12400 results for ""statistically+reactive"+taxa+in+microbial+community"

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• A Phase I Study With a Personalized Neoantigen Cancer Vaccine in Glioblastoma Multiforme

  Neoantigens, which are derived from tumor-specific protein-coding gene mutations, are exempt from central tolerance, can generate robust immune responses and function as bona fide antigens that facilitate tumor rejection. A strategy of using multi-epitope and personalized neoantigen vaccination has previously been tested in patients with high-risk melanoma. We demonstrated that this strategy is feasible for glioblastoma (GBM) which typically has a relatively low mutation load and an immunologically 'cold' tumor microenvironment. We conducted whole exome sequencing (WES) of tumor and normal cells from individual GBM patients to identify tumor-specific mutations. We assessed the expression of mutated alleles by RNA-sequencing of tumor, and used personalized neoantigen-targeting vaccines to immunize newly diagnosed GBM patients following surgical resection and conventional radiotherapy in a phase I/Ib study. Patients who did not receive dexamethasone, a highly potent corticosteroid that is frequently prescribed to treat cerebral oedema in GBM patients, generated circulating polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses that were enriched in a memory phenotype and showed an increase in the number of tumor-infiltrating T cells. Using single-cell T cell receptor analysis, we provided an evidence that neoantigen-specific T cells from the peripheral blood can migrate into an intracranial GBM tumor. Neoantigen-targeting vaccines thus have the potential to favorably alter the immune environment of GBM.In order to discover cancer antigens derived from annotated and unannotated protein-coding regions of the genome, we carried out matched ribosome profiling (Ribo-Seq) on two GBM samples. We discovered novel or unannotated open reading frames (nuORFs) and their expression levels as well as somatic mutations within the nuORFs, which could be used to predict potential neoantigens.

  Study phs001519

• Cell-Free DNA Genomic and Fragmentomic Features for Early Outcome Prediction in Diffuse Large B-Cell Lymphoma

  Purpose: Diffuse large B-cell lymphoma (DLBCL) patients need an accurate and early risk stratification strategy as prompt therapy escalation may improve outcome. Patients and methods: We evaluated cell free DNA (cfDNA) genomic and fragmentomic features in 190 patients with large B-cell lymphoma from more than 40 hospitals in the Benelux using Whole Genome Sequencing (WGS). We defined a new metric called ACT score (Aberrations, Contribution of short fragments, Terminal motif analyses) by combining four cfDNA signals and evaluated its performance to predict end-of-treatment (EOT) response and survival. Results: Individual cfDNA features and ACT score were altered per EOT response after one cycle of treatment (T1). The ACT score at T1 outperformed all individual cfDNA features in predicting EOT response (AUC = 0.74). Patients with a positive ACT score had an inferior outcome compared to ACT score negative patients [progression-free survival (PFS): HR 5.0 (95% CI 3.1-8.2), log-rank test, p < 0.0001) and overall survival (OS): HR 6.5 (95% CI 3.5-12.2), log-rank test, p < 0.0001]. The 2-year PFS in ACT score positive and negative patients were 29.8% and 78.1%, respectively. The prognostic value of the ACT score is independent of the International Prognostic Index and interim imaging. Conclusions: ACT score computed from a single plasma sample collected after one cycle of treatment can predict clinical outcome. This low-cost and easy-to-interpret test does not require tissue biopsies or a priori knowledge of mutations and has the potential to aid patient selection in interventional clinical trials and risk-adapted treatment strategies.

  Study EGAS50000000412

• A Multifactorial Tumor and Immune Cell Profile Determines Response to Immune Checkpoint blockade in Melanoma

