title: Influence of glioma's multidrug resistance phenotype on (99m)Tc-tetrofosmin uptake.
abstract: OBJECTIVE
  Multidrug resistance (MDR) remains a major obstacle to successful chemotherapeutic treatment of cancer. Several chemotherapeutic and radiopharmaceutical agents are substrates of the pumps encoded by the MDR genes, and therefore, their accumulation is prevented. We evaluated in vivo whether [(99m)Tc]tetrofosmin ((99m)Tc-TF) uptake is influenced by the MDR profile of gliomas.
  
  
  METHODS
  Eighteen patients with histologically confirmed glioma were included in the study. Brain single-photon emission computed tomography by (99m)Tc-TF was performed within a week prior to surgical excision, and the expression of MRP5 was assessed by immunohistochemistry. Radiotracer accumulation was assessed by a semiquantitative method, calculating the lesion-to-normal uptake ratio.
  
  
  RESULTS
  Using Spearman's ρ analysis, we found no correlation between tracer uptake expressed as lesion-to-normal and MRP5 expression. There was a significant correlation between glioma aggressiveness as assessed by Ki-67/MIB-1 and MRP5 expression.
  
  
  CONCLUSIONS
  The present data suggest that (99m)Tc-TF uptake is not influenced by glioma's MDR phenotype. Thus, (99m)Tc-TF constitutes a suitable radiotracer for imaging gliomas.
authors.affiliation: Department of Neurosurgery, University Hospital of Ioannina, Ioannina, Greece. alexiougrg@yahoo.gr
authors.forename: George A
authors.initials: GA
authors.lastname: Alexiou
authors.forename: Anna
authors.initials: A
authors.lastname: Goussia
authors.forename: Athanasios P
authors.initials: AP
authors.lastname: Kyritsis
authors.forename: Spyridon
authors.initials: S
authors.lastname: Tsiouris
authors.forename: Antigoni
authors.initials: A
authors.lastname: Ntoulia
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Malamou-Mitsi
authors.forename: Spyridon
authors.initials: S
authors.lastname: Voulgaris
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Fotopoulos
mesh_terms: D000328:Adult; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics*; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D010641:Phenotype; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; C078700:technetium tc-99m tetrofosmin