Genetic polymorphisms and haplotype of hormone-related genes are associated with the risk of breast cancer in Chinese women

Sex hormones play important roles in breast cancer (BC) development. This study investigated associations between BC risk and hormone-related gene variants in Chinese women. In a cohort of 336 patients with histopathologically confirmed BC and 390 age-matched controls, we genotyped seven single nucleotide polymorphisms (SNPs) in five hormone-related genes: estrogen receptor-a (ESR1), aromatase (CYP19), catechol-O-methyl transferase (COMT), sex hormone-binding globulin (SHBG), and glutathione S-transferase (GSTP1). Among these seven SNPs, the SNPs in GSTP1 rs1695 [A/G; odds ratio (OR): 1.68; 95% confidence interval (CI): 1.23-2.30] and ESR1 rs2046210 (C/T; OR: 1.39; 95% CI = 1.02-1.91) were associated with an increased risk among heterozygote carriers. Homozygotes of minor alleles of CYP19 rs10046 (CC) were associated with a reduced risk of BC with OR: 0.61 (95% CI = 0.39-0.95). In addition, a stratified analysis by menopausal status indicated that the association of the CYP19 polymorphisms (rs10046 and rs700519) with BC risk was mainly evident in premenopausal women, and the association of CYP19 rs700519 with BC risk was significant in women less than 50 years old. Haplotype analysis identified 15 common haplotypes (>1%). The haplotype TGGGGTC was significantly associated with BC risk compared with the reference haplotype CGAGGTC (OR > 1000, P < 0.0001). Our data demonstrate that these ESR1, GSTP1, and CYP19 polymorphisms are associated with risk of BC, and the risk haplotype TGGGGTC could help to identify populations with high susceptibility to BC in Chinese women.