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Series GSE8525 Query DataSets for GSE8525
Status Public on Jul 01, 2008
Title Genotypic and gene expression studies in Congenital Melanocytic Nevi: insight into initial step of tumoral melanogenesis
Organism Homo sapiens
Experiment type Expression profiling by array
Summary 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
Overall design 6 Large Congenital Melanocytic Naevi (CMN), (4 BRAFV600E mutated samples and 2 cases with chromosomal translocations involving BRAF) were co-hybridized with normal control (pool of 13 foreskins) on Human Exonic Evidence Based Oligonucleotide (HEEBO) arrays (Stanford Functional Genomics Facility, California, USA) containing 44544 70mer probes. Hybridizations were replicated with dye swap.
Contributor(s) Dessars B, De Raeve L, El Housni H, Lefort A, Morandini R, Ghanem G, Van den Eynde B, Ma W, Roseeuw D, Vassart G, Libert F, Heimann P
Citation(s) 18633438
Submission date Jul 19, 2007
Last update date Mar 17, 2012
Contact name Frederick Libert
Organization name ULB
Department IRIBHM
Lab C2-140
Street address 808 route de Lennik
City Brussels
ZIP/Postal code B-1070
Country Belgium
Platforms (1)
GPL5621 SFGF HEEBO Human Set v1.00
Samples (12)
GSM211573 Large Congenital Melanocytic Naevi (CMN) : NCG21_1
GSM211574 Large Congenital Melanocytic Naevi (CMN) : NCG21_2
GSM211577 Large Congenital Melanocytic Naevi (CMN) : NCG22_1
BioProject PRJNA101651

Download family Format
SOFT formatted family file(s) SOFTHelp
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Series Matrix File(s) TXTHelp

Supplementary file Size Download File type/resource
GSE8525_RAW.tar 49.2 Mb (http)(custom) TAR (of GPR)
Processed data included within Sample table

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