P-glycoprotein expression by technetium-99m-MIBI scintigraphy in hematologic malignancy.
Our aim was to ascertain the relationship between the degree of 99mTc-MIBI uptake and the level of p-glycoprotein (Pgp) expression determined by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR) techniques in patients with hematologic malignancy.


METHODS
A total of 21 samples (19 patients) were evaluated. Two patients had repeat studies after therapy. Thirteen samples were studied at the time of initial diagnosis and 8 during relapse after therapy. After MIBI imaging, either bone marrow aspiration or peripheral blood was obtained for flow cytometric and RT-PCR analyses. Flow cytometry was performed using two different antibodies. After the injection of 555 MBq MIBI, whole-body and pelvic spot images were acquired using a dual-head gamma camera. The uptake in the bone marrow was evaluated against the background (adjacent soft tissue) by both qualitative (scoring system) and quantitative (tm/bkg ratios) analyses.


RESULTS
For flow cytometry, the limit for Pgp overexpression was set at >15% Pgp-positive mononuclear bone marrow or peripheral blood cells. There was an inverse correlation between the levels of Pgp and MIBI imaging using both the qualitative (scoring system) and quantitative (tm/bkg ratios) analyses (p = 0.022). Mean values were statistically different between Pgp+ and Pgp- groups for both qualitative and quantitative analyses (p = 0.009 and 0.024, respectively). For RT-PCR, there was statistical support toward a difference in the mean values between Pgp+ and Pgp- groups by qualitative analysis (p = 0.061); however, no statistical difference was found between these two groups by quantitative analysis (p = 0.179).


CONCLUSIONS
Based on the strong correlation between the imaging and flow cytometry and a statistical support toward the correlation between the imaging and RT-PCR, MIBI imaging may be used for the in vivo detection of Pgp in patients with hematologic malignancy.
Department of Nuclear Medicine, Hacettepe University Medical Faculty, Ankara, Turkey.
L
L
Kostakoglu
D
D
Guc
H
H
Canpinar
A
A
Kars
E
E
Alper
P
P
Kiratli
M
M
Hayran
U
U
Gündüz
E
E
Kansu
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D019450:Genes, MDR; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000000981:diagnostic imaging* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D012333:RNA, Messenger; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi