Premium
Modifying Effects of IL‐6 Polymorphisms on Body Size–Associated Breast Cancer Risk
Author(s) -
Slattery Martha L.,
Curtin Karen,
Sweeney Carol,
Wolff Roger K.,
Baumgartner Richard N.,
Baumgartner Kathy B.,
Giuliano Anna R.,
Byers Tim
Publication year - 2008
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2007.44
Subject(s) - breast cancer , medicine , odds ratio , haplotype , genotype , overweight , obesity , confidence interval , waist–hip ratio , body mass index , cancer , gynecology , oncology , waist , genetics , biology , gene
Objective: The association between obesity and breast cancer risk is complex. We examined whether the association between body size and breast cancer risk is modified by interleukin‐6 ( IL6 ) genotype. Methods and Procedures: Five polymorphisms in the IL‐6 gene (rs1800797/‐596A>G, rs1800796/‐572G>C, rs1800795/‐174G>C, rs2069832/IVS2G>A, and rs2069849 exon 5 C>T) were studied. We investigated IL6 genotypes and haplotypes with indicators of body size among non‐Hispanic white (NHW) and Hispanic/American Indian (AI) breast cancer cases and controls living in the Southwestern United States. Results: We observed lower mean levels of BMI among NHW women who carried one or two copies of the GGCAC haplotype (in order: rs1800797, rs1800796, rs1800795, rs2069832, and rs2069849; P trend 0.02). This haplotype, with an estimated frequency of 43% in NHW study controls, was considerably less common in Hispanic/AI controls (19%). We did not detect significant interactions between IL6 genotypes or haplotypes and BMI categorized as low/normal (<25), overweight (25 to <30), or obese (≥30) and breast cancer risk in either NHW or Hispanic/AI women. However, we detected consistent and significant interactions between waist‐to‐hip ratio (WHR) and IL6 rs1800795/‐174 G>C genotype for breast cancer risk. These associations were restricted to postmenopausal NHW women. Among women without recent hormone exposure, those with a WHR >0.9 and the rs1800795 GG genotype had a greater than threefold increased risk of breast cancer (odds ratios (ORs) 3.22, 95% confidence intervals (CIs) 1.27, 817) when compared with women with a WHR <0.8 and the rs1800795 GG genotype ( P interaction 0.01). Discussion: These data suggest that IL‐6 genotypes may influence breast cancer risk in conjunction with central adiposity.