title: E2A-PBX1 exhibited a promising prognosis in pediatric acute lymphoblastic leukemia treated with the CCLG-ALL2008 protocol.
abstract: OBJECTIVE
  The objective of this study was to observe the prognosis of pediatric patients with E2A-PBX1-positive acute lymphoblastic leukemia (ALL) from the treatment with the CCLG-ALL2008 protocol.
  
  
  METHODS
  Three hundred and forty-nine Chinese pediatric patients with pre-B-cell ALL were enrolled in this study from December 2008 to September 2013. Of these, 20 patients with E2A-PBX1 expression and 223 without the gene expression were stratified into two cohorts. Clinical and biological characteristics and 5-year event-free survival (EFS), relapse-free survival (RFS), and overall survival (OS) were analyzed and compared between these two groups.
  
  
  RESULTS
  The E2A-PBX1 fusion transcript was detected in 20 of 349 (5.7%) patients. Compared with the gene-negative subgroup, patients with E2A-PBX1 were younger in age but did not show significant differences in white blood cell (WBC) count or gender distribution at primary diagnosis. Moreover, there were more inferior karyotypes detected in the E2A-PBX1 subgroup (P=0.035). With the CCLG-ALL2008 treatment protocol, patients with E2A-PBX1 showed a favorable treatment response with lower minimal residual disease (MRD) levels (<10-4) at time point 1 (TP1,P=0.039) but no superior steroid response or histological remission. We also observed a promising survival outcome, with a 5-year EFS reaching 95.0%±4.9% versus 66.3%±3.9% in the gene-negative group (P=0.039). However, we did not find significant differences in RFS (P=0.061) and OS (P=0.113).
  
  
  CONCLUSIONS
  Our data provided clinical observation of Chinese pediatric patients. Patients with E2A-PBX1-positive ALL benefited well from the CCLG-ALL2008 protocol, a risk-based intensified treatment trial, with lower levels of MRD and longer RFS duration though they had no favorable characteristics at primary diagnosis.
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Hailong
authors.initials: H
authors.lastname: He
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Peifang
authors.initials: P
authors.lastname: Xiao
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Jianqin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Yina
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Lv
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Fan
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Yihuan
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Department of Hematology and Oncology, The Children's Hospital of Soochow University, Suzhou, People's Republic of China.
authors.forename: Shaoyan
authors.initials: S
authors.lastname: Hu
keywords: CCLG-ALL2008 protocol; E2A-PBX1 gene transcript; acute lymphoblastic leukemia; pediatric; prognosis