Stratified genotypic data to assess the combined influence of both p53 and BRCA2 polymorphisms on breast cancer risk revealed that the G/A at the -26 position of BRCA2 in combination with the Pro allele at the codon 72 locus provided fivefold protection against breast cancer (P = 0.0001, OR = 0.2, 95% CI = 0.1 to 0.4) (Table 2). This evidence concerns the gene BRCA2 and breast cancer.