title: Expression of CD66c and CD25 in acute lymphoblastic leukemia as a predictor of the presence of BCR/ABL rearrangement.
abstract: BACKGROUND
  Expression of myeloid or T cell lymphoid in precursor B cell acute lymphoblastic leukemia (pre-B cell ALL), which is referred to as aberrant expression, is quite a common phenomenon. CD66c is a myeloid marker which has aberrant expression in pre-B cell ALL, with strong correlation with non-random genetic changes (BCR/ABL rearrangement). Another leukemia associated marker (CD25) is frequently expressed in pre-B cell ALL. The frequency of CD25-expressing lymphoblasts has been found to be significantly higher in BCR/ABL-positive vs. BCR/ABL-negative patients.
  
  
  METHODS
  In a cohort of 103 patients diagnosed with pre-B cell ALL or biphenotypic leukemia and studied for expression of CD66c and CD25 at presentation, we evaluated the frequency of expression of either or both in BCR/ABL positive cases.
  
  
  RESULTS
  Surface CD66c was expressed by 70 cases (68%) and CD25 was expressed by 33 cases (32%) while both were expressed together on 29 cases (28%). BCR/ABL was positive in 18/103 patients. All BCR/ABL positive cases were positive for surface CD66c and CD25.
  
  
  CONCLUSIONS
  Positivity for both leukemia-associated antigens CD66c and CD25 in combination can predict the presence of BCR/ABL rearrangement in pre-B cell ALL. While this finding does not replace the detection of BCR/ABL abnormality by cytogenetic or molecular techniques, it does provide an early and handy tool for prediction and management of high-risk cases of pre-B cell ALL, especially in centers with limited laboratory facilities.
authors.affiliation: Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Center Riyadh, Saudi Arabia. towaidah@kfshrc.edu.sa
authors.forename: Tarek M
authors.initials: TM
authors.lastname: Owaidah
authors.forename: Faisal I
authors.initials: FI
authors.lastname: Rawas
authors.forename: Mazen F
authors.initials: MF
authors.lastname: Al Khayatt
authors.forename: Nasser B
authors.initials: NB
authors.lastname: Elkum
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism*; D058851:GPI-Linked Proteins; D006801:Humans; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014178:Translocation, Genetic; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; C504117:CEACAM6 protein, human; D015815:Cell Adhesion Molecules; D058851:GPI-Linked Proteins; D053645:Interleukin-2 Receptor alpha Subunit; D016044:Fusion Proteins, bcr-abl