Abstract 2837: Diverse associations betweenESR1polymorphisms and breast cancer development and progression

Abstract Purpose: To test the hypothesis that polymorphisms of ESR1, encoding estrogen receptor α (ERα), are associated with susceptibility, clinical phenotype, and progression of breast cancer. Patients and Methods: A case-control study was performed on 940 patients with incident breast cancer and 1547 healthy female controls. Fifteen single-nucleotide polymorphisms (SNPs) tagging all major polymorphisms of this gene were genotyped. Frequencies of SNPs were compared between cases and controls to identify SNPs associated with cancer susceptibility, and between cases with different clinical phenotypes to determine the role of ESR1 polymorphism in cancer progression. Results. Three SNPs, located in one cluster in intron 1, were found to be important and the variant alleles showed a significant association with a decreased breast cancer risk and, coincidently, with low ERα expression in tumors. The tumorigenic contribution of these intron-1 SNPs was more obvious in combination with reproductive risk factors (p for interaction<0.05). Interestingly, the same SNPs showed a significant correlation with worse clinical phenotypes, including poor differentiation of tumor cells and a late stage. These intron 1 SNPs also showed a significant association with the five-year survival rate of all patients, but had opposite effects in ERα-negative and ERα-positive early-stage patients. Conclusions: Our findings provide support for diverse roles of ESR1 polymorphism in determining susceptibility in different stages of breast cancer. The differences between the important ESR1 SNPs identified in Chinese women in this study and those identified in studies on Western women with breast cancer suggest different roles of ERα in these two populations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2837.