title: Effects of tamoxifen on insulin-like growth factors, IGF binding proteins and IGFBP-3 proteolysis in breast cancer patients.
abstract: BACKGROUND
  Recently an association between increased serum insulin-like growth factor I (IGF-I) levels and the development of breast cancer was demonstrated. Tamoxifen used in the postoperative treatment of breast cancer patients may exert significant effects on the IGF-I system.
  
  
  METHODS
  To examine the effect of Tamoxifen treatment (20 mg/day) on changes in the IGF-I axis in 11 breast cancer patients before and after 4 months of Tamoxifen treatment and compared to 8 healthy subjects. IGF-I, IGF-II, IGFBP-1, IGFBP-2, IGFBP-3 and IGFBP-6 were examined by specific assays. IGFBPs were examined by Western ligand blotting and IGFBP-3 proteolytic activity by specific protease assay.
  
  
  RESULTS
  Serum IGF-I was decreased before (63%) and increased during Tamoxifen treatment (60%). Total IGFBP-3 levels measured by IRMA were unchanged, however, intact IGFBP-3 measured by WLB was decreased (58%) before and increased (67%) during Tamoxifen treatment. IGFBP-3 proteolysis was increased before and reduced during treatment. IGFBP-4 and IGFBP-6 were decreased before and increased during Tamoxifen treatment.
  
  
  CONCLUSIONS
  Significant changes in the IGF system were demonstrated before and during Tamoxifen treatment and may in part be involved in the effects of Tamoxifen treatment in breast cancer patients.
authors.affiliation: Institute of Experimental Clinical Research, Aarhus Kommunehospital, Aarhus University Hospital, Aarhus C, Denmark. henning.gronbaek@dadlnet.dk
authors.forename: Henning
authors.initials: H
authors.lastname: Grønbaek
authors.forename: Vasilios
authors.initials: V
authors.lastname: Tanos
authors.forename: Dror
authors.initials: D
authors.lastname: Meirow
authors.forename: Tamar
authors.initials: T
authors.lastname: Peretz
authors.forename: Itamar
authors.initials: I
authors.lastname: Raz
authors.forename: Allan
authors.initials: A
authors.lastname: Flyvbjerg
mesh_terms: D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy*; D016022:Case-Control Studies; D010450:Endopeptidases / Q000378:metabolism; D020847:Estrogen Receptor Modulators / Q000494:pharmacology*; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood*; D013002:Somatomedins / Q000378:metabolism*; D013629:Tamoxifen / Q000494:pharmacology*
chemical_list: D020847:Estrogen Receptor Modulators; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D013629:Tamoxifen; D010450:Endopeptidases; C080473:insulin-like growth factor binding protein-3 protease