title: Expression of multidrug resistance-associated ABC transporters in B-CLL is independent of ZAP70 status.
abstract: OBJECTIVE
  To assess whether the poor prognosis of ZAP70-positive B-cell chronic lymphocytic leukemia (CLL) is associated with the overexpression of ABC transporter genes that are responsible for pleiotropic drug resistance.
  
  
  METHODS
  The transcript level of ten drug transporters was analyzed using semiquantitative and quantitative RT-PCR in control hematopoietic cells, in 41 CLL patient samples and in 5 lymphoma cell lines. ZAP70 status was determined by immunoblotting.
  
  
  RESULTS
  Of all analyzed transporters, MDR1, MDR2, MRP1, MRP4, MRP5, and MRP7 were expressed at a significantly higher level in B lymphocytes when compared with other hematopoietic cells in peripheral blood. A subgroup of 41 CLL patient samples showed similar or higher expression of these genes than control B cells, and CLL cells exhibited high expression when compared with multiple lymphoma cell lines. No significant correlation between ZAP70 expression and ABC transporter expression was observed.
  
  
  CONCLUSIONS
  The ZAP70 status is independent of the multidrug resistance phenotype in CLL.
authors.affiliation: III Medical Department, Technische Universität München, Ismaninger Street 15, 81675, Munich, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hoellein
authors.forename: Thomas
authors.initials: T
authors.lastname: Decker
authors.forename: Christian
authors.initials: C
authors.lastname: Bogner
authors.forename: Madlen
authors.initials: M
authors.lastname: Oelsner
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hauswald
authors.forename: Christian
authors.initials: C
authors.lastname: Peschel
authors.forename: Ulrich
authors.initials: U
authors.lastname: Keller
authors.forename: Thomas
authors.initials: T
authors.lastname: Licht
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001773:Blood Cells / Q000378:metabolism / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000378:metabolism; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D014407:Tumor Cells, Cultured; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human