Women who have an abnormal BRCA1 or BRCA2 gene run a lifetime risk of up to 85% of developing breast cancer, while the increased risk of developing ovarian cancer is about 55% for women with BRCA1 mutations and about 25% for women with BRCA2 mutations. Most recently, huge studies analyzing effects of single nucleotide variations in genomic DNA, so-called single nucleotide polymorphisms (SNP), on breast cancer risk of BRCA1/BRCA2 mutation carriers have identified so-called modifier SNP that can decrease or increase the individual lifetime risk.