10175 results for "cancer rna-seq"

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• Mutations in the RAS/MAPK pathway drive replication repair deficient hypermutated tumors and confer sensitivity to MEK inhibition

  The RAS/MAPK pathway is an emerging targeted pathway across a spectrum of both adult and pediatric cancers. Typically, this is associated with a single, well-characterized point mutation in an oncogene. Hypermutant tumors which harbor many somatic mutations may obscure the interpretation of such targetable genomic events. We find that replication repair deficient (RRD) cancers which are universally hypermutant and affect children born with RRD cancer predisposition, are enriched for RAS/MAPK mutations (p=10-8). These mutations are not random, exist in subclones, and increase in allelic frequency over time. The RAS/MAPK pathway is activated both transcriptionally and at the protein level in patient derived RRD tumors and these tumors responded to MEK inhibition in vitro and in vivo. Treatment of patients with RAS/MAPK hypermutant gliomas reveal durable responses to MEK inhibition. Our observations suggest that hypermutant tumors may be addicted to oncogenic pathways resulting in favorable response to targeted therapies.

  Study EGAS00001005008

• A Proteogenomic Analysis of Clear Cell Renal Cell Carcinoma in a Chinese Population

  Clear cell renal cell carcinoma (ccRCC) is a common and aggressive subtype of renal cancer. Here we conduct a comprehensive proteogenomic analysis of 232 tumor and adjacent non-tumor tissue pairs from Chinese ccRCC patients. By comparing with tumor adjacent tissues, we find that ccRCC shows extensive metabolic dysregulation and an enhanced immune response. Molecular subtyping classifies ccRCC tumors into three subtypes (GP1–3), among which the most aggressive GP1 exhibits the strongest immune phenotype, increased metastasis, and metabolic imbalance, linking the multi-omics-derived phenotypes to clinical outcomes of ccRCC. Nicotinamide N-methyltransferase (NNMT), a one-carbon 38 metabolic enzyme, is identified as a potential marker of ccRCC and a drug target for GP1. We demonstrate that NNMT induces DNA-dependent protein kinase catalytic subunit (DNA-PKcs) homocysteinylation, increases DNA repair, and promotes ccRCC tumor growth. This study provides insights into the biological underpinnings and prognosis assessment of ccRCC, revealing targetable metabolic vulnerabilities.

  Study EGAS00001006005

• Multimodal immunogenomic biomarker analysis of tumors from pediatric patients enrolled to a phase 1-2 study of single-agent atezolizumab

  We report herein an extensive exploratory biomarker analysis of refractory tumors taken from pediatric patients prior to receiving atezolizumab monotherapy in the phase 1-2 iMATRIX-atezolizumab trial (NCT02541604). A high percentage of CD8+ T cells and elevated protein levels of programmed cell death ligand 1 (PD-L1) were associated with progression-free survival (PFS). T-cell receptor (TCR) sequencing revealed that diverse infiltrating TCR repertoire at baseline was prognostic. We found no associations between panel-based tumor mutation burden (TMB) or specific genetic aberrations with PFS in this study. Through a pan-cancer gene co-expression network analysis, we developed a novel tumor-agnostic Pediatric Cytotoxicity and Antigen Presentation (PedCAP) signature that was associated with improved PFS in the iMATRIX-atezo study. Our study highlights features of immune response in pediatric cancers when treated with immune checkpoint inhibitors and provides a multi-biomarker pediatric immunogram framework to guide prospective clinical trials in pediatric cancers.

  Study EGAS00001006004

• Germline TP53 mutations undergo copy number gain years prior to tumor diagnosis

  Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome associated with germline TP53 mutations. We performed whole-genome sequence (WGS) analysis of tumors from 22 TP53 mutation carriers. We observed somatic mutations affecting Wnt, PI3K/AKT signaling, epigenetic modifiers and homologous recombination genes as well as mutational signatures associated with prior chemotherapy. We identified near-ubiquitous early loss of heterozygosity of TP53, with gain of the mutant allele. This occurred earlier in these tumors compared to tumors with somatic TP53 mutations, suggesting the timing of this mark may distinguish germline from somatic TP53 mutations. Phylogenetic trees of tumor evolution, reconstructed from bulk and multi-region WGS, revealed that LFS tumors exhibit comparatively limited heterogeneity. Overall, our study delineates early copy number gains of mutant TP53 as a characteristic mutational process in LFS tumorigenesis, likely arising very early in life or in utero.years prior to tumor diagnosis.

  Study EGAS00001005982

• WGS of MAPKi acquired resistant samples from patients and PDX models

  Blocking cancer genomic instability, which generates diverse variants that enable rapid adaptations, may prevent tumor escape from therapies. We show that, after MAPK inhibitor (MAPKi) therapy in patients and patient-derived xenografts, acquired-resistant genomes of metastatic cutaneous melanoma accumulate amplicons of resistance-driver, non-homologous end-joining (NHEJ), and homologous recombination repair (HRR) genes within complex genomic rearrangements (CGRs) and extrachromosomal circular DNAs (ecDNAs). Also, chromothriptic genomic regions enrich for mutations and may engender ecDNAs and CGRs. Overall, somatic mutations within ecDNA- and CGR-amplicons enrich for HRR signatures, and, in acquired resistance, ecDNA (versus CGR) mutations enrich for APOBEC3 signatures. Breakpoint-sequence analysis suggests NHEJ as critical to double-stranded DNA break repair underlying CGR and ecDNA formation. In vivo, NHEJ-targeting by a DNA-PKCS inhibitor prevented acquired MAPKi-resistance by reducing the size of ecDNAs and CGRs early on combination treatment. Thus, targeting the cause(s), as opposed to the consequences, of genomic instability prevents acquired resistance.

