12153 results for "cancer rna-seq"

in 18.18 milliseconds.

• Methylation Biomarkers can Distinguish Pleural Mesothelioma from Healthy Pleura and other Pleural Pathologies

  Pleural mesothelioma (PM) is a rare cancer type. This study developed a methylation-based biomarker assay to distinguish PM from healthy pleura and other pleural conditions. By analyzing methylation data, 744 hypermethylated CpG sites specific to PM were identified and validated with high accuracy. Using the bisulfite-free IMPRESS technique, the assay was further validated in a diverse cohort, showing strong performance in distinguishing tumoral from non-tumoral samples and PM from pleural metastases. These findings support the assay’s potential as a robust diagnostic tool for PM.

  Study EGAS00001008153

• Familial breast cancer targeted sequencing with ONT

  A large cohort of 600 cases with familial breast cancer as classified by the Spanish Society of Medical Oncology (SEOM) Clinical Guidelines Update that were recruited during 6 years at Hospital Universitario Morales Meseguer (Murcia, Spain) were retrospectively evaluated to select 16 cases with no positive finding in NGS analysis of 20 genes implicated in this disease. These 16 cases were selected for further investigation using nanopore sequencing. This method involved the use of adaptive sampling enrichment, targeting a panel of 18 human genome regions, which contained the 20 genes (PTEN, ATM, BRCA2, PALB2, CDH1, TP53, NF1, RAD51D, BRCA1, RAD51C ,BRIP1, STK11, CHEK2, EPCAM, MSH2, MSH6, BARD1, MLH1, PMS2, NBN). In 5 samples (P1, P2, P4, P15 and P16) no selection of long reads was performed. Additionally, in 3 samples (P7, P9 and P10), both procedures were performed in two independent runs, and for the second run of P7, the DNA was previously fragmented using g-TUBE Covaris® (ref 520079) according to the protocol for 6 kb fragments.

  Dataset EGAD00001011106

• The mutational landscape of normal human endometrial epithelium

  All normal somatic cells are thought to acquire mutations. However, characterisation of the patterns and consequences of somatic mutation in normal tissues is limited. Uterine endometrium is a dynamic tissue undergoing cyclical shedding and reconstitution lined by a gland-forming epithelium. Whole genome sequencing of normal endometrial glands showed that most are clonal cell populations derived from a recent common ancestor, with mutation burdens differing from other normal cell types and many fold lower than endometrial cancers. Mutational signatures found ubiquitously account for most mutations. Many, in some women all, endometrial glands are colonised by cell clones carrying driver mutations in cancer genes, often with multiple drivers. Total and driver mutation burdens increase with age, but are also influenced by other factors, including body mass index and parity, and clones with drivers often originate during early decades of life. The somatic mutational landscapes of normal cells differ between cell types and are revealing the procession of neoplastic change leading to cancer.

  Dataset EGAD00001004547

• The landscape of somatic mutation in normal colorectal epithelial cells

  The colorectal adenoma-carcinoma sequence has provided a paradigmatic framework for understanding the successive somatic genetic events and consequent clonal expansions leading to cancer. As for most cancer types, however, understanding of the earliest phases of colorectal neoplastic change, which may occur in morphologically normal tissue, is comparatively limited because of the difficulty of detecting somatic mutations in normal cells. Each colorectal crypt is a small clone of cells derived from a single recently-existing stem cell. Here, we sequenced hundreds of normal crypts from 42 individuals. Signatures of multiple mutational processes were revealed, some ubiquitous and continuous, others only found in some individuals, in some crypts or during some phases of the cell lineage from zygote to adult cell. Likely driver mutations were present in ~1% of normal colorectal crypts in middle-aged individuals, indicating that adenomas and carcinomas are rare outcomes of a pervasive process of neoplastic change across morphologically normal colorectal epithelium.

  Dataset EGAD00001004192

• Direct transcriptional consequences of somatic mutation in breast cancer

  The disordered transcriptomes of cancer encompass direct effects of somatic mutation on transcription; co-ordinated secondary alterations in transcriptional pathways; and increased transcriptional noise. To catalogue the rules governing how somatic mutation Overall, 59% of 6980 exonic substitutions were expressed. Compared to other classes, nonsense mutations showed lower expression levels than expected with patterns characteristic of nonsense-mediated decay. 14% of 4234 genomic rearrangements caused transcriptional abnormalities, including exon skips, exon reusage, fusion transcripts and premature poly-adenylation. We found productive, stable transcription from sense-to-antisense gene fusions and gene-to-intergenic rearrangements, suggesting that these mutation classes may drive more transcriptional disruption than previously suspected. Systematic integration of transcriptome with genome data therefore reveals the rules by which transcriptional machinery interprets somatic mutation.

