title: Detection of CpG island hypermethylation of caspase-8 in neuroblastoma using an oligonucleotide array.
abstract: BACKGROUND
  The caspase-8 gene (CASP8) is frequently inactivated in unfavorable neuroblastomas through DNA methylation. The present study utilized oligoarrays to evaluate the methylation status of a CpG island located between exons 2 and 3 of caspase 8 in neuroblastomas.
  
  
  METHODS
  DNA derived from 70 neuroblastomas was amplified by PCR after bisulfate modification and subjected to analysis on a self-made oligoarray that utilized a polycarbodiimide-coated slide to detect methylation of six intragenic CpG islands of caspase 8. In 30 cases, the methylation status was also analyzed by sequencing. In six cases, the PCR product was cloned into a vector and analyzed.
  
  
  RESULTS
  Among the 70 tumor-derived DNAs, methylation was not detected in 18 cases, one methylated CpG was found in 12 cases, two in 18 cases, three in 3 cases, four in 8 cases, five in 1 case and six in 10 cases. All methylated CpG loci detected by sequencing were detected by oligoarray, but some methylated CpGs in three loci were detected by oligoarray alone. In these discrepant loci, methylation was detected in some clones after subcloning, indicating that the oligoarray might be more sensitive than sequencing. The CASP8 expression level was depressed in the tumors having two distinct CpG doublets. These results were significantly correlated with MYCN amplification and with clinical outcomes.
  
  
  CONCLUSIONS
  A significant difference in the methylation status within the CpG island of CASP8 was shown between favorable and unfavorable subtypes, and CASP8 methylation detected by oligoarray may be useful in the clinical evaluation of neuroblastomas.
authors.affiliation: Department of Surgery, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan.
authors.forename: Arata
authors.initials: A
authors.lastname: Kamimatsuse
authors.forename: Kaoru
authors.initials: K
authors.lastname: Matsuura
authors.forename: Shogo
authors.initials: S
authors.lastname: Moriya
authors.forename: Ikuko
authors.initials: I
authors.lastname: Fukuba
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yamaoka
authors.forename: Emi
authors.initials: E
authors.lastname: Fukuda
authors.forename: Naomi
authors.initials: N
authors.lastname: Kamei
authors.forename: Keiko
authors.initials: K
authors.lastname: Hiyama
authors.forename: Taijiro
authors.initials: T
authors.lastname: Sueda
authors.forename: Eiso
authors.initials: E
authors.lastname: Hiyama
mesh_terms: D000293:Adolescent; D000328:Adult; D053181:Caspase 8 / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D018899:CpG Islands / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007438:Introns / Q000235:genetics; D009447:Neuroblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D011379:Prognosis; D015996:Survival Rate; D055815:Young Adult
chemical_list: D004247:DNA; D053181:Caspase 8