Influence of glioma's multidrug resistance phenotype on (99m)Tc-tetrofosmin uptake.
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.
Alexiou
George A
GA
Department of Neurosurgery, University Hospital of Ioannina, Ioannina, Greece. alexiougrg@yahoo.gr
Goussia
Anna
A
Kyritsis
Athanasios P
AP
Tsiouris
Spyridon
S
Ntoulia
Antigoni
A
Malamou-Mitsi
Vassiliki
V
Voulgaris
Spyridon
S
Fotopoulos
Andreas D
AD
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
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; C078700:technetium tc-99m tetrofosmin