4911 results for "*oma"

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• Reprogramming of stroma-derived chemokine networks drives the loss of tissue organization in nodal B cell lymphoma

  Here, we utilized single-cell and spatial mapping to interrogate the mechanisms directing tissue architecture in human lymph nodes (LN) and its disruption in nodal B cell lymphoma. Specifically, we mapped the cellular landscape of follicular lymphoma (FL; n=6) and diffuse large B cell lymphoma (DLBCL; n=8) alongside non-malignant reactive LNs (rLN; n=5) using single-cell RNA sequencing. Our data support the central role of LN-resident stromal cells in chemokine-driven lymphocyte zonation and reveal an inflammatory feedback loop fueled by tumor-reactive T cells, triggering stromal remodeling, progressive loss of homeostatic chemokine gradients and tissue organization from non-malignant to FL and DLBCL. Collectively, our results highlight the principles of LN organization and suggest how lymphoma-induced microenvironmental reprogramming drives loss of tissue organization.

  Study EGAS00001006986

• An IL-1β driven neutrophil-stromal cell axis fosters a BAFF-rich microenvironment in multiple myeloma

  The bone marrow is continuously occupied by high numbers of neutrophils, and a tumor-supportive bias of these cells could significantly impact bone marrow-confined malignancies. In multiple myeloma, the bone marrow is characterized by inflammatory stromal cells with the potential to influence neutrophils. Here, we investigated myeloma-associated alterations in marrow neutrophils and the impact of stromal inflammation on neutrophil function. Mature neutrophils in myeloma marrow are activated and tumor-supportive, transcribing increased levels of pro-inflammatory cytokines, including IL-1β, and myeloma cell survival factors, such as the BCMA-ligand BAFF. Neutrophils were re-activated after first-line treatment, while this regimen reduced, but did not normalize, stromal inflammation. Interactions with inflammatory stroma induced neutrophil activation, including BAFF secretion, in a STAT3-dependent manner and once activated, neutrophils gained the ability to reciprocally induce stromal activation. Combined, our data define the presence of a neutrophil-stromal cell feed-forward loop driving tumor-supportive inflammation that could impact disease recurrence.

  Study EGAS00001007038

• ACT-Discover: identifying karyotype heterogeneity in pancreatic cancer evolution using ctDNA

  Background Liquid biopsies, and the dynamic tracking of somatic mutations within circulating tumour DNA (ctDNA) can provide insight into the dynamics of cancer evolution and the intra-tumour heterogeneity that fuels treatment resistance. However, identifying and tracking dynamic changes in somatic copy-number alterations (SCNAs), which have been associated with poor outcome and metastasis, using ctDNA is challenging. Pancreatic adenocarcinoma is a disease which has been considered to harbour early punctuated events in its evolution, leading to an early fitness peak, with minimal further subclonal evolution. Methods To interrogate the role of SCNAs in pancreatic adenocarcinoma cancer evolution, we applied whole-exome sequencing of 55 longitudinal cell-free DNA (cfDNA) samples taken from 24 patients (including 8 from whom a patient-derived xenograft (PDX) was derived) with metastatic disease prospectively recruited into a clinical trial. We developed a method, Aneuploidy in Circulating Tumour DNA (ACT-Discover), that leverages haplotype phasing of paired tumour biopsies or PDXs to identify SCNAs in cfDNA with greater sensitivity. Results SCNAs were observed within 28 of 47 evaluable cfDNA samples. Of these events, 30% could only be identified by harnessing the haplotype-aware approach leveraged in ACT-Discover. The exceptional purity of PDX tumours enabled near-complete phasing of genomic regions in allelic imbalance, highlighting an important auxiliary function of PDXs. Finally, although the classical model of pancreatic cancer evolution emphasises the importance of early, homogenous somatic events as a key requirement for cancer development, ACT-Discover identified substantial heterogeneity of SCNAs, including parallel focal and arm-level events, affecting different parental alleles within individual tumours. Indeed, ongoing acquisition of SCNAs was identified within tumours throughout the disease course, including within an untreated metastatic tumour. Conclusions This work demonstrates the power of haplotype phasing to study genomic variation in cfDNA samples and reveals undiscovered intra-tumour heterogeneity with important scientific and clinical implications. Implementation of ACT-Discover could lead to important insights from existing cohorts, or underpin future prospective studies seeking to characterise the landscape of tumour evolution through liquid biopsy.

