First Transcriptome Analysis of Hepatoblastoma in Brazil: Unraveling the Pivotal Role of Noncoding RNAs and Metabolic Pathways.

Hepatoblastoma stands as the most prevalent liver cancer in the pediatric population. Characterized by a low mutational burden, chromosomal and epigenetic alterations are key drivers of its tumorigenesis. Transcriptome analysis is a powerful tool for unraveling the molecular intricacies of hepatoblastoma, shedding light on the effects of genetic and epigenetic changes on gene expression. In this study conducted in Brazilian patients, an in-depth whole transcriptome analysis was performed on 14 primary hepatoblastomas, compared to control liver tissues. The analysis unveiled 1,492 differentially expressed genes (1,031 upregulated and 461 downregulated), including 920 protein-coding genes (62%). Upregulated biological processes were linked to cell differentiation, signaling, morphogenesis, and development, involving known hepatoblastoma-associated genes (DLK1, MEG3, HDAC2, TET1, HMGA2, DKK1, DKK4), alongside with novel findings (GYNG4, CDH3, and TNFRSF19). Downregulated processes predominantly centered around oxidation and metabolism, affecting amines, nicotinamides, and lipids, featuring novel discoveries like the repression of SYT7, TTC36, THRSP, CCND1, GCK and CAMK2B. Two genes, which displayed a concordant pattern of DNA methylation alteration in their promoter regions and dysregulation in the transcriptome, were further validated by RT-qPCR: the upregulated TNFRSF19, a key gene in the embryonic development, and the repressed THRSP, connected to lipid metabolism. Furthermore, based on protein-protein interaction analysis, we identified genes holding central positions in the network, such as HDAC2, CCND1, GCK, and CAMK2B, among others, that emerged as prime candidates warranting functional validation in future studies. Notably, a significant dysregulation of non-coding RNAs (ncRNAs), predominantly upregulated transcripts, was observed, with 42% of the top 50 highly expressed genes being ncRNAs. An integrative miRNA-mRNA analysis revealed crucial biological processes associated with metabolism, oxidation reactions of lipids and carbohydrates, and methylation-dependent chromatin silencing. In particular, four upregulated miRNAs (miR-186, miR-214, miR-377, and miR-494) played a pivotal role in the network, potentially targeting multiple protein-coding transcripts, including CCND1 and CAMK2B. In summary, our transcriptome analysis highlighted disrupted embryonic development as well as metabolic pathways, particularly those involving lipids, emphasizing the emerging role of ncRNAs as epigenetic regulators in hepatoblastomas. These findings provide insights into the complexity of the hepatoblastoma transcriptome and identify potential targets for future therapeutic interventions.

Broad responses to chemical adducts shape the natural antibody repertoire in early infancy.

Natural antibodies are an integral part of innate humoral immunity yet their development and polyreactive nature are still enigmatic. Here, we show that characteristic monoclonal natural antibodies recognize common chemical moieties or adducts, supporting the view that polyreactive antibodies may often correspond to anti-adduct antibodies. We next examined the development of immunoglobulin M (IgM) and IgG to 81 ubiquitous adducts from birth to old age. Newborn IgM only reacted to a limited number of consensus determinants. This highly restricted neonatal repertoire abruptly diversified around 6 months of age through the development of antibodies to environmental antigens and age-driven epigenetic modifications. In contrast, the IgG repertoire was diverse across the entire life span. Our studies reveal an unrecognized component of humoral immunity directed to common adducts. These findings set the ground for further investigations into the role of anti-adduct B cell responses in homeostatic functions and pathological conditions.

High-Resolution Magic-Angle-Spinning NMR in Revealing Hepatoblastoma Hallmarks.

Cancer is one of the leading causes of death in children and adolescents worldwide; among the types of liver cancer, hepatoblastoma (HBL) is the most common in childhood. Although it affects only two to three individuals in a million, it is mostly asymptomatic at diagnosis, so by the time it is detected it has already advanced. There are specific recommendations regarding HBL treatment, and ongoing studies to stratify the risks of HBL, understand the pathology, and predict prognostics and survival rates. Although magnetic resonance imaging spectroscopy is frequently used in diagnostics of HBL, high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy of HBL tissues is scarce. Using this technique, we studied the alterations among tissue metabolites of ex vivo samples from (a) HBL and non-cancer liver tissues (NCL), (b) HBL and adjacent non-tumor samples, and (c) two regions of the same HBL samples, one more centralized and the other at the edge of the tumor. It was possible to identify metabolites in HBL, then metabolites from the HBL center and the border samples, and link them to altered metabolisms in tumor tissues, highlighting their potential as biochemical markers. Metabolites closely related to liver metabolisms such as some phospholipids, triacylglycerides, fatty acids, glucose, and amino acids showed differences between the tissues.

