Publications by authors named "Gerard P Zambetti"

Adrenocortical tumors (ACTs) are infrequent neoplasms in children and adolescents and are typically associated with clinical symptoms reflective of androgen overproduction. Pediatric ACTs typically occur in the context of a germline mutation, can be cured when diagnosed at an early stage, but are difficult to treat when advanced or associated with concurrent and alterations. Recent work has demonstrated DNA methylation patterns suggestive of prognostic significance.

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Article Synopsis
  • The study investigates the genetic and epigenetic factors that contribute to synchronous bilateral Wilms tumor in 68 patients through various sequencing and analysis techniques.
  • Key findings indicate that predisposition can stem from pre-zygotic germline genetic variants found in blood DNA and post-zygotic epigenetic changes, particularly hypermethylation at the 11p15.5 region.
  • Among the tumors analyzed, a significant proportion exhibited either normal imprinting, loss of heterozygosity, or epigenetic hypermethylation, highlighting the complexity of the tumor's genetic background.
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plays a critical role as a tumor suppressor by controlling cell cycle progression, DNA repair, and apoptosis. Post-translational modifications such as acetylation of specific lysine residues in the DNA binding and carboxy-terminus regulatory domains modulate its tumor suppressor activities. In this study, we addressed the functional consequences of the germline p.

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The histone lysine demethylases KDM4A-C are involved in physiologic processes including stem cell identity and self-renewal during development, DNA damage repair, and cell-cycle progression. KDM4A-C are overexpressed and associated with malignant cell behavior in multiple human cancers and are therefore potential therapeutic targets. Given the role of KDM4A-C in development and cancer, we aimed to test the potent, selective KDM4A-C inhibitor QC6352 on oncogenic cells of renal embryonic lineage.

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The germline TP53 p.R337H mutation is reported as the most common germline TP53 variant. It exists at a remarkably high frequency in the population of southeast Brazil as founder mutation in two distinct haplotypes with the most frequent co-segregating with the p.

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This study comprehensively evaluated the landscape of genetic and epigenetic events that predispose to synchronous bilateral Wilms tumor (BWT). We performed whole exome or whole genome sequencing, total-strand RNA-seq, and DNA methylation analysis using germline and/or tumor samples from 68 patients with BWT from St. Jude Children's Research Hospital and the Children's Oncology Group.

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Two major concerns associated with cancer development in Paraná state, South Brazil, are environmental pollution and the germline TP53 p.R337H variant found in 0.27−0.

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Increased mRNA is associated with disease relapse in favorable histology Wilms tumor (WT). This study sought to understand the mechanism of increased expression by determining the association between and WT1 and N-MYC, two proteins important in Wilms tumor pathogenesis that have been shown to regulate expression. Three out of 45 (6.

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Pediatric adrenocortical tumors (ACTs) are rare and heterogeneous. Approximately 50% of children with ACT carry a germline variant; however, the genetic underpinning of remaining cases has not been elucidated. In patients having germline variants, loss of maternal chromosome 11 and duplication of the paternal copy [paternal uniparental disomy, (UPD)] occurs early in tumorigenesis and explains the overexpression of , the hallmark of pediatric ACT.

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Germline splicing variants are uncommon, and their clinical relevance is unknown. However, splice-altering variants at exon 4-intron 4 junctions are relatively enriched in pediatric adrenocortical tumors (ACT). Nevertheless, family histories of cancer compatible with classic Li-Fraumeni syndrome are rarely seen in these patients.

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The TP53-R337H founder mutation exists at a high frequency throughout southern Brazil and represents one of the most common germline TP53 mutations reported to date. It was identified in pediatric adrenocortical tumors in families with a low incidence of cancer. The R337H mutation has since been found in association with early-onset breast cancers and Li-Fraumeni syndrome (LFS).

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Purpose: Pediatric adrenocortical carcinomas (ACCs) are aggressive; the overall survival of patients with ACCs is 40%-50%. Appropriate staging and histologic classification are crucial because children with incomplete resections, metastases, or relapsed disease have a dismal prognosis. The clinical course of pediatric adrenocortical tumors (ACTs) is difficult to predict using the current classification schemas, which rely on subjective microscopic and gross macroscopic variables.

