The estrogen receptor alpha C975G variant in familial and sporadic breast cancer: a case-control study.

The estrogen receptor alpha (ESR1) mediates the effect of estrogen in target tissues. Estrogen is important in breast cancer development and several polymorphic variants in the ESR1 gene have been investigated for association with breast cancer. The C975G variant is the most extensively studied and has been suggested to be a risk factor.,The frequency of the C975G variant was investigated in 288 sporadic, 197 low-risk non-BRCA1/2 familial and 191 high-risk non-BRCA1/2 familial breast cancer cases and 653 controls.,There was a lower frequency of the C975G variant in high-risk familial breast cancer cases compared to the controls (18% versus 22%, p=0.046). The odds ratio (OR) for the GG homozygotes was 0.2 (95% CI: 0.06-0.8) compared to the CC homozygotes. No association was seen with sporadic or low-risk familial breast cancer.,The results of this study indicated that the common C975G variant may have an effect on familial breast cancer susceptibility.