3883 results for "*geneti*"

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• Genetic analysis of non-small cell lung cancer patients and PDX tumor harboring driver gene alteration

  Genetic analysis of non-small cell lung cancer patients and PDX tumors with EGFR mutation, ALK fusion, ROS1 fusion, etc.

  Study JGAS000413

• Microarray genotyping of idiopathic hypersomnia patients (11 orexin mutation-positive patients, 85 orexin mutation-negative patients)

  We performed a principal component analysis (PCA) to determine whether population stratification or differences in the genetic background are present between the orexin mutation-positive and -negative idiopathic hypersomnia groups. Genome-wide single nucleotide polymorphism (SNP) data in patients with idiopathic hypersomnia (orexin mutation-positive patients and orexin mutation-negative patients) were utilized for the PCA.

  Study JGAS000508

• Genetic alterations that deregulate RB and PDGFRA signaling pathways drive tumor progression in IDH2-mutant astrocytoma

  In IDH-mutant astrocytomas, IDH2 mutation is quite rare and biological mechanisms underlying tumor progression in IDH2-mutant astrocytoma remain elusive. Here, we report a unique case of IDH2 mutant astrocytoma, CNS WHO grade 3 that developed tumor progression. We performed a comprehensive genomic and epigenomic analysis for primary and recurrent tumors and found that both tumors harbored recurrent IDH2R172K and TP53R248W mutation with CDKN2A/B hemizygous deletion. We also found amplifications of CDK4 and MDM2 with PDGFRA gain in the recurrent tumor and upregulated protein expressions of these genes. We further developed, for the first time, a xenograft mouse model of IDH2R172K mutant astrocytoma from the recurrent tumor, but not from the primary tumor. Consistent with parent recurrent tumor cells, amplifications of CDK4 and MDM2 with PDGFRA gain was found, while CDKN2A/B was identified as homozygous deletion in the xenografts, qualifying for integrated diagnosis of astrocytoma, IDH2-mutant, CNS WHO grade 4. Cell viability assay found that CDK4/6 inhibitor and PDGFR inhibitor potently decreased cell viability in recurrent tumor cells, as compared to primary tumor cells. These findings suggest that gene alterations that activate retinoblastoma (RB) signaling pathways and PDGFR may drive tumor progression and xenograft formation in IDH2-mutant astrocytoma, which is equivalent to progressive IDH1-mutant astrocytoma. Also, our findings suggest that these genomic alterations may represent therapeutic targets in IDH2-mutant astrocytoma.

  Study JGAS000646

• Genomics characterization of primary central nervous system lymphoma

  Primary central nervous system lymphoma (PCNSL) is a rare malignancy confined to the central nervous system (CNS). Despite low tendency of systemic dissemination, its prognosis is poor with median overall survival of 2?4 years. Due to its rarity, knowledge of genomic alterations underling PCNSL pathogenesis is severely limited. Here we performed whole-exome sequencing on 44 PCNSL and paired normal specimens, revealing high penetrance of nonsynonymous somatic mutations in PIM1 (95.5%), BTG2 (88.6%) and MYD88 (81.8%). Interestingly we found oncogenic mutations in GRB2, and this effect was cancelled when transformed cells are treated with inhibitors to downstream kinases MAP2K1/2. Further, when tumor cells carries MYD88 mutations, the same mutations were also found at low frequency in peripheral blood mononuclear cells (PBMNC), implying that MYD88 mutation?positive precancerous cells originate outside CNS and develop to lymphoma with additional genetic hits that fit the CNS environment.

  Study JGAS000021

• Durable clinical impacts and mechanisms of action and resistance in histone K27 methylation-targeting epigenetic therapy

  Epigenomes allow the rectification of disordered cancer gene expressions, thereby providing new targets for pharmacological interventions in cancer therapy. The clinical utility of targeting histone H3 lysine tri-methylation (H3K27me3) as an epigenetic hallmark has been demonstrated. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumor cells remain unclear. Here we show the potency and mechanisms of action and resistance of a newly developed EZH1/2 dual inhibitor, valemetostat, in the clinical trials of patients with adult T-cell leukemia/lymphoma (ATL). Valemetostat administration reduced the tumor size and demonstrated durable clinical benefits. Integrative single-cell analyses of patients before and after the administration of valemetostat showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, such as tumor suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. The acquired mutations at the EZH2???compound interface result in the propagation of the clones with re-increased H3K27me3. In patients free of this mutation, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation at the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting chromatin homeostasis might provide opportunities for further sustained epigenetic cancer therapies.

