title: Aberrant methylation of multiple genes in neuroblastic tumours. relationship with MYCN amplification and allelic status at 1p.
abstract: Aberrant hypermethylation occurs in tumour cell CpG islands and is an important pathway for the repression of gene transcription in cancers. We investigated aberrant hypermethylation of 11 genes by methylation-specific polymerase chain reaction (PCR), after treatment of the DNA with bisulphite, and correlated the findings with MYCN amplification and allelic status at 1p in a series of 44 neuroblastic tumours. This tumour series includes five ganglioneuromas (G), one ganglioneuroblastoma (GN) and 38 neuroblastomas (six stage 1 tumours; five stage 2 tumours; six stage 3 cases; 19 stage 4 tumours, and two stage 4S cases). Aberrant methylation of at least one of the 11 genes studied was detected in 95% (42 of 44) of the cases. The frequencies of aberrant methylation were: 64% for thrombospondin-1 (THBS1); 30% for tissue inhibitor of metalloproteinase 3 (TIMP-3); 27% for O6-methylguanine-DNA methyltransferase (MGMT); 25% for p73; 18% for RB1; 14% for death-associated protein kinase (DAPK), p14ARF, p16INK4a and caspase 8, and 0% for TP53 and glutathione S-transferase P1 (GSTP1). No aberrant methylation was observed in four control normal tissue samples (brain and adrenal medulla). MYCN amplification was found in 11 cases (all stage 4 neuroblastomas), whereas allelic loss at 1p was identified in 16 samples (13 stage 4 and two stage 3 neuroblastomas, and one ganglioneuroma). All but one case with caspase 8 methylation also displayed MYCN amplification. Our results suggest that promoter hypermethylation is a frequent epigenetic event in the tumorigenesis of neuroblastic tumours, but no specific pattern of hypermethylated genes could be demonstrated.
authors.affiliation: Laboratorio de Oncogenética Molecular, Dept. C. Experimental, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046, Madrid Spain.
authors.forename: P
authors.initials: P
authors.lastname: Gonzalez-Gomez
authors.forename: M J
authors.initials: MJ
authors.lastname: Bello
authors.forename: J
authors.initials: J
authors.lastname: Lomas
authors.forename: D
authors.initials: D
authors.lastname: Arjona
authors.forename: M E
authors.initials: ME
authors.lastname: Alonso
authors.forename: C
authors.initials: C
authors.lastname: Amiñoso
authors.forename: I
authors.initials: I
authors.lastname: Lopez-Marin
authors.forename: N P
authors.initials: NP
authors.lastname: Anselmo
authors.forename: J L
authors.initials: JL
authors.lastname: Sarasa
authors.forename: M
authors.initials: M
authors.lastname: Gutierrez
authors.forename: C
authors.initials: C
authors.lastname: Casartelli
authors.forename: J A
authors.initials: JA
authors.lastname: Rey
mesh_terms: D002648:Child; D002675:Child, Preschool; D019175:DNA Methylation; D005260:Female; D005784:Gene Amplification; D016259:Genes, myc / Q000235:genetics*; D006801:Humans; D007223:Infant; D019656:Loss of Heterozygosity; D008297:Male; D009447:Neuroblastoma / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods