title: Tc-99m MIBI SPECT is useful for noninvasively predicting the presence of MDR1 gene-encoded P-glycoprotein in patients with hepatocellular carcinoma.
abstract: OBJECTIVE
  Resistance to chemotherapeutic drugs continues to be one of the major unsolved problems in the treatment of cancer. Multidrug resistance is defined as the ability of cells exposed to a single drug to develop resistance to a broad range of structurally and functionally unrelated drugs as a result of enhanced outward transport of drugs mediated by P-glycoprotein that is encoded by multidrug resistance genes. Recent evidence has shown that Tc-99m MIBI is a suitable transport substrate for P-glycoprotein. A potential advantage of Tc-99m MIBI SPECT is its superiority to diagnose noninvasively the presence of P-glycoprotein overexpression in vivo. In this study, the authors determined the association of enhanced MIBI efflux in Tc-99m MIBI SPECT with overexpression of P-glycoprotein in hepatocellular carcinoma.
  
  
  METHODS
  Thirty-five patients with hepatocellular carcinoma were enrolled in the study. Tc-99m MIBI SPECT was performed 10 minutes after intravenous injection of 20 mCi Tc-99m MIBI. All patients had liver biopsy or surgery within 1 week of MIBI imaging. Immunohistochemical study of the biopsy or resected hepatocellular carcinoma specimens was performed using the avidin-biotin-peroxidase technique with monoclonal antibody JSB-1 directed against P-glycoprotein.
  
  
  RESULTS
  On Tc-99m MIBI SPECT, 30 of 35 (85.7%) patients with hepatocellular carcinoma had no Tc-99m MIBI uptake in tumor lesions, whereas five patients with hepatocellular carcinoma had Tc-99m MIBI uptake in tumor lesions. P-glycoprotein expression was observed in tumor tissues of all the patients without Tc-99m MIBI uptake, whereas among the five patients with Tc-99m MIBI uptake, no P-glycoprotein expression was seen in tumor lesions (P < 0.015).
  
  
  CONCLUSIONS
  Tc-99m MIBI SPECT is useful for noninvasively predicting the presence of MDR1 gene-encoded P-glycoprotein in patients with hepatocellular carcinoma.
authors.affiliation: Department of Gastroenterology, Ajou University, Suwon, Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Kim
authors.forename: S W
authors.initials: SW
authors.lastname: Cho
authors.forename: K J
authors.initials: KJ
authors.lastname: Lee
authors.forename: K B
authors.initials: KB
authors.lastname: Hahm
authors.forename: H J
authors.initials: HJ
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Yim
authors.forename: Y M
authors.initials: YM
authors.lastname: Jin
authors.forename: C H
authors.initials: CH
authors.lastname: Park
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D019450:Genes, MDR; D006801:Humans; D007124:Immunoenzyme Techniques; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi