Association of estrogen receptor-α A908G (K303R) mutation with breast cancer risk.

Genetic mutations in premalignant breast lesions may have a role in malignancy progression or influence the behavior of subsequent disease. A point mutation in estrogen receptor-α (ER-α) as A908G (Lys303→Arg) was originally involved to hypersensitive to estrogen breast hyperplasia. We detected this mutation among Iranian women with invasive breast cancer. A population-based case-control study was conducted in 150 newly diagnosed invasive breast cancer and 147 healthy control individuals controls to screen for presence of the ER-α A908G mutation by using single-strand conformation polymorphism (SSCP) analysis and 33Pcycle DNA sequencing. We detected the 10.7% ER-α A908G mutation in the form of heterozygote genotype only among cancer patients (χ(2)=22.752, P=0.00). The allelic frequency of mutant allele AGG in codon 303 was significantly (χ(2)=29.709, P=0.001) higher in patients with the family history of breast cancer (28.9%) than those without the family history of breast cancer (1.9%). Our data suggest that ER-α codon 303 mutation is correlated with various aspects of breast cancer in Iran. ER-α genotype might represent a surrogate marker for predicting breast cancer developing later in life.