Ontology highlight
ABSTRACT:
PROVIDER: PRJNA832532 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Large Congenital Melanocytic Naevi have a higher propensity to malignant transformation compared to acquired naevi. They thus represent a good model for studying initial steps of melanocarcinogenesis. We have performed genotypic (karyotype, FISH and mutational analyses) and differential expression studies on a large cohort of medium (n=3) and large (n=24) congenital melanocytic naevi. Unlike malignant melanoma, chromosomal abnormalities were rare and single, a feature probably reflecting the benignity of these lesions. Mutational screening showed a high frequency of NRAS mutations in our series, while BRAF mutations were less common. Differential expression study between tumoral and normal melanocytes did not show significant alterations of cellular processes such as cell proliferation, cell migration/invasion, angiogenesis, apoptosis, and immune/inflammatory responses. However, significant down-regulation of genes involved in pigmentation and up-regulation of genes playing a role in DNA protection were observed. Lastly, our micro-arrays displayed up-regulation of genes mediating chemoresistance in cancer. As alteration of pigmentation mechanisms can trigger oxidative damage, increased expression of genes involved in maintenance of DNA integrity might reflect the ability of naevocytic cells to self protection against cellular stress. Furthermore, the observed alterations linked to chemoresistance might partially account for the well known inefficacy of chemotherapy in malignant melanoma. Keywords: cell type comparison
2008-07-01 | GSE8525 | GEO
Project description:Large and giant congenital melanocytic nevi (CMN) are rare melanocytic lesions mostly caused by post-zygotic acquisition of NRAS alteration. However, large/giant CMN may exhibit phenotypic differences among distinct areas patients and in addition, patients differ in features such as presence of multiple CMN or Spilus-like lesions. Overall, 50 fresh-frozen biopsies corresponding to 37 phenotypically characterized areas of large/giant CMNs, 9 satellite lesions, 1 acquired nevus and 3 healthy skin biopsies were analyzed by a multigene panel and RNA sequencing (RNA-seq). Mutational screening showed mutations in 76.2% of large/giant CMN. NRAS mutation was found in 57.1% of cases, and mutations in other genes such as BRAF, KRAS, APC and MET were detected in 14.3% of patients. RNA-seq revealed the fusion transcript ZEB2-ALK and SOX5-RAF1 in large/giant CMN from two patients without point mutations. Both alterations were not detected in unaffected skin and were detected in different affected skin. These findings suggest that large/giant CMN may result from distinct molecular events in addition to NRAS mutations including point mutations and fusions transcripts.
2019-10-24 | GSE120597 | GEO
Project description:Targeted genetic therapy for congenital melanocytic naevi
| PRJEB64644 | ENA
Project description:Among children with multiple congenital melanocytic naevi (CMN), 25% have no established genetic cause. Here, we study 169 CMN patients, 38 of whom were double wild-type for NRAS/BRAF mutations. Nineteen of these 38 patients had sufficient tissue to undergo RNAseq, which revealed mosaic BRAF fusions in 11/19 patients and mosaic RAF1 fusions in 1/19. These findings offer a genetic diagnosis to an additional group of patients opening the possibility for treatment options.
2023-09-30 | E-MTAB-13182 | biostudies-arrayexpress
Project description:Genetic profiles of large/giant congenital melanocytic nevi with familial or sporadic occurrence.
| PRJNA977656 | ENA
Project description:The most common mutation in human melanoma, BRAF(V600E), activates the serine/threonine kinase BRAF and causes excessive activity in the mitogen-activated protein kinase pathway. BRAF(V600E) mutations are also present in benign melanocytic naevi, highlighting the importance of additional genetic alterations in the genesis of malignant tumours. Such changes include recurrent copy number variations that result in the amplification of oncogenes. For certain amplifications, the large number of genes in the interval has precluded an understanding of the cooperating oncogenic events. Here we have used a zebrafish melanoma model to test genes in a recurrently amplified region of chromosome 1 for the ability to cooperate with BRAF(V600E) and accelerate melanoma. SETDB1, an enzyme that methylates histone H3 on lysine 9 (H3K9), was found to accelerate melanoma formation significantly in zebrafish. Chromatin immunoprecipitation coupled with massively parallel DNA sequencing and gene expression analyses uncovered genes, including HOX genes, that are transcriptionally dysregulated in response to increased levels of SETDB1. Our studies establish SETDB1 as an oncogene in melanoma and underscore the role of chromatin factors in regulating tumorigenesis. DNA was enriched from short-term cultures of cells and chromatin immunoprecipitations (ChIPs) were analyzed by Solexa sequencing. ChIPs were performed using an antibody against SetDB1 in WM853.2. Whole cell extracts are provided for WM262, WM451Lu and WM853.2 cells.
2012-03-17 | E-GEOD-36579 | biostudies-arrayexpress
Project description:Mosaic BRAF fusions are a recurrent cause of congenital melanocytic naevi targetable by MEK inhibition
| PRJEB64546 | ENA
Project description:Congenital melanocytic nevi (CMN) and common acquired melanocytic nevi (AMN) are skin conditions that result from an excess of melanocytes arising during fetal development or detected postnatally. Appropriately weighted whole-genome methylation analysis can be used as a basis for further research in dermatopathology and, in this application, provides new insights into nevus biology.
2024-06-17 | GSE268769 | GEO