11932 results for "cancer rna-seq"

in 16.59 milliseconds.

• cfRRBS on cfDNA from pediatric cancer

  In the clinical management of pediatric solid tumors, histological examination of tumor tissue obtained by a biopsy remains the gold standard to establish a conclusive pathological diagnosis. The DNA methylation pattern of a tumor is known to correlate with the histopathological diagnosis across cancer types and is showing promise in the diagnostic workup of tumor samples. This methylation pattern can be detected in the cell-free DNA. Here, we provide proof-of-concept of histopathologic classification of pediatric tumors using cell-free reduced representation bisulfite sequencing (cf-RRBS) from retrospectively collected plasma and cerebrospinal fluid samples. We determined the correct tumor type in 49 out of 60 (81.6%) samples starting from minute amounts (less than 10 ng) of cell-free DNA. We demonstrate that the majority of misclassifications were associated with sample quality and not with the extent of disease. Our approach has the potential to help tackle some of the remaining diagnostic challenges in pediatric oncology in a cost-effective and minimally invasive manner.

  Study EGAS00001004194

• Whole exome sequencing of long-term, never relapse exceptional responders of trastuzumab-treated HER2+ metastatic breast cancer

  Trastuzumab has significantly improved the overall survival of patients with HER2+ metastatic breast cancer (MBC). However, outcomes can vary, with patients progressing within 1-year of treatment or exceptional cases of complete response to trastuzumab for ≥ 10 years. Identification of the underlying genomic aberrations of “exceptional responders (ExRs)” compared to “rapid non-responders (NR)” increases our understanding of the mechanisms involved in MBC progression and identification of biomarkers of trastuzumab response and resistance. Whole exome sequencing was performed on six ExRs compared to five NR. The overall fraction of genome copy number alteration (CNA) burden was higher in NR patients (P=0.07), while more significantly pronounced in copy number gains (P=0.03) in NR compared to ExRs. Delineation of the distribution of CNA burden across the genome identified a greater degree of CNA burden in NR within chr8 (P=0.02) and in chr17 (P=0.06) and conferred a statistically significant benefit in overall survival.

  Study EGAS00001004486

• Latency and interval therapy affect the evolution in metastatic colorectal cancer

  While comparison of primary tumor and metastases has highlighted genomic heterogeneity in colorectal cancer (CRC), previous studies have focused on a single metastatic site or limited genomic testing. Combining data from whole exome and ultra-deep targeted sequencing, we explored possible evolutionary trajectories beyond the status of these mutations, particularly among patient-matched metastatic tumors. Our findings confirm the persistence of known clinically-relevant mutations (e.g. those of RAS family of oncogenes) in CRC primary and metastases, yet reveal that latency and interval systemic therapy affect the course of evolutionary events within metastatic lesions. Specifically, our analysis of patient-matched primary and multiple metastatic lesions, developed over time, showed a similar genetic composition for liver metastatic tumors, which were 21-months apart. This genetic makeup was different from those identified in lung metastases developed before manifestation of the second liver metastasis. These results underscore the role of dormancy in the evolutionary path of metastatic CRC.

  Study EGAS00001003646

• Homologous recombination DNA repair deficiency and PARP inhibition activity in primary triple negative breast cancer

  Triple negative breast cancer (TNBC) encompasses molecularly different subgroups, with a subgroup harboring evidence of defective homologous recombination (HR) DNA repair. Within a phase 2 window clinical trial, RIO trial (EudraCT 2014-003319-12), we investigate the activity of PARP inhibitors in 43 patients with untreated TNBC. The primary endpoint, decreased Ki67, occurs in 12% of TNBC. Multiple different approaches identify HR deficiency in the majority of TNBC, 69% with the mutational-signature-based HRDetect assay. Cancers with mutational signatures of HR deficiency have a functional defect in HR. Following rucaparib treatment there is no association of Ki67 change with HR deficiency. In contrast, early circulating tumor DNA dynamics identify activity of rucaparib in cancers with mutation-signatures of HR deficiency, with rucaparib inducing expression of interferon response genes in HR deficient cancers. The majority of TNBCs have a defect in DNA repair, identifiable by mutational signature analysis, that may be targetable with PARP inhibitors.

