A CYP1A1 restriction fragment length polymorphism is associated with breast cancer in African-American women.

We examined the role of CYP1A1 polymorphisms as potential molecular markers of breast cancer susceptibility in Caucasian and African-American women. The case-control study involved 51 women with breast cancer and 269 female controls. In African-Americans, the frequency of the homozygous MspI polymorphism was 3.5% in controls and 19% in breast cancer cases. The odds ratio of breast cancer with the MspI homozygous variant was 9.7 (95% confidence interval: 2.0-47.9). This association was not observed in Caucasian women. The exon 7 and AA polymorphisms were not associated with breast cancer in either group. The mechanism for the observed association between the MspI polymorphism and breast cancer is unclear. It is possible that the CYP1A1 MspI RFLP is linked with other polymorphisms in the African-American population, either in the CYP1A1 gene, which is involved in estrogen metabolism, or other genes related to risk of breast cancer.