title: Differential uptake of (18)F-fluorodeoxyglucose by experimental tumors xenografted into immunocompetent and immunodeficient mice and the effect of immunomodification.
abstract: OBJECTIVE
  To study the contribution of immunologic background to the uptake of fluorine-18-fluorodeoxyglucose ((18)F-FDG) by the tumor tissues.
  
  
  METHODS
  The uptakes of (18)F-FDG to the same experimental tumor model (SCCVII) xenografted into immunocompetent and immunodeficient (athymic) mice were compared. In addition, the immunomodifying effect of steroid on the uptake of (18)F-FDG by these tumors was investigated.
  
  
  RESULTS
  The uptake of (18)F-FDG by the tumors in immunocompetent mice was significantly higher than that in immunodeficient (athymic) mice. Although steroid pretreatment had no effect on the tumor uptake in immunodeficient mice, it significantly decreased the tumor uptake in immunocompetent mice.
  
  
  CONCLUSIONS
  The higher tumor uptake of (18)F-FDG observed in immunocompetent mice, modulated by steroid pretreatment, was contributed by the host immune reaction, probably cellular immunity employed by T-lymphocytes. These findings can clinically conclude that the intense accumulation of (18)F-FDG in the metastatic lymph nodes, which contain only a small number of cancer cells, was caused by the enhanced uptake of (18)F-FDG by activated T-lymphocytes due to host immunity against cancer cells present in metastatic lymph nodes.
authors.affiliation: Department of Nuclear Medicine and Diagnostic Imaging, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, Japan.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Mamede
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Saga
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ishimori
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.forename: Noriko
authors.initials: N
authors.lastname: Sato
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Higashi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Mukai
authors.forename: Hisataka
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Junji
authors.initials: J
authors.lastname: Konishi
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18