3798 results for "*oma"

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• 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

• Establishing stable brain tumor stem cell lines and translational research for new treatments

  Choroid plexus carcinomas (CPCs) have dismal prognoses with limited clinical options. A lack of characterized cell lines has hindered the development of new treatment strategies. Here, we perform whole genome sequencing analyses of two cell lines established from CPCs. Whole genome sequencing (WGS),was performed in CCHE-45 and NGT131 cell lines. Both cell lines harbored pathogenic TP53 point mutations; CCHE-45 additionally displayed TP53 loss. Furthermore, alterations of the NOTCH and WNT pathways were also detected in both cell lines. Two protein-coding gene fusions, BZW2-URGCP, and CTTNBP2-ERBB4, mutations of two oncodrivers, GBP-4 and KRTAP-12-2, and several copy number alterations were observed in CCHE-45, but not NGT131. The discovered difference's importance and implications highlight the possible diversity of choroid plexus carcinoma and call for additional research to fully understand disease pathogenesis. Whole genome sequencing revealed that the two choroid plexus carcinoma cell lines shared TP53 mutations and other common pathway alterations and activation of NOTCH and WNT pathways. Noticeable differences were also observed. These cell lines can serve as valuable models to propose new treatments in these rare but deadly brain tumors.

  Study JGAS000657

• Genetic and transcriptional landscape of plasma cells in POEMS syndrome

  POEMS syndrome is a rare paraneoplastic disease, associated with monoclonal plasma cells whose pathogenic importance remains unclear. We performed comprehensive genetic analyses of plasma cells in 20 patients with POEMS syndrome. Whole exome sequencing and targeted sequencing identified 7 recurrently mutated genes: KLHL6, LTB, EHD1, EML4, HEPHL1, HIPK1, and PCDH10. None of the driver gene mutations frequently found in multiple myeloma (MM) such as NRAS, KRAS, BRAF, and TP53 was detected. Copy number analysis showed chromosomal abnormalities shared with monoclonal gammopathy of undetermined significance (MGUS). RNA sequencing revealed a transcription profile specific to POEMS syndrome, especially in terms of tumorigenesis. Unexpectedly, disease-specific VEGFA expression was not increased in POEMS syndrome. Our study illustrates that the genetic and transcriptional profiles of plasma cells in POEMS syndrome are distinct from MM and MGUS, indicating its unique pathogenesis.

  Study JGAS000150

• intratumor heterogeneity in colorectal adenoma and carcinoma

  To investigate intratumor heterogeneity in precancerous lesions of colorectal cancers (PCRCs), we performed whole-exome sequencing of 53 tumor and 10 matched-normal samples from 10 laterally spreading tumors in the colon and rectum, which were histologically diagnosed as adenoma with/without adenocarcinoma.

  Study JGAS000092

• Molecular analysis of diffuse cerebellar gliomas

  Among diffuse gliomas, oligodendrogliomas show relatively better prognosis, respond well to radiotherapy and chemotherapy, and seldom progress to very aggressive tumors. To elucidate the genetic and epigenetic background for such behavior and tumor evolution during tumor relapse, we comparatively analyzed 12 pairs of primary and recurrent oligodendrogliomas with 1p/19q-codeletion. Initial treatment for these patients was mostly chemotherapy alone. Temozolomide was used for 3, and procarbazine, nimustine and vincristine (PAV chemotherapy) were used for 7 patients. World Health Organization histological grade at recurrence was mostly stable; it was increased in 2, the same in 9, and decreased in 1 cases. Whole-exome sequencing demonstrated that the rate of shared mutation between the primary and recurrent tumors was relatively low, ranging from 3.2-57.9% (average, 33.3%), indicating a branched evolutionary pattern. The trunk alterations that existed throughout the course were restricted to IDH1 mutation, 1p/19q-codeletion, and TERT promoter mutation, and mutation of the known candidate tumor suppressor genes CIC and FUBP1 were not consistently observed between primary and recurrent tumors. Multiple sampling from different regions within a tumor showed marked intratumoral heterogeneity. Notably, in general, the number of mutations was not significantly different after recurrence, remaining under 100, and no hypermutator phenotype was observed. FUBP1 mutation, loss of chr. 9p21, and TCF12 mutation were among a few recurrent de novo alterations that were found at recurrence, indicating that these events were clonally selected at recurrence but were not enough to enhance malignancy. Genome-wide methylation status, measured by Illumina 450 K arrays, was stable between recurrence and the primary tumor. In summary, although oligodendroglioma displays marked mutational heterogeneity, histological malignant transformation accompanying events such as considerable increase in mutation number and epigenetic profile change were not observed at recurrence, indicating that noticeable temporal and spatial genetic heterogeneity in oligodendrogliomas does not result in rapid tumor progression.

  Study JGAS000106

• Elucidation of molecular mechanism of NAFLD-HCC

  We aimed to elucidate the interaction between cancer cells and immune cells in the tumor immune microenvironment of non-viral hepatocellular carcinoma.

  Study JGAS000311

• Establishment of xenogfafts and cultured cell lines from clinical samples

  The purpose of the present study was to clarify the presence or absence of alterations in the molecular properties of patient-derived xenografts (PDXs) with up to eight passages in endometrial carcinomas. Alterations in the proportion of immunohistochemically positive/negative cells for PAX8, estrogen receptor, PAX2, and PTEN were observed in established PDXs of endometrioid carcinomas and carcinosarcomas, whereas proportions of cells with AE1/AE3, TP53, ARID1A PMS2, and MSH6 were maintained. Variants of cancer-associated genes in PDX compared to those in the parental tumors were examined in two cases, a frameshift deletion in BRCA1 was observed in the parental tumor tissue, and additional genomic alterations were found in the PDXs of this case. Genomic and phenotypic alterations in endometrial carcinoma PDXs relative to the parental tumors were observed and were partly associated with endometrial cancer-specific characteristics in cellular differentiation and gene mutations.

  Study JGAS000585

• Comprehensive molecular and clinicopathological profiling of glioma

  Various molecular profiles are needed to classify malignant brain tumors, including gliomas, based on the latest classification criteria of the World Health Organization, and their poor prognosis necessitates new therapeutic targets. The Todai OncoPanel 2 RNA Panel (TOP2-RNA) is a custom-target RNA-sequencing (RNA-seq) using the junction capture method to maximize the sensitivity of detecting 455 fusion gene transcripts and analyze the expression profiles of 1,390 genes. This study aimed to classify gliomas and identify their molecular targets using TOP2-RNA. A total of 124 frozen samples of malignant gliomas were subjected to TOP2-RNA for classification based on their molecular profiles and the identification of molecular targets.

  Study JGAS000671

• Viral integration analysis of hepatocellular carcinoma using virus capture sequence.

  Hepatitis B viral (HBV) DNA is frequently integrated into the genome of hepatocellular carcinoma (HCC) in patients with chronic HBV infection (chronic HBV, hereafter), whereas it is yet to be clarified in patients after HBV disappearance (prior HBV, hereafter). This study aimed to identify viral integration such as HBV and adeno-associated virus type 2 (AAV2) into the HCC genome as oncogenic event.

  Study JGAS000194

• Single cell sequences in patients with malignant tumors

  We perfomed single cell RNA and TCR sequencing of 2 lung adenocarcinoma patients and 3 head and neck squamous cell carcinoma to assess the detailed biological mechanisms of resistance to immune checkpoint inhibitors.

  Study JGAS000480