title: Usefulness of 99mTc-sestamibi scintigraphy in suggesting the therapeutic effect of chemotherapy against gastric cancer.
abstract: OBJECTIVE
  Imaging with (99m)Tc-sestamibi ((99m)Tc-MIBI) has been used to assess 170-kDa P-glycoprotein (P-gp) expression and predict chemotherapy responses in several types of malignancy, such as breast and lung cancers. The purpose of this study was to evaluate the relationship between (99m)Tc-MIBI accumulation in tumors and sensitivity to chemotherapy in gastric cancer patients.
  
  
  METHODS
  Thirty-six patients with advanced gastric cancer underwent (99m)Tc-MIBI scintigraphy before chemotherapy. Patients also underwent endoscopic biopsy, and the expression of P-gp or multidrug resistance-associated protein was analyzed by immunohistochemical staining. The relationship between the accumulation of (99m)Tc-MIBI in tumors and responses to chemotherapy with 5-fluorouracil/cis-diamminedichloroplatinum(II) or epirubicin was examined.
  
  
  RESULTS
  Higher accumulation of (9m)Tc-MIBI in tumors was observed in 25 and 23 of 36 gastric cancer patients at the early (30 min) and delayed (120 min) images, respectively. Accelerated accumulation of (99m)Tc-MIBI negatively correlates with increased expression of P-gp, but not of multidrug resistance-associated protein, as determined by immunohistochemistry in gastric cancer tissues. The response rate to 5-fluorouracil/cis-diamminedichloroplatinum(II) chemotherapy in patients with high (99m)Tc-MIBI accumulation (15.4%) was much lower than that in patients with low (99m)Tc-MIBI accumulation (54.5%). In contrast, patients with high (99m)Tc-MIBI accumulation show a higher response rate (41.7%) to chemotherapy with epirubicin, which is known to be a substrate of P-gp transporter.
  
  
  CONCLUSIONS
  (99m)Tc-MIBI scintigraphy is useful to suggest the responses to chemotherapy of patients with advanced gastric cancer.
authors.affiliation: Department of Surgery, Tazuke-Kofukai Medical Research Institute and Kitano Hospital, Osaka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawata
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Kanai
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sasada
authors.forename: Shingo
authors.initials: S
authors.lastname: Iwata
authors.forename: Naritaka
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Arimichi
authors.initials: A
authors.lastname: Takabayashi
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000328:Adult; D000368:Aged; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002945:Cisplatin / Q000627:therapeutic use; D015251:Epirubicin / Q000494:pharmacology; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging / Q000379:methods; D019275:Radiopharmaceuticals; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000188:drug therapy*; D017256:Technetium Tc 99m Sestamibi
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D019275:Radiopharmaceuticals; D015251:Epirubicin; D017256:Technetium Tc 99m Sestamibi; D002945:Cisplatin; D005472:Fluorouracil