  The complex crosstalk between tumor and immune cells during immune checkpoint blockade mandates the development of integrated models that interpret the anti-tumor immune response and predict clinical outcome. We have integrated genome-wide sequence and structural alterations with pre and on-therapy transcriptomic and T cell repertoire features for a cohort of 64 immunotherapy-naïve melanomas treated with anti-PD1 monotherapy or combined anti-PD1 and anti-CTLA4 therapy. While tumor mutation burden (TMB) was associated with improved response to therapy, expressed mutation burden was superior to TMB in predicting outcome. An increased pre-existing T cell density differentiated responding from non-responding tumors independent of therapy. Importantly, T cell repertoire reshaping determined by T cell receptor (TCR) clonotypic regressions and expansions reflected response to therapy such that a more dynamic repertoire predicted improved clinical outcome. Through whole-transcriptome analyses, we discovered differential abundance of B cell subsets in responding tumors, which highlights the importance of the interplay between pre-existing T and B cell immunity in shaping therapeutic response. Tumor temporal trajectories during therapy revealed distinct patterns of molecular response related to expressed mutation elimination or retention that accurately interpreted clinical response. High-dimensional genomic, transcriptomic and immune repertoire data were integrated by both a machine learning and a censored regression approach, resulting in a harmonized multi-modal predictor of response to immune checkpoint blockade. B cell abundance, expressed mutation load and tumor aneuploidy were combined to identify patients at high risk for recurrence, such that high risk patients had a significantly shorter progression-free survival (HR=9.18, 95% CI: 3.14-26.85, p=3.4e-06) especially in the anti-PD1/anti-CTLA4 group (HR=20.34, 95% CI: 4.08-101.32, p=1.68e-06).

  Study EGAS00001004548

• Stromal-induced epithelial-mesenchymal transition induces drug resistance in acute lymphoblastic leukemia

  Bone marrow (BM) microenvironment-induced drug resistance in acute lymphoblastic leukemia (ALL) is thought to be mediated by intercellular interaction of leukemic cells with BM niches, but the mechanistic basis of resistance is poorly understood. Here, we genomic and functional analyses, we show that ALL-BM mesenchymal stromal cells (MSC) interactions encompass direct cell-cell adhesion via integrin α4β1, uni-directional secretion of soluble factors from MSC to ALL, and bidirectional transfer of cellular vesicles through tunneling nanotubes. We show that this crosstalk drives an epithelial-mesenchymal transition (EMT)-like program in ALL cells adhering to MSC, thereby triggering stem cell-like features including drug resistance and survival advantage. Moreover, single-cell RNA sequencing of cell line and primary ALL samples identified a hybrid cell state derived from B-ALL adhered to MSC, that exhibits both B-ALL and MSC gene signatures that are orchestrated by an EMT-like program. Multiple EMT-activating pathways including WNT/β-catenin, cytokine/STAT3, TGFβ, NOTCH1, and NF-κB-dependent signaling pathways are activated in MSC-adherent ALL cells; however, only the inhibition of either WNT/β-catenin or cytokine/STAT3 pathway could attenuate the survival and drug resistance of ALL cells adherent to MSC. Notably, we identified that this hybrid cell state exhibited elevated WNT/β-catenin-mediated transcriptional activity. Finally, we show that blocking of the interaction of β-catenin and CBP interaction abrogates the survival and drug resistance of ALL cells adhered to MSC, indicating that targeting of an EMT-like program is potential therapeutic regimen in targeting cell extrinsically acquired drug resistance in ALL.

  Study EGAS00001006120

• 1 Intratumoral genetic heterogeneity and clonal evolution following neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal tumors.

  Purpose: Neoadjuvant chemoradiotherapy (nCRT) is the standard treatment forpatients with locally advanced rectal cancer. However, little is known about the effect of nCRT in the mutational landscape and intratumoral genetic heterogeneity (ITGH) of rectal tumors. Moreover, response to nCRT vary substantially among patients and the genetic determinants of treatment response are not fully understood. Here, we sought to determine the impact of nCRT in the mutational landscape and ITGH of rectal tumors and to identify putative drivers of therapeutic resistance. Patients and Methods: We analyzed whole-exome sequencing (WES) and clinical data from 79 primary non-treated rectal cancers obtained from The Cancer Genome Atlas (TCGA). We also compared the mutational landscape of a matched set of peripheral blood cells, irradiated tumor-adjacent colonic mucosa and pre and post-treatment tumor samples to determine the iatrogenic effects of nCRT and its impact in tissue genetic heterogeneity. Finally, we performed WES of 7 matched pre and post-treatment tumor samples to examine how nCRT affects the clonal architecture of rectal tumors. Results: We show that rectal tumors exhibit remarkable ITGH, which increases with disease progression. We also show that nCRT, per se, does not introduce novel somatic mutations, nor alters the clonal architecture of the irradiated colonic mucosa. Instead, we show that it acts as a potent selective pressure, favoring the expansion of tumor cell subpopulations more prone to resist therapy and increasing ITGH in the residual tumor. Conclusion: Our results reveal the highly heterogeneous and dynamic clonal architecture of rectal tumors undergoing nCRT. Our results also uncover putative genetic determinants of response to nCRT and a possible role for ITGH in predicting treatment outcome.

