Association study of susceptibility loci with specific breast cancer subtypes in Chinese women

To determine whether recent genome-wide association studies that reported 45 susceptibility loci in European women are also risk factors for breast cancer in Chinese women. We selected and genotyped 40 single nucleotide polymorphisms (SNPs) using the Sequenom iPlex platform in a female Chinese cohort of 2,901 breast cancer cases and 2,789 healthy controls. We evaluated these SNPs with the risk of breast cancer and further by estrogen receptor (ER) status, progestin (PR) status, human epidermal growth factor receptor-2 (HER-2) status, and four breast cancer subtypes (Luminal A type, Luminal B type, HER-2 overexpression type and Basal-like type). We first confirmed that the SNP rs9693444 on 8p12 was associated with breast cancer in Chinese women (P = 6.44 × 10−4). Furthermore, we identified four susceptibility loci that were associated with specific tumor subtypes. Statistically significant differences were detected with the association of rs6828523 (4q34.1/ADAM29) with ER-positive breast cancer (P = 1.27 × 10−3) and the association of rs4849887 (2q14.2) with PR-positive breast cancer (P = 1.29 × 10−3). Of the four breast cancer subtypes, the associations of rs12493607 (3p24.1/TGFBR2) with HER-2 overexpression in breast cancer (P = 1.09 × 10−3) and rs11075995 (16q12.2/FTO) with basal-like breast cancer (P = 1.64 × 10−4) were statistically significant. This study is the first to show that these 5 susceptibility loci (8p12, 4q34.1/ADAM29, 2q14.2, 3p24.1/TGFBR2, and 16q12.2/FTO) correlate with breast cancer (overall and specific subtypes) in Chinese women, which has improved our understanding of the genetic basis of specific breast cancer subtypes.