title: BCR-ABL1 and CD66c exhibit high concordance in minimal residual disease detection of adult B-acute lymphoblastic leukemia.
abstract: OBJECTIVE
  To investigate the relationship between surface expression of CD66c and the breakpoint cluster region-Abelson (BCR-ABL1) fusion gene in B-acute lymphoblastic leukemia (B-ALL) at primary diagnosis, and their concordance during minimal residual disease (MRD) monitoring.
  
  
  METHODS
  Bone marrow biopsies were collected from newly diagnosed B-ALL patients (n = 43) between September 2011 and September 2014. Karyotyping was used to detect Philadelphia chromosome (Ph), and fluorescence in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect BCR-ABL1 fusion gene. Immunophenotyping was performed by flow cytometry for leukemia. Patients with both CD66c expression and BCR-ABL1 were further assessed for MRD during treatment.
  
  
  RESULTS
  Overall, 26/43 (60.5%) B-ALL patients were positive for BCR-ABL1 fusion gene expression, and all Ph positive cases (17/43; 39.5%) expressed BCR-ABL1 and CD66c. CD66c was expressed at significantly higher levels in BCR-ABL1 positive than negative patients (24/26, 92.3% vs. 11/17, 64.7%; P = 0.042), and furthermore, in all Ph positive cases (17/17, 100% vs. 18/26, 69.2%; P = 0.014). When BCR-ABL1 was set as the gold standard for the presence or absence of MRD after treatment, both CD66c alone and the MRD panel including CD66c demonstrated high diagnostic performance for the detection of MRD, with values of area under the receptor operation curve (ROC) of 0.881 vs. 0.891 respectively.
  
  
  CONCLUSIONS
  The stable expression pattern of CD66c has noteworthy clinical value in B-ALL not only in the recognition of abnormal leukemia cells at primary diagnosis but also in monitoring of MRD during the treatment, especially in patients without definitely cytogenetic or molecular abnormal, and thus, warrants further investigation as a routine clinical marker for MRD detection by flow cytometry.
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Gu-Sheng
authors.initials: GS
authors.lastname: Tang
authors.affiliation: Department of Sterile Supply, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Shen-Glan
authors.initials: SG
authors.lastname: Gong
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Yang
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Hu
authors.affiliation: Department of Hematology, Changhai Hospital, Second Military Medical University Shanghai, China.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Wang
keywords: B-acute lymphoblastic leukemia (B-ALL); BCR-ABL1; CD66c; diagnostic performance; minimal residual disease (MRD)