  Study EGAS00001003250

• Evolutionary dynamics of residual disease in human glioblastoma

  Glioblastoma is the most common and aggressive adult brain malignancy against which conventional surgery and chemoradiation provide limited benefit. Even when a good treatment response is obtained, recurrence inevitably occurs either locally (c.80%) or distally (c.20%), driven by cancer clones that are often genomically distinct from those in the primary tumour. Glioblastoma cells display a characteristic infiltrative phenotype, invading the surrounding tissue and often spreading across the whole brain. We hypothesised that cancer cells responsible for relapse reside in two compartments of residual disease that are left behind after treatment: the infiltrated normal brain parenchyma, and the sub-ventricular zone (SVZ). In this model, residual disease subclones diverge early during glioblastoma evolution, may remain dormant in the normal parenchyma and are responsible for recurrence. To test our hypothesis, we performed whole-exome sequencing of 69 multi- region samples collected using fluorescence-guided resection from 11 patients, including the infiltrating tumour margin (M) and the SVZ for each patient, as well as matched blood. We used a phylogenomic approach to dissect the spatio-temporal evolution of each tumour and unveil the relation between residual disease and the main tumour mass. We also analysed two patients with paired primary-recurrence samples with matched residual disease. Our results suggest that the infiltrative phenotype is an early evolutionary trait of glioblastoma, giving rise to the tumour mass detected at surgery. After treatment, the same infiltrative clone may seed the growth of a recurrent tumour, thus representing the ‘missing link’ between the primary tumour and recurrent disease. These results are consistent with recognised clinical phenotypic behaviour and suggest that more specific therapeutic targeting of cells in the infiltrated brain parenchyma may improve patient’s outcome.

  Study EGAS00001003043

• The Immune Microenvironment, Genome–Wide Copy Number Aberrations and Survival in Mesothelioma

  IntroductionResults of recent clinical studies of immune checkpoint inhibitors in malignant pleural mesothelioma (MPM) have dampened initial enthusiasm. However, the immune environment and targets of these treatments such as program cell death protein 1 (PD-1) and its ligand PD-L1 have not been well characterised in MPM. Using a large cohort of patients, we investigated PD-L1 expression, immune infiltrates and genome-wide copy number status and correlated them to clinicopathological features.Patients and methodsTissue microarrays were constructed and stained with PD-L1(clone E1L3N, CST), CD4, CD8 and FOXP3 antibodies. PD-L1 positivity was defined as ≥5% membranous staining regardless of intensity and PD-L1+hi as ≥50%. Genomic DNA from a representative subset of 113 patients was used for genome-wide copy number analysis. The percent genome alteration (PGA) was computed as a proxy for genomic instability, and statistical analyses were used to relate copy number aberrations (CNA) to other variables.ResultsAmongst 329 patients evaluated, PD-L1+ was detected in 130/311 (41.7%), but PD-L1+hi was only seen in 30/311 (9.6%). PD-L1+ correlated with non–epithelioid histology and increased infiltration with CD4+, CD8+ and FOXP3+ lymphocytes. PD-L1+hi expression correlated with worse prognosis (HR = 2.37; 95%CI= 1.57-3.56; P &lt; 0.001) on univariate analysis, but not in multivariate analysis. Higher PGA was associated with epithelioid histology and poorer survival (HR = 1.59; 95%CI= 1.01-2.5; P = 0.04), but not PD-L1 expression.ConclusionPD-L1 expression was associated with non-epithelioid MPM, poor clinical outcome and increased immunological infiltrates. Increased genomic instability did not correlate with PD-L1 expression, but was associated with poorer survival.

  Study EGAS00001002323

• Survival Benefit and Genetic Profile of Pemetrexed as Initial Chemotherapy in Selected Chinese Patients with Advanced Lung Adenocarcinoma

