title: [Prognostic significance of TEL/AML1 rearrangement and its additional genetic changes in Korean childhood precursor B-acute lymphoblastic leukemia].
abstract: BACKGROUND
  TEL (ETV6)/AML1 (RUNX1) rearrangement is observed in approximately 20-25% of childhood precursor B-ALL and is associated with a favorable outcome. Additional genetic changes, associated with TEL/AML1, are frequently found. We evaluated the prevalence and prognostic significance of TEL/AML1 rearrangement and additional genetic changes in the TEL and AML1 genes in Korean childhood precursor B-ALL.
  
  
  METHODS
  We performed FISH using LSITEL/AML1 ES probe (Vysis, USA) in 123 children diagnosed as having precursor B-ALL and assessed clinical relevance of the TEL/AML1 rearrangement and additional genetic abnormalities.
  
  
  RESULTS
  The frequency of TEL/AML1 was 17.1% (21/123) in patients with precursor B-ALL. TEL/ AML1-positive group showed male predominance (P=0.012) and younger age of onset than TEL/ AML1-negative group by 1.6 yr (P=0.013). The outcome of TEL/AML1-positive group tended to show lower incidences of relapse (1/21 vs 20/102), death (1/21 vs 17/102) and longer event free survival. Among TEL/AML1-positive patients, unrearranged TEL deletion, AML1 gain, and unrearranged TEL deletion combined with AML1 gain were detected in 61.9%, 23.8%, and 9.5%, respectively. There were no significant differences in the clinical features and outcome according to the presence or absence of additional genetic changes.
  
  
  CONCLUSIONS
  The frequency of TEL/AML1 and additional genetic changes in TEL and AML1 is higher than previous studies in Korean children, and in close agreement with usually reported one, 20-25%. TEL/AML1-positive group showed a tendency toward better prognosis. Further study is needed to clarify the prognostic significance of additional changes in TEL and AML1 based on a large sample size.
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Hee Young
authors.initials: HY
authors.lastname: Chung
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Kim
authors.forename: Kyung Ran
authors.initials: KR
authors.lastname: Jun
authors.forename: Seongsoo
authors.initials: S
authors.lastname: Jang
authors.forename: Chan-Jeoung
authors.initials: CJ
authors.lastname: Park
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Chi
authors.forename: Ho Joon
authors.initials: HJ
authors.lastname: Im
authors.forename: Jong Jin
authors.initials: JJ
authors.lastname: Seo
authors.forename: Eul-Ju
authors.initials: EJ
authors.lastname: Seo
mesh_terms: D000367:Age Factors; D044466:Asian People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics*; D018572:Disease-Free Survival; D005260:Female; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D007958:Leukocyte Count; D008297:Male; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000401:mortality; D011379:Prognosis; D050783:Proto-Oncogene Proteins c-ets / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D056910:Republic of Korea; D015996:Survival Rate; D014178:Translocation, Genetic; D000097764:ETS Translocation Variant 6 Protein
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D050783:Proto-Oncogene Proteins c-ets; D012097:Repressor Proteins; D000097764:ETS Translocation Variant 6 Protein; C493728:RUNX1 protein, human