5495 results for "*oma"

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• Paediatric Hepatic International Tumour Trial (JPLT2: PHITT)

  Hepatoblastoma (HBL) is the most common primary liver tumor in children. Despite their diversity in histopathological phenotype and clinical outcome, the underlying molecular aberrations have not been fully understood. Here we describe a comprehensive landscape of genomic, epigenomic, and transcriptomic heterogeneity among the 163 cases of HBLs and transitional liver cell tumors (TLCTs) collected in the multicenter clinical trial JPLT-2. The total numbers of mutational events in HBLs are very few (0.52 SNVs/Mb on exonic regions) but show a positive correlation with the age of onset. While dysregulation of Wnt-pathway related genes was observed (somatic deletion or mutations of CTNNB1 and germline or somatic mutations of APC) in 83.6% of the HBL cases, TERT promoter mutations are mainly in the elderly HBLs (> 8 years old), meeting with the proposed criteria of TLCT. These TLCT cases are clustered in the hypermethylated epigenotype in promoter and enhancer regions. Copy number analyses also revealed recurrent 11p15.5 UPD/LOHs including the IGF2/H19 region (31.6%), focal deletions in 4q35 (15.8%) and focal amplifications in 2q24.3 (7.0%) predominantly in the child and infant HBLs. Motif enrichment analysis of the specific hypomethylated enhancers in these HBL subtypes suggests specific binding of ASCL2, the regulatory transcription factor for definitive endoderm and digestive systems. Transcriptome and histochemical analysis revealed that ASCL2 is upregulated not in HCC and TLCT but in child and infant HBL, suggesting their ?cell of origin? derived from the premature hepatoblast with high proliferative potential such as intestinal epithelial cells. Systematic molecular profiling of HBL will provide a fundamental understanding of hepatoblast carcinogenesis and clues for risk stratification.

  Study JGAS000236

• DNA methylation at HBV integrants and flanking host genomes

  Integration of DNA viruses into the human genome plays an important role in various types of tumors, including hepatitis B virus (HBV)-related hepatocellular carcinoma. However, the molecular details and clinical impact of HBV integration on either the human or HBV epigenomes are unknown. Here, we show that methylation of the integrated HBV DNA is related to the methylation status of the flanking human genome. We developed a next-generation sequencing-based method for structural methylation analysis of integrated viral genomes (denoted G-NaVI). This method is a novel approach that enables enrichment of viral fragments for sequencing using unique baits based on the sequence of the HBV genome. We detected integrated HBV sequences in the genome of the PLC/PRF/5 cell line and found variable levels of methylation within the integrated HBV genomes. Allele-specific methylation analysis revealed that the HBV genome often became significantly methylated when integrated into highly methylated host sites. After integration into unmethylated human genome regions such as promoters, however, the HBV DNA remains unmethylated and may eventually play an important role in tumorigenesis. The observed dynamic changes in DNA methylation of the host and viral genomes may functionally affect the biological behavior of HBV. These findings may impact public health given that millions of people worldwide are carriers of HBV. We also believe our assay will be a powerful tool to increase our understanding of the various types of DNA virus-associated tumorigenesis.

  Study JGAS000015

• Genome-wide copy number analysis of neuroblastoma

  Neuroblastoma is the most common extracranial solid tumor in childhood. Despite the improvement of risk-stratified therapies, overall survival rate of high-risk group is still as low as 40-50%. To investigate genome-wide copy number profiles of neuroblastoma, we performed SNP array analysis and PCR-based amplicon deep sequencing of neuroblastoma-related genes in 522 neuroblastoma samples.

  Study JGAS000046

• Deciphering the aggressive nature of morphoeic basal cell carcinoma

  Morphoeic basal cell carcinoma (mBCC) has a high risk of local recurrence compared to the more indolent nodular subtype reflected by a different set of driver mutations including FLNB and HECTD4. Surrounding mBCC stroma is abnormal, containing mutations such as EPHA3. Hedgehog pathway over-expression is seen in both the tumour and stroma of morphoeic tissue with the latter potentially being partly responsible for its aggressive nature and risk of recurrence.

  Study EGAS00001001915

• Comprehensive genetic landscape, immune checkpoint profiling, and establishment of patient-derived xenograft (PDX) of metachronous brain tumors from constitutive mismatch repair deficiency with a biallelic variant on MSH6

  Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare genetic disorder caused by biallelic pathogenic variants in mismatch repair genes (PMS2, MSH6, MLH1, or MSH2) resulting in the development of a variety of different tumors, including brain neoplasms. This study molecularly characterized a Brazilian child with CMMRD, harboring two metachronous brain tumors (medulloblastoma and high-grade glioma), and established a patient-derived xenograft (PDX) of the CMMRD-associated brain tumor. Keywords: Brazil, Constitutional mismatch repair deficiency syndrome, exome, MSH6, medulloblastoma, high-grade glioma.