Unraveling the Genetic Architecture of Hepatoblastoma Risk: Birth Defects and Increased Burden of Germline Damaging Variants in Gastrointestinal/Renal Cancer Predisposition and DNA Repair Genes.

The ultrarare hepatoblastoma (HB) is the most common pediatric liver cancer. HB risk is related to a few rare syndromes, and the molecular bases remain elusive for most cases. We investigated the burden of rare damaging germline variants in 30 Brazilian patients with HB and the presence of additional clinical signs. A high frequency of prematurity (20%) and birth defects (37%), especially craniofacial (17%, including craniosynostosis) and kidney (7%) anomalies, was observed. Putative pathogenic or likely pathogenic monoallelic germline variants mapped to 10 cancer predisposition genes (CPGs: APC, CHEK2, DROSHA, ERCC5, FAH, MSH2, MUTYH, RPS19, TGFBR2 and VHL) were detected in 33% of the patients, only 40% of them with a family history of cancer. These findings showed a predominance of CPGs with a known link to gastrointestinal/colorectal and renal cancer risk. A remarkable feature was an enrichment of rare damaging variants affecting different classes of DNA repair genes, particularly those known as Fanconi anemia genes. Moreover, several potentially deleterious variants mapped to genes impacting liver functions were disclosed. To our knowledge, this is the largest assessment of rare germline variants in HB patients to date, contributing to elucidate the genetic architecture of HB risk.

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.

HDAC1-Dependent Repression of Markers of Hepatocytes and P21 Is Involved in Development of Pediatric Liver Cancer.

BACKGROUND & AIMS: Epigenetic regulation of gene expression plays a critical role in the development of liver cancer; however, the molecular mechanisms of epigenetic-driven liver cancers are not well understood. The aims of this study were to examine molecular mechanisms that cause the dedifferentiation of hepatocytes into cancer cells in aggressive hepatoblastoma and test if the inhibition of these mechanisms inhibits tumor growth. METHODS: We have analyzed CCAAT/Enhancer Binding Protein alpha (C/EBPα), Transcription factor Sp5, and histone deacetylase (HDAC)1 pathways from a large biobank of fresh hepatoblastoma (HBL) samples using high-pressure liquid chromatography-based examination of protein-protein complexes and have examined chromatin remodeling on the promoters of markers of hepatocytes and p21. The HDAC1 activity was inhibited in patient-derived xenograft models of HBL and in cultured hepatoblastoma cells and expression of HDAC1-dependent markers of hepatocytes was examined. RESULTS: Analyses of a biobank showed that a significant portion of HBL patients have increased levels of an oncogenic de-phosphorylated-S190-C/EBPα, Sp5, and HDAC1 compared with amounts of these proteins in adjacent regions. We found that the oncogenic de-phosphorylated-S190-C/EBPα is created in aggressive HBL by protein phosphatase 2A, which is increased within the nucleus and dephosphorylates C/EBPα at Ser190. C/EBPα-HDAC1 and Sp5-HDAC1 complexes are abundant in hepatocytes, which dedifferentiate into cancer cells. Studies in HBL cells have shown that C/EBPα-HDAC1 and Sp5-HDAC1 complexes reduce markers of hepatocytes and p21 via repression of their promoters. Pharmacologic inhibition of C/EBPα-HDAC1 and Sp5-HDAC1 complexes by Suberoylanilide hydroxamic acid (SAHA) and small interfering RNA-mediated inhibition of HDAC1 increase expression of hepatocyte markers, p21, and inhibit proliferation of cancer cells. CONCLUSIONS: HDAC1-mediated repression of markers of hepatocytes is an essential step for the development of HBL, providing background for generation of therapies for aggressive HBL by targeting HDAC1 activities.

DNA methylation as a key epigenetic player for hepatoblastoma characterization.

