4836 results for "*oma"

in 18.73 milliseconds.

• Tracking the genomic evolution of esophageal adenocarcinoma through neoadjuvant chemotherapy

  Esophageal adenocarcinomas (EACs) are associated with dismal prognosis. Deciphering the evolutionary histories of this disease may shed light on therapeutically tractable targets and reveal changing mutational processes during the disease course and following neoadjuvant chemotherapy (NAC). We exome sequenced 40 tumor regions from 8 patients with operable EACs both before and after platinum-containing NAC. This revealed the evolutionary genomic landscape of EACs with the presence of heterogeneous driver mutations, parallel evolution, early genome doubling events and an association between high intratumor heterogeneity and poor response to NAC. Multi-region sequencing demonstrated a significant reduction in T>G mutations within a CTT context when comparing early and late mutational processes and the presence of a platinum signature with enrichment of C>A mutations within a CpC context following NAC. EACs are characterized by the presence of amplifications containing targetable oncogenes present before and after chemotherapy that may provide a rationale for future therapeutic approaches.

  Study EGAS00001001254

• Spatio-temporal evolution of the primary glioblastoma genome

  Tumor recurrence following treatment is the major cause of mortality for glioblastoma multiforme (GBM) patients. Thus, insights on the evolutionary process at recurrence are critical for improved patient care. Here, we describe our genomic analyses of 38 GBM patients with the initial and recurrent tumor specimens for each individual. A substantial divergence in the landscape of driver alterations was associated with distant appearance of a recurrent tumor from the initial tumor, suggesting that the genomic profile of the initial tumor can mislead targeted therapies for the distally recurred tumor. In addition, in contrast to IDH1-mutated gliomas, IDH1-wild-type primary GBMs rarely developed hypermutation following temozolomide (TMZ) treatment, indicating low risk of TMZ-induced hypermutation for these patients under the standard regimen.

  Study EGAS00001001041

• Intra-tumor heterogeneity and clonal evolution patterns towards platinum-resistant high-grade serous ovarian cancer

  Although many high-grade serous ovarian carcinoma (HGSOC) patients are initially sensitive to the standard-of-care platinum-based therapy, intra-tumor heterogeneity may fuel selection towards platinum-resistant clones over subsequent lines of therapy. We performed whole-exome coupled to ultra-deep re-sequencing and copy number alteration (CNA) profiling on 31 matched diagnosis and relapse tumors from HGSOC patients treated with platinum. Genetic heterogeneity within tumor pairs varied extremely, with some recurrent tumors being identical and others completely different from the primary tumor. All primary tumors showed evidence of homologous recombination (HR)-deficiency, but none of them carried reactivating mutations in the HR pathway at relapse, also not when becoming resistant to subsequent lines of platinum. We did also not identify other mutations, CNAs or pathways that were enriched in platinum-resistant clones. However, a platinum score consisting of 13 CNAs correlated significantly with platinum-free interval (PFI) after first-line therapy in multiple cohorts of >450 primary HGSOCs. A relative increase of this score in the relapsed tumor correlated with a change in PFI during subsequent therapy. Clonal evolution under platinum therapy contributes to genetic heterogeneity within tumor pairs, implicating that genetic tests linked to targeted treatment options for recurrent HGSOC need to be performed on biopsies collected at relapse. Platinum resistance of an initially platinum-sensitive HR-deficient HGSOC at relapse is not caused by reactivation of the HR pathway, suggesting that these tumors are still responsive to PARP inhibitors, instead, several chromosomal aberrations contribute to a score predictive of disease outcome under platinum therapy, both in first and subsequent lines of platinum therapy.

  Study EGAS00001001244

• Independent development of lymphoid and histiocytic malignancies from a shared early precursor

  Recent reports have described lineage flexibility in patients with recurrent hematologic malignancies. We encountered a boy with T-lineage acute lymphoblastic leukemia, non-Langerhans cell histiocytosis and histiocytic sarcoma. All tumors showed identical T-cell receptor rearrangements, but SNP arrays and whole exome sequencing revealed unique aberrations in each tumor. From the genetic data we conclude that the tumors were derived from a precursor cell with lineage plasticity for both lymphoid and myeloid development. From this precursor cell, the tumors evolved with independent genetic progression in a non-linear manner.