  Study EGAS50000000351

• TTFields Glioblastoma Data Access Committee, Charité – Universitätsmedizin Berlin

  This Data Access Committee is responsible for reviewing and approving data access requests for genomic and associated clinical data from patients with glioblastoma, IDH wildtype, treated with surgery, standard chemoradiotherapy and Tumor Treating Fields at Charité – Universitätsmedizin Berlin. The DAC ensures that any data use is consistent with the patients’ informed consent, the study’s ethical approval and applicable data protection regulations. Approved applicants may use the data only for biomedical research on brain tumours and related methods, must not attempt re-identification of participants, and may not share the data with unauthorized third parties

  Dac EGAC50000000843

• Recurrent COPA mutation drives R-spondin-independent Wnt activation in intestinal tumors

  The majority of intestinal tumors harbor mutations in canonical Wnt pathway genes such as APC, whereas the lack of such alterations in a subset of tumors implies alternative tumorigenic routes. Here, we identify recurrent in-frame deletion in COPA, frequently co-occurring with USP9X truncating mutation, in small intestinal adenoma and adenocarcinoma. Patient-derived and CRISPR-engineered small intestinal organoids carrying COPA in-frame deletions exhibit R-spondin-independent yet Wnt ligand-dependent growth, maintaining LGR5 expression without canonical Wnt drivers. Mechanistically, COPA mutation stabilizes frizzled co-receptor LRP6 irrespective of R-spondin, sustaining Wnt pathway activation under growth factor-restricted conditions. USP9X loss further potentiates this phenotype. Unlike canonical Wnt pathway members, COPA encodes the alpha-subunit of coatomer complex I, which engages in vesicle trafficking with little prior linkage to intestinal tumorigenesis. Our findings establish COPA mutation as a novel and atypical intestinal tumor driver and implicate USP9X loss as a cooperating lesion.

  Study JGAS000868

• DAC for study CMMRD–associated high-grade glioma

  This Data Access Committee (DAC) is responsible for de-identified, summarized somatic variant call data derived from paired tumor–blood Whole-exome sequencing of human samples in a glioma research study. Access requests are approved without additional restrictions and are granted solely for health-related research purposes.

  Dac EGAC50000000855

• Relapse CHL study

  Classical Hodgkin Lymphoma (CHL) is characterized by a complex tumor microenvironment (TME) that supports disease progression. While immune cell recruitment by Hodgkin and Reed–Sternberg (HRS) cells is well-documented, the role of non-malignant B cells in relapse remains unclear. Using single-cell RNA sequencing (scRNA-seq) on paired diagnostic and relapsed CHL samples, we identified distinct shifts in B cell populations, particularly an enrichment of naïve B cells and a reduction of memory B cells in early-relapse compared to late-relapse and newly diagnosed CHL. The enrichment of naïve B cells in early relapse biopsies was confirmed in independent validation cohorts using scRNA-seq and immunohistochemistry. Notably, naïve B cells in early-relapse samples exhibited high expression of LGALS9, an immunosuppressive molecule known to interact with T cell immunoglobulin and mucin domain 3 (TIM-3) on regulatory T cells (Tregs). Cell-cell interaction analysis revealed the importance of interactions between LGALS9+ naïve B cells and TIM-3+ Tregs in the early-relapse setting. Spatial analysis by imaging mass cytometry confirmed close proximity of LGALS9+ naïve B cells with TIM-3⁺ CD4⁺ T cells and HRS cells, pointing to their role in shaping an immunosuppressive niche. Our findings highlight a previously unrecognized population of LGALS9⁺ naïve B cells with immunoregulatory potential in early-relapse CHL and provide new insights into the spatial and transcriptional architecture of the relapsed TME in CHL.

  Study EGAS00001008222

• WES of Mino-VEN-R Mantle Cell Lymphoma Cells

  This project investigates the genetic basis of therapy resistance in mantle cell lymphoma (MCL) using whole exome sequencing (WES) of the Mino_VEN_R cell line, a model of resistance to pirtobrutinib, a non-covalent BTK inhibitor. Our study suggested that drug-tolerant persister (DTP) cells evade therapy through metabolic and phenotypic reprogramming. By analyzing the exome profile of resistant cells, this study aims to identify mutations associated with treatment escape and cellular plasticity. The findings will contribute to a better understanding of resistance mechanisms and support the development of more effective therapeutic strategies.

  Study EGAS50000001088