99mTechnetium-SESTAMIBI uptake in malignant lymphomas. Correlation with chemotherapy response.
BACKGROUND
The rationale of the present study is based on the property of technetium-SESTAMIBI to enter malignant and other highly metabolic cells, and then to be pumped out of them by the multidrug-resistant (MDR) system, strongly depending on the expression of the MDR-1 gene encoded P-glycoprotein (Pgp-170).


RESULTS
Forty-one patients with malignant lymphoma were studied before chemotherapy. Images were taken 30 min (early) and 180 min (late) after intravenous injection of (99m)Tc-MIBI, and then visually interpreted. They were correlated with clinical response defined as chemosensitive (ChS) when a >6 month remission was attained, and chemoresistant (ChR) to any other response. Of 41 patients, 27 had an early positive uptake, 18 (67%) were ChS, and 9 (33%) ChR. Of these 27 patients, 19 also had late positive scans; 15 (79%) were ChS, and only 4 were ChR (p = 0.037). Conversely, 10 of 14 remaining patients with negative early scans were ChR. Eight patients had an early positive study; however, the late retention of (99m)Tc-MIBI was negative and the relationship to chemotherapy response was not conclusive. A breakdown of data was made according to histology. Patients with low grade lymphoma had the strongest correlation between (99m)Tc-MIBI uptake and chemosensitivity. Patients with high grade lymphoma had only a trend, and patients with Hodgkin's disease had an indefinable correlation.


CONCLUSIONS
This study takes advantage of the relationship between the ability to uptake and retain (99m)Tc-MIBI, a Pgp-170 substrate, by lymphomatous tumors. This attribute, combined with other clinical data, could help to select tailored treatments for patients that are likely to be chemoresistant before treatment.
Departamento de Bioquímica Clínica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.
Alberto
A
Lazarowski
Juan
J
Dupont
José
J
Fernández
Guy
G
Garay
Alejo
A
Florín
Jorge
J
Solimano
Dardo
D
Riveros
Roberto
R
Cacchione
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005709:Gallium Isotopes; D006801:Humans; D008223:Lymphoma / Q000188:drug therapy* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics*; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
D005709:Gallium Isotopes; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi