Background: Prostate cancer is the most common cancer among U.S. men. Androgens and growth hormones are thought to be associated with prostate cancer risk, though past research has produced mixed results. Methods: We conducted a nested case-control study of biomarkers of prostate cancer risk within the Multiethnic Cohort. Demographic, dietary, and other exposure information was collected by self-administered questionnaire in 1993-1996. Biospecimens were collected between 1997 and 2006.We compared prediagnostic serum levels of testosterone, dihydrotestosterone (DHT), sex-hormone binding globulin (SHBG), 3\#945;-androstanediol glucuronide (3\#945;-diol G), insulin-like growth factor I (IGF-I), IGF-II, insulin-like growth factor binding protein 1 (IGFBP-1), and IGFBP-3 from 467 incident prostate cancer cases and 934 cancer free controls. Controls were matched to the cases on geographic site (HI, LA), ethnicity, age at specimen collection (± 1 year), date (± 1 month) and time of day (± 2 hours) of sample collection, and fasting status (<6, 6-7, 8-9, 10+ hours). Multivariate conditional logistic regression models were used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Results: Serum concentrations of testosterone, DHT, SHBG, 3\#945;-diol G, IGF-I, IGF-II, IGFBP-1, and IGFBP-3 were not associated with risk of prostate cancer. The OR for DHT was 0.81, 95% CI:0.57-1.15 and the OR for IGF-I was 1.23, 95% CI:0.85-1.78, both comparing the fourth quartile to the first quartile of serum concentration. Tests for trend of quartiles of serum concentrations also did not show any association. Results were relatively unchanged for men with advanced prostate cancer and their matched controls. Analysis by ethnic group showed an increased risk for Latino men in the second (OR=3.67, 95% CI: 1.63-8.24) and third (OR=2.96, 95% CI:1.19-7.40) tertiles of IGF-I serum levels compared to the first tertile. However, sample sizes for ethnic specific analyses were small. Conclusion: In this multiethnic population, serum concentrations of testosterone, DHT, SHBG, 3\#945;-diol G, IGF-I, IGF-II, IGFBP-1, and IGFBP-3 were not associated with prostate cancer risk. However, the follow-up period was relatively short. A suggested increased risk for IGF-I in Latino men merits further study, with greater statistical power.

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 4872.

100th AACR Annual Meeting-- Apr 18-22, 2009; Denver, CO

American Association for Cancer Research
2009