title: Serum insulin-like growth factor-I levels and prostatic intraepithelial neoplasia: a clue to the relationship between IGF-I physiology and prostate cancer risk.
abstract: Serum insulin-like growth factor-I (IGF-I) levels at the higher end of the reference range have been associated with increased risk for the future development of prostate cancer. We determined whether high serum IGF-I levels are associated with precancerous lesions of the prostate. We conducted a case-control study to determine whether high serum IGF-I levels were associated with the presence of high-grade prostatic intraepithelial neoplasia (HGPIN) among patients who presented for prostate biopsy because of an abnormal serum prostate-specific antigen level or digital rectal exam. We measured serum IGF-I and insulin-like growth factor binding protein-3 (IGFBP-3) prior to prostate biopsy and compared them between 103 men with HGPIN (cases) and 205 men with normal prostate histology (controls). The mean IGF-I level in patients with HGPIN (130.2 ng/mL) was significantly higher compared with controls (118.8 ng/mL, P = 0.01). The mean IGFBP-3 level in patients with HGPIN (2,393.9 ng/mL) was also higher compared with controls (2,276.0 ng/mL, P = 0.06). After adjusting for age, prostate-specific antigen, digital rectal examination, and ethnic background, the odds ratio for a HGPIN diagnosis among men in the highest relative to the lowest quartile of serum IGF-I level was 1.94 (95% confidence interval, 1.0-3.7; P = 0.04). The potential association between a high serum IGF-I level and the presence of HGPIN may represent an important clue to understanding the basis for the relationship between IGF-I physiology and prostate cancer risk. Larger studies will be required to confirm this relationship.
authors.affiliation: Sunnybrook and Women's College Health Sciences Centre, 2075 Bayview Avenue, MG-406 Toronto, Ontario, Canada, M4N 3M5. robert.nam@utoronto.ca
authors.forename: Robert K
authors.initials: RK
authors.lastname: Nam
authors.forename: John
authors.initials: J
authors.lastname: Trachtenberg
authors.forename: Michael A S
authors.initials: MA
authors.lastname: Jewett
authors.forename: Ants
authors.initials: A
authors.lastname: Toi
authors.forename: Andrew
authors.initials: A
authors.lastname: Evans
authors.forename: Marjan
authors.initials: M
authors.lastname: Emami
authors.forename: Steven A
authors.initials: SA
authors.lastname: Narod
authors.forename: Michael
authors.initials: M
authors.lastname: Pollak
mesh_terms: D000368:Aged; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D017430:Prostate-Specific Antigen / Q000097:blood; D019048:Prostatic Intraepithelial Neoplasia / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012307:Risk Factors
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D017430:Prostate-Specific Antigen