  Study EGAS00001004405

• The landscape of chromothripsis across adult cancer types

  Chromothripsis is a recently identified mutational phenomenon, by which a presumably single catastrophic event generates extensive genomic rearrangements of one or a few chromosome(s). Considered as an early event in tumour development, this form of genome instability plays a prominent role in tumour onset. Chromothripsis prevalence might have been underestimated when using low-resolution methods, and pan-cancer studies based on sequencing are rare. We analysed chromothripsis in 28 tumour types covering all major adult cancers (634 tumours, 316 whole-genome and 318 whole-exome sequences). We show that chromothripsis affects a substantial proportion of human cancers, with a prevalence of 49% across all cases. Chromothripsis generates entity-specific genomic alterations driving tumour development, including clinically relevant druggable fusions. Chromothripsis is linked with specific telomere patterns and univocal mutational signatures in distinct tumour entities. Longitudinal analysis of chromothriptic patterns in 24 matched tumour pairs reveals novel insights in the clonal evolution of tumours with chromothripsis. (H021)

  Study EGAS00001004250

• Mutation analysis of core biopsies from localized breast cancer patients

  Targeted next-generation sequencing (NGS) of 93 frequently mutated genes in breast cancer using the QIAseq Human Breast Cancer Targeted Panel (QIAGEN), which uses digital sequencing by incorporating unique molecular barcodes (UMI).

  Dataset EGAD00001008396

• Ancestry and somatic profile predict acral melanoma origin and prognosis – WXS

  Acral melanoma, which is not ultraviolet (UV)-associated, is the most common type of melanoma in several low- and middle-income countries including Mexico. Latin American samples are significantly underrepresented in global cancer genomics studies, which directly affects patients in these regions as it is known that cancer risk and incidence may be influenced by ancestry and environmental exposures. To address this, we characterise the genome and transcriptome of 123 acral melanoma tumours from 92 Mexican patients, a population notable because of its genetic admixture. Compared with other studies of melanoma, we found fewer frequent mutations in classical driver genes such as BRAF, NRAS or NF1. While most patients had predominantly Amerindian genetic ancestry, those with higher European ancestry had increased frequency of BRAF mutations and a lower median number of structural variants. The tumours with activating BRAF mutations have a transcriptional profile more similar to cutaneous non-volar melanocytes, suggesting that acral melanomas in these patients may arise from a distinct cell of origin compared to other tumours arising in these locations. KIT mutations were found in a subset of these tumours, and quadruple wild-type samples (non BRAF/NRAS/NF1/KIT) differed from mutated samples in their structural genomic profile and overall and recurrence-free survival patterns. Transcriptional profiling defined three expression clusters; these characteristics were associated with recurrence-free and overall survival. We highlight potential novel low-frequency drivers, such as PTPRJ, NF2 and RDH5. Our study enhances knowledge of this understudied disease and underscores the importance of including samples from diverse ancestries in cancer genomics studies.

  Dataset EGAD00001015755

• Single-nucleus ATAC-seq of human fetal liver hematopoiesis

  The fetal liver is the primary haematopoietic organ during early human development, yet the timing and regulatory mechanisms governing blood formation remain incompletely understood. To define the cellular, transcriptional, and epigenetic changes underlying human fetal liver hematopoiesis over development, we generated a high-resolution, time-resolved single-nucleus multiome atlas of human fetal liver spanning 5–18 post-conception weeks (PCW) for CD45+CD235- cells. In total, 308,021 high-quality nuclei from 53 donors were profiled using paired chromatin accessibility and transcriptomic modalities. This study is for the chromatin accessibility.

  Study EGAS50000001632

• Exome-seq data of two non-obstructive azoospermia patients

  Azoospermia, characterized by the absence of spermatozoa in the ejaculate is a common cause of male infertility with a poorly characterized etiology. Exome sequencing analysis of two azoospermic brothers allowed the identification of a homozygous splice mutation in SPINK2, encoding a serine protease inhibitor believed to target acrosin, the main sperm acrosomal protease. In accord with these findings we observed that homozygous Spink2 KO male mice had azoospermia. Moreover, despite normal fertility, heterozygous male mice had a high rate of morphologically abnormal spermatozoa and a reduced sperm motility. Further analysis demonstrated that in the absence of Spink2, protease-induced stress initiates Golgi fragmentation and prevents acrosome biogenesis leading to spermatid differentiation arrest. We also observed a deleterious effect of acrosin overexpression in HEK cells, effect that was alleviated by SPINK2 coexpression confirming its role as acrosin inhibitor. These results demonstrate that SPINK2 is necessary to neutralize proteases during their cellular transit towards the acrosome and that its deficiency induces a pathological continuum ranging from oligoasthenoteratozoospermia in heterozygotes to azoospermia in homozygotes.

  Dataset EGAD00001003326

• ChIP-seq of GOF p53 mutants

  Gain-of-function TP53 mutations were detected in 41.3% of cases, in which co-occurring del(17p) underscored a dominant effect in >25%. Missense mutations of TP53 clustered within the core DNA-binding domain, where R249S was most common. To explore the transcriptional effect of mutant p53(R249S), we performed chromatin immunoprecipitation-sequencing in the HCC cell line HKCI-11, which has a p53(R249S) mutation, and the human hepatocyte line MIHA, which is p53(WT). The results revealed distinct binding profiles between wildtype p53 and p53 mutant.

  Study EGAS00001002463