liver cancer

Hepatoblastoma, the most common pediatric liver cancer, is tightly linked to excessive Wnt/beta-catenin signaling. Here, we used microarray analysis to identify two tumor subclasses resembling distinct phases of liver development and a discriminating 16-gene signature. beta-catenin activated different transcriptional programs in the two tumor types, with distinctive expression of hepatic stem/progenitor markers in immature tumors. This highly proliferating subclass was typified by gains of chromosomes 8q and 2p and upregulated Myc signaling. Myc-induced hepatoblastoma-like tumors in mice strikingly resembled the human immature subtype, and Myc downregulation in hepatoblastoma cells impaired tumorigenesis in vivo. Remarkably, the 16-gene signature discriminated invasive and metastatic hepatoblastomas and predicted prognosis with high accuracy.

The methylation status of RASSF1A promoter predicts responsiveness to chemotherapy and eventual cure in hepatoblastoma patients

Despite the progress of therapy, outcomes of advanced hepatoblastoma patients who are refractory to standard preoperative chemotherapy remain unsatisfactory. To improve the mortality rate, novel prognostic markers are needed for better therapy planning. We examined the methylation status of 13 candidate tumor suppressor genes in 20 hepatoblastoma tumors by conventional methylation-specific PCR (MSP) and found hypermethylation in 3 of the 13 genes. We analyzed the methylation status of these 3 genes (RASSF1A, SOCS1 and CASP8) in 97 tumors and found hypermethylation in 30.9, 33.0 and 15.5%, respectively. Univariate analysis showed that only the methylation status of RASSF1A but not the other 2 genes predicted the outcome, and multivariate analysis showed a weak contribution of RASSF1A methylation to overall survival. Using quantitative MSP, we found RASSF1A methylation in 44.3% of the 97 tumors. CTNNB1 mutation was detected in 67.0% of the 97 tumors. While univariate analysis demonstrated RASSF1A methylation, CTNNB1 mutation and other clinicopathological variables as prognostic factors, multivariate analysis identified RASSF1A methylation (p = 0.043; relative risk 9.39) and the disease stage (p = 0.002; relative risk 7.67) but not CTNNB1 mutation as independent prognostic factors. In survival analysis of 33 patients in stage 3B or 4, patients with unmethylated tumor had better overall survival than those with methylated tumor (p = 0.035). RASSF1A methylation may be a promising molecular-genetic marker to predict the treatment outcome and may be used to stratify patients when clinical trials are carried out.

Whole-genome profiling of chromosomal aberrations in hepatoblastoma using high-density single-nucleotide polymorphism genotyping microarrays

To identify the genomic profile and elucidate the pathogenesis of hepatoblastoma (HBL), the most common pediatric hepatic tumor, we performed high-density genome-wide single-nucleotide polymorphism (SNP) microarray analyses of 17 HBL samples. The copy number analyzer for GeneChip(R) (CNAG) and allele-specific copy number analysis using anonymous references (AsCNAR) algorithms enabled simple but sensitive inference of allelic composition without using paired normal DNA. Chromosomal aberrations were observed in 15 cases (88%). Gains in chromosomes 1q, 2 (or 2q), 8, 17q, and 20 and losses in chromosomes 4q and 11q were frequently identified. High-grade amplifications were detected at 7q34, 14q11.2, and 11q22.2. Several types of deletions, except homozygous deletion, were identified. Most importantly, copy-neutral loss of heterozygosity (uniparental disomy [UPD]) at 11p15 was detected in four of the 17 HBL samples. Insulin-like growth factor II (IGF2) and H19 genes were located within this region. The methylated status of this region indicated the paternal origin of the UPD. The expression patterns of IGF2 and H19 were opposite between genes with and without the UPD. This difference in the expression patterns might influence the clinical features of HBL.

Promoter hypermethylation of the RASSF1A gene predicts the poor outcome of patients with hepatoblastoma

BACKGROUND

Despite the progress of therapy, about 25% of patients with hepatoblastoma succumb to the disease. Prognostic factors, as well as improved therapies, are needed for these patients. We investigated the incidence and clinical significance of genetic and epigenetic aberrations in hepatoblastoma.

PROCEDURE

beta-catenin mutation was analyzed by sequencing and promoter hypermethylation of the RASSF1A and SFRP genes by methylation-specific PCR after bisulfate treatment of DNA samples from 39 hepatoblastomas. Association of the clinical and biological features, including sex, age of patients, stage of the disease, the histological type, and the beta-catenin and RASSF1A status with overall survival was evaluated using univariate and multivariate analysis.

