To the Editors,

Recently, We read an article named “Estrogen receptor alpha (ERS1) SNPs c454-397T>C (PvuII) and c454-351A>G (XbaI) are risk biomarkers for breast cancer development” with huge interests and it was published online in Mol Biol Rep [1]. This paper written by Madeira et al. pointed out that no statistically significant associations were found between XbaI polymorphism and the risk of breast cancer.

Madeira’s work was amazing. However, after reviewing the data reported by Madeira et al., we find a key issue that is noticeable and worth mentioning. According to Madeira’s data, we were aware that the control groups of XbaI deviated from HWE (P < 0.05), because of which an unpersuasive conclusion was drawn about the link between XbaI polymorphism and the risk of breast cancer.

Up to now, extensive researches have been carried out to investigate the relations between XbaI polymorphism and the risk of breast cancer. Anyway, previous conclusions were inconsistent [2, 3], which might be caused by the small sample size. Meanwhile, different inclusion and exclusion criteria should also be taken into considerations. In summary, the conclusions drawn by Madeira should be interpreted with caution. In the coming future, massive and rigorous studies will still be needed so that associations between XbaI polymorphism and the risk of breast cancer can be better assessed.