  Study JGAS000553

• Comprehensive analyses of genetic aberrations in gastroenterological tumors

  Intestinal metaplasia (IM) is a risk factor of gastric cancer in gastric mucosa with Helicobacter pylori infection. To explore the susceptibility to the cancer development in pure gastric IM, we investigated landscape of genetic alterations in gastric single-glands with IM.

  Study JGAS000269

• Phase II clinical trial of adult Philadelphia chromosome-negative precursor B-cell acute lymphocytic leukemia with combination chemotherapy

  Adults with B-ALL showed extremely inferior outcomes when compared to children. Genetic basis undelying adult B-ALL is largely unknown. We performed integrated analysis of RNA-seq and target DNA-seq for the patients enrolled in BALL213 study.

  Study JGAS000278

• Targeted exome sequencing identify compound heterozygous TYK2 mutations in patients with primary immunodeficiency who developed EBV-associated lymphoma

  In this study, we evaluated 2 siblings with primary immunodeficiency who developed EBV-associated lymphoma. Immunophenotyping of PBMCs revealed that both patients had significant T cell lymphopenia characterized by low na?ve CD4+ T cell counts. To identify the causative genetic mutations in the patients, we performed targeted exome sequencing using the Illumina MiSeq on the patients and their parents. The results showed a novel compound heterozygous mutations in the gene encoding tyrosine kinase 2 (TYK2) in the patients.

  Study JGAS000098

• High-coverage whole exome sequence in non-TRU-type lung adenocarcinomas

  In order to elucidate the key genetic events in non-TRU-type lung cancer, we selected 43 non-TRU-type lung adenocarcinomas and performed a whole exome sequence and RNA-seq analysis using a next-generation sequencer. The results of the analysis identified mutations in TP53, KRAS and NKX2-1 as the top three significantly mutated genes, while the EGFR mutation was rare in this cohort. Eight NKX2-1 mutations (5 frameshift, 2 nonsense, and one missense) were identified, with one case harboring two distinct NKX2-1 mutations (missense and frameshift). All NKX2-1 mutants were transcriptionally inactive in reporter assays. Histologically, invasive mucinous adenocarcinomas accounted for most of the NKX2-1 mutations (5 cases), while 1 enteric and 1 acinar adenocarcinoma harbored the NKX2-1 mutation.

  Study JGAS000105

• Immunohistochemical and molecular pathological search in gastrointestinal tumors

  Purpose: RSPO fusions are recently identified recurrent genetic alterations in colorectal cancer (CRC), which lead to WNT pathway activation and are potential therapeutic targets. We aimed to investigate the clinicopathological and molecular features of RSPO fusion-positive CRCs. Experimental Design: We screened 1019 CRCs for RSPO fusions using multiplex reverse transcription polymerase chain reaction. RSPO fusion-positive tumors were characterized for their clinicopathological features and subjected to whole exome sequencing (WES). Results: Our analysis identified 29 CRCs with RSPO fusions (2.8%), consisting of 5 with an EIF3E-RSPO2 fusion and 24 with PTPRK-RSPO3 fusions. The patients were 17 females and 12 males with the median age of 64 years. Thirteen tumors were located in the right colon, 8 were in the left colon, and 8 were in the rectum. Histologically, most of the tumors (24/29, 83%) were classified as adenocarcinomas, not otherwise specified. However, about half of the tumors (13/29, 45%) had a focal or extensive mucinous component, which is significantly more frequent compared with RSPO fusion-negative tumors (13%; p = 8.1 �� 10-7). Four tumors (14%) were mismatch repair-deficient, three of which were associated with MLH1 promoter methylation. WES identified KRAS, BRAF, and NRAS mutations in a total of 27 cases (93%). In contrast, pathogenic mutations in major WNT pathway genes other than RSPO fusions were virtually absent. The presence of an RSPO fusion tended to show shorter overall and recurrence-free survivals in stage II and III patients although the differences were not significant. Conclusions: RSPO fusion-positive CRCs constitute a rare subgroup of CRCs with several characteristic clinicopathological and genetic features. The mutual exclusivity with other WNT pathway gene alterations supports RSPO fusions as valid therapeutic targets in CRC.

  Study JGAS000538