Search Results - EGA European Genome-Phenome Archive

Tamoxifen Response at Single Cell Resolution in Estrogen Receptor Positive Primary Human Breast Tumors

Primary breast tissue, normal and cancerous, was collected immediately after resection. The tissue was dissociated and treated with 10uM tamoxifen or control media for 12 hours in suspension. Single cell libraries were then created using a 10x Genomics gel bead droplet-based kit and sequenced via Illumina sequencing platforms. Differences in cell response to tamoxifen was observed between cell types and distinct responsive and unresponsive cell populations were determined.

Study phs003186

Overcoming Clinical Resistance to EZH2 Inhibition Using Rational Epigenetic Combination Therapy

Essential epigenetic dependencies have become evident in many cancers. Based on functional antagonism between BAF/SWI/SNF and PRC2 in SMARCB1-deficient sarcomas, we and colleagues recently completed the clinical trial of the EZH2 inhibitor tazemetostat, leading to its FDA approval. However, the principles of tumor response to epigenetic therapy in general and tazemetostat in particular remain unknown. Using functional genomics of patient tumors and diverse experimental models, we defined molecular mechanisms of tazemetostat resistance. We found distinct classes of acquired mutations that converge on the RB1/E2F axis, decoupling EZH2-dependent differentiation and cell cycle control. This allows tumor cells to escape tazemetostat-induced G1 arrest despite EZH2 inhibition and suggests a general mechanism for effective EZH2 therapy. Using RNA-sequencing of patient tumor specimens, we identified specific genes as markers of a deficient RB1/E2F axis, which we propose as prospective biomarkers for therapy stratification. This offers a paradigm for rational epigenetic combination therapy suitable for immediate translation to clinical trials.This study was performed on archived tumor tissue collected as part of the above clinical trial at Memorial Sloan Kettering Cancer Center. Patient tumors were classified into "Response" or "Progression" groups based on RECIST 1.1 criteria. "Response" included tumors exhibiting a complete response, partial response, or stable disease. All other tumors were classified under the "Progression" group. Archived frozen tumor samples were weighed and up to 20-30mg were homogenized in RLT buffer, followed by extraction using the AllPrep DNA/RNA Mini Kit (QIAGEN catalog 80204) according to the manufacturer's instructions. RNA was eluted in 13 μL nuclease-free water. After RiboGreen quantification and quality control by Agilent BioAnalyzer, 1 μg of total RNA with DV200 percentages varying from 78% to 100% underwent ribosomal depletion and library preparation using the TruSeq Stranded Total RNA LT Kit (Illumina catalog RS-122-1202) according to instructions provided by the manufacturer with 8 cycles of PCR. Samples were barcoded and sequenced using NovaSeq 6000 in a PE150 mode, with the NovaSeq 6000 S4 Reagent Kit (Illumina). On average, 84 million paired reads were generated per sample and 70% of the data mapped to mRNA. For analysis, read adaptors were trimmed and quality filtered using 'trim_galore' and mapped to GRCh38/hg19 reference genome using STAR v2.7.9 with default parameters.

Study phs003188

Extrachromosomal DNA Amplification Contributes to Small Cell Lung Cancer Heterogeneity and is Associated with Worse Outcomes

Small-cell lung cancer (SCLC) is a very aggressive neuroendocrine lung cancer often associated with oncogenic MYC amplifications, which are known to drive SCLC heterogeneity marked by neuroendocrine (NE) and non-neuroendocrine (non-NE) cell states. The genetic mechanisms of MYC amplification and phenotypic plasticity between cell states is not known. Using data from cell-lines and a few patient-derived samples along with integrated whole-genome sequencing, long-range optical mapping, single-cell DNA sequencing, and fluorescence in situ hybridization, we have attempted to successfully characterize extrachromosomal DNA (ecDNA) as the primary source of MYC amplifications and driver fusions in SCLC.

Study phs003190

RNA Splicing Dysregulation in the Pathogenesis of Chronic Lymphocytic Leukemia

RNA splicing dysregulation is a hallmark of cancers, promoting the onset and progression of disease. In chronic lymphocytic leukemia (CLL), spliceosome mutations leading to aberrant splicing occurs in approximately 20% of patients. However, the underlying mechanism for splicing defects in spliceosome unmutated CLL cases remains elusive. To discover posttranscriptional regulation of RNA splicing, we performed RNA sequencing using RNA derived from B cells from 6 healthy donors and 36 CLL patients, along with MAZTER sequencing from 9 CLL patients (8 matched with RNA sequencing cohort) and B cells from 5 healthy donors. We found that CLL cells have dysregulated m6A modification sites on transcripts from splicing factors, suggesting a critical role of m6A modification in RNA splicing dysregulation.

Study phs003191

Genomic Analysis of Prostate Tumor Heterogeneity in Metastasis

To investigate the molecular changes, mutations, and signaling pathways that characterize the initial steps of prostate cancer metastasis to the lymph nodes, we analyzed 19 discrete lymph node (LN) metastases, 97 primary tumor foci, 39 benign lymph nodes, and 10 normal adjacent prostate tissue samples from 43 patients enrolled in a clinical trial (NCT01808222) of extended lymphadenectomy and metastasis excision guided by [18F]-fluciclovine PET imaging for high risk, newly diagnosed prostate cancer conducted at Emory University. These patients fell within high or very high-risk groups (T3a, Gleason score 8-10, or PSA greater than 20 ng/ml). Of these patients, 16 had LN metastases at least 4 mm in diameter, and 20 patients had no metastases. For metastatic patients, we performed RNA and Whole Exome Sequencing (WES) on three primary tumor foci, one benign LN, and all LN metastases greater than 4mm in diameter. For non-metastatic patients, we sequenced two primary tumor foci and one benign LN. In total, RNAseq was performed on 165 tissue samples from 43 patients, and WES was performed on 137 samples from 35 patients.

Study phs003404

Genomic Analyses of Germline and Somatic Variation in High-Grade Serous Ovarian Cancer

The goal of this study was to identify and characterize germline and somatic genetic variation in women with high grade serous ovarian cancers treated at a single cancer center and their associations with relapse-free and overall survival. We conducted paired tumor/normal targeted next-generation sequencing of 577 genes in pathways of DNA repair, response to DNA damage, cell-cycle regulation, programmed cell death, MAPK, and P13K/AKT/MTOR signaling in 114 tumors from 71 women. In addition, we investigated single copy number alterations (SCNAs) and loss of heterozygosity in a subset of 61 tumors. We validated our results with data from ovarian tumors in TCGA. Our results were similar to other studies of high-grade serous carcinomas. As an example, we found that approximately one third of the tumors harbored loss of function variants in homologous recombination genes and that >90% had TP53 somatic mutations. Through GISTIC analysis of the OncoScan data on tumor DNA from 61 cases, we identified several regions of high copy number alterations including including NOTCH3 and PIK3R2 that were significantly associated with an increase in cancer recurrence and a reduction in overall survival. We identified few changes in mutation profiles where we had multiple tissues, either from multiple surgeries or from the primary site to metastatic sites within the same surgery. However, we did not investigate copy number alterations in multiple tissues from the same individuals, and so it may be that copy number alterations are more important. Data available through dbGAP will be the BAM files and the phenotypic data on the tumor samples, the age, race, ethnicity of the participants and their outcomes, and the Oncoscan OSCHP files.

Study phs003198

RNA-Seq Data From Early Stage Triple Negative Breast Cancer Tumors Treated With TVEC and Chemotherapy (MCC18621)

This study is a phase 1/phase 2 trial testing the combination of talimogene laherparepvec (TVEC) and neoadjuvant chemotherapy for the treatment of stage II-III triple negative breast cancer. The trial demonstrated that the addition of TVEC to neoadjuvant chemotherapy was feasible, and resulted in a pathological complete response (pCR) rate of 45.9%, residual cancer burden (RCB) 0-1 rate of 65%, and event free survival of 89%. The macrodissected formalin-fixed paraffin-embedded (FFPE) samples were from 50 patients treated across two phases at different timepoints (pre-treatment, 6th week of treatment, and surgical resection). RNA-Seq data is provided along with clinical classifiers.

