title: Serum levels of insulin-like growth factor binding protein-3 in benign and malignant breast disease.
abstract: BACKGROUND
  The insulin-like growth factors IGF-I and IGF-II and their major binding protein IGFBP-3 influence the growth of breast cancer cells in vitro. Some benign non-breast tumours appear to be associated with increased serum IGFBP-3 levels which would tend to reduce bioactive-free IGF concentrations. The present study investigates whether this pattern also occurs in neoplastic breast disease.
  
  
  METHODS
  Serum IGF-I, IGF-II and IGFBP-3 were measured by specific radioassay in 12 women with benign breast disease, 31 patients with breast cancer and in age-matched controls.
  
  
  RESULTS
  The mean (+/-SD) serum IGFBP-3 concentration was higher in benign breast disease (3.6+/-0.7 mg/L) than in controls (2.7+/-0.6 mg/L) or in breast cancer patients (2.7+/-0.5 mg/L) (P = 0.001). Serum IGF-I and IGF-II levels were not significantly different among the groups. However, the index of free unbound IGF measured as the molar ratio of IGF-I plus IGF-II divided by IGFBP-3 was significantly lower in benign breast disease than in the other subjects.
  
  
  CONCLUSIONS
  Either the production or clearance of IGFBP-3 is altered in benign breast disease so that there is less free IGF available to cells. This may serve to protect against malignant transformation in patients with benign breast disorders.
authors.affiliation: Department of Endocrinology, School of Medicine, Auckland University, New Zealand. ian@ahsl.co.nz
authors.forename: I M
authors.initials: IM
authors.lastname: Holdaway
authors.forename: B H
authors.initials: BH
authors.lastname: Mason
authors.forename: A E
authors.initials: AE
authors.lastname: Lethaby
authors.forename: V
authors.initials: V
authors.lastname: Singh
authors.forename: J E
authors.initials: JE
authors.lastname: Harman
authors.forename: M
authors.initials: M
authors.lastname: MacCormick
authors.forename: I D
authors.initials: ID
authors.lastname: Civil
mesh_terms: D000328:Adult; D001941:Breast Diseases / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008875:Middle Aged
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II