Plasma DNA Methylation-Based Biomarkers for MPNST Detection in Patients With Neurofibromatosis Type 1.

Malignant peripheral nerve sheath tumor (MPNST) development is characterized by an altered DNA methylation landscape, which presents a promising area for developing MPNST-specific biomarkers for screening patients with NF1. Genome-wide DNA methylation profiling of a cohort of 13 patients with MPNST (29 samples of tumor and adjacent neurofibroma tissues) and of NF1-MPNST cell lines was performed to identify and validate candidate MPNST-specific CpG sites (CpGs). A logistic regression prediction model was constructed to select MPNST-specific CpGs distinct from adjacent neurofibromas and normal tissues.

Experimental models of undifferentiated pleomorphic sarcoma and malignant peripheral nerve sheath tumor.

Undifferentiated pleomorphic sarcoma (UPS) and malignant peripheral nerve sheath tumor (MPNST) are aggressive soft tissue sarcomas that do not respond well to current treatment modalities. The limited availability of UPS and MPNST cell lines makes it challenging to identify potential therapeutic targets in a laboratory setting. Understanding the urgent need for improved treatments for these tumors and the limited cellular models available, we generated additional cell lines to study these rare cancers.

Enhancer reprogramming in PRC2-deficient malignant peripheral nerve sheath tumors induces a targetable de-differentiated state.

Malignant peripheral nerve sheath tumors (MPNSTs) are soft tissue sarcomas that frequently harbor genetic alterations in polycomb repressor complex 2 (PRC2) components-SUZ12 and EED. Here, we show that PRC2 loss confers a dedifferentiated early neural-crest phenotype which is exclusive to PRC2-mutant MPNSTs and not a feature of neurofibromas. Neural crest phenotype in PRC2 mutant MPNSTs was validated via cross-species comparative analysis using spontaneous and transgenic MPNST models.

Comparison of Cancer Prevalence in Patients With Neurofibromatosis Type 1 at an Academic Cancer Center vs in the General Population From 1985 to 2020.

Importance: Neurofibromatosis type 1 (NF1) is a complex genetic disorder that is associated with not only neurofibromas, but also an increased susceptibility to other neoplasms.

Objective: To evaluate the prevalence of neoplasia and outcomes among patients with NF1.

Design, Setting, And Participants: This cohort study was conducted among patients with NF1 at a single academic cancer center from 1985 to 2020 with median (range) follow-up of 2.

AXL Inhibition Enhances MEK Inhibitor Sensitivity in Malignant Peripheral Nerve Sheath Tumors.

Dysregulation of the receptor tyrosine kinase AXL is known to promote cancer cell growth and survival in many sarcomas, including the rare subtype, malignant peripheral nerve sheath tumors (MPNST). MPNSTs are largely chemoresistant and carry a poor prognosis. AXL is an attractive potential therapeutic target, as it is aberrantly expressed, and its activation may be an early event in MPNST.

Co-targeting PI3K, mTOR, and IGF1R with small molecule inhibitors for treating undifferentiated pleomorphic sarcoma.

Undifferentiated pleomorphic sarcomas (UPSs) are aggressive mesenchymal malignancies with no definitive cell of origin or specific recurrent genetic hallmarks. These tumors are largely chemoresistant; thus, identification of potential therapeutic targets is necessary to improve patient outcome. Previous studies demonstrated that high expression of activated protein kinase B (AKT) in patients with UPS corresponds to poor disease-specific survival.

Stalled DNA Replication Forks at the Endogenous GAA Repeats Drive Repeat Expansion in Friedreich's Ataxia Cells.

Friedreich's ataxia (FRDA) is caused by the expansion of GAA repeats located in the Frataxin (FXN) gene. The GAA repeats continue to expand in FRDA patients, aggravating symptoms and contributing to disease progression. The mechanism leading to repeat expansion and decreased FXN transcription remains unclear.

Deep sequencing of mitochondrial genomes reveals increased mutation load in Friedreich's ataxia.

Objective: Friedreich's ataxia (FRDA) is an autosomal recessive trinucleotide repeat expansion disorder caused by epigenetic silencing of the frataxin gene (FXN). Current research suggests that damage and variation of mitochondrial DNA (mtDNA) contribute to the molecular pathogenesis of FRDA. We sought to establish the extent of the mutation burden across the mitochondrial genome in FRDA cells and investigate the molecular mechanisms connecting FXN downregulation and the acquisition of mtDNA damage.

Establishment and Maintenance of Primary Fibroblast Repositories for Rare Diseases-Friedreich's Ataxia Example.

Friedreich's ataxia (FRDA) represents a rare neurodegenerative disease caused by expansion of GAA trinucleotide repeats in the first intron of the FXN gene. The number of GAA repeats in FRDA patients varies from approximately 60 to <1000 and is tightly correlated with age of onset and severity of the disease symptoms. The heterogeneity of Friedreich's ataxia stresses the need for a large cohort of patient samples to conduct studies addressing the mechanism of disease pathogenesis or evaluate novel therapeutic candidates.

Expanded GAA repeats impede transcription elongation through the FXN gene and induce transcriptional silencing that is restricted to the FXN locus.

Friedreich's ataxia (FRDA) is a severe neurodegenerative disease caused by homozygous expansion of the guanine-adenine-adenine (GAA) repeats in intron 1 of the FXN gene leading to transcriptional repression of frataxin expression. Post-translational histone modifications that typify heterochromatin are enriched in the vicinity of the repeats, whereas active chromatin marks in this region are underrepresented in FRDA samples. Yet, the immediate effect of the expanded repeats on transcription progression through FXN and their long-range effect on the surrounding genomic context are two critical questions that remain unanswered in the molecular pathogenesis of FRDA.

Genome-wide association study of maternal and inherited loci for conotruncal heart defects.

Conotruncal and related heart defects (CTDs) are a group of serious and relatively common birth defects. Although both maternal and inherited genotypes are thought to play a role in the etiology of CTDs, few specific genetic risk factors have been identified. To determine whether common variants acting through the genotype of the mother (e.

Exon sequencing of PAX3 and T (brachyury) in cases with spina bifida.

Background: Based on studies in animals and humans, PAX3 and T (brachyury) are candidate genes for spina bifida. However, neither gene has been definitively identified as a risk factor for this condition.

Methods: Sanger sequencing was used to identify variants in all PAX3 and T exons and promoter regions in 114 spina bifida cases.

A UPF3-mediated regulatory switch that maintains RNA surveillance.

Nonsense-mediated decay (NMD) is an RNA decay pathway that downregulates aberrant mRNAs and a subset of normal mRNAs. The regulation of NMD is poorly understood. Here we identify a regulatory mechanism acting on two related UPF (up-frameshift) factors crucial for NMD: UPF3A and UPF3B.

Nonsense codons trigger an RNA partitioning shift.

T-cell receptor-beta (TCRbeta) genes naturally acquire premature termination codons (PTCs) as a result of programmed gene rearrangements. PTC-bearing TCRbeta transcripts are dramatically down-regulated to protect T-cells from the deleterious effects of the truncated proteins that would otherwise be produced. Here we provide evidence that two responses collaborate to elicit this dramatic down-regulation.