Study phs003199

E5103 Correlative Studies

ECOG-ACRIN E5103 (E5103) was a phase III adjuvant breast cancer trial that randomized 4994 patients with node-positive or high-risk node-negative breast cancer to intravenous doxorubicin and cyclophosphamide every 2 or 3 weeks (at the discretion of treating physician), for four cycles of adriamycin and cyclophosphamide (AC) followed by 12 weeks of weekly paclitaxel (80 mg/m2) alone (Arm A), or to the same chemotherapy with either concurrent bevacizumab (Arm B), or concurrent plus sequential bevacizumab (Arm C). To develop predictive genetic biomarkers for chemotherapy efficacy and toxicities, we have successfully performed genome-wide genotyping and whole exome sequencing in the germline (blood) DNA of 3215 and 672 patients, respectively, from the E5103 trial to investigate the association of genetic variants with chemotherapy efficacy and toxicities. Case and control studies were performed with genome-wide analyses (GWAS) and whole exome analyses (WES) across all arms of E5103 to identify genotypes at single-nucleotide polymorphisms (SNPs) and deleterious gene mutations that were associated with paclitaxel-induced peripheral neuropathy (TIPN). Through GWAS, we have identified a SNP, rs3125923, and through WES, Cytochrome P450 oxidoreductase (POR), that was significantly associated with grade 3-4 TIPN.

Study phs003201

Melbourne Collaborative Cohort Study DNA Methylation Studies

This dataset contains raw Illumina 450K blood DNA methylation data from a subset of participants in the Melbourne Cohort Study (MCCS), a prospective study of 41,513 healthy adult volunteers (24,469 women) aged between 27 and 76 years when recruited between 1990 and 1994. Nested case-control studies: DNA methylation data were generated as part of cancer case-control studies nested in the MCCS. Participants were cancer-free at blood draw; blood samples were taken at baseline (1990-1994) for 97% of participants; and for 3% of participants at the second wave of follow-up (2003-2007). Eight separate studies were conducted of breast, prostate, colorectal, lung, kidney, urothelial and gastric cancer and B-cell lymphoma, for a total of > 3,500 cancer cases. Controls were individually matched to cases on age, sex, and country of birth using incidence density sampling. Additional matching on smoking history was made for the study of lung cancer. Longitudinal study: For a subset of 1,100 participants with baseline DNA methylation measures (from dried blood spots) who were selected as controls in the nested case-control studies, repeated methylation measures were made using wave 2 follow-up samples (also from dried blood spots) to study longitudinal DNA methylation changes. Project aims: 1. Nested case-control studies: To assess prospective associations between peripheral blood DNA methylation and risk of eight cancer types (breast, prostate, colorectal, lung, kidney, urothelial cell and gastric cancer, and mature B-cell neoplasms). 2. Longitudinal study: To assess associations between lifestyle changes and changes in peripheral blood DNA methylation.

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Molecular Determinants of Esophageal Cancer in Tanzania

We describe the genomic profiles of 61 esophageal squamous cell carcinoma (ESCC) cases from Tanzania and compare them to profiles from an existing cohort of ESCC cases from Malawi. We also provide a comparison to ESCC tumors in The Cancer Genome Atlas Program (TCGA). Despite a high burden of ESCC in Eastern Africa, investigations into the genomics in this region are nascent. This represents the largest comprehensive genomic analysis of ESCC from sub-Saharan Africa to date. We observed substantial transcriptional overlap with other squamous histologies via comparison with TCGA PanCan dataset. DNA analysis revealed known mutational patterns, both genome-wide as well as in genes known to be commonly mutated in ESCC. TP53 mutations were the most common somatic mutation in tumors from both Tanzania and Malawi but were detected at lower frequencies than previously reported in ESCC cases from other settings. In a combined analysis, two unique transcriptional clusters were identified: a proliferative/epithelial cluster and an invasive/migrative/mesenchymal cluster. Mutational signature analysis of the Tanzanian cohort revealed common signatures associated with aging and cytidine deaminase activity and an absence of signature 29, which was previously reported in the Malawi cohort.

