title: Presence of differentiating neuroblasts in bone marrow is a favorable prognostic factor for bone marrow metastatic neuroblastoma at diagnosis.
abstract: BACKGROUND
  The prognostic impact of the presence of differentiating neuroblasts in bone marrow (BM) remains unclear in BM metastatic neuroblastoma (NB). We aimed to identify the prognostic impact of differentiating neuroblasts in BM at diagnosis and after chemotherapy.
  
  
  METHODS
  A total of 51 patients diagnosed with BM metastatic NB at Asan Medical Center between January 1990 and July 2005 were enrolled. BM histology and laboratory data along with overall survival (OS) were compared with regard to the differentiation status of neuroblasts in BM at diagnosis and after chemotherapy.
  
  
  RESULTS
  Among the 51 patients, 13 (25.5%) exhibited differentiating neuroblasts in BM at diagnosis and 17/51 (33.3%) exhibited them after chemotherapy. The only significant difference among patient groups was the improved OS in patients with differentiated neuroblasts in BM at diagnosis (P=0.021). In contrast, the differentiation status of neuroblasts in BM after chemotherapy did not affect OS (P=0.852).
  
  
  CONCLUSIONS
  Our study is the first report describing the presence of differentiating neuroblasts in BM. The presence of differentiating neuroblasts in BM at diagnosis may be a favorable prognostic factor for patients with BM metastatic NB; however, the same phenomenon after chemotherapy is irrelevant to prognosis.
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Park
authors.forename: Sollip
authors.initials: S
authors.lastname: Kim
authors.forename: Chan-Jeoung
authors.initials: CJ
authors.lastname: Park
authors.forename: Seongsoo
authors.initials: S
authors.lastname: Jang
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Chi
authors.forename: Kyung-Nam
authors.initials: KN
authors.lastname: Koh
authors.forename: Ho Joon
authors.initials: HJ
authors.lastname: Im
authors.forename: Jong Jin
authors.initials: JJ
authors.lastname: Seo
mesh_terms: D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001853:Bone Marrow / Q000473:pathology*; D001854:Bone Marrow Cells / Q000166:cytology*; D019046:Bone Marrow Neoplasms / Q000175:diagnosis* / Q000556:secondary; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D060787:Neoplasm Grading; D009447:Neuroblastoma / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D011379:Prognosis; D016019:Survival Analysis; D055815:Young Adult
keywords: Bone marrow; Differentiating neuroblasts; Metastasis; Neuroblastoma; Prognosis