3335 results for "*geneti*"

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• Genome and gene analysis of gastrointestinal cancer and elucidation of its clinicopathological significance

  Cancer develops through the accumulation of genetic and epigenetic aberrations. To identify sequential molecular alterations that occur during the development of hepatocellular carcinoma (HCC), we molecularly compared 52 early and 108 overt HCC samples by genome sequencing. Gene mutations in the p53/RB1 pathway, WNT pathway, MLLs, SWI/SNF complexes, and AKT/PI3K pathway were common in HCC. In the early phase of all entities, TERT was the most frequently upregulated gene owing to diverse mechanisms. Despite frequent somatic mutations in driver genes, including CTNNB1 and TP53, early HCC was a separate molecular entity from overt HCC as each had a distinct expression profile. Notably, WNT target genes were not activated in early HCC, regardless of CTNNB1 mutation status, because ?-catenin did not translocate into the nucleus due to the E-Cadherin/?-catenin complex at the membrane. Conversely, WNT targets were definitively upregulated in overt HCC with CTNNB1 mutation associated with downregulation of CDH1 and hypomethylation of CpG islands in the target genes. Similarly, cell cycle genes downstream of the p53/RB pathway were upregulated only in overt HCC with TP53 and/or RB1 gene mutations associated with chromosomal deletion of 4q and/or 16q. Differing from the expression profile, HCC was epigenetically distinguished into four subclasses: normal-like methylation, global-hypomethylation (favorable prognosis), stem-like methylation (poor prognosis), and CpG island methylation. These methylation statuses were globally maintained through HCC progression. Taken together, additional molecular events besides driver gene mutations cooperatively contribute to transcriptional activation of downstream targets as HCC progresses, according to the methylation status of the associated genes.

  Study JGAS000233

• Effective screening strategy for deafness using a new-genetation sequencing platform: a consecutive analysis

  The diagnosis of the genetic etiology of deafness contributes to the clinical management of patients. We performed the following four genetic tests in three stages for 52 consecutive deafness subjects in one facility. We used the Invade assay and Sanger sequencing for the GJB2 gene or SLC26A4 gene in the first stage test, TaqMan genotyping assay in second stage test, and targeted exon sequencing using the massively parallel DNA sequencing in third stage test. Overall, we identified the genetic cause in 40% (21/52) of patients. The diagnostic rates of the first-, second- and third-stage genetic testing were 17%(9/52), 9%(4/43) and 21% (8/39), respectively. The combination approach using these genetic tests appears to be useful as a diagnostic tool for deafness patients. We recommended that genetic testing for the screening of common mutations in deafness genes using the Invader assay or TaqMan genotyping assay be performed as the initial evaluation. For the remaining undiagnosed cases, targeted exon sequencing using MPS is clinically and economically beneficial. This data set was MPS reads data (fastq) for 39 sensorineural hearing loss patients.

  Study JGAS000032

• Rapid detection of expanded short tandem repeats in personal genomics using hybrid sequencing.

  Long expansions of short tandem repeats (STRs); i.e., DNA repeats of 2-6 nucleotides, are associated with some genetic diseases. Cost-efficient high throughput sequencing can quickly produce billions of short reads that would be useful for uncovering disease-associated STRs. However, enumerating STRs in short reads remains largely unexplored because of the difficulty in elucidating STRs much longer than 100 bp, the typical length of short reads. We propose ab initio procedures for sensing and locating long STRs promptly by utilizing the frequency distribution of all STRs and paired-end read information. We validated the reproducibility of this method using biological replicates and used it to locate an STR associated with a brain disease (SCA31). Subsequently, we sequenced this STR site in eleven SCA31 samples using SMRT? sequencing (Pacific Biosciences), determined 2.3-3.1 kb sequences at nucleotide resolution, and revealed that (TGGAA)- and (TAAAATAGAA)-repeat expansions determined the instability of the repeat expansions associated with SCA31. Our method could also identify common STRs, (AAAG)- and (AAAAG)-repeat expansions, which are remarkably expanded at four positions in an SCA31 sample. This is the first proposed method for rapidly finding disease-associated long STRs in personal genomes using hybrid sequencing of short and long reads.

  Study JGAS000002

• Whole exome sequencing of familial MDS, Two patients

  Although several causal genes of familial myelodysplastic syndromes (MDS) have been identified, the genetic landscape and the molecular pathogenesis are not totally understood. To explore novel driver genes and their pathogenetic significance, we performed whole exome sequence analysis of two individuals from a familial MDS pedigree and several candidate single-nucleotide variants were identified. Knockdown screening revealed that downregulation of a candidate gene enhanced colony forming capacity of primary murine bone marrow (BM) stem/progenitor cells. Our results indicate that a familial MDS-associated germline mutation in the candidate gene induces accumulation of DNA double-strand breaks, possibly through impaired PCNA polyubiquitination.

  Study JGAS000162

• Identification of therapeutic target molecules for prostate cancer by using next generation sequencer

  Comprehensive transcriptional characterization of cancer tissues can reveal important molecular signatures associated with the disease progression. Long non-coding RNA (LncRNA) has a diversity of functions such as transcription, epigenetic and gene regulation in cancer cells including prostate cancer cells. Here, we performed directional RNA-sequence (RNA-seq) on clinical samples obtained from prostate cancer (PC) and lethal castration-resistant PC (CRPC) patients to identify novel molecular signatures including protein coding genes and non-coding RNAs induced in CRPC tissues.

