title: 99mTc-MIBI scintigraphy as an indicator of the chemosensitivity of anthracyclines in patients with breast cancer.
abstract: BACKGROUND
  Chemoresistance of tumor cells is involved with many factors, one of which is the P-glycoprotein function to pump anthracyclines out of cells. 99mTc-MIBI accumulates in several tumors, and some of these cells wash out 99mTc-MIBI through P-glycoprotein.
  
  
  METHODS
  We investigated if the wash-out of 99mTc-MIBI from the tumor in fifteen female patients with breast cancer could be related with the chemosensitivity of anticancer agents; doxorubicin (DOX), epirubicin (FAM), pinorubicin (PINO), mitomycin (MMC), cisplatin (CDDP), and 5-fluorouracil (5-FU), in each tumor tissues. The wash-out of 99mTc-MIBI, defined as retention index, was quantified from an early and delayed 99mTc-MIBI imaging. The chemosensitivity of the anticancer agent, and inhibition ratio, was determined in vitro assay by using surgical specimens obtained from patients who underwent 99mTc-MIBI imaging. P-glycoprotein in the surgical specimen was studied by immunohistochemical staining on its paraffin section using a monoclonal antibody.
  
  
  RESULTS
  Inhibition ratio of anthracycline agent, DOX, FAM or PINO, was well correlated with retention index of 99mTc-MIBI with coefficient of 0.75, 0.60, or 0.62, respectively, whereas a poor relationship was observed for MMC and CDDP. The retention indices of 99mTc-MIBI were remarkably small for patients in the P-glycoprotein positive group.
  
  
  CONCLUSIONS
  99mTc-MIBI retention index quantified from its early and delayed scintigraphy is a good indicator to predict the chemosensitivity of anthracyclines in untreated breast cancer.
authors.affiliation: Department of Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Fujii
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: A
authors.initials: A
authors.lastname: Kubo
authors.forename: K
authors.initials: K
authors.lastname: Enomoto
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Kubota
authors.forename: S W
authors.initials: SW
authors.lastname: Matsuzaki
authors.forename: M
authors.initials: M
authors.lastname: Kitajima
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000328:Adult; D000368:Aged; D018943:Anthracyclines / Q000627:therapeutic use* / Q000633:toxicity; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D002470:Cell Survival / Q000187:drug effects; D002945:Cisplatin / Q000633:toxicity; D004317:Doxorubicin / Q000633:toxicity; D015251:Epirubicin / Q000633:toxicity; D005260:Female; D005472:Fluorouracil / Q000633:toxicity; D006801:Humans; D008875:Middle Aged; D008937:Mitomycins / Q000633:toxicity; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012044:Regression Analysis; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018943:Anthracyclines; D008937:Mitomycins; D019275:Radiopharmaceuticals; D015251:Epirubicin; D004317:Doxorubicin; D017256:Technetium Tc 99m Sestamibi; D002945:Cisplatin; D005472:Fluorouracil