A prospective study of insulin-like growth factor-I, IGF-binding proteins-1, -2 and -3 and lung cancer risk in women

Abstract

Insulin-like growth factor-I (IGF-I) has mitogenic and anti-apoptotic properties and has been implicated in the development of breast, colorectum, prostate and lung cancer. IGF binding proteins (IGFBPs) are not only carrier proteins for IGFs but also hold a central position in IGF ligand-receptor interactions through influences on the bioavailability and distribution of IGFs in the extracellular environment. A case-control study nested within the New York University Women's Health Study Cohort included 93 women diagnosed with lung cancer at least 6 months after recruitment into the study. Two controls (n = 186) were matched to each case on age, date of blood sampling, menopausal status, day of menstrual cycle and questionnaire data of smoking status at the time of blood donation. Serum IGF-I, IGFBP-1, -2 and -3, insulin and cotinine were measured. Mean serum levels of IGF-I, IGFBP-1, -2 and -3 were not significantly different between the case and control groups. Univariate logistic regression analyses showed no association of lung cancer risk with serum levels of IGF-I or any of the IGFBPs. These results remained virtually the same in multivariate analyses, including adjustment for cotinine, time since last meal, BMI, IGF-I or IGFBP-3, respectively. Exclusion of cases diagnosed within 3 years of recruitment in the cohort, or restriction of the analyses to adenocarcinomas only, did not alter these results. Our study does not offer evidence in support of an association between prediagnostic serum levels of IGF-I or IGFBP-1, -2 and -3 and lung cancer risk in women.