BRCA2 and breast cancer: Our analysis of the interaction between -26 BRCA2 and codon 72 p53 polymorphