title: IGF-I and breast cancer: a meta-analysis.
abstract: IGFs are peptide hormones involved in the regulation of cell proliferation, differentiation and apoptosis. IGFs are regulated by endocrine and paracrine mechanisms; however, their action in tissue is determined by circulating levels and local production of IGFs and IGF-binding proteins (IGFBPs). Some, but not all, epidemiologic studies have associated high circulating levels of IGF-I with increased risk of breast cancer among premenopausal women. To evaluate the overall association of IGF-I and IGFBP-3 levels with breast cancer risk, we performed a meta-analysis on 16 publications of epidemiologic and clinical studies. Analyses were performed for all women as well as for pre- and postmenopausal women separately. Hedges' standardized mean differences (HSMDs) and odds ratios (ORs) were used to estimate the effect of IGF-I and IGFBP-3. Data analysis showed that circulating levels of IGF-I were not significantly higher in breast cancer patients than in controls for all women and for the postmenopausal group (HSMD = 0.024 and 0.035, respectively; p > 0.40) but were significantly higher (HSMD = 0.170, p < 0.001) for the premenopausal group. ORs for breast cancer risk were 1.05 (95% CI 0.94-1.17), 0.93 (95% CI 0.80-1.10) and 1.39 (95% CI 1.16-1.66). The HSMD of IGFBP-3 was 0.18 (p < 0.001), and the OR for breast cancer was 1.42 (95% CI 1.15-1.74) for premenopausal women. Our results support the suggested association between high IGF-I and IGFBP-3 levels and increased risk of breast cancer in premenopausal women.
authors.affiliation: Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA. rshi@lsuhsc.edu
authors.forename: Runhua
authors.initials: R
authors.lastname: Shi
authors.forename: Herbert
authors.initials: H
authors.lastname: Yu
authors.forename: Jerry
authors.initials: J
authors.lastname: McLarty
authors.forename: Jonathan
authors.initials: J
authors.lastname: Glass
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood / Q000453:epidemiology*; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D016239:MEDLINE; D016017:Odds Ratio; D017697:Premenopause; D012307:Risk Factors
chemical_list: D014408:Biomarkers, Tumor; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I