  We retrospectively collected patients (n=1047) enrolled in the Chinese Patient Assistance Program from multiple centers who received pemetrexed alone or combined with platinum as initial chemotherapy and continued pemetrexed maintenance therapy for advanced lung adenocarcinoma from November 2014 to June 2017. The outcomes were duration of treatment (DOT) and overall survival (OS). Clinical features were analyzed for their influence on the treatment effect and prognosis. Next-generation sequencing (NGS) was performed to identify genetic biomarkers associated with the efficacy of pemetrexed. The median DOT was 9.1 months (95% CI: 8.5-9.8), and the median OS was 26.2 months (95% CI: 24.2-28.1). OS was positively correlated with DOT (r=0.403, P&lt;0.001). Multivariable analysis showed that smoking status and Eastern Cooperative Oncology Group (ECOG) performance status (PS) were independently associated with DOT; smoking status, ECOG PS, targeted therapy, and EGFR/ALK/ROS1 status were independently associated with OS. NGS in 22 patients with available samples showed genes with high mutation rates were: TP53 (54.5%), EGFR (50.0%), MYC (18.2%), PIK3CA (13.6%). When grouped based on progression-free survival (PFS) reported in the PARAMOUNT study, the DOT &gt;6.9 months set was associated with PIK3CA, ALK, BRINP3, CDKN2A, CSMD3, EPHA3, KRAS, and RB1 mutations, while ERBB2 mutation was observed only in the DOT ≤6.9 months set. This study shows that initial chemotherapy with pemetrexed is an effective regimen for advanced lung adenocarcinoma in selected Chinese patients. There is no specific genetic profile predicting the benefit of pemetrexed found by NGS. Biomarkers predicting the efficacy of pemetrexed need further exploration.

  Study EGAS00001004546

• Genetic immune escape landscape in primary and metastatic cancer

  Immune surveillance escape is a hallmark of tumorigenesis1. Multiple studies have characterized the immune escape landscape across several untreated early-stage primary cancer types2–4. However, whether late-stage treated metastatic tumors present differences in genetic immune escape (GIE) prevalence and dynamics remains unclear. Here, we performed a pan-cancer characterization of GIE prevalence across six immune escape pathways in 6,457 uniformly processed Whole Genome Sequencing (WGS) tumor samples including 58 cancer types from 1,943 primary untreated patients and 4,514 metastatic patients. To effectively address the complexity of the Human Leukocyte Antigen (HLA-I) locus and to characterize its tumor status, we developed LILAC, an open-source integrative framework. We demonstrate that one in four tumors harbor GIE alterations, with high mechanistic and frequency variability across cancer types. GIE prevalence is highly consistent between primary and metastatic tumors for most cancer types with few exceptions such as prostate and thyroid carcinomas that have increased immune evasion frequencies in metastatic tumors. Positive selection analysis revealed that GIE alterations are frequently selected for in tumor evolution and that focal LOH of HLA-I, unlike non-focal LOH of HLA-I, tends to lose the HLA allele that presents the largest neoepitope repertoire. We also unraveled tumor genomic features contributing to immune escape incidence, including DNA repair deficiency, APOBEC activity, tobacco associated mutation load and viral DNA integration. Finally, there is a strong tendency for mid and high tumor mutation burden (TMB) tumors to preferentially select LOH of HLA-I for GIE whereas hypermutated samples favor global immune evasion strategies. Our results indicate that genetic immune escape is generally a pre-metastatic event during tumor evolution and that tumors adapt different strategies depending on their neoepitope burden.

  Study EGAS00001006123

• Dynamics of circulating tumor DNA in acute myeloid leukemia (AML) patients who undergo allogeneic transplantation

  Allogeneic hematopoietic cell transplantation (allo-HCT) is the only curative option for many patients with acute myeloid leukemia (AML). With the increasing use of non-myeloablative conditioning regimens, it is widely assumed that the cytotoxic conditioning itself does not eradicate all leukemia cells. Instead, the donor-derived immune cells are believed to eliminate residual leukemia cells over time. This so-called graft-versus-leukemia (GvL) is postulated to be the primary mechanism by which allo-HCT achieves sustained remissions in patients with AML. However, the precise quantification of GvL effects and its contribution to leukemia eradication has not yet been demonstrated by sequential, highly sensitive measurements of residual disease at various time points following allo-HCT. In the current study, we employed a novel, highly sensitive and specific plasma-based assay to track mutations in the leukemia cells of 14 patients before and after allo-HCT. If the primary therapeutic benefit of allo-HCT is truly mediated through a GvL effect, we hypothesized that leukemia cells would persist following cytotoxic conditioning and would often be reduced after post-transplant immunosuppression was discontinued. In the majority of patients (11 of 14, 79%), the conditioning used for allo-HCT did not eradicate the leukemia cells. In seven of these 11 patients, the leukemia cells persisted until immunosuppression was discontinued, at which time the persistent leukemia cells were reduced or eradicated. These results demonstrate the feasibility of using circulating tumor DNA (ctDNA) as a dynamic marker of GvL as well as minimal residual disease for patients with AML undergoing alloHCT, and have substantial implications for their management.

  Study EGAS00001007969