title: Circulating methylated-DCR2 gene in serum as an indicator of prognosis and therapeutic efficacy in patients with MYCN nonamplified neuroblastoma.
abstract: BACKGROUND
  MYCN amplification (MNA) in neuroblastoma is a strong indicator of poor prognosis. However, some MYCN nonamplified (non-MNA) cases show poor outcomes, and examining the status of the gene requires an operation, which may have surgical complications. Therefore, a new marker is needed to identify cases of non-MNA neuroblastomas with poor prognoses using less risky procedures. Aberrant hypermethylation of the DCR2 promoter has recently been associated with rapidly progressing neuroblastoma. We aimed to develop a noninvasive DCR2 methylation assay for patients with neuroblastoma using serum DNA, which predominantly originates from tumor-released DNA.
  
  
  METHODS
  Using DNA-based real-time PCR, we simultaneously quantified a methylated-DCR2 specific sequence (M) and a reference sequence (R) located in the promoter region in serum DNA, and evaluated DCR2 methylation status as M/R ratios in 86 patients with neuroblastoma.
  
  
  RESULTS
  Serum DCR2 M/R ratios were strongly correlated with those in the tumor (r=0.67; P=0.002). DCR2 methylation was associated with stage both in the whole neuroblastoma group and in the non-MNA group (P<0.001), and DCR2-methylated patients showed significantly poorer 5-year event-free survival in the whole neuroblastoma group (43% versus 84%; P<0.001), especially in the non-MNA group (12% versus 96%;P<0.001). Among five DCR2-methylated patients whose clinical courses were followed, serum M/R ratios were close to 0 in the patients in remission, whereas the ratios increased in patients who relapsed.
  
  
  CONCLUSIONS
  Detection of methylated-DCR2 in serum DNA has promise as a noninvasive assay for predicting prognosis and therapeutic efficacy in neuroblastoma, especially in non-MNA cases. Furthermore, it might be a sensitive marker of tumor recurrence in DCR2-methylated cases.
authors.affiliation: Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yagyu
authors.forename: Takahiro
authors.initials: T
authors.lastname: Gotoh
authors.forename: Tomoko
authors.initials: T
authors.lastname: Iehara
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Miyachi
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Katsumi
authors.forename: Satoko
authors.initials: S
authors.lastname: Tsubai-Shimizu
authors.forename: Ken
authors.initials: K
authors.lastname: Kikuchi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tamura
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Imamura
authors.forename: Akiko
authors.initials: A
authors.lastname: Misawa-Furihata
authors.forename: Tohru
authors.initials: T
authors.lastname: Sugimoto
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sawada
authors.forename: Hajime
authors.initials: H
authors.lastname: Hosoi
mesh_terms: D019175:DNA Methylation; D005260:Female; D005784:Gene Amplification; D006801:Humans; D007223:Infant; D008297:Male; D000071447:N-Myc Proto-Oncogene Protein; D009447:Neuroblastoma / Q000097:blood / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D009687:Nuclear Proteins / Q000235:genetics*; D015513:Oncogene Proteins / Q000235:genetics*; D011379:Prognosis; D016896:Treatment Outcome; D053319:Tumor Necrosis Factor Decoy Receptors / Q000235:genetics*
chemical_list: C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; C451501:TNFRSF10D protein, human; D053319:Tumor Necrosis Factor Decoy Receptors