RAD51 and breast cancer: In a Japanese population of 20 breast cancer cases with a strong family history and 25 individuals with other high-risk factors such as bilateral breast cancer, and so on, a G>A nucleotide substitution was detected by SSCP in two individuals with bilateral breast cancer, which results in an arginine residue being substituted for a glutamine residue at amino acid position 150 of RAD51 [22].