  Study EGAS00001001353

• Whole genome sequencing of metastatic melanomas from a patient with primary resistance to BRAF inhibition

  Here, we investigated the underlying cause of treatment failure in a patient with BRAF mutant melanoma who presented primary resistance. We used whole-genome sequencing (WGS) to characterise five metastatic tumours from a BRAF mutant melanoma patient who presented intrinsic resistance.

  Study EGAS00001000580

• Exome Sequencing to Define the Landscape of Plasma Cells in Systemic Light chain Amyloidosis

  Systemic light chain amyloidosis (AL) is characterized by the deposition of immunoglobulin light chains as amyloid fibrils in different organs, where they form toxic protein aggregates. The underlying disease is a plasma cell disorder, but limited whole exome data are available. We report the findings of an exome sequencing study in AL to define a plasma cell signature and compare this to monoclonal gammopathy of undefined significance (MGUS) and myeloma (MM). Twenty-four samples from unselected newly diagnosed untreated AL patients were analysed. CD138+ cells were isolated from bone marrow cells using MACSorting (Miltenyi Biotech, Bisley, UK). Cells were lysed in RLT+ buffer and DNA/RNA extracted using the AllPrep kit (Qiagen, Manchester, UK). Peripheral blood was isolated from patients, white blood cells purified by Ficoll-Pacque and DNA extracted using the QIAamp DNA mini kit (Qiagen). There were a median of 47 acquired nonsynonymous variants (range 4-253) per patient. Thirty percent of patients yielded a mutation in a myeloma driver gene. These mutations were either clonal or sub-clonal. There was evidence of MAPK activation with NRAS mutations, NF-κB activation and DNA repair pathway alterations. Exome data were used to determine the cytogenetic groups of AL samples and identified hyperdiploidy in 33% of cases and t(11;14) in 33% of cases. All translocations were generated via class switch recombination and breakpoints on chromosome 11 fell into the expected regions. A novel translocation, unlikely to be driving disease progression was identified involving RCC1. Finally, further analysis of the APCS gene encoding for the SAP protein did not show any biased genotype in the AL population in comparison to the general population. We conclude that exome sequencing identifies a genetic make-up of AL that is similar to other plasma cell disorders such as MM and MGUS. This not only includes copy number abnormalities and translocations but also nonsynonymous mutations.

  Study EGAS00001001418

• Myeloma_Follow_up_Pilot

  Targeted capture of exonic and intronic regions of interest for the study of genomic alterations in multiple myeloma.

  Study EGAS00001000743

• Clonal_expansion_of_mutated_cell_population_in_bladder_urothelium_

  1cm biospies of from patients undergoing bladder cystectomy will be collected. The underlying muscle and stroma will be removed and the remaining epithelia dissected into small sequential areas which will be sent for ultra-deep exome sequencing using a panel of known cancer and viral genes. Sequence analysis using similar methods to Martincorena I et al (Science 2015, 348:880) will provide an idea of the somatic mutational landscape in these patient samples. Individual patient muscle samples will also be sequenced as a reference.

  Study EGAS00001001687

• Melanoma_C32_ENU_Resistance_to_Single_Agent_Therapy

  This study involves mutagenizing C32, a melanoma cell line, with ENU to identify those mutations which engender resistance to a targeted treatment.

  Study EGAS00001001697

• Linking genes, genomic instability and molecular subgroups in medulloblastoma

  Brain tumors are the second most common pediatric cancer and carry the highest mortality rates in this age group. Medulloblastoma is the most frequent malignant brain tumor of childhood. Recent studies indicate that medulloblastoma comprises at least four sub-entities (SHH-signaling, WNT-signaling, Group-C, Group-D) that differ in molecular alterations, cell of origin, clinicopathological features and outcome. Further characterization of the entire spectrum of genomic alterations underlying the formation of these distinct groups is urgently needed to identify diagnostic and prognostic biomarkers for clinical management and uncover novel therapeutic targets.

  Study EGAS00001000085