In vivo detection of multidrug-resistant (MDR1) phenotype by technetium-99m sestamibi scan in untreated breast cancer patients

Silvana Del Vecchio, Andrea Ciarmiello, Maria I. Potena, Maria V. Carriero, Ciro Mainolfi, Gerardo Botti, Renato Thomas, Maria Cerra, Giuseppe D'Aiuto, Takashi Tsuruo, Marco Salvatore

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Technetium-99m sestamibi is a transport substrate recognised by the multidrug-resistant P-glycoprotein (Pgp). To test whether99mTc-sestamibi efflux is enhanced in breast carcinomas overexpressing Pgp, we determined the efflux rates of99mTc-sestamibi and Pgp levels in tumours from 30 patients with untreated breast carcinoma. Patients were intravenously injected with 740 MBq of99mTc-sestamibi and underwent a 15-min dynamic study followed by the acquisition of static planar images at 0.5, 1, 2 and 4 h. Tumour specimens were obtained from each patient 24 h after99mTc-sestamibi scan and Pgp levels were determined using125I-MRK16 monoclonal antibody and in vitro quantitative autoradiography. All breast carcinomas showed high uptake of99mTc-sestamibi and data from region of interest analysis on sequential images were fitted with a monoexponential function. The efflux rates of99mTc-sestamibi, calculated from decay-corrected time-activity curves, ranged between 0.00121 and 0.01690 min-1 and were directly correlated with Pgp levels measured in the same tumours (r=0.62;P99mTc-sestamibi efflux from tumours of group A was 2.7 times higher than that observed in tumours of group B (0.00686±0.00390 min-1 vs 0.00250±0.00090 min-1, P99mTc-sestamibi showed a sensitivity and a specificity of 80% and 95%, respectively. In conclusion, the efflux rate of99mTc-sestamibi may be used for the in vivo identification of the multidrug resistant (MDR1) phenotype in untreated breast cancer patients.

Original languageEnglish
Pages (from-to)150-159
Number of pages10
JournalEuropean Journal Of Nuclear Medicine
Issue number2
Publication statusPublished - Feb 1997


  • Breast carcinoma
  • Multidrug resistance
  • P-glycoprotein
  • Technetium-99m sestamibi

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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