BACKGROUND: Hepatoblastoma (HB) is a rare embryonal liver tumor of children. Although intrinsic biological differences between tumors can affect prognosis, few groups have studied these differences. Given the recent increased attention to epigenetic mechanisms in the genesis and progression of these tumors, we aimed to classify HB samples according to the stages of liver development and DNA methylation machinery. BASIC PROCEDURES: We evaluated the expression of 24 genes associated with DNA methylation and stages of hepatocyte differentiation and global DNA methylation. Using bioinformatics tools and expression data, we propose a stratification model for HB. MAIN FINDINGS: Tumors clustered into three groups that presented specific gene expression profiles of the panel of DNA methylation enzymes and hepatocyte differentiation markers. In addition to reinforcing these embryonal tumors' molecular heterogeneity, we propose that a panel of 13 genes can stratify HBs (TET1, TET2, TET3, DNMT1, DNMT3A, UHRF1, ALB, CYP3A4, TDO2, UGT1A1, AFP, HNF4A, and FOXA2). DNA methylation machinery participates in the characterization of HBs, directly reflected in diverse DNA methylation content. The data suggested that a subset of HBs were similar to differentiated livers, with upregulation of mature hepatocyte markers, decreased expression of DNA methylation enzymes, and higher global methylation levels; these findings might predict worse outcomes. CONCLUSIONS: HBs are heterogeneous tumors. Despite using a small cohort of 21 HB samples, our findings reinforce that DNA methylation is a robust biomarker for this tumor type.

Mibefradil alters intracellular calcium concentration by activation of phospholipase C and IP3 receptor function.

Mibefradil is a tetralol derivative originally developed as an antagonist of T-type voltage-gated calcium (Ca2+) channels to treat hypertension when used at nanomolar dosage. More recently, its therapeutic application in hypertension has declined and has been instead repurposed as a treatment of cancer cell proliferation and solid tumor growth. Beyond its function as a Cav blocker, the micromolar concentration of mibefradil can stimulate a rise in [Ca2+]cyt although the mechanism is poorly known. The chanzyme TRPM7 (transient receptor potential melastanin 7), the release of intracellular Ca2+ pools, and Ca2+ influx by ORAI channels have been associated with the increase in [Ca2+]cyt triggered by mibefradil. This study aims to investigate the cellular targets and pathways associated with mibefradil's effect on [Ca2+]cyt. To address these questions, we monitored changes in [Ca2+]cyt in the specialized mouse epithelial cells (LS8 and ALC) and the widely used HEK-293 cells by stimulating these cells with mibefradil (0.1 µM to 100 µM). We show that mibefradil elicits an increase in [Ca2+]cyt at concentrations above 10 µM (IC50 around 50 µM) and a fast Ca2+ increase capacity at 100 µM. We found that inhibiting IP3 receptors, depleting the ER-Ca2+ stores, or blocking phospholipase C (PLC), significantly decreased the capacity of mibefradil to elevate [Ca2+]cyt. Moreover, the transient application of 100 µM mibefradil triggered Ca2+ influx by store-operated Ca2+ entry (SOCE) mediated by the ORAI channels. Our findings reveal that IP3R and PLC are potential new targets of mibefradil offering novel insights into the effects of this drug.

Detection of mosaicism for segmental and whole chromosome imbalances by targeted sequencing.

Mosaic segmental and whole chromosome copy number alterations are postzygotic variations known to be associated with several disorders. We have previously presented an efficient targeted sequencing approach to simultaneously detect point mutations and copy number variations (CNVs). In this study, we evaluated the efficiency of this approach to detect mosaic CNVs, using seven postnatal and 19 tumor samples, previously characterized by chromosomal microarray analyses (CMA). These samples harbored a total of 28 genomic imbalances ranging in size from 0.68 to 171 Mb, and present in 10-80% of the cells. All CNV regions covered by the platform were correctly identified in postnatal samples, and only seven out of 19 CNVs from tumor samples were not identified either because of a lack of target probes in the affected genomic regions or an absence of minimum reads for an alteration call. These results demonstrate that, in a research setting, this is a robust approach for detecting mosaicism in cases of segmental and whole chromosome alterations. Although the current sequencing platform presented a resolution similar to genomic microarrays, it is still necessary to further validate this approach in a clinical setting in order to replace CMA and sequencing analyses by a single test.

Hepatoblastomas exhibit marked NNMT downregulation driven by promoter DNA hypermethylation.