  Dataset EGAD00001002237

• Genomic Analyses of Germline and Somatic Variation in High-Grade Serous Ovarian Cancer

  The goal of this study was to identify and characterize germline and somatic genetic variation in women with high grade serous ovarian cancers treated at a single cancer center and their associations with relapse-free and overall survival. We conducted paired tumor/normal targeted next-generation sequencing of 577 genes in pathways of DNA repair, response to DNA damage, cell-cycle regulation, programmed cell death, MAPK, and P13K/AKT/MTOR signaling in 114 tumors from 71 women. In addition, we investigated single copy number alterations (SCNAs) and loss of heterozygosity in a subset of 61 tumors. We validated our results with data from ovarian tumors in TCGA. Our results were similar to other studies of high-grade serous carcinomas. As an example, we found that approximately one third of the tumors harbored loss of function variants in homologous recombination genes and that >90% had TP53 somatic mutations. Through GISTIC analysis of the OncoScan data on tumor DNA from 61 cases, we identified several regions of high copy number alterations including including NOTCH3 and PIK3R2 that were significantly associated with an increase in cancer recurrence and a reduction in overall survival. We identified few changes in mutation profiles where we had multiple tissues, either from multiple surgeries or from the primary site to metastatic sites within the same surgery. However, we did not investigate copy number alterations in multiple tissues from the same individuals, and so it may be that copy number alterations are more important. Data available through dbGAP will be the BAM files and the phenotypic data on the tumor samples, the age, race, ethnicity of the participants and their outcomes, and the Oncoscan OSCHP files.

  Study phs003198

• Investigating the Role of Neddylation in the Repair of Topoisomerase I-Mediated DNA Damage in Colorectal Cancer

  Colorectal cancer is one of the most lethal cancers worldwide. First-line chemotherapy for metastatic CRC (mCRC) entails a combination of irinotecan with 5-fluorouracil and leucovorin (FOLFIRI). Irinotecan is a prodrug that is converted within the cell to its active metabolite SN38, a potent TOP1 inhibitor. TOP1 relieves DNA torsional strain arising from DNA metabolism by cleaving one strand of the DNA duplex and forming an enzyme-DNA covalent intermediate that can be trapped by inhibitors. The resulting TOP1 DNA-protein crosslinks (TOP1-DPCs) interfere with replication and transcription and induce cell death if left unrepaired. I have established the role of the ubiquitin-proteasome pathway in TOP1-DPC repair, but it remains unknown how ubiquitylation is activated. One possibility is that collision between advancing replication forks and the DPCs triggers a specific ubiquitin ligase to target DPCs for degradation. The DDB1-CUL4 (Cullin 4)-RBX1 (CRL4) ubiquitin ligase complex performs a salient role in both replication and DNA repair upon its activation by auto-NEDD8 modification (neddylation), but it is unknown whether it plays a role for TOP1-DPC repair. We plan to define the role of neddylation for TOP1-DPC repair during replication and examine irinotecan plus pevonedistat (PEV), a NEDD8-activating enzyme inhibitor in multiple clinical trials, in CRC patient-derived preclinical models including 3D organoids. The three in-house organoids, from which samples have been submitted to dbGaP, were sequenced as a means of verifying their identity as colon cancer organoids, to allow us to investigate the combination of TOP1 inhibitors and PEV and the molecular mechanisms underlying this drug combination in these organoids.

  Study phs003257

• Clinical and Molecular Features of Acquired Resistance to Immunotherapy in Non-Small Cell Lung Cancer

  PD-(L)1 blockade has been shown to promote durable responses in non-small cell lung cancer (NSCLC) patients and has been rapidly incorporated into the treatment regimens for many with advanced disease. Despite this, mechanisms of acquired resistance (AR) to PD-(L)1 have not been well understood. To address the clinical and molecular landscape of AR to PD-(L)1 blockade in NSCLC patients, a large clinical cohort of AR to PD-(L)1 blockade in lung cancer was examined. In conjunction, a systematic genomic and transcriptomic analysis in a subset of patients (n = 29) with available tissue samples was conducted. To investigate the molecular mechanisms of AR to PD-1 blockade from pre- and/or post-treatment tumors, microarray-based whole transcriptome expression data for 29 tumor samples, and whole exome sequencing (WES) data from 34 tumor samples was generated from this subset. Microarray data was uploaded to the Gene Expression Omnibus (GEO) database. Most AR tumors showed retained or increased inflammatory characteristics with significant upregulation of IFNγ which was suggestive of persistent albeit insufficient anti-tumor immune response. This finding expounds upon the prior pre-clinical and translational data supporting the intricate role of IFNγ in sensitivity and resistance to immunotherapy. Whereas initial IFNγ exposure may be fundamental to T cell activation (a hallmark of immune response), persistent IFNγ related effects and upregulation may potentially signal immune dysfunction and IFNγ insensitivity in contrast. The inflammatory phenotypes identified have implications for future rational development of new immunotherapy strategies for patients with AR.

  Study phs002834

• Sequencing of 3D Organoids Derived From Colorectal Cancer Patients

  This study focuses on the whole-exome sequencing (WES) of patient-derived organoids (PDOs) established from colorectal cancer (CRC) tumors collected at Columbia University. CRC remains a major cause of cancer-related mortality due to its metastatic progression and resistance to therapy. To model CRC at the patient level, we generated 3D organoid cultures from primary and metastatic tumors, preserving their genetic and phenotypic characteristics. The study cohort consists of 9 CRC patients with microsatellite-stable adenocarcinomas from the ascending, transverse, and descending colon, as well as the rectum, with differentiation statuses ranging from well to moderate and moderate-poor. Notably, for one patient, we generated organoids from both the primary tumor and matched liver metastases, allowing for a comparative analysis of tumor evolution. PDOs were derived from these tumors and subjected to WES at early passage to profile somatic mutations, copy number variations, and other genomic alterations to identify mutational signatures. Mutations identified in the PDOs were cross-referenced and confirmed with mutational data from the Columbia Solid Tumor Panel, which was conducted on all tumor tissues prior to organoid establishment. Molecular technologies employed include next-generation sequencing (NGS) for WES, enabling high-resolution characterization of the genomic landscape of CRC PDOs. WES of PDOs allowed us to classify tumor samples based on oncogenic mutations and mutation types, with a specific focus on PIK3CA. Notably, the efficacy of PI3Kα-specific pharmacologic inhibitors in suppressing organoid growth was dependent on the mutational status of KRAS and PIK3CA, underscoring the importance of genomic context in therapeutic response. The dataset available through dbGaP includes raw WES data from CRC PDOs.

  Study phs003965

• The phase II Neo-Pembro trial: neoadjuvant pembrolizumab in stage IV high-grade serous ovarian cancer

  While immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, their efficacy in high-grade serous ovarian cancer (HGSOC) remains limited. Nevertheless, some patients achieve lasting responses, emphasizing the need to understand how the tumor microenvironment and molecular characteristics influence ICI response. We hypothesized higher efficacy of ICI when used in the neoadjuvant setting and preceded by induction chemotherapy. The phase 2 Neo-Pembro study (NCT03126812) included 33 untreated patients with stage IV HGSOC who were planned for 6 cycles of carboplatin-paclitaxel and interval cytoreductive surgery. Pembrolizumab (pembro) was added from cycle two and continued for one year. The primary objective was to assess intratumoral immune activation, through multiplexed immunofluorescence and immune-related gene expression. Our data provide evidence of immune activation, characterized by an increase in CD3+, CD8+, CD8+/FOXP3+ ratio, and TNF-α and interferon-γ signaling, and was most evident in major pathologic responders, which were 9/33 patients (27%, 95%CI 14-46) at time of surgery. Pathologic response was strongly associated with overall survival. At a median follow-up of 52.8 months, 8/9 major responders were alive, including 6 patients without recurrence, and 4 of 24 minor responders were alive, including one patient without recurrence. PD-L1 expression and homologous recombination deficiency were predictive of major response and may serve as potential biomarkers, warranting further exploration. In a post-hoc comparison, major responders treated with pembro had significantly better overall survival than major responders in a historic cohort treated without pembro. Our data indicate that immune activation was stronger in the subset of major pathologic responders and these patients may derive long-term survival benefits from the addition of neoadjuvant pembro.

  Study EGAS50000000781