title: Lymphoblast biology and outcome among children with Down syndrome and ALL treated on CCG-1952.
abstract: BACKGROUND
  Patients with Down syndrome (DS) and standard risk (SR) acute lymphoblastic leukemia (ALL-DS) are reported to have inferior event free (EFS) and overall survival (OS) compared to patients without DS (ALL-NDS).
  
  
  METHODS
  We compared the prevalence of favorable and unfavorable clinical and biologic features, toxicity and outcome within the ALL-DS and ALL-NDS cohorts of 2,174 eligible patients with SR-ALL enrolled on CCG-1952.
  
  
  RESULTS
  Fifty-nine patients (3%) had ALL-DS. DS patients were less likely to have either favorable (hyperdiploidy, triple trisomy of chromosomes 4, 10, and 17, TEL-AML1 rearrangement) or unfavorable (T-cell ALL, hypodiploidy, adverse translocations) biologic features. Toxicity occurred significantly more often and number of days hospitalized was significantly greater in ALL-DS than in ALL-NDS. ALL-DS patients had an inferior 4-year EFS compared to the NDS cohort. However, EFS was equivalent when the comparison excluded ALL-NDS with favorable biologic features. OS was significantly inferior for ALL-DS.
  
  
  CONCLUSIONS
  The absence of favorable biologic features within ALL-DS contributes to the difference in EFS previously observed between DS and NDS SR-ALL cohorts.
authors.affiliation: Pediatric Hematology/Oncology/BMT, University of Colorado Health Sciences Center, Denver, Colorado, USA. bassal.mylene@tchden.org
authors.forename: Mylène
authors.initials: M
authors.lastname: Bassal
authors.forename: Mei K
authors.initials: MK
authors.lastname: La
authors.forename: James A
authors.initials: JA
authors.lastname: Whitlock
authors.forename: Harland N
authors.initials: HN
authors.lastname: Sather
authors.forename: Nyla A
authors.initials: NA
authors.lastname: Heerema
authors.forename: Paul S
authors.initials: PS
authors.lastname: Gaynon
authors.forename: Linda C
authors.initials: LC
authors.lastname: Stork
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D004314:Down Syndrome / Q000150:complications*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011003:Ploidies; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D011379:Prognosis; D016896:Treatment Outcome