Hepatoblastomas exhibit the lowest mutational burden among pediatric tumors. We previously showed that epigenetic disruption is crucial for hepatoblastoma carcinogenesis. Our data revealed hypermethylation of nicotinamide N-methyltransferase, a highly expressed gene in adipocytes and hepatocytes. The expression pattern and the role of nicotinamide N-methyltransferase in pediatric liver tumors have not yet been explored, and this study aimed to evaluate the effect of nicotinamide N-methyltransferase hypermethylation in hepatoblastomas. We evaluated 45 hepatoblastomas and 26 non-tumoral liver samples. We examined in hepatoblastomas if the observed nicotinamide N-methyltransferase promoter hypermethylation could lead to dysregulation of expression by measuring mRNA and protein levels by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blot assays. The potential impact of nicotinamide N-methyltransferase changes was evaluated on the metabolic profile by high-resolution magic angle spinning nuclear magnetic resonance spectroscopy. Significant nicotinamide N-methyltransferase downregulation was revealed in hepatoblastomas, with two orders of magnitude lower nicotinamide N-methyltransferase expression in tumor samples and hepatoblastoma cell lines than in hepatocellular carcinoma cell lines. A specific TSS1500 CpG site (cg02094283) of nicotinamide N-methyltransferase was hypermethylated in tumors, with an inverse correlation between its methylation level and nicotinamide N-methyltransferase expression. A marked global reduction of the nicotinamide N-methyltransferase protein was validated in tumors, with strong correlation between gene and protein expression. Of note, higher nicotinamide N-methyltransferase expression was statistically associated with late hepatoblastoma diagnosis, a known clinical variable of worse prognosis. In addition, untargeted metabolomics analysis detected aberrant lipid metabolism in hepatoblastomas. Data presented here showed the first evidence that nicotinamide N-methyltransferase reduction occurs in hepatoblastomas, providing further support that the nicotinamide N-methyltransferase downregulation is a wide phenomenon in liver cancer. Furthermore, this study unraveled the role of DNA methylation in the regulation of nicotinamide N-methyltransferase expression in hepatoblastomas, in addition to evaluate the potential effect of nicotinamide N-methyltransferase reduction in the metabolism of these tumors. These preliminary findings also suggested that nicotinamide N-methyltransferase level may be a potential prognostic biomarker for hepatoblastoma.

Insights Into the Somatic Mutation Burden of Hepatoblastomas From Brazilian Patients.

Hepatoblastoma is a very rare embryonal liver cancer supposed to arise from the impairment of hepatocyte differentiation during embryogenesis. In this study, we investigated by exome sequencing the burden of somatic mutations in a cohort of 10 hepatoblastomas, including a congenital case. Our data disclosed a low mutational background and pointed out to a novel set of candidate genes for hepatoblastoma biology, which were shown to impact gene expression levels. Only three recurrently mutated genes were detected: CTNNB1 and two novel candidates, CX3CL1 and CEP164. A relevant finding was the identification of a recurrent mutation (A235G) in two hepatoblastomas at the CX3CL1 gene; evaluation of RNA and protein expression revealed upregulation of CX3CL1 in tumors. The analysis was replicated in two independents cohorts, substantiating that an activation of the CX3CL1/CX3CR1 pathway occurs in hepatoblastomas. In inflammatory regions of hepatoblastomas, CX3CL1/CX3CR1 were not detected in the infiltrated lymphocytes, in which they should be expressed in normal conditions, whereas necrotic regions exhibited negative labeling in tumor cells, but strongly positive infiltrated lymphocytes. Altogether, these data suggested that CX3CL1/CX3CR1 upregulation may be a common feature of hepatoblastomas, potentially related to chemotherapy response and progression. In addition, three mutational signatures were identified in hepatoblastomas, two of them with predominance of either the COSMIC signatures 1 and 6, found in all cancer types, or the COSMIC signature 29, mostly related to tobacco chewing habit; a third novel mutational signature presented an unspecific pattern with an increase of C>A mutations. Overall, we present here novel candidate genes for hepatoblastoma, with evidence that CX3CL1/CX3CR1 chemokine signaling pathway is likely involved with progression, besides reporting specific mutational signatures.

TET Upregulation Leads to 5-Hydroxymethylation Enrichment in Hepatoblastoma.

