Estrogen receptor alpha gene polymorphisms and breast cancer risk.

We conducted a hospital-based case-control study to evaluate the association between the XbaI and PvuII restriction fragment length polymorphisms (RFLPs) in intron I of the estrogen receptor alpha (ER alpha) gene and breast cancer risk. The study population consisted of 205 histologically confirmed incident breast cancer cases and 205 age-matched controls with no present and previous history of cancer. The PvuII genotype distribution did not show any difference between cases and controls, but the adjusted odds ratio (OR) for the XbaI X allele containing genotypes was 0.4 (95% CI: 0.3-0.6) compared with the xx genotype. The decrease in the OR appeared to be more attributable to the postmenopausal women; the ORs were 0.3 (95% CI: 0.1-0.5) and 0.5 (95% CI: 0.3-0.9) for postmenopausal and premenopausal women, respectively. Our results therefore suggest that the ER alpha XbaI polymorphism modifies individual susceptibility to breast cancer in Korean women.