Study phs003217

Whole Exome Sequencing and RNA-Seq to Characterize the Somatic Breast Cancer Landscape Among Latinas in California

Somatic mutational profiles are increasingly being used to guide treatment. However, there is a dearth of data from non-European populations. To address this gap, we conducted paired tumor/normal whole exome paired-end sequencing and tumor RNA-Seq on 146 breast tumors from 140 Hispanic/Latina (H/L) women with breast cancer. We characterized somatic mutations, copy number alterations, tumor subtypes [Prediction Analysis of Microarray 50 (PAM50)], Catalogue Of Somatic Mutations In Cancer (COSMIC) mutation signatures and expression profiles, and compared them to breast tumors from non-Hispanic White (White) women in The Cancer Genome Atlas (TCGA). Using MutSigCV, we found that the most commonly mutated genes, including TP53, RUNX1, PTEN, PIK3CA, MAP3K1, GATA3, CDH1 and CBFB, were similar to those in breast tumors from non-Hispanic white women. Novel findings were that outliers of BLTP2 (aka KIAA0100) over-expression and COSMIC mutational signature 16 were more common in tumors from H/L women than White women. We also identified that the known germline APOBEC3A/B deletion variant was significantly more common in H/L women and was associated with indigenous American ancestry. Data available through dbGaP will be whole-exome sequencing (WES) and RNA sequencing (RNA-Seq) data, as well as phenotypic data, including estrogen receptor, progesterone receptor, and HER2 receptor status, tumor histology, stage, and grade, and age at diagnosis.

Study phs003218

Hi-C Profiling of Solid Tumor Samples

Structural variants, such as translocations, inversions, duplications, and deletions, have long been recognized as mutations that can contribute to the initiation and progression of cancer. This can occur through a variety of mechanisms, including changes in gene dosage and the generation of fusion genes. In recent years, it is becoming increasingly clear that these events also can alter how genomes are organized in 3D space in the nucleus and contribute to changes in enhancer-promoter regulation. However, it remains poorly understand how often 3D genome structural changes occur in cancers, what genes are affected by these events, and in which tumor types. This study is part of ongoing work to better characterize 3D genome structural changes across a variety of tumor types to better understand where and when 3D genome structure changes as the result of structural variation in cancer genomes and to characterize the genes and tumor types affected.

Study phs003227

Single Cell Genotypic and Phenotypic Analysis of Measurable Residual Disease in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a group of blood cancers with high mortality. Even though complete remission is often achieved, majority of the AML patients still relapse. Measurable residual disease (MRD), defined as the population of cancer cells which persists following chemotherapy, is responsible for AML relapse. Understanding the biology enabling MRD clones to resist therapy is necessary to guide the development of curative treatments more effectively. Discriminating residual leukemic clones, preleukemic clones, and normal precursors remains a challenge with current MRD tools. We developed a single cell MRD (scMRD) assay by combining flow cytometric enrichment of the targeted precursor/blast population with integrated single cell DNA sequencing (scDNA-seq) and immunophenotyping (Tapestri, Missionbio). The platform utilizes a custom amplicon panel covering 109 amplicons across 31 genes frequently mutated in AML and a panel of 42 oligo-conjugated antibodies against surface makers. We applied our scMRD assay to sequence 30 MRD samples (multiplexed into 6) from 29 AML patients to study the clonal architecture and protein correlation. In addition, 2 MRD samples were sequenced with scDNA+protein sequencing technology without enrichment or multiplexing. Five patients with AML at diagnosis were also sequenced with scDNA+protein sequencing technology without enrichment or multiplexing. In order to establish the sensitivity of our scMRD assay, we spiked AML cells into normal bone marrow cells. We sequenced 12 such spiked samples after multiplexing.