  Study JGAS000198

• GWAS for atrial fibrillation in the Japanese population

  We performed a genome-wide association study (GWAS) that utilized 8,180 atrial fibrillation cases and 28,612 controls and followed up in an additional 3,120 cases and 125,064 controls in the Japanese population. We replicated previously reported loci and identified six novel loci. Five of the six novel loci were specifically associated with atrial fibrillation in the Japanese population after comparing our data to individuals of European ancestry, suggesting there might be different susceptibility genetic factors across ancestries. Our study has discovered variants in genes HAND2, KCND3 and NEBL that are relevant to atrial fibrillation susceptibility. The involvement of PPFIA4 and SH3PXD2A in axon guidance also suggested its role in the disease pathogenesis. Our findings may contribute to a better understanding of atrial fibrillation susceptibility and pathogenesis.

  Study JGAS000101

• Clonal structure and oncogenic potential of liver cirrhosis tissues.

  Hepatocellular carcinoma (HCC) recurrently develops in cirrhotic liver composed of numbers of regenerative nodules (RNs). The biologic or genetic basis of RNs for hepatocarcinogenesis remains unclear at present. Thus, to uncover the basis of cirrhotic liver for multicentric tumorigenesis, we investigated the oncogenic potential of RNs in LC tissues using multi-omics analysis.

  Study JGAS000134

• Defined Lifestyle and Germline Factors Predispose Asian Populations to Gastric Cancer

  Gastric cancer (GC) is one of the leading causes of cancer mortality throughout the world, with the highest incidence in east-Asia. Although the somatic genetics of GC has extensively been characterized by recent advances in cancer genome sequencing, the germline and environmental effects on GC and their ethnic differences have poorly been understood. Here, we performed genomic scale trans-ethnic analysis of 531 GC cases (319 Asian and 212 non-Asians), by integrating east-Asian and public GC datasets. There is one distinct GC subclass with clear alcohol-associated mutation signature and strong Asian specificity, and almost all the cases in the subclass are attributable to alcohol intake behavior, smoking habit, and Asian-specific ALDH2 defective allele. Alcohol-related GCs have low mutation burden and a characteristic immune profile of increased B-cell infiltration into the tumor area in relation to cancer cell-intrinsic CXCL13 chemokine expression. In addition to germline variants of genes involved in BRCA pathways, we found frequent (7.4%) germline CDH1 variants among Japanese GCs. Most of them were attributed to a few recurrent SNVs shared by both Japanese and Koreans, suggesting the existence of common ancestral events and widespread distributions of these pathogenic variants among east-Asian populations. Specifically, approximately one-fifth of diffuse-type GCs were attributable to the combination of alcohol intake and defective-ALDH2 allele or to germline CDH1 variants. These results revealed uncharacterized impacts of germline variants and their interplays with lifestyles in the high incidence areas.

  Study JGAS000229

• Expression profiling of Gorlin iPSCs in the osteoblast induction culture

  In this study, we utilized human induced pluripotent stem cell (iPSC)-based models of the two diseases, named Gorlin syndrome and McCune Albright synfrome, to understand the roles of Hh signaling in osteogenesis, especially in mineralization. To examine which signaling pathways and genetic networks were affected by Gorlin syndrome-associated PTCH1 mutation in human osteoblastogenesis, we performed RNA sequencing (RNA-seq) analysis in the osteoblast induction culture of WT and Gorlin iPSCs.

  Study JGAS000218

• DNA demethylation is associated with malignant progression of low-grade gliomas

  To elucidate the mechanisms of tumor progression is key to discovering strategies for treating patients with lower-grade glioma. Thus to characterize the changes in the molecular profile during malignant progression, we performed methylation array analysis (122 tumors), whole-exome sequencing (36 tumors and matched normal samples), and RNA sequencing (31 tumors). This cohort included 24 matched pairs of initial lower-grade gliomas and recurrent tumors, most of which showed malignant progression when they recurred. Nearly half of IDH-mutant glioblastomas that had progressed from lower-grade gliomas exhibited characteristic partial DNA demethylation in previously methylated genomic regions of their corresponding initial tumors, which had the glioma CpG island methylator phenotype (G-CIMP). In these glioblastomas, cell cycle-related genes were upregulated, RB and PI3K-AKT pathway genes were frequently altered. Notably, bioinformatics analysis revealed that late-replicating domain was significantly enriched in the demethylated regions that were mostly located in non-regulatory regions, suggesting that the loss of DNA methylation during malignant transformation may involve mainly passive demethylation due to a delay in maintenance of methylation during accelerated cell division. Nonetheless, a limited number of genes including IGF2BP3, which potentially drives cell proliferation, were presumed to be upregulated due to demethylation of their promoter. Thus, cell proliferation was further promoted by passive demethylation in the promoter region of these oncogenic genes. Our data indicated that demethylation of the G-CIMP profile found in a subset of recurrent gliomas reflects accelerated cell divisions accompanied by malignant transformation. Oncogenic genes activated by such epigenetic change represent potential therapeutic targets.

  Study JGAS000146