  Study EGAS00001007077

• Genome-wide cell-free DNA biological patterns in patients with cancer

  The structure of cell-free DNA (cfDNA) is altered in the blood of cancer patients. From whole genome sequencing we retrieved the cfDNA fragment-end composition using a new software (FrEIA), as well as the cfDNA size and tumor fraction in three independent cohorts (n=925 cancer from >10 types and 321 control samples). At 95% specificity, we detect 72% of cancer samples using at least one cfDNA measure, including 64% of early-stage cancer (n=220). cfDNA detection correlates with a shorter overall (p=0.018) and recurrence-free (p=0.006) survival in patients with resectable esophageal adenocarcinoma. Integrating cfDNA measures with machine learning in an independent test set (n=396 cancer, 90 controls) achieve a detection accuracy of 82% and AUROC of 96%. In conclusion, harnessing the biological features of cfDNA can improve at no-extra cost the diagnostic performance of liquid biopsies.

  Study EGAS00001007400

• Hepatoblastoma tumoroid biobank as a key resource for tumour genetics

  Study EGAS00001008251

• WGS dataset of Hepatoblastoma tumoroid biobank as a key resource for tumour genetics

  WGS dataset of Hepatoblastoma tumoroid biobank with WGS of tumor and matched tumoroids

  Dataset EGAD00001015671

• RNAseq: Acquired non-permissive bone marrow microenvironment impairs hematopoietic stem cell proliferation and maintenance and B-cell development post-HSCT

  Defects in B-cell reconstitution upon hematopoietic stem-cell (HSC) transplantation (HSCT) are a common observation, yet the mechanism remains unexplained. The bone marrow (BM) stroma, including mesenchymal stromal cells (MSCs), guides HSC maintenance and B-lymphopoiesis by secreting crucial cytokines. We report acquired, permanent, selective and complete B-cell deficiency in the context of full donor-chimerism in a patient with X-linked lymphoproliferative disease and aimed to identify the contribution of the BM-microenvironment in disrupted B-cell reconstitution post-HSCT. We studied longitudinal BM samples from the patient and his identical twin, both of whom underwent HSCT with the same donor with opposite outcomes in B-cell reconstitution. In the index patient BM, we observed progressive loss of proliferation of HSCs and a selective block at the pre-BI cell stage. In vitro modeling studies showed limited survival of patient-HSCs and a relative accumulation of pre-B cells. Patient-derived MSCs failed to support survival and proliferation of HSCs and B-cell development of healthy-HSCs which was correlated with reduced CXCL12 levels. Using bulk RNA-sequencing of MSCs and in vitro functional studies, we showed global changes in the patients’ MSCs and a progressive loss of CXCL12 expression. Indeed, survival of patients HSCs improved supplementing in vitro development culture with CXCL12, suggesting a contribution of defective CXCL12 signaling to the phenotype. In summary, our data show that an acquired defect in the BM-stromal microenvironment and exhaustion of HSCs and committed progenitors may cause a permanent non-permissive state for normal B-cell development.

  Study EGAS50000001437

• The genomic landscape of lung adenocarcinoma in East Asians

  We performed exome sequencing of 210 and transcriptome sequencing of 181 LUADs of Chinese patients. For more details, please see publication "Genomic landscape of lung adenocarcinoma in East Asians" by Chen J. et. al. in Nature Genetics 2020. https://www.nature.com/articles/s41588-019-0569-6.

  Study EGAS00001002941

• PFA ependymoma cancer study

  Sequencing data related the PFA ependymoma study (Michealraj et al., Cell 2020), a lethal glial malignancy of the hindbrain found in babies and toddlers.

  Study EGAS00001004312

• Patient-derived organoids as predictive models for drug testing and repurposing in glioblastoma therapy

  Glioblastoma multiforme (GBM) remains a highly aggressive brain tumor with limited treatment options and poor prognosis. Temozolomide (TMZ) is the only approved first-line therapy, but frequent resistance limits its efficacy, highlighting the urgent need for alternative treatments. Patient-derived glioblastoma organoids (GBOs) offer a promising preclinical model for personalized drug testing and therapy development.

  Study EGAS50000001221