Study phs003233

Deterministic Evolution and Stringent Selection During Pre-Neoplasia

The earliest events during human tumor initiation are poorly characterized but may hold clues as to how to detect and prevent malignancy. Here we model this occult process by engineering TP53 deficiency in primary human gastric organoids and performing experimental evolution in multiple clonally derived cultures over two years, thereby defining causal relationships between this common initiating genetic lesion and resulting phenotypes. TP53 loss induced progressive aneuploidy, including copy number alterations and complex structural variants that are common in established gastric cancers, and which accrued along a defined temporal order. Longitudinal single cell sequencing of TP53 deficient gastric organoids similarly indicates progression towards malignant transcriptional programs. Moreover, lineage tracing with expressed cellular barcodes revealed highly reproducible dynamics whereby initially rare subclones with shared transcriptional programs repeatedly attain clonal dominance. This powerful platform for experimental evolution reveals stringent selection and convergence at the genotypic and phenotypic levels in pre-malignant epithelial organoids, illuminating evolutionary constraints and barriers to malignant transformation.

Study phs003249

Genetic Analysis of Skin Cells

Cutaneous squamous cell carcinoma (cSCC) is a form of skin cancer originating from keratinocytes in the skin. They have high mutation burdens, primarily driven by UV-radiation-induced DNA damage. The order in which mutations undergo selection during the evolution of cSCC is not known. A subset of cSCCs grow out of benign neoplasms called actinic keratoses. To better understand the evolution of cSCC, we identified cases of cSCCs adjacent to actinic keratoses. From these cases, we separately microdissected the surrounding normal skin, the actinic keratosis, and the cSCC, and we performed targeted DNA-sequencing on the tissue from each area. We reconstructed tumor phylogenies and performed spatial transcriptomics on the 10X FFPE Visium platform on a subset of cases. Collectively, these studies revealed the mutational and gene expression changes that arise during the evolution of cSCC.

Study phs003282

Investigating the Role of Neddylation in the Repair of Topoisomerase I-Mediated DNA Damage in Colorectal Cancer

Colorectal cancer is one of the most lethal cancers worldwide. First-line chemotherapy for metastatic CRC (mCRC) entails a combination of irinotecan with 5-fluorouracil and leucovorin (FOLFIRI). Irinotecan is a prodrug that is converted within the cell to its active metabolite SN38, a potent TOP1 inhibitor. TOP1 relieves DNA torsional strain arising from DNA metabolism by cleaving one strand of the DNA duplex and forming an enzyme-DNA covalent intermediate that can be trapped by inhibitors. The resulting TOP1 DNA-protein crosslinks (TOP1-DPCs) interfere with replication and transcription and induce cell death if left unrepaired. I have established the role of the ubiquitin-proteasome pathway in TOP1-DPC repair, but it remains unknown how ubiquitylation is activated. One possibility is that collision between advancing replication forks and the DPCs triggers a specific ubiquitin ligase to target DPCs for degradation. The DDB1-CUL4 (Cullin 4)-RBX1 (CRL4) ubiquitin ligase complex performs a salient role in both replication and DNA repair upon its activation by auto-NEDD8 modification (neddylation), but it is unknown whether it plays a role for TOP1-DPC repair. We plan to define the role of neddylation for TOP1-DPC repair during replication and examine irinotecan plus pevonedistat (PEV), a NEDD8-activating enzyme inhibitor in multiple clinical trials, in CRC patient-derived preclinical models including 3D organoids. The three in-house organoids, from which samples have been submitted to dbGaP, were sequenced as a means of verifying their identity as colon cancer organoids, to allow us to investigate the combination of TOP1 inhibitors and PEV and the molecular mechanisms underlying this drug combination in these organoids.

Study phs003257

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