Search Results - EGA European Genome-phenome Archive

PDAC Prognosis Biomarkers in Genomic and Transcriptomic Molecular Data

Our study was designed to identify biomarkers related to the prognosis of Pancreatic Ductal AdenoCarcinoma (PDAC) patients using genomic variants and gene expression in coding regions of the human genome (exome). PDAC is the 7th cause of cancer deaths and is among types of cancer having the poorest prognosis. To improve treatment outcomes of PDAC, biomarkers related to PDAC prognosis are needed. The goals of our study are to find genomic and transcriptomic biomarkers, which can classify prognosis subtype of PDAC patients, and eventually to predict subtypes or prognosis for each patient. In this study, we generated Whole Exome Sequencing (WES) and exome capture RNA sequencing data of 450 tumor and matched normal samples from 150 PDAC patients. Our data may be useful for understanding genomic and transcriptomic features, prognosis prediction, and precision medicine for PDAC.

Study phs002347

Lineage Plasticity and Immune Cell Heterogeneity Are Coordinately Dysregulated Through Changes in FOXA1 Expression in Bladder Cancers with Squamous Differentiation

We performed whole exome sequencing (WES) of paired, macrodissected regions of urothelial carcinoma (UC), not otherwise specified (NOS-UC) and squamous differentiation (SqD) from 21 bladder tumors in which distinct and separable NOS-UC and SqD regions were present (total 42 exomes, in addition to matched normal exomes). Mean tumor mutational burden (TMB) was higher in the SqD versus the NOS-UC regions. Consistent with the higher TMB, the SqD regions also had a higher neoantigen burden than the patient-matched NOS-UC regions. The SqD regions also exhibited higher karyotypic complexity with a higher median ploidy relative to the paired NOS-UC regions. Phylogenetic analysis of the WES data confirmed that the morphologically distinct regions of all 21 tumors arose from a shared precursor with a median of 68 (range 16 – 852) non-synonymous mutations shared between the NOS-UC and SqD regions, and the overall data were indicative of early branched evolution. As whole exome sequencing did not identify a shared mutational alteration or genomic signature unique to the SqD or NOS-UC components, we therefore performed expression profiling of separable SqD and NOS-UC regions of 12 bladder tumors from the WES cohort with RNA quality sufficient for whole transcriptome RNA-sequencing (RNAseq, total of 24 regions). Based on centroid clustering analysis of expression data, all 12 regions of SqD were basal-squamous subtype based on the TCGA molecular classification schema. Notably, 8 of the NOS-UC regions were also basal-squamous subtype, with only four pairs exhibiting discordant transcriptional subtypes (three NOS-UC regions were luminal-infiltrated, one luminal-papillary). To better quantify differences in the transcriptional profiles of the paired NOS-UC and SqD regions, we used single sample gene set enrichment analysis (ssGSEA) to assess for enrichment of luminal or basal-squamous gene expression. ssGSEA analysis revealed that the SqD regions expressed higher levels of basal-squamous genes based on the BASE47 gene set and UPK/KRT gene sets; whereas the matched NOS-UC regions expressed higher levels of luminal genes. These differences in the levels of expression of basal and luminal genes were observed even in cases in which both the NOS-UC and SqD regions were basal-squamous subtype based the TCGA molecular classification schema. Exomes from eight patients in this study have previously been deposited in dbGaP: accession number phs001783 as part of the study "Exome Recapture and Sequencing of Prospectively Characterized Clinical Specimens From Cancer Patients".

Study phs002357

Derivation and Investigation of The First Human Cell-Based Model of Beckwith-Wiedemann Syndrome

Beckwith-Wiedemann Syndrome (BWS) is the most common human imprinting disorder, and phenotypes include hepatomegaly and hepatoblastoma development. In approximately 20% of patients, this syndrome is caused by uniparental isodisomy of the paternal allele across chromosome 11p15 (pUPD11). From fibroblasts cultured from 2 BWS patients with pUPD11, we derived induced pluripotent stem cells (iPSC) and differentiated to hepatocytes to study a model of the BWS liver transcriptome through RNA-Seq. Compared to 2 similarly derived controls, we observed differential expression in insulin signaling, cell proliferation, and cell cycle pathways, indicating their potential importance in the liver overgrowth and oncogenesis associated with BWS.

Study phs002365

Genomic and Transcriptomic Markers Associated with Response to Immune Checkpoint Blockade

The neoantigen presentation score (NEOPS) study was designed to better understand molecular determinants of response to immunotherapies, including pembrolizumab and nivolumab in stage III or IV melanoma patients. From this work, we developed a composite approach to predicting neoantigens (NEOPS), which takes into account additional escape mechanisms, including HLA LOH (human leukocyte antigen loss of heterozygosity) and the impact of deleterious mutations to the antigen presentation machinery (APM), yielding an improved prediction of response to immunotherapy compared to TMB (tumor mutational burden) or neoantigen burden alone.

Study phs002388

Gene Variants in Pheochromocytoma and Paraganglioma

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors that arise from chromaffin cells in the adrenal medulla and in extra-adrenal locations, respectively. PPGL has the strongest hereditary risk of all endocrine neoplasms with about 40% of cases harboring germline mutations and another 25-30% of cases arising from somatic mutations. To date, over 20 susceptibility genes have been suggested to play a role in PPGL pathogenesis, with more genes still being researched. This project will seek to identify new candidate genes in apparently sporadic PPGLs to reveal a possible genetic background in cases without variants in known susceptibility genes. Knowledge of the genetic background and the genes involved in the pathogenesis of PPGL allows for clustering and/or development of targeted therapies for the tumors that cannot be surgically resected or tumors that have metastasized.  

Study phs002405

Chromatin Accessibility Landscape of Human Pancreatic Ductal Adenocarcinoma (PDAC)

Therapeutic options in pancreatic ductal adenocarcinoma (PDAC) are largely limited to cytotoxic chemotherapy without the benefit of molecular markers predicting response. By ATAC-seq analyses of EpCAM+ PDAC malignant epithelial cells sorted from 54 freshly resected human tumors, we discovered a signature of 1092 chromatin loci displaying differential accessibility between patients with disease-free survival (DFS) < 1 year and patients with DFS > 1 year. Using this signature, we further develop a chromatin accessibility microarray methodology termed “ATAC-Array”, an easy-to-use platform obviating the time and cost of next-generation sequencing. PDAC prognosis can be predicted by ATAC-array, which represents a low-cost, clinically feasible technology for assessing chromatin accessibility profiles.

Study phs002394

Transcriptomic Profiling of Patient Derived Alternative Lengthening of Telomeres (ALT) and Non-MYCN-Amplified Neuroblastoma Cell Lines

Patient derived neuroblastoma cell lines are excellent tools to study biology of the disease. While many previous studies sequenced neuroblastoma cell lines, there are very few ALT and non-MYCN-amplified neuroblastoma cell lines that were sequenced previously. Here, we present raw RNA sequencing data for 3 ALT (CHLA-90, SK-N-FI, COG-N-515) and 8 non-MYCN-amplified telomerase positive (CHLA-171, Felix, COG-N-579h, COG-N-615, COG-N-618h, COG-N-619h, COG-N-708h, COG-N-709) neuroblastoma cell lines. Additionally, gene expression data are provided as a supplement files.

Study phs002421

Tandem DNA Repeats Activate hTERT Gene Transcription

Multiple independent sequence variants of the hTERT locus have been associated with telomere length and cancer risks in genome-wide association studies. Here, we identified an intronic variable number tandem repeat, VNTR2-1, as an enhancer-like element, which activated hTERT transcription in a cell and chromatin-dependent manner. VNTR2-1, consisting of 42-bp repeats with an array of E-boxes, cooperated with the proximal promoter in hTERT regulation by bHLH transcription factors and maintained hTERT expression during embryonic stem cell differentiation. Genomic deletion of VNTR2-1 in MelJuSo melanoma cells markedly reduced hTERT transcription, leading to telomere shortening, cellular senescence, and impairment of xenograft tumor growth. Interestingly, VNTR2-1 lengths varied widely in human populations.  To assess the genetic polymorphism of VNTR2-1 in human populations, we analyzed genomic DNA samples of Caucasian Americans and African Americans enrolled in the Georgia Centenarian Study.  VNTR2-1 in these genomic DNA samples were PCR amplified and subjected to sequencing analysis usinb the PacBio® SMRT method. The result showed that all VNTR2-1 alleles in Caucasian Americans contained 76 or more 42-bp repeats, whereas 32% of VNTR2-1 alleles in African Americans had fewer than 76 repeats.  

Study phs002428

Development and Validation of Organoids from Fibrolamellar Carcinoma Human Cells

Fibrolamellar hepatocellular carcinoma (FL-HCC) is a rare liver tumor affecting adolescents and young adults with no history of primary liver disease or cirrhosis. We collected fibrolamellar tumor tissue and the adjacent non-tumor liver from patients at the time of surgery. We only used tumor tissue that was validated as fibrolamellar by the presence of the DNAJB1-PRKACA fusion gene. The freshly resected tissue was dissociated and grown as organoids. This yielded 21 patient-derived organoid lines. From the tumor tissue we developed twelve organoids from metastases and three from the liver tumor. Additionally, we generated six organoid lines from the adjacent non-tumor liver. The tumor organoids were all shown to recapitulate the histologic morphology, immunohistochemistry, and transcriptome of the tumor tissue from which they were derived.

Study phs002439

Wistar PDX Development and Trial Center

Overall the outcomes of patients with metastatic melanoma have improved dramatically over the last decade due to an improved understanding of the molecular drivers of this disease. In particular, multiple targeted therapy regimens have been approved for patients with a BRAFV600E/K mutation, which are present in ~50% of cutaneous melanomas. These treatments achieve clinical responses in ~80% of patients with a BRAFV600E/K mutation, thus providing proof-of-concept of the therapeutic potential for personalized therapeutic strategies. However, most of the patients will progress within 2 years of starting those therapies. Further, currently there are no targeted therapies that have been shown to be effective in patients with a wild-type BRAF. Thus, there are unmet clinical needs to develop treatments that prevent or overcome resistance to existing therapies for patients with a BRAFV600E/K mutation, and that are effective in patients without a BRAF mutation. In order to facilitate the development of new therapeutic strategies, over the last 5 years we have led a major effort to develop a broad collection of PDX models to reflect the clinical, histological, and genetic heterogeneity of this disease. Our collection of PDX models represents one of the largest collections for any human malignancy, and our initial testing demonstrates that the collection accurately recapitulates the oncogenic drivers and molecular heterogeneity that is observed in patients. This collection also includes a subset of PDX established from patients with acquired resistance to targeted therapies that have been maintained on those agents in vivo to sustain their resistant phenotype. Together these efforts have generated a robust resource to develop, refine, and prioritize new personalized combinatorial therapies for patients. Thus, we propose to establish a multi-disciplinary and multi-institutional PDTC Program focused on the use and continued expansion of our robust melanoma PDX collection to identify new therapeutic approaches that fill important clinical gaps in this disease.

Study phs002432

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