RESULTS

beta-catenin mutation and RASSF1A methylation were found in 22 (56.4%) and 15 (38.5%) of 39 hepatoblastomas, respectively, but SFRPs methylation was not found in any of them. RASSF1A and SFRPs were unmethylated in five adjacent normal liver tissues. Patients with a RASSF1A methylated tumor were older in age (>or=2 years, P=0.036), at more advanced stages (P=0.009), and had more frequent beta-catenin mutation (P<0.001) and poorer outcome (P<0.001) than those with a RASSF1A unmethylated tumor. While univariate analysis showed the prognostic significance of age, stage, the histological type, and the beta-catenin and RASSF1A status, multivariate analysis showed only the RASSF1A methylation status as an independent factor predicting outcome (relative risk, 10.51; 95% CI, 1.21 approximately 90.97; P=0.033).

CONCLUSIONS

RASSF1A methylation may be a novel molecular-genetic marker for treatment outcome in hepatoblastoma if confirmed by studies examining a larger number of hepatoblastomas.

Cytogenetic evaluation of a large series of hepatoblastomas: Numerical abnormalities with recurring aberrations involving 1q12-q21

Hepatoblastoma is a malignant embryonal liver tumor that occurs almost exclusively in infants and very young children. Previous cytogenetic studies of hepatoblastoma have investigated small series or individual cases. This report is on the cytogenetics of a large series of 111 hepatoblastoma specimens, with cytogenetic results consecutively karyotyped over a 12-year period. Abnormal karyotypes were observed in 55 cases (approximately 50% of the total). Numerical aberrations were observed in 41 cases (36% of the total), particularly trisomies of chromosomes 2, 8, and 20. Chromosome losses were less common than chromosome gains. Structural abnormalities were observed in 43 cases (39% of the total). Unbalanced translocations resulting in trisomy 1q and involving breakpoints at 1q12-21 were the most common structural abnormality, observed in 20 tumors (18% of total cases); the corresponding translocated chromosome was highly varied. The previously reported t(1;4) was observed in seven cases. Most tumors with translocations involving 1q12-21 also displayed numerical chromosome aberrations, the most common of which were chromosomal trisomies, whereas tumors with other structural rearrangements had fewer numerical abnormalities.

Prenatally detected trisomy 20 mosaicism

BACKGROUND

Trisomy 20 is one of the more common mosaic trisomies detected on amniocentesis and presents with a normal outcome in over 90% of reported cases. Trisomic cells are almost never confirmed in newborn blood and are only rarely found in other fetal or placental samples. Nonetheless, some abnormal outcomes have been reported, including unexplained fetal demise, intrauterine growth restriction, and multiple congenital anomalies. Because of the lack of molecular studies on such cases, it is unknown whether the origin of trisomy or presence of uniparental disomy (UPD) could have some influence on outcome.

METHODS

We present data on six cases of trisomy mosaicism, two detected by chorionic villous sampling (CVS) and four by amniocentesis (AF), submitted to our laboratory for molecular studies.

RESULTS AND CONCLUSIONS

A meiotic origin of the trisomy could be confirmed in only one of these cases. In addition, uniparental disomy was excluded in all four cases for which parents were available for testing. The four cases with low levels of trisomy in amniotic fluid (0%, 10%, 11%, and 12%) were associated with a normal outcome. The remaining two cases of trisomy 20 had high levels of trisomy in amniotic fluid (96% and 58%) and had abnormal outcomes (developmental delay in one and stillbirth with IUGR and severe oligohydramnios in the other). Including previously published cases, there is a clear association with the level of trisomy and outcome, with only 4% abnormal outcomes when <40% trisomic cells were detected. Higher levels of trisomy were also observed in male fetuses as compared to female fetuses (p = 0.01); however, there were no sex differences in frequency of abnormal outcomes.

Classic and Molecular Cytogenetic Analyses Reveal Chromosomal Gains and Losses Correlated with Survival in Head and Neck Cancer Patients

Purpose: Genetic biomarkers of head and neck tumors could be useful for distinguishing among patients with similar clinical and histopathologic characteristics but having differential probabilities of survival. The purpose of this study was to investigate chromosomal alterations in head and neck carcinomas and to correlate the results with clinical and epidemiologic variables.

Experimental Design: Cytogenetic analysis of short-term cultures from 64 primary untreated head and neck squamous cell carcinomas was used to determine the overall pattern of chromosome aberrations. A representative subset of tumors was analyzed in detail by spectral karyotyping and/or confirmatory fluorescence in situ hybridization analysis.

