title: The expression of CD56 antigen is associated with poor prognosis in patients with acute myeloid leukemia.
abstract: BACKGROUND
  The expression of CD56 is considered a bad prognostic factor for overall survival, lower rates or short complete remission and extramedullary invasion but the results are controversial. The importance of validating new prognostic parameters in acute leukemias was the reason to investigate the CD56 expression in blast cells of patients with acute myeloid leukemia.
  
  
  METHODS
  A cohort of 48 patients treated at Hospital de Clinicas de Porto Alegre and diagnosed with acute myeloid leukemia as classified by the French-American-British group (FAB) criteria using cell morphology, cytochemistry and flow cytometry were evaluated.
  
  
  RESULTS
  Eight cases (16.7%) were CD56 positive without correlation to age or gender. The highest incidence of CD56 positivity was in FAB subtypes M4 and M5. The death rate during induction was not significantly different between patients with and without CD56 expression (62.5% vs. 27.5%; p-value = 0.097). However, patients that expressed CD56 had significantly lower overall survival than those who did not (mean 4.0 months vs. 14.5 months; p-value = 0.03).
  
  
  CONCLUSIONS
  The data suggest that expression of CD56 in acute myeloid leukemia may be indicative of poor prognosis because it is associated with a shorter overall survival. The death rate during induction was not significantly different despite an apparent difference in proportions between groups.
authors.affiliation: Clinical Pathology Service, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul - UFRGS, Porto Alegre, RS, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Alegretti
authors.forename: Christina Matzenbacher
authors.initials: CM
authors.lastname: Bittar
authors.forename: Rosane
authors.initials: R
authors.lastname: Bittencourt
authors.forename: Amanda Kirchner
authors.initials: AK
authors.lastname: Piccoli
authors.forename: Laiana
authors.initials: L
authors.lastname: Schneider
authors.forename: Lúcia Mariano
authors.initials: LM
authors.lastname: Silla
authors.forename: Suzane Dal
authors.initials: SD
authors.lastname: Bó
authors.forename: Ricardo Machado
authors.initials: RM
authors.lastname: Xavier