FGFR2 Genetic Polymorphisms Modify the Association of Oral Contraceptive Use with the Risk of Breast Cancer in Chinese Women 徐 望 红 firstname.lastname@example.org 复旦大学公共卫生学院流行病学教研室 上海市肿瘤研究所流行病室
研 究 背 景 • Breast cancer • most common cancer in women • a hormone-related malignancy • a complex and multi-factorial disease • a result of interplays between different exposures and host susceptibility
Oral contraceptives (OC) • exogenous hormones • classified as group 1 carcinogens Schneider HP, et al. Climacteric. 2005;8:311-6. Cogliano V, et al. Lancet Oncol. 2005;6:552-3. • consistent positive association with breast cancer risk in western populations Kahlenborn C, et al. Mayo Clin Proc. 2006;81(10):1290-302. Collaborative Group on Hormonal Factors in Breast Cancer. Lancet. 1996;347:1713-27. • null association in Asian populations Kawai M, et al.Cancer Causes Control. 2010;21(1):135-45. Dorjgochoo T, et al. Int J Cancer. 2009;124(10):2442-9. Ursin G, et al. Am J Epidemiol. 1999;150(6):561-7. Huang CS, et al. Br J Cancer. 1999;80(11):1838-43. Yuan JM, et al. Cancer Res. 1988;48(7):1949-53.
FGFR2 gene • well recognized breast cancer susceptibility gene • multiple SNPs in association with breast cancer risk across ethnic groups • a sex hormone-dependent role of FGFR2 gene in breast cancer
研 究 假 设 • FGFR2 genetic polymorphisms may modify the association between OC use and breast cancer risk in Chinese women
材 料 与 方 法 A two-stage population-based case-control study • SBCS-I (1996-1998) • 1459 of 1602 newly-diagnosed breast cancer cases at age 25-65 • 1556 of 1724 eligible controls • 1193 (82%) cases and 1310 (84%) controls donated a blood sample • SBCS-II (2002-2005) • 1989 incident cases (83.7%) aged 25 to 70 years old • 1989 population controls (70.4%) • 969 (48.7%) cases and 975 (49.0%) controls provided a blood sample
Epidemiological data • Demographic characteristics • Menstrual and reproductive history • OCs use and postmenopausal HRT • Prior disease history • Physical activity • Tobacco and alcohol use • Diet • Weight history • Family history of cancer • Measured body weight, height, and circumferences of the waist and hips
Genotyping data • From a GWAS scan covering about 120 kb of the FGFR2 gene plus 10 kb region of its 5' upstream and 5 kb region of its 3' downstream • Genotyping conducted using Affymetrix Genome-Wide Human SNP array 6.0 following Affymetrix’s protocol • 42 SNPs genotyped • 19 had minor allele frequency of > 0.05 • Imputation conducted using the program MACH • 93 imputed SNPs • 26 SNPs had minor allele frequency of > 0.05 and average imputation quality score of > 0.90.
结 果 Table 1. Comparison of demographic characteristics between breast cancer cases and controls, the Shanghai Breast Cancer Study a From χ2 test (categorical variables) or t test (continuous variables).
Table 2. Association of sex hormones use and breast cancer risk among Chinese women, the Shanghai Breast Cancer Study OR: adjusted for age, educational levels, age at menarche, menopausal status, breast cancer in 1st-degree relatives, number of live births and body mass index.
Figure 1. Age-adjusted ORs and 95%CI for breast cancer with FGFR2 genetic polymorphisms by OC use, the Shanghai Breast Cancer Study OR per allele: adjusted for age, educational levels, age at menarche, menopausal status, breast cancer in 1st-degree relatives, number of live births and body mass index
rs755793 rs2303568 No. of MA OC use No. of MA OC use rs3135730 rs1078806 No. of MA No. of MA OC use OC use Figure 2. Breast cancer odds ratios estimates for OC use according to the number of minor alleles of FGFR2 SNPs, the Shanghai Breast Cancer Study
Table 3. Haplotype analysis of FGFR2 with the risk of breast cancer under dominant model, the Shanghai Breast Cancer Study Hap1: in the order of rs7073360, rs3135749, rs3135747, rs755793, rs3135739, rs3135737, rs3135736, rs12245334 and rs9888022. Hap2: in the order of rs2303568 and rs3135730. Hap3: in the order of rs7073360, rs3135749, rs3135747, rs755793, rs3135739, rs3135737, rs3135736, rs12245334, rs9888022, rs2303568, rs3135730 and rs1078806. OR: adjusted for age, educational levels, age at menarche, menopausal status, breast cancer in 1st-degree relatives, number of live births and body mass index. a additionally adjusted for oral contraceptive use.
讨 论 • First study reporting the modifying effect of FGFR2 in the OCs-breast cancer association • effect of OC use in breast cancer depends on the genotypes of FGFR2 at rs755793, rs2303568, 3135730 and rs1078806 • dose-response relationship between duration of OC use and cancer risk among women carrying at least one minor allele at rs755793, rs2303568 and rs3135730 or those having two minor alleles at rs1078806 • unclear function of the loci and poorly understood mechanism underlying the results
Strengths • population-based study design • large sample size • high participation rate • homogeneous ethnic background • extensive coverage of the FGFR2 gene
Limitations • possibility of chance • very few users of OCs containing estrogen or progesterone only • no enough statistical power to evaluate the interaction between HRT use and FGFR2
Significance • test our hypothesis • provide a possible explain for the null OC-breast cancer • association in Chinese women • support the hormone-dependent nature of FGFR2 gene • important implications in personalized prevention of breast • cancer
致 谢 美国Vanderbilt大学 上海市肿瘤研究所 高玉堂 项永兵 • Wei Zheng • Xiao-ou Shu • Jirong Long • Qiuyin Cai • Qi Dai 上海市疾病预防控制中心 复旦大学公共卫生学院 • 赵根明 • 卢伟 • 郑莹 • 顾凯 • 鲍萍萍 This research was supported by NSFC 30872180