Previous studies found some potentially functional SNPs of RAD51 gene family polymorphisms (eg, RAD51‐135 G > C, XRCC2 R188H, XRCC3 T241M) to be associated with various types of cancer risks, including prostate cancer and lung cancer, breast cancer.37, 38 RAD51D protein is believed to have ssDNA binding activity and DNA‐–timulated adenosine triphosphatase (ATPase) activity. Here, XRCC2 is linked to breast cancer.