Estrogen receptor polymorphism at codon 325 and risk of breast cancer in women before age forty

Abstract

Background: The estrogen receptor (ER) protein is believed to play a role in the development and progression of breast cancer. In a previously published U.S. clinic-based study, a polymorphism in the ER gene (codon 325, CCC → CCG) was found to be more common in 34 case subjects with a family history of breast cancer than in 154 case subjects without such a history (mean allele frequencies ± standard error = 0.28 ± 0.05 versus 0.11 ± 0.02; P<.001). To determine whether this polymorphism is a risk factor for early-onset breast cancer, we conducted a population-based, case-control- family study in Australia. Methods: Case subjects under the age of 40 years with a first primary breast cancer and..