Hepatoblastoma is an embryonal liver tumor carrying few genetic alterations. We previously disclosed in hepatoblastomas a genome-wide methylation dysfunction, characterized by hypermethylation at specific CpG islands, in addition to a low-level hypomethylation pattern in non-repetitive intergenic sequences, in comparison to non-tumoral liver tissues, shedding light into a crucial role for epigenetic dysregulation in this type of cancer. To explore the underlying mechanisms possibly related to aberrant epigenetic modifications, we evaluated the expression profile of a set of genes engaged in the epigenetic machinery related to DNA methylation (DNMT1, DNMT3A, DNMT3B, DNMT3L, UHRF1, TET1, TET2, and TET3), as well as the 5-hydroxymethylcytosine (5hmC) global level. We observed in hepatoblastomas a general disrupted expression of these genes from the epigenetic machinery, mainly UHRF1, TET1, and TET2 upregulation, in association with an enrichment of 5hmC content. Our findings support a model of active demethylation by TETs in hepatoblastoma, probably during early stages of liver development, which in combination with UHRF1 overexpression would lead to DNA hypomethylation and an increase in overall 5hmC content. Furthermore, our data suggest that decreased 5hmC content might be associated with poor survival rate, highlighting a pivotal role of epigenetics in hepatoblastoma development and progression.

Estudo genômico do tumor embrionário hepatoblastoma / Genomic study of the embryonal tumor hepatoblastoma

O hepatoblastoma, câncer de fígado mais comum na infância, é um tumor embrionário que se supõe surgir da interrupção da diferenciação hepática durante a embriogênese. O genoma deste tipo tumoral carrega poucas alterações somáticas, principalmente aneuploidias cromossômicas e mutações em CTNNB1. Essa relativa escassez de mutações somáticas representa um desafio à estratificação de risco dos pacientes e ao desenvolvimento de terapias direcionadas. Neste trabalho, investigamos por sequenciamento de exoma o espectro de mutações somáticas em um grupo de 10 hepatoblastomas, pareados com suas respectivas amostras germinativas, incluindo um caso de tumor congênito. Os dados genômicos revelaram que os hepatoblastomas tem número reduzido de mutações somáticas codificadoras não-sinônimas (média de ~6 variantes/tumor, com exclusão do caso congênito), totalizando 94 mutações (92 diferentes) nos 10 tumores, mapeadas em 87 genes. Apenas três genes apresentaram mutações detectadas em mais de uma amostra, CTNNB1, CX3CL1 e CEP164. As mutações foram validadas pelo sequenciamento de um painel composto pelos genes identificados no exoma, também utilizado para investigar estes genes em um grupo adicional de 12 tumores; apenas mutações em CTNNB1 foram detectadas neste grupo adicional. Mutações somáticas em CTNNB1 foram detectadas em ~54% do grupo estudado (22 hepatoblastomas): sete variantes patogênicas do tipo nucleotídeo único (SNV) ou indel foram identificadas em oito hepatoblastomas (~36%), uma delas nunca previamente descrita (A21_S33del); deleções intragênicas foram detectadas por sequenciamento Sanger em quatro outros tumores (~18%). A proteína ß-catenina foi avaliada por imunohistoquímica, apresentando translocação para o núcleo, o que indica ativação da via WNT; esse resultado também foi observado em tumores nos quais mutações em CTNNB1 não foram detectadas. O principal achado do estudo do exoma de hepatoblastomas foi a identificação de uma mutação somática recorrente no éxon 3 do gene CX3CL1 (A235G), observada em dois diferentes tumores. A análise de expressão gênica e proteica de CX3CL1 e de seu receptor CX3CR1 revelou aumento de expressão de CX3CL1 em hepatoblastomas; este resultado foi replicado em duas coortes independentes. O detalhamento da análise evidenciou um padrão bimodal: (a) linfócitos infiltrados em regiões tumorais de inflamação pós-quimioterapia eram negativos para essas proteínas, que deveriam estar expressas neste tipo celular em condições normais, enquanto as células tumorais as expressavam; (b) nas áreas de necrose tumoral pós-quimioterapia, houve detecção das proteínas CX3CL1/CX3CR1 nos linfócitos, mas não nas células tumorais. Em conjunto, estes resultados sugerem que a ativação da via CX3CL1/CX3CR1 ocorre em parte dos hepatoblastomas, independentemente da detecção de mutações, o que parece ser um achado relevante, potencialmente relacionado a inflamação e/ou resistência à quimioterapia. Adicionalmente, três assinaturas mutacionais foram detectadas nos hepatoblastomas, duas delas com predomínio das assinaturas do COSMIC, HB-S1 (COSMIC 1 e 6, presentes em todos os tipos de câncer) e HB-S2, com similaridades à assinatura COSMIC 29, relacionada apenas a carcinoma oral de células escamosas (gengivo-bucal) associado ao hábito de mascar tabaco; uma nova assinatura mutacional foi observada em um subconjunto de hepatoblastomas (HB-S3), com padrão inespecífico de pequeno aumento de mutações C>A. As assinaturas mutacionais já relatadas para câncer de fígado não foram evidentes nestes hepatoblastomas, sugerindo um processo mutacional diferente em sua origem. Por fim, análise de mutações germinativas no caso de hepatoblastoma congênito levou à identificação de variantes germinativas em genes de predisposição a câncer (BRCA1 e FAH), levantando a questão do papel da predisposição genética no desenvolvimento destes tumores embrionários (AU)

