11810 results for "cancer rna-seq"

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• DLK1 Distinguishes Subsets of NF1-Associated Malignant Peripheral Nerve Sheath Tumors with Divergent Molecular Signatures

  Study Design and Aims We aimed to investigate the molecular mechanisms underlying the malignant transformation of pre-existing neurofibromas (PNST) to malignant peripheral nerve sheath tumors (MPNST) in individuals with neurofibromatosis type 1 (NF1). Our primary focus was on the role of DLK1 in this transformation process and its potential as a biomarker for diagnosis, risk assessment, and therapeutic stratification. Population InformationThis study consisted of a case set of peripheral nerve sheath tumor specimens, including plexiform neurofibromas, atypical neurofibromas, and MPNSTs, acquired under IRB approval at our institution. The majority of the subjects had neurofibromatosis type 1. Principal Findings DLK1 Overexpression: The study found that DLK1 is significantly increased in MPNST compared to non-malignant neurofibromas.Early Marker: DLK1 overexpression may precede histological changes indicative of malignancy.Serum Levels: Higher serum levels of DLK1 were observed in both mice and humans with MPNST.Molecular Stratification: Divergent levels of DLK1 expression identified distinct MPNST subsets with unique molecular characteristics and potential therapeutic targets.Clinical Implications: Overexpression of DLK1 was associated with the reactivation of embryonic signatures, an immunosuppressive microenvironment, and poorer overall survival in NF1-MPNST patients. Data Availability Whole exome sequencing, bulk RNA sequencing, and single-cell RNA sequencing data from this study will be made available through the database of Genotypes and Phenotypes (dbGaP) to support further research and validation studies.

  Study phs003835

• Coding and small non-coding transcriptional landscape of tuberous sclerosis complex cortical tubers: implications for pathophysiology and treatment

  Tuberous Sclerosis Complex (TSC) is a rare genetic disorder that results from a mutation in the TSC1 or TSC2 genes leading to constitutive activation of the mechanistic target of rapamycin complex 1 (mTORC1). TSC is associated with autism, intellectual disability and severe epilepsy. Cortical tubers are believed to represent the neuropathological substrates of these disabling manifestations in TSC. In the presented study we used high-throughput RNA sequencing in combination with systems-based computational approaches to investigate the complexity of the TSC molecular network. Overall we detected 438 differentially expressed genes and 991 differentially expressed small non-coding RNAs in cortical tubers compared to autopsy control brain tissue. We observed increased expression of genes associated with inflammatory, innate and adaptive immune responses. In contrast, we observed a down-regulation of genes associated with neurogenesis and glutamate receptor signaling. MicroRNAs represented the largest class of over-expressed small non-coding RNA species in tubers. In particular, our analysis revealed that the miR-34 family (including miR-34a, miR-34b and miR-34c) was significantly over-expressed. Functional studies demonstrated the ability of miR-34b to modulate neurite outgrowth in mouse primary hippocampal neuronal cultures. This study provides new insights into the TSC transcriptomic network along with the identification of potential new treatment targets.

  Study EGAS00001002485

• Complete Genomics Deep Whole-Genome Sequencing of Circulating Tumor Cells from a Patient with Metastatic Breast Cancer

  Circulating tumor cells (CTCs) are considered to be informative non-invasive biopsy for the early detection, diagnosis or therapy guidance of cancer. CTCs also contain most of the heterogeneity found across multiple metastatic sites. In this study, we combine recently improved CTC isolation methods, resulting in almost pure CTCs, with advanced whole genome sequencing (WGS) based on Long Fragment Read (LFR) technology to demonstrate, for the first time, the research and clinical utility of an accurate, comprehensive, phased, and quantitative genomic analysis of CTCs. In particular, genomes of 34 CTCs, collected at two different time points from a patient whose metastatic breast cancer ultimately became resistant to standard treatments, were analyzed as 3072 barcoded sub-genomic compartments of long DNA. An average read coverage of 23X per cell enabled the high-resolution detection of somatic variants, cancer copy number variations (CNVs) and structural variants, including 133 CNVs shorter than 1Mb and an early chromothripsis-like event.

  Study phs001028

• Divergence between high metastatic tumor burden and low circulating tumor DNA concentration in metastasized breast cancer

  Circulating tumor DNA (ctDNA) was reported to represent a highly sensitive biomarker of metastatic cancer disease directly reflecting tumor burden and dynamics. Here we investigated the role of ctDNA in patients with metastatic breast cancer. In an index patient with more than 100,000 circulating tumor cells (CTCs) in serial blood analyses, whole genome, exome, or targeted deep sequencing of the primary tumor, metastases, and 551 CTCs were consistent with a genetically homogeneous cancer. However, the allele fractions (AFs) of ctDNA were only 2-3% in each analysis, which did neither reflect the tumor burden nor the dynamics of this progressive disease by far. Indeed, plasma analyses of 71 further patients demonstrated highly variable AFs of mutant fragments, which frequently did not correspond to the tumor burden. These results provide insights into mechanisms involved in CTC and ctDNA release into the circulation and have important implications for diagnostic tests based on liquid biopsies.

  Study EGAS00001000625

• Next_gen_seq_of_eye_cancers

  Retinoblastoma (RB), the commonest eye cancer in children was the first cancer for which a genetic cause was identified: the Rb1 gene is a tumour suppressor gene that is mutated in RB. The Rb1 gene defect alone does not predict the clinical outcome. We propose to study other possible mechanisms: 1. Stepwise further mutations occur in RB, increasing its carcinogenesis. We will sequence the whole genome in RB tissue, and relate the different genes expressed to the treatments used. 2. Extracellular matric proteins contribute to a tumour permissive environment for RB to continue to grow. This includes Samll Leucine Rich Proteoglycans (SLRP), a family of 15 secreted extracellular matrix proteins involved in eye development. 3. Cancer stem cells (CSC), a subpopulation of treatment resistant cells, drive RB tumours, and whether these stem cells can be manipulated for new therapies. The aim of this study is to assist finding targeted diagnostic techniques and treatments for RB.

  Study EGAS00001002309

• 65 prostate cancer cases WGS and transcriptome sequencing project

  We obtained whole-genome and transcriptome sequencing of tumor-benign pairs from 65 Asian prostate cancer (PCa) patients. Taken together with the TCGA PCa cohort, our integration analysis provides the first comprehensive mutational landscape of PCas across major ethnics worldwide and reveals potential novel role of frequent altered chromatin remodeler genes in PCas without androgen receptor (AR) alteration and complex rearrangements derived from Chromoplexy. In addition, we identified 5 putative tumor suppressor genes (TSGs) chains including one on chromosome 13q with novel findings of PCDH9 (deletions in 15/65 tumors) which was implicated in aggressive progression of prostate cancer. Finally, the integrative pathway and co-expression network analysis followed by the functional study indicated the frequent altered genes, particularly focal amplifications of PLXNA1 (11/65), in semaphoring signaling of axon guidance pathway may interact with PI3K/AKT and AR signaling and also contribute to the aggressiveness and progression of prostate cancer.

  Study EGAS00001000888

• A comprehensive assessment of somatic mutation detection in cancer using whole genome sequencing

  As whole genome sequencing for cancer genome analysis becomes a clinical tool, a full understanding of the variables affecting sequencing analysis output is required. Using tumor-normal sample pairs from two different types of cancer, chronic lymphocytic leukemia and medulloblastoma, we conducted a benchmarking exercise within the context of the International Cancer Genome Consortium. We compare sequencing methods, analysis pipelines, and even validation methods. Here we show that using PCR-free methods and increasing sequencing depth to ~100x showed benefits, as long as the tumor:control coverage ratio remains balanced. We observe widely varying mutation call rates and low concordance among analysis pipelines, reflecting the artifact-prone nature of the raw data and lack of standards for dealing with the artifacts. However, armed with the benchmark mutation set we have created, we show that many issues are in fact easy to remedy and have an immediate positive impact on mutation detection accuracy.

  Study EGAS00001001539

• Subtype specific progression from DCIS to invasive breast cancer

  Breast cancer consists of at least five main molecular “intrinsic” subtypes, which are reflected in both pre-invasive and invasive disease. Although previous studies have suggested that many of the molecular features of invasive breast cancer are established early, it is unclear what mechanisms drive progression, and whether the mechanisms of progression are dependent or independent of subtype. We have generated mRNA, miRNA and DNA copy number profiles from a total of 59 in situ lesions and 85 invasive tumors, in order to comprehensively identify those genes, signaling pathways, processes, and cell types that are involved in breast cancer progression. Our work provides evidence that there are molecular features associated with disease progression that are unique to the intrinsic subtypes. We additionally establish subtype-specific signatures that are able to identify a small proportion of pre-invasive tumors with expression profiles that resemble invasive carcinoma, indicating a higher likelihood of future disease progression.

  Study EGAS00001001866

• Molecular evolution and clinical trajectories of prostate cancer identifies novel markers for risk stratification

  Prostate cancer is a highly heterogeneous disease that is thought to develop over many years. Identifying the earliest somatic changes can give important insights into the tumour evolution and aid in stratifying high- from low-risk diseases. Here we pursued integrative whole-genome, transcriptome and methylome-based analysis of early-onset prostate cancer patients. Characterisation of genomic alterations across 270 PCa tumours revealed age-related genomic alterations and mutation signatures including BRCAness and APOBEC. We used methylation- and expression-data to identify four molecular subgroups, which included a highly aggressive tumour subgroup that frequently involved recurrent duplications and increased expression of ESRP1. Analysis of 12,000 tissue-microarray tumour samples demonstrated that ESRP1 is a candidate biomarker associated with faster proliferation rate and shorter time to relapse. We combine the patterns of molecular co-occurrence, risk-stratification and subgroup information to deconvolute tumor heterogeneity, which reveal complex but recurrent clinical trajectories of prostate cancer.

  Study EGAS00001002923

• Genome-wide cell-free DNA termini in patients with cancer

  The structure, fragmentation patterns and terminal sequences of cell-free DNA (cfDNA) are altered by nucleases and biological mechanisms in the blood of cancer patients. The cfDNA fragment-end composition recovered from low coverage WGS (<1 fold coverage) using a bespoke software (FrEIA) is aberrant in the plasma from cancer patient (n = 418, 655 samples) compared to controls (n = 117). As a standalone test FrEIA allows detection down to ~0.2% tumor fraction in vitro and in silico at 95% specificity, leading to a sensitivity of ~71% for detecting lung cancer (14/22 stage I-II, 27/38 stage III, 92/127 stage IV) and ~68% for detecting esophageal adenocarcinoma (26/44 stage II, 46/62 stage III). Additional cfDNA biological patterns can be combined with FrEIA increasing the diagnostic potential of low coverage WGS at minimal cost (mean AUROC = 0.96). Integrating multiple cfDNA biological signal augments the diagnostic performance of liquid biopsy.

  Study EGAS00001006142