PvuII polymorphism of estrogen receptor-α gene in breast cancer

Estrogen receptor (ER) is a ligand-inducible transcription factor that mediates estrogen action in target tissue. Several common polymorphisms of the ERα gene have been reported to be associated with alterations in receptor expression in breast cancer.

A case-control study was designed to compare 250 breast cancer patients with 250 age-matched healthy controls. The frequency distribution of PvuII polymorphism in the ERα gene was assessed by PCR-RFLP method.

The frequency of the PP genotype (35.3%) was increased significantly in breast cancer patients when compared to controls (19.8%), with a corresponding increase in P allele frequency (χ(2)= 16.4; P = 0.0003). The OR for genotypes PP vs. Pp was 1.989 (95% CI: 1.2708 to 3.113). Premenopausal women with breast cancer had an elevated frequency of the PP genotype (22.8%) as compared to postmenopausal women (16.8%). The frequency of the PP genotype was increased in patients positive for ER and HER-2/neu as compared to those with receptor-negative status. The pp and p allele frequencies were increased in progesterone-receptor-negative status. When stage of the disease was considered, both Pp and pp genotype frequencies were elevated in patients with advanced stage breast cancer. The frequency of the P allele and PP genotype frequencies tended to increase with increase in body mass index, whereas the Pp genotype frequency was elevated only in obese patients. The reverse was observed in the case of pp genotype frequency.

The study thus highlighted the influence of ERα PvuII polymorphism on the development and progression of breast cancer.