Plasma insulin-like growth factor 1 is positively associated with low-grade prostate cancer in the Health Professionals Follow-up Study 1993–2004
✍ Scribed by Katharina Nimptsch; Elizabeth A. Platz; Michael N. Pollak; Stacey A. Kenfield; Meir J. Stampfer; Walter C. Willett; Edward Giovannucci
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- French
- Weight
- 151 KB
- Volume
- 128
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Abstract
The insulin‐like growth factor (IGF) axis plays a role in growth and progression of prostate cancer. High circulating IGF‐1 levels have been associated with an increased risk of prostate cancer. Results for IGF binding protein 3 (IGFBP‐3) are inconclusive. Some studies have indicated that the positive association with IGF‐1 is observed only for low‐grade prostate cancer (Gleason sum < 7). We previously reported in the Health Professionals Follow‐up Study (HPFS) a direct positive association between ELISA‐measured plasma IGF‐1 and IGFBP‐3 and risk of prostate cancer (462 cases diagnosed after providing a blood specimen (between 1993 and 1995), but before February 1998). With additional follow‐up through January 31st 2004, and 1,331 case–control pairs in total, we were now able to investigate low‐grade (Gleason sum < 7, n = 635) and high‐grade (Gleason sum ≥ 7, n = 515) prostate cancer separately. Matched odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression. ORs of total prostate cancer comparing top to bottom quartiles were 1.41 (95% CI 1.12–1.78, p‐trend = 0.001) for IGF‐1 and 1.58 (95% CI 1.24–2.01, p‐trend = 0.003) for IGFBP‐3. IGF‐1 was more strongly associated with low‐grade (OR = 1.61 top versus bottom quartile, 95% CI 1.16–2.25, p‐trend = 0.01), than with high‐grade (OR = 1.29, 95% CI 0.89–1.88, p‐trend = 0.12) prostate cancer (p‐heterogeneity = 0.08). We hypothesize that these findings reflect that high‐grade prostate cancers are more autonomous, and, thus, less sensitive to the action of IGF‐1 than low‐grade cancers.