Hepatoblastoma, the most common liver cancer in infancy, is an embryonal tumor supposed to arise from differentiation impairment during embryogenesis. Hepatoblastomas genomes carry few somatic changes, mainly chromosomal aneuploidies and mutations in the CTNNB1 gene. This relative paucity of somatic mutations poses a challenge to risk stratification and development of targeted therapies. In this work, we investigated the burden of somatic mutations in a cohort of 10 hepatoblastomas paired with their respective germline samples, including a case of congenital tumor. Data revealed a low number of non-synonymous somatic coding mutations (mean of ~6 variants/tumor), totalizing 94 mutations in the 10 tumors, mapped in 87 genes; only three genes exhibited mutations detected in more than one sample, CTNNB1, CX3CL1 and CEP164. Target sequencing was used for validation and screening of the mutated genes in an additional group of 12 tumors; only CTNNB1 mutations were detected in this additional group. CTNNB1 mutations were detected in ~54% of the cohort (22 hepatoblastomas): seven single nucleotide variant or indel mutations were identified in eight hepatoblastomas (~36%), including the A21_S33del mutation, not previously reported; intragenic deletions were detected by Sanger sequencing in 4 tumors (~18%). The ß-catenin protein was evaluated by immunohistochemistry, presenting translocation to the nucleus, indicating activation of the WNT pathway; this result was also observed in tumors without CTNNB1 mutations. The main finding of the exome study was the identification of a recurrent somatic mutation in the exon 3 of the CX3CL1 gene (A235G) in two different hepatoblastomas. Gene expression and protein analysis of CX3CL1 and its receptor CX3CR1 revealed increased expression of CX3CL1 in hepatoblastomas, a result that was replicated in two independent cohorts. A bimodal pattern of expression was observed: (a) lymphocytes infiltrated in tumor regions of inflammation post-chemotherapy were negative for these proteins, which should be expressed in this cell type under normal conditions, while the tumor cells expressed them; (b) in areas of tumor necrosis after chemotherapy, CX3CL1/CX3CR1 proteins were detected in lymphocytes, but not in tumor cells. Taken together, these results suggest that activation of the CX3CL1/CX3CR1 pathway occurs in part of the hepatoblastomas, regardless of mutation detection, potentially related to inflammation and/or resistance to chemotherapy. Additionally, three mutational signatures were detected, two of them with a predominance of signatures of COSMIC, HB-S1 (COSMIC 1 and 6, present in all types of cancer) and HB-S2 (COSMIC 29 signature, related only to oral cell carcinoma gingival-buccal associated with the habit of chewing tobacco). A new mutational signature was observed in a subset of hepatoblastomas (HB-S3), with a non-specific pattern of small increase in C>A mutations. Mutational signatures already reported for liver cancer were not evident in these hepatoblastomas, suggesting a different mutational process. Finally, an exploration of germline mutations in the congenital hepatoblastoma led to the identification of variants in genes of cancer predisposition (BRCA1 and FAH), raising the question of the role of genetic predisposition in the development of these embryonal tumors (AU)

DNA methylation landscape of hepatoblastomas reveals arrest at early stages of liver differentiation and cancer-related alterations.

Hepatoblastomas are uncommon embryonal liver tumors accounting for approximately 80% of childhood hepatic cancer. We hypothesized that epigenetic changes, including DNA methylation, could be relevant to hepatoblastoma onset. The methylomes of eight matched hepatoblastomas and non-tumoral liver tissues were characterized, and data were validated in an independent group (11 hepatoblastomas). In comparison to differentiated livers, hepatoblastomas exhibited a widespread and non-stochastic pattern of global low-level hypomethylation. The analysis revealed 1,359 differentially methylated CpG sites (DMSs) between hepatoblastomas and control livers, which are associated with 765 genes. Hypomethylation was detected in hepatoblastomas for ~58% of the DMSs with enrichment at intergenic sites, and most of the hypermethylated CpGs were located in CpG islands. Functional analyses revealed enrichment in signaling pathways involved in metabolism, negative regulation of cell differentiation, liver development, cancer, and Wnt signaling pathway. Strikingly, an important overlap was observed between the 1,359 DMSs and the CpG sites reported to exhibit methylation changes through liver development (p<0.0001), with similar patterns of methylation in both hepatoblastomas and fetal livers compared to adult livers. Overall, our results suggest an arrest at early stages of liver cell differentiation, in line with the hypothesis that hepatoblastoma ontogeny involves the disruption of liver development. This genome-wide methylation dysfunction, taken together with a relatively small number of driver genetic mutations reported for both adult and pediatric liver cancers, shed light on the relevance of epigenetic mechanisms for hepatic tumorigenesis.

The genetic and epigenetic landscapes of hepatoblastomas

Primary liver cancers are rare in children, and the most common type is hepatoblastoma (HB), an embryonal tumor with histological features that resemble different stages of liver cell differentiation. However, mainly because of its rarity, molecular data on HB tumorigenesis remain scarce. This article reviews the current knowledge regarding genetic and epigenetic alterations reported in HB cases, with emphasis on the recent findings of next-generation sequencing studies (AU)

Germline CDKN2A mutations in Brazilian patients of hereditary cutaneous melanoma.

Approximately 10 % of all cutaneous melanoma cases occur in a familial context. The major susceptibility gene for familial melanoma is CDKN2A. In Latin America, genetic studies investigating melanoma predisposition are scarce. The aim of this work was to investigate germline CDKN2A point mutations and genomic rearrangements in a cohort of 59 Brazilian melanoma-prone patients. Screening of CDKN2A alterations was performed by sequencing and multiplex ligation probe amplification. Germline CDKN2A mutations affecting p16(INK4a) were detected in 8 unrelated probands (13.6 %), including 7 familial cases and one patient with multiple melanomas; 4 out of 8 mutation carriers met the criteria for familial melanoma and had multiple primary lesions. Although this study adds to the literature on melanoma susceptibility in Latin America, it is limited by the small size of the cohort. Our findings suggest that stringent inclusion criteria led to a substantially increased rate of CDKN2A mutation detection. This consideration should be taken into account when referring patients for genetic screening in a setting of limited budget, such as in developing countries.

Atendimento psicoeducativo em grupo para mulheres no pós-parto: relato de experiência / Psychoeducational assistance group for women in the postpartum period: an experience report

Este relato de experiência tem por objetivo abordar uma metodologia de atendimento psicoeducativo em grupo para mulheres no pós-parto de bebês nascidos a termo e prematuros baseada na prática em psicologia clínica de duas das autoras. O atendimento em grupo de mães tem como bases teóricas a Psicologia Evolucionista (PE) e a Terapia Cognitivo-Comportamental (TCC). A primeira fornece referencial conceitual para a compreensão do processo de desenvolvimento e do que é um bebê humano, e a segunda, a metodologia para o atendimento às mães. As mães relataram diminuição da ansiedade ao participarem dos grupos, bem como do sentimento de solidão por entenderem que suas angústias também aconteciam com outras mulheres. Esse é um estudo inicial, em que não foram aplicados instrumentos para uma avaliação mais objetiva da redução de ansiedade. Desse modo, estudos controlados precisam ser desenvolvidos para testar a validade da proposta de atendimento psicoeducativo no pós-parto.(AU)

The aim of this experience report is to approach a methodology of psychoeducational care in groups for postpartum women with term and preterm infants, based on both authors' clinical practice. The experience report is based on evolutionary psychology (EP) and cognitive behavioral therapy (CBT). The first provides a conceptual framework for understanding the development process and what a human baby is. The latter, the methodology employed to the care of the mothers. The mothers report a decrease in anxiety after taking part in the group, as well as, feeling less lonely as they learn that other women also suffer from similar anguish. This is an initial study and no instruments were used in order to verify objectively the anxiety reduction. Hence, controlled studies have to be developed as a means to observe the validity of psychoeducational care in the postpartum.(AU)