title: Expression of CD25 is a specific and relatively sensitive marker for the Philadelphia chromosome (BCR-ABL1) translocation in pediatric B acute lymphoblastic leukemia.
abstract: BACKGROUND
  Precursor B acute lymphoblastic leukemia (B-ALL) is the most common cancer in children and overall, has an excellent prognosis. However, the Philadelphia chromosome translocation (Ph+), t(9;22)(q34;q11), is present in a small subset of patients and confers poor outcomes. CD25 (IL-2 receptor alpha chain) expression has been associated with Ph+ B-ALL in adults, but no similar study has been performed in pediatric B-ALL.
  
  
  METHODS
  A retrospective analysis of 221 consecutive pediatric patients with a diagnosis of B-ALL (blood and/or bone marrow) from 2009 to 2012 was performed to determine an association between Ph+ B-ALL and CD25 expression. A threshold of 25% was used to define positive cases for CD25 expression by flow cytometry.
  
  
  RESULTS
  There were 221 patients with a diagnosis of B-ALL ranging from 2 to 22 years (median, 6 years). Eight (3.6%) B-ALL patients were positive for the Philadelphia chromosome translocation (Ph+ B-ALL) and 213 were negative (Ph-negative B-ALL). CD25 expression was observed in 6 of 8 (75%) Ph+ B-ALL patients and 6 of 213 (2.8%) Ph-negative B-ALL patients. CD25 expression was significantly higher in Ph+ B-ALL compared to Ph-negative B-ALL, with median CD25 expression of 64% (range 0-93%) and 0.1% (range 0-91%), respectively (P ≤ 0.0002). Therefore, CD25 expression as a predictor of Ph+ B-ALL had 75% sensitivity, 97% specificity, 50% positive predictive value and 99% negative predictive value.
  
  
  CONCLUSIONS
  CD25 expression is a specific and relatively sensitive marker for the identification of Ph+ B-ALL in the pediatric population.
authors.affiliation: Texas Children's Cancer and Hematology Centers Houston, Texas ; Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Amos S
authors.initials: AS
authors.lastname: Gaikwad
authors.affiliation: Department of Pathology and Genomic Medicine, Houston Methodist Hospital Houston, Texas.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Donohue
authors.affiliation: Department of Pathology, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: M Tarek
authors.initials: MT
authors.lastname: Elghetany
authors.affiliation: Department of Pathology, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Sheehan
authors.affiliation: Department of Hematopathology, MD Anderson Cancer Center Houston, Texas.
authors.forename: Xinyan Y
authors.initials: XY
authors.lastname: Lu
authors.affiliation: Texas Children's Cancer and Hematology Centers Houston, Texas ; Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Gramatges
authors.affiliation: Texas Children's Cancer and Hematology Centers Houston, Texas ; Department of Pediatrics, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: McClain
authors.affiliation: Department of Pathology, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Toni-Ann
authors.initials: TA
authors.lastname: Mistretta
authors.affiliation: Department of Pathology, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Jyotinder N
authors.initials: JN
authors.lastname: Punia
authors.affiliation: Texas Children's Cancer and Hematology Centers Houston, Texas.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Moore
authors.affiliation: Texas Children's Cancer and Hematology Centers Houston, Texas.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Goltsova
authors.affiliation: Texas Children's Cancer and Hematology Centers Houston, Texas.
authors.forename: Michael
authors.initials: M
authors.lastname: Cubbage
authors.affiliation: Department of Pathology, Texas Children's Hospital and Baylor College of Medicine Houston, Texas.
authors.forename: Choladda V
authors.initials: CV
authors.lastname: Curry
mesh_terms: D000293:Adolescent; D000367:Age Factors; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis*; D008297:Male; D010677:Philadelphia Chromosome; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000276:immunology* / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D014178:Translocation, Genetic; D015854:Up-Regulation; D055815:Young Adult
chemical_list: C581634:BCR-ABL1 fusion protein, human; D014408:Biomarkers, Tumor; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D016044:Fusion Proteins, bcr-abl
keywords: B acute lymphoblastic leukemia; B-ALL; BCR-ABL; CD25; Ph+; Ph+ B-ALL; Philadelphia chromosome; flow cytometry; pediatric; t(9;22)