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The p53 tumor suppressor transcriptionally regulates a myriad of genes involved in cell cycle control, DNA repair, cell survival, and cell metabolism and represents one of the most well-studied inhibitors of tumorigenesis. Since the discovery of TP53 in 1979, somatic mutations have been shown to be extremely common; more than 50% of human cancers carry loss-of-function mutations in TP53. Inherited or germline TP53 mutations are rare and are involved in complex hereditary cancer predisposition disorders, and affected family members can develop diverse tumor types and multiple primary cancers at young ages.

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Germline mutations in cause a rare high penetrance cancer syndrome, Li-Fraumeni syndrome (LFS). Here, we identified a rare tetramerization domain missense mutation, c.1000G>C;p.

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Cancer risk is highly variable in carriers of the common R337H founder allele, possibly due to the influence of modifier genes. Whole-genome sequencing identified a variant in the tumor suppressor (E134*/Glu134Ter/rs146752602) in a subset of R337H carriers. Haplotype-defining variants were verified in 203 patients with cancer, 582 relatives, and 42,438 newborns.

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Childhood adrenocortical tumors (ACTs) are rare, representing ∼0.2% of all pediatric malignancies and having an incidence of 0.2-0.

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Phosphodiesterases (PDEs) form a superfamily of enzymes that catalyze the hydrolysis of cyclic nucleotides adenosine 3'5'-cyclic monophosphate (cAMP) and guanosine 3'5'-cyclic monophosphate (cGMP) to their inactive 5' monophosphates. cAMP plays a critical role as a second messenger in endocrine tissues, and activation of cAMP signaling has been reported in endocrine tumors. Germline variants in PDEs have been associated with benign cortisol-secreting adrenocortical adenomas and testicular germ cell cancer but not adrenocortical carcinoma.

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The lack of model systems has limited the preclinical discovery and testing of therapies for Wilms tumor (WT) patients who have poor outcomes. Herein, we establish 45 heterotopic WT patient-derived xenografts (WTPDX) in CB17 scid mice that capture the biological heterogeneity of Wilms tumor (WT). Among these 45 total WTPDX, 6 from patients with diffuse anaplastic tumors, 9 from patients who experienced disease relapse, and 13 from patients with bilateral disease are included.

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Li-Fraumeni syndrome (LFS) is a highly penetrant cancer predisposition syndrome caused by heterozygous germline mutations in the gene. Although more than 200 missense and null mutations are well established as disease-causing, little is known about the pathogenicity and cancer risks associated with small in-frame deletions. This leads to challenges in variant classification and subsequent difficulty making a molecular diagnosis.

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The p53 tumor suppressor pathway is frequently inactivated in human cancers. However, there are some cancer types without commonly recognized alterations in p53 signaling. Here we report that histone demethylase KDM5A is involved in the regulation of p53 activity.

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The incidence of variable congenital malformation (CM) among 399 municipalities in the state of Paraná, southern Brazil, suggests the etiological role of environmental factors. This study examined a) environmental concentrations of chlorine anions (Cl) associated with organochlorines (OCs) and b) associations between these chemicals and agricultural output with CMs using a geographical information system. In one of the three years during the sampling period (2008, 2009 or 2010) Cl, dichlorodiphenyltrichloroethane (p,p'-DDT), dichlorodiphenyldichloroethylene (p,p'-DDE), dichlorodiphenyldichloroethane (p,p'-DDD), and endosulfan levels were measured in 465 (465/736, 63%) catchment basins.

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Multifocal synchronous or metachronous atypical teratoid rhabdoid tumors (ATRTs) and non-central nervous system malignant rhabdoid tumors (extra-CNS MRTs) are rare cancers. We reviewed the clinical and radiologic characteristics of affected patients seen at our institution. Genotyping and analysis of copy number abnormalities (CNAs) in SMARCB1 were performed in germline and tumor samples.

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Purpose The clinical features, pathogenesis, and outcomes in children with adrenocortical tumors (ACTs) without germline TP53 mutations have not been systematically studied. Herein, we describe these correlates and analyze their association with outcome. Patients and Methods Genomic DNA was analyzed for TP53, CTNNB1, CDKN1C, ATRX, and chromosome 11p15 abnormalities.

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A common criticism of studying rare diseases is the often-limited relevance of the findings to human health. Here, we review ∼15 years of research into an unusual germline TP53 mutation (p.R337H) that began with its detection in children with adrenocortical carcinoma (ACC), a remarkably rare childhood cancer that is associated with poor prognosis.

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