title: Plasma levels of insulin-like growth factor-1 and binding protein-3, and their association with bladder cancer risk.
abstract: OBJECTIVE
  Because insulin-like growth factors (IGFs) and their binding proteins have been implicated in the development of prostate, breast, colon and lung cancer, we examined the role of IGF-1 and IGF binding protein-3 levels in bladder cancer risk.
  
  
  METHODS
  We used an enzyme-linked immunosorbent assay to compare plasma levels of IGF-1 and IGF binding protein-3 in 154 patients with bladder cancer and 154 controls from an ongoing case-control study.
  
  
  RESULTS
  Mean IGF-1 was significantly higher in cases than in controls (175.8 versus 153.2 ng./ml., p <0.01). Mean IGF binding protein-3 was significantly lower in cases than in controls (2,632.9 versus 3,056.6 ng./ml., p <0.01). The highest quartile plasma levels of IGF-1 were associated with an increased risk of bladder cancer (OR 3.10, 95% CI 1.43 to 6.70) and the highest quartile plasma levels of IGF binding protein-3 were associated with a reduced risk of bladder cancer (OR 0.38, 95% CI 0.19 to 0.78). The effects were more striking when IGF-1 and IGF binding protein-3 levels were analyzed together. In addition, a higher molar ratio of IGF-1-to-IGF binding protein-3 was associated with an increased risk of bladder cancer (OR 4.30, 95% CI 1.99 to 9.28). Dose-response relationships were evident when subjects were categorized into quartiles by the values of IGF-1, IGF binding protein-3 and the molar ratio in controls.
  
  
  CONCLUSIONS
  To our knowledge this is the first study to suggest that patients with bladder cancer have higher plasma levels of IGF-1 and lower levels of IGF binding protein-3 than controls. Thus, measuring plasma IGF-1 and IGF binding protein-3 may be useful for assessing bladder cancer risk.
authors.affiliation: Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhao
authors.forename: H Barton
authors.initials: HB
authors.lastname: Grossman
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Spitz
authors.forename: Seth P
authors.initials: SP
authors.lastname: Lerner
authors.forename: Kerang
authors.initials: K
authors.lastname: Zhang
authors.forename: Xifeng
authors.initials: X
authors.lastname: Wu
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000097:blood* / Q000209:etiology
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I