title: Drug resistance associated properties of blasts subpopulations with different CD34 expression in childhood acute lymphoblastic leukemia (ALL).
abstract: OBJECTIVE
  The objective of this study was to investigate expression of drug resistance associated genes in CD34+ and CD34- leukemic subpopulations in childhood acute lymphoblastic leukemia (ALL).
  
  
  METHODS
  ALL samples with heterogeneous CD34 expression were separated into CD34-positive and CD34-negative subpopulations and mRNA levels of MDR1, LRP, BCRP and BCL-2 genes were compared.
  
  
  RESULTS
  BCL-2 gene expression levels did not differ significantly between CD34+ vs CD34- subpopulations in most analyzed ALL cases. Oppositely, MDR1 gene had >two-fold differences in expression levels between subpopulations in the majority of ALL cases. In T-lineage ALL CD34- fractions had increased level of BCRP and LRP genes in comparison with CD34+ ones whereas in most of B-lineage ALL expression of these genes did not differ.
  
  
  CONCLUSIONS
  It was not found the unique pattern of resistance related genes expression in CD34+ vs CD34- subpopulations. However, in majority of studied pediatric ALL cases with CD34 heterogeneous expression one of subpopulations (positive or negative) could have an advantage for survival through elevated expression of drug resistance related genes.
authors.affiliation: Belarusian Research Center for Pediatric Oncology and Hematology, Minsk, Belarus. t_shman@yahoo.com
authors.forename: T V
authors.initials: TV
authors.lastname: Shman
authors.forename: U U
authors.initials: UU
authors.lastname: Fedasenka
authors.forename: V P
authors.initials: VP
authors.lastname: Savitski
authors.forename: A M
authors.initials: AM
authors.lastname: Kustanovich
authors.forename: O V
authors.initials: OV
authors.lastname: Aleinikova
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000293:Adolescent; D018952:Antigens, CD34 / Q000032:analysis*; D045744:Cell Line, Tumor; D002648:Child; D002675:Child, Preschool; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020394:Vault Ribonucleoprotein Particles / Q000235:genetics; D000099187:Major Vault Protein
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D018952:Antigens, CD34; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein; C513055:ABCB1 protein, human; C116614:ABCG2 protein, human