  Study EGAS00001006874

• Preferential infiltration of unique Vγ9Jγ2‐Vδ2 T cells into glioblastoma multiforme

  Glioblastoma multiforme (GBM) is clinically highly aggressive as a result of evolutionary dynamics induced by cross-talk between cancer cells and a heterogeneous group of immune cells in tumor microenvironment. The brain harbors limited numbers of immune cells with few lymphocytes and macrophages; thus, innate‐like lymphocytes, such as γδ T cells, have important roles in antitumor immunity. Here, we characterized GBM‐infiltrating γδ T cells, which may have roles in regulating the GBM tumor microenvironment and cancer cell gene expression. V(D)J repertoires of tumor‐infiltrating and blood‐circulating γδ T cells from four patients were analyzed by next-generation sequencing-based T-cell receptor (TCR) sequencing in addition to mutation and immune profiles in four GBM cases. In all tumor tissues, abundant innate and effector/memory lymphocytes were detected, accompanied by large numbers of tumor‐associated macrophages and closely located tumor‐infiltrating γδ T cells, which appear to have anti-tumor activity. The immune-related gene expression analysis using the TCGA database showed that the signature gene expression extent of γδ T cells were more associated with those of cytotoxic T and Th1 cells and M1 macrophages than those of Th2 cells and M2 macrophages. Although the most abundant γδ T cells were Vγ9Vδ2 T cells in both tumor tissues and blood, the repertoire of intratumoral Vγ9Vδ2 T cells was distinct from that of peripheral blood Vγ9Vδ2 T cells and was dominated by Vγ9Jγ2 sequences, not by canonical Vγ9JγP sequences that are mostly commonly found in blood γδ T cells. Collectively, unique GBM‐specific TCR clonotypes were identified by comparing TCR repertoires of peripheral blood and intra‐tumoral γδ T cells. These findings will be helpful for the elucidation of tumor-specific antigens and development of anticancer immunotherapies using tumor-infiltrating γδ T cells.

  Dataset EGAD00001004862

• Whole genome and Whole exome sequencing of patient-derived xenograft models of endometrial cancer

  Whole genome and Whole exome sequencing of patient-derived xenograft models of endometrial cancer

  Dataset EGAD00001008326

• Comparison of sequencing assays for sensitive detection of circulating tumour DNA in stage IA-IV breast cancer

  This study compared different assays for the detection of circulating tumour DNA (ctDNA) in serial plasma from stage IA-IV breast cancer patients, targeting structural variants (SVs), single nucleotide variants (SNVs) and/or somatic copy-number aberrations (SCNAs). SV-multiplex PCR, SNV-/SV-hybrid capture, and different depths of whole-genome sequencing (WGS) were used to evaluate ctDNA levels, demonstrating concordant results. SNV-hybrid capture targeting 1,347-7,491 mutations was the most sensitive assay, detecting 67% (36/54) of samples down to an allele fraction (AF) of 0.00024%. SV-multiplex PCR, targeting 21-47 mutations, detected 63% (34/54) of samples down to 0.00047% AF and has potential as a clinical assay.

  Dataset EGAD00001008589

• Origination of Ovarian Cancer is Dependent on Specific Aneuploidy Landscape

  Ovarian high-grade serous carcinoma (HGSC), a highly chromosomally instable malignancy, develops through sequential stages of precursors in fallopian tubes including histologically unremarkable but TP53 mutated clones (p53 signature) and serous tubal intraepithelial carcinoma (STIC). Here, we applied RealSeqS to assess aneuploidy in 127 microdissected tubal regions. We found nearly all p53 signatures lost the entire Chr17 chromosome, offering a “two-hit” mechanism of both TP53 and BRCA1 in BRCA1 germline mutation carriers. Proliferatively active STICs harbor gains of 19q12 (CCNE1), 19q13.2, 8q24 (MYCyc), or 8q arm, while proliferatively dormant STICs show 22q loss. Based on aneuploidy patterns in a training set (n= 67), we developed an algorithm, REAL-FAST, to classify NFTE and STICs into 5 clusters. In an independent validation set (n= 72), REAL-FAST was able to detect STIC/HGSC with high sensitivity and specificity. Taken together, REAL-FAST promises a molecular test for diagnosing HGSC precursor lesions based on specific aneuploidy patterns.

  Study EGAS00001007220

• Unraveling mutagenic processes influencing the tumor mutational patterns of individuals with Constitutional Mismatch Repair Deficiency

  Constitutional mismatch repair deficiency (CMMRD), caused by bi-allelic germline variants in one of the mismatch repair (MMR) genes, is a childhood cancer predisposition syndrome that often results in the development of multiple tumors early in life. A better understanding of mutational processes driving subsequent CMMRD tumors could advance optimal treatment. Therefore, we performed a genomic characterization of 41 tumors from 17 individuals with CMMRD. Mutational patterns in these tumors were found to be influenced by multiple factors, including the affected MMR genes, tumor types and somatic polymerase proofreading mutations. Temozolomide treatment left prominent mutational signatures in two second primary hematologic malignancies. Furthermore, a novel indel signature was found in 54% of the tumors, characterized by one base pair cytosine insertions in cytosine homopolymers. In conclusion, the analysis of sequential tumors in individuals with CMMRD reveals diverse mutational patterns influenced by the underlying mutated MMR gene, tumor type and treatment history.

  Study EGAS00001007660