Background: Insulin-like growth factor-1 (IGF-I) is important in normal
brain development but in the adult brain, IGF-I overexpression may be a
risk factor for tumor development.
Methods: We examined the association between circulating concentrations
of IGF-I and IGFBP-3 in relation to risk of gliomas (74 low-grade, 206
high-grade gliomas), meningiomas (n = 174) and acoustic neuromas (n =
49) by using a case-control design nested in the European Prospective
Investigation into Cancer and Nutrition. IGF-I and IGFBP-3 were measured
by ELISAs. Conditional logistic regression was used to compute ORs and
corresponding 95% CIs.
Results: The risk of low-grade gliomas was elevated with increased IGF-I
(OR = 3.60, 95% CI: 1.11-11.7; top vs. bottom quartile) and decreased
with elevated IGFBP-3 concentrations (OR = 0.28, 95% CI: 0.09-0.84)
after mutual adjustment of these two factors; these results became
nonsignificant after exclusion of the first year of follow-up. No
association was observed for high-grade gliomas or meningiomas. Both
high IGF-I and IGFBP-3 concentrations were associated with risk of
acoustic neuromas (IGF-I: OR = 6.63, 95% CI: 2.27-19.4, top vs. bottom
tertile; IGFBP-3: OR = 7.07, 95% CI: 2.32-21.6), even after excluding
the first year of follow-up.
Conclusion: High concentrations of IGF-I might be positively associated
with risk of low-grade gliomas and acoustic neuromas, although we cannot
exclude reverse causation, in particular for low-grade gliomas.
Impact: Factors of the IGF axis might be involved in the etiology of
some types of brain tumors. Cancer Epidemiol Biomarkers Prev; 20(10);
2174-82. (C) 2011 AACR
