Assessment of the P-glycoprotein expression by 99mTc-MIBI bone marrow imaging in patients with untreated leukaemia.
The ability of cancer cells to become simultaneously resistant to different drugs is a significant impediment to successful chemotherapy. 99mTc-MIBI has been reported to be a transport substrate for P-glycoprotein (Pgp). The aim of the study was to ascertain the relationship between the degree of 99mTc-MIBI uptake and the level of Pgp expression in patients with newly diagnosed leukaemia. A total of 26 patients (12 female and 14 male; mean age 46.8+/-3.7 years) with newly diagnosed leukaemia were included in the study. None of the patients had been previously treated with chemotherapy. Images were obtained 20 min post-injection of 740 MBq 99mTc-MIBI. Whole-body and planar spot images of the pelvis and thorax were acquired. The uptake of the MIBI in the bone marrow was evaluated using a qualitative and also a quantitative scoring system with determination of the tumour-to-background (T/B) ratios. Flow cytometry was performed for determining the Pgp expression of the blast cells in the bone marrow aspiration samples. There was a statistically significant inverse relationship between the Pgp level in numeric values and both mean qualitative (P<0.001; r=-0.665) and quantitative (P=0.001; r=-0.606) results of 99mTc-MIBI imaging. Both the mean qualitative score and the T/B ratios were higher in patients who were Pgp negative than in those who were Pgp positive (P<0.001 and P<0.001, respectively). These data indicate that an increased level of Pgp expression is correlated with a low accumulation of 99mTc-MIBI in bone marrow of patients with leukaemia. 99mTc-MIBI bone marrow imaging, as a method of functional imaging, can give in vivo information concerning the functional expression of the MDR phenotype in patients with untreated leukaemia.
Ak
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Department of Nuclear Medicine, Osmangazi University Medical Faculty, Eskişehir, Turkey. ilknur_ak@yahoo.com
Aslan
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Vardareli
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Gülbaş
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D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000000981:diagnostic imaging* / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D005260:Female; D006801:Humans; D007938:Leukemia / Q000000981:diagnostic imaging* / Q000378:metabolism*; D015470:Leukemia, Myeloid, Acute / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000000981:diagnostic imaging / Q000378:metabolism; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014915:Whole-Body Counting / Q000379:methods
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi