title: Expression of interleukin 15 in primary adult acute lymphoblastic leukemia.
abstract: BACKGROUND
  Interleukin-15 (IL-15) has been associated with the growth, survival and biological behavior of leukemic cells and response to therapy. We determined the expression of IL-15 in lymphoblasts and evaluated its potential impact on the outcome in adult acute lymphoblastic leukemia (ALL).
  
  
  METHODS
  Between June 1999 and June 2006, ALL samples were collected from 87 adult patients before initiation of antineoplastic therapy. These patients were enrolled in the German Multicenter Acute Lymphoblastic Leukemia June 1999 and July 2003 study trials. The expression of IL-15 in leukemic cells was analyzed by real-time polymerase chain reaction.
  
  
  RESULTS
  The expression of IL-15 correlated with the immunophenotype: T-lineage ALL had a more than 4-fold higher IL-15 mRNA expression as compared with B-cell precursor (BCP)-ALL (P < .001). Patients with BCR-ABL(+)-BCP-ALL had lower IL-15 expression compared with BCR-ABL(-)-BCP-ALL (P = .041). Furthermore, higher expression of IL-15 was associated with mediastinal (P = .001) and lymph node infiltration (P = .051), but not with hepatomegaly and splenomegaly. Notably, high IL-15 expression in BCP-ALL was associated with an inferior relapse-free survival (RFS) at 5 years (0.17 +/- 0.13 vs 0.47 +/- 0.13) (P = .008), but there was no impact on overall survival (P = .249).
  
  
  CONCLUSIONS
  Differential expression of IL-15 in adult ALL at diagnosis was associated with clinical features and outcome, in particular, RFS. It remains to be evaluated whether IL-15 might be a relevant therapy target, or might be used for risk stratification.
authors.affiliation: Department of Hematology, Oncology and Transfusion Medicine, Campus Benjamin Franklin, Charity Medical Center, Hindenburgdamm 30, 12203 Berlin, Germany. shuling.wu@charite.de
authors.forename: Shuling
authors.initials: S
authors.lastname: Wu
authors.forename: Lars
authors.initials: L
authors.lastname: Fischer
authors.forename: Nicola
authors.initials: N
authors.lastname: Gökbuget
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwartz
authors.forename: Thomas
authors.initials: T
authors.lastname: Burmeister
authors.forename: Michael
authors.initials: M
authors.lastname: Notter
authors.forename: Dieter
authors.initials: D
authors.lastname: Hoelzer
authors.forename: Hendrik
authors.initials: H
authors.lastname: Fuchs
authors.forename: Igor Wolfgang
authors.initials: IW
authors.lastname: Blau
authors.forename: Wolf K
authors.initials: WK
authors.lastname: Hofmann
authors.forename: Eckhard
authors.initials: E
authors.lastname: Thiel
mesh_terms: D000293:Adolescent; D000328:Adult; D018572:Disease-Free Survival; D005260:Female; D015870:Gene Expression; D006801:Humans; D016130:Immunophenotyping; D019409:Interleukin-15 / Q000235:genetics*; D007621:Karyotyping; D008207:Lymphatic Metastasis; D008297:Male; D008479:Mediastinal Neoplasms / Q000556:secondary; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D019409:Interleukin-15