Results: Recurrent losses of chromosomes Y (26 cases) and 19 (14 cases), and gains of chromosomes 22 (23 cases), 8 and 20 (11 cases each) were observed. The most frequent structural aberration was del(22)(q13.1) followed by rearrangements involving 6q and 12p. The presence of specific cytogenetic aberrations was found to correlate significantly with an unfavorable outcome. There was a significant association between survival and gains in chromosomes 10 (P = 0.008) and 20 (P = 0.002) and losses of chromosomes 15 (P = 0.005) and 22 (P = 0.021). Univariate analysis indicated that acquisition of monosomy 17 was a significant (P = 0.0012) factor for patients with a previous family history of cancer.

Conclusions: The significant associations found in this study emphasize that alterations of distinct regions of the genome may be genetic biomarkers for a poor prognosis. Losses of chromosomes 17 and 22 can be associated with a family history of cancer.

Cytogenetic abnormalities in hepatoblastoma: report of two new cases and review of the literature suggesting imbalance of chromosomal regions on chromosomes 1, 4, and 12

Two cases of hepatoblastoma with unique karyotypic changes are described. One case was that of a 2-year-old boy with an unbalanced chromosomal translocation involving 4q35 as the sole chromosomal abnormality. The clonal karyotype of this tumor was 46,XY,add(4)(q35)[3]/46,XY[9]. In the other case, that of a 2-year-old boy, karyotypic analyses revealed the clonal karyotype as 57,XY,+del(1)(p22),+2,+5,+6,+7,+8,+del(12)(p12),+18,+19,+20,+22[4]/46,XY[12]. Review of these two cases, together with previous reports, underscored the significance of numerical and/or structural chromosomal abnormalities of 1q, 4q, 2, 8, and 20 in the development of hepatoblastoma. The present results show that imbalance of the terminal region of 4q could be the sole chromosomal abnormality in a hepatoblastoma. We also found that imbalance of chromosomal regions on chromosomes 1 and 12 may contribute to the development of hepatoblastoma.

Hepatoblastoma in a patient with a partial trisomy 9p syndrome: a case report

After an uneventful pregnancy, a boy was born by vacuum extraction at 40.6 weeks' gestation. Physical examination revealed several malformations due to a partial trisomy 9p [karyotype: 46,XY, dup(9)(p13p24)]. Three months after birth, the boy presented with a hepatoblastoma without distant metastases which was treated with chemotherapy combined with surgery. At the last follow-up, 15 years after the resection of the hepatoblastoma, he was still in complete remission. To our knowledge this is the first case report of a patient with a constitutional partial trisomy 9p associated with hepatoblastoma.

Hepatoblastoma--evolution of management and outcome and significance of histology of the resected tumor. A 31-year experience with 40 cases

BACKGROUND/PURPOSE

The aim of this study was to retrospectively evaluate and compare the clinical features, treatment strategy, pathology, and outcome of all patients with hepatoblastoma treated at an African hospital over a 31-year period (1970 to 2001).

METHODS

Forty patients with hepatoblastoma were divided into 3 groups according to the treatment given. Group I (1970 to 1983, 14 patients) had no protocol therapy; group II (1984 to 1988, 6 patients) received protocol treatment according to Children's Study Group (CCSG) guidelines; group III (1989 to 2001, 20 patients) received SIOPEL protocol therapy. All available clinical, surgical, radiologic, and pathologic data were reviewed and analyzed.

RESULTS

Overall patient survival was as follows: group I, 14%; group II, 50%, and group III, 80%. Deaths in group II were caused by chemotherapy-induced immunosuppression only. Prognostic data for group III showed that all tumor-related deaths could be predicted by identifying multifocal disseminated growth patterns (P =.001) or vascular invasion (P =.001) in resected tumors. Of the 40 diagnostic tumor biopsies performed, 2 significant complications (1 death, 1 intraperitoneal tumor seeding) occurred. Histologic criteria evaluating these biopsies were not predictive of overall survival.

CONCLUSIONS

The introduction of protocol therapy has resulted in a marked improvement in survival. Immunosuppression-related sepsis in our setting resulted in unacceptable mortality in patients treated according to CCSG guidelines. A diagnostic biopsy in hepatoblastoma is of value but not without complications. Preoperative chemotherapy followed by complete surgical excision according to International Society of Paediatric Oncology guidelines yields excellent results with a current survival rate of 80%.