Association of CYP1B1 haplotypes and breast cancer risk in Caucasian women.

CYP1B1 is a key enzyme involved in estrogen metabolism and may play an important role in the development and progression of breast cancer. In a population-based case-control study, we examined eight CYP1B1 haplotype-tagging single nucleotide polymorphisms in relation to invasive breast cancer risk. Analyses were based on 1,655 cases and 1,470 controls; all women were Caucasian. Among the individual single nucleotide polymorphisms, one (rs9341266) was associated with increased risk of breast cancer (P(trend) = 0.021), although the association was no longer significant after adjusting for multiple tests. A marginally significant haplotype effect was identified (P(global) = 0.015), with significant associations identified for 2 uncommon haplotypes comprising 4% of the controls. Results suggest that genetic variation in CYP1B1 has at most a minor influence on breast cancer susceptibility among Caucasian women.