3735 results for "*oma"

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• Phylogenetic Analyses of Melanoma Reveal Complex Patterns of Metastatic Dissemination

  Subpopulations of cells in a primary melanoma can disseminate and establish metastases. Still, the precise ancestral relationship between primary tumors and their metastases is not well understood. Using whole-exome sequencing (for discovery) and targeted sequencing (for validation), we analyzed mutation patterns of primary melanomas and two or more metastases in each of 8 patients to determine their phylogenetic relationships, profiling a total of 31 total tumors. The resulting data show that in 6 of 8 cases, genetically unique cell populations in the primary metastasized in parallel to distinct anatomic sites, rather than sequentially. These data also indicate that individual metastases were sometimes founded by multiple cell populations of the primary that were genetically distinct.

  Study phs000941

• Genetic Analysis of Desmoplastic Melanoma

  Desmoplastic melanoma is an infrequent variant of melanoma with sarcomatous histology, distinct clinical behavior, and unknown pathogenesis. We performed low-coverage genome and high-coverage exome sequencing of 20 desmoplastic melanomas, followed by targeted sequencing of 293 genes to validate candidate genes. A high mutation burden (median 62 mutations/Mb) ranked desmoplastic melanoma among the most highly mutated cancers. Mutation patterns strongly implicate UV-radiation as the dominant mutagen, indicating a superficially located cell of origin. Novel alterations included recurrent promoter mutations of NF-kappa B inhibitor epsilon, NFKBIE (IkBε) in 14.5% of samples. Commonly mutated oncogenes in melanomas, in particular BRAF(V600E) and NRAS(Q61K/R), were absent. Instead, other genetic alterations known to activate the MAPK and PI3K signaling cascades were identified in 73% of samples, affecting NF1, CBL, ERBB2, MAP2K1, MAP3K1, BRAF, EGFR, PTPN11, MET, RAC1, SOS2, NRAS, and PIK3CA, some of which being candidates for targeted therapies. Reprinted from: Shain, A. H. et al. Exome sequencing of desmoplastic melanoma identifies recurrent NFKBIE promoter mutations and diverse activating mutations in the MAPK pathway. Nat. Genet. With permission from Nature Genetics

  Study phs000977

• The Mutational Landscape of CTCL and Sezary Syndrome

  Sezary syndrome is a leukemic and aggressive form of cutaneous T-cell lymphoma (CTCL) resulting from the malignant transformation of skin-homing central memory CD4+ T cells. To identify new genetic alterations involved in Sezary syndrome and CTCL transformation we performed whole-exome sequencing of tumor-normal sample pairs from 26 Sezary syndrome and 16 CTCL patients. These analyses revealed a distinctive pattern of somatic copy number alterations in Sezary syndrome including highly prevalent recurrent chromosomal deletions involving the TP53, RB1, PTEN, DNMT3A, and CDKN1B tumor suppressor genes. Mutation analysis identified a broad spectrum of somatic mutations involving key genes involved in epigenetic regulation (TET2, CREBBP, MLL3, BRD9, SMARCA4 and CHD3) and signaling, including mutations in MAPK1, BRAF, CARD11 and PRKG1 driving increased MAPK, NFKB and NFAT activity upon T-cell receptor stimulation. Collectively, our findings provide new insights into the genetics of Sezary syndrome and CTCL and support the development of personalized therapies targeting key oncogenically activated signaling pathways for the treatment of these diseases.

  Study phs000994

• Identification of Putative Neoantigens in Stage III Melanoma

  This study of three metastatic melanoma patients utilized exome sequencing and RNA sequencing to help identify putative neoantigen peptides that could be further validated by standard immunological assays before design of a personalized vaccine. For each set of neoantigens identified and verified by standard assays, we designed GMP peptides that correspond to the top neoantigens, then used these to condition dendritic cell isolates from each patient. The conditioned dendritic cells were used as the vaccine in three rounds of vaccination, followed by monitoring for T cell memory response to each of the neoantigens.

  Study phs001005

• Lobular Carcinomas In Situ Display Intra-Lesion Genetic Heterogeneity and Clonal Evolution in the Progression to Invasive Disease

  This study comprises prospectively accrued, microdissected fresh frozen samples of multifocal lobular carcinoma in situ (LCIS), ductal carcinoma in situ (DCIS), invasive lobular carcinoma and invasive ductal carcinoma from patients undergoing prophylactic or therapeutic mastectomies after a diagnosis on LCIS diagnosed and managed at Memorial Sloan Kettering Cancer Center (MSKCC). Microdissected samples were subjected to paired-end whole exome sequencing on an Illumina HiSeq 2000. The data generated were used to define the landscape of somatic genetic alterations of LCIS, DCIS, invasive lobular carcinoma and invasive ductal carcinoma, to define clonal relatedness of these lesions and to investigate the clonal shifts in the progression from in situ to invasive breast cancer.

  Study phs001006

• The Genetic Landscape of Metastasis and Recurrence in Head and Neck Squamous Cell Carcinoma

  Recurrence and/or metastasis occur in more than half of patients with head and neck squamous cell carcinoma (HNSCC) and pose the greatest threats to long-term survival. The genetic alterations underlying recurrent/metastatic HNSCC are unknown. This study represents the first whole exome sequencing (WES) cohort study of patient-matched tumor pairs in recurrent or metastatic HNSCC. Synchronous lymph node metastases are genetically more similar to their paired index primary tumors than metachronous recurrent tumors are. Newly arisen mutations in recurrent or metastatic tumors, may have therapeutic implications. Several genes were found to be mutated in multiple metastatic or recurrent tumors, but not in their respective primaries, including C17orf104, ITPR3, and DDR2. DDR2 mutations have been shown to confer enhanced sensitivity to Src-family kinase (SFK) inhibitors in other malignancies. Similarly, we found HNSCC cell lines harboring endogenous and engineered DDR2 mutations to be more sensitive to the SFK inhibitor dasatinib, than those with WT DDR2. This study outlines the first compendium of somatic mutations in primary, metastatic and/or recurrent HNSCC cancers that arise in individual patients; and demonstrates how such data can be used to interrogate potential predictive/prognostic biomarkers to inform and guide personalized therapy.

  Study phs001007

• GWAS in an Amerindian Ancestry Population Reveals Novel Systemic Lupus Erythematosus Risk Loci and the Role of European Admixture

  The study comprises SLE patients recruited from specialist rheumatology clinics from the United States, Mexico, Argentina, Chile and Peru. Two strategies were used to enrich samples for Native American ancestry: a. previously genotyped Hispanic and Latin American and US Native American individuals were selected according to their ancestry based on 253 ancestry informative markers as part of the Lupus Large Association 2 Study. The approximate 35% of the samples were primarily of European and Native American admixture was selected; b. the recruitment of patients took place primarily in countries with little African admixture. All samples were genotyped on the HumanOmni1-Quad BeadChip using manifest H at the Oklahoma Medical Research Foundation. The Illumina clustering algorithm with GenomeStudio v2011.1 was used.

  Study phs001025

• Comprehensive Genomic Characterization of Acral Melanoma

  In this study, we performed paired tumor/normal long insert whole genome and exome sequencing and tumor RNA sequencing on primary or metastatic acral melanoma tumors collected from 34 patients. Patients were enrolled from either Vanderbilt University or the Memorial Sloan-Kettering Cancer Center. We report an integrated analysis of DNA and RNA sequencing data to describe genomic and transcriptomic characteristics of acral melanoma.

  Study phs001036

• Inhibiting DNA Methylation Causes an Interferon Response in Cancer via dsRNA Including Endogenous Retroviruses

  We show that DNA methyltransferase inhibitors (DNMTis) upregulate immune signaling in cancer through the viral defense pathway and re-expression of epigenetically silenced endogenous retrovirus. In melanoma patients treated with an immune checkpoint therapy, high viral defense signature expression in tumors significantly associates with durable clinical response and DNMTi treatment sensitizes to anti-CTLA4 therapy in a pre-clinical melanoma model.

  Study phs001038

• Genetic Basis for Clinical Response to CTLA-4 Blockade in Melanoma

  Immune checkpoint inhibitors are effective cancer treatments, but molecular determinants of clinical benefit are unknown. Ipilimumab and tremelimumab are antibodies against cytotoxic T-lymphocyte antigen 4 (CTLA-4). Anti-CTLA-4 treatment prolongs overall survival in patients with melanoma. CTLA-4 blockade activates T cells and enables them to destroy tumor cells. We obtained tumor tissue from patients with melanoma who were treated with ipilimumab or tremelimumab. Whole-exome sequencing was performed on tumors and matched blood samples. Somatic mutations and candidate neoantigens generated from these mutations were characterized. Neoantigen peptides were tested for the ability to activate lymphocytes from ipilimumab-treated patients. Malignant melanoma exomes from 64 patients treated with CTLA-4 blockade were characterized with the use of massively parallel sequencing. A discovery set consisted of 11 patients who derived a long-term clinical benefit and 14 patients who derived a minimal benefit or no benefit. Mutational load was associated with the degree of clinical benefit (P = 0.01) but alone was not sufficient to predict benefit. Using genomewide somatic neoepitope analysis and patient-specific HLA typing, we identified candidate tumor neoantigens for each patient. We elucidated a neo-antigen landscape that is specifically present in tumors with a strong response to CTLA-4 blockade. We validated this signature in a second set of 39 patients with melanoma who were treated with anti-CTLA-4 antibodies. Predicted neoantigens activated T cells from the patients treated with ipilimumab.

  Study phs001041