title: Insulin-like growth factor-I gene polymorphism and breast cancer risk in Chinese women.
abstract: The evidence that high circulating levels of insulin-like growth factor-I (IGF-I) are associated with an increased risk of breast cancer among premenopausal women lends credence to the hypothesis that genetic polymorphisms in the IGF-I gene may be involved in the disease. A population-based case-control study was conducted to assess the association of IGF-I gene polymorphisms [(CA)n repeats in the promoter region] with breast cancer risk and plasma IGF-I level in Chinese women. The study included 1,041 incident breast cancer cases diagnosed from August 1996 through March 1998 in Shanghai and 1,086 randomly selected, age frequency-matched controls from the general population. Although no relation between plasma IGF-I levels and IGF-I genotypes was found, women who carried the genotypes containing the (CA)17 or (CA)19 allele were associated with a significantly decreased (OR = 0.80, 95% CI: 0.64-1.00) or increased (OR = 1.23, 95% CI: 1.04-1.47) risk of breast cancer, respectively, and women who carried the genotypes containing any of the 4 rare alleles, (CA)11, (CA)13, (CA)16 and (CA)23, were associated with a nonsignificantly increased risk of breast cancer (OR = 1.92, 95% CI: 0.92-4.02) compared to those who did not carry the specific alleles. The associations with the (CA)17 or (CA)19 allele were predominantly present among premenopausal women and in a dose-response manner. The meta-analysis results indicated that IGF-I genotypes containing the (CA)19 were consistently associated with increased risk of breast cancer across studies (overall OR = 1.22, 95% CI: 1.06-1.41, p for heterogeneity test = 0.524). The findings of this study support the hypothesis that IGF-I gene polymorphisms may be a significant genetic factor for breast cancer susceptibility.
authors.affiliation: Department of Medicine and Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA. wanqing.wen@vanderbilt.edu
authors.forename: Wanqing
authors.initials: W
authors.lastname: Wen
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Herbert
authors.initials: H
authors.lastname: Yu
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Smith
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D002681:China; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D017697:Premenopause; D011401:Promoter Regions, Genetic; D012307:Risk Factors
chemical_list: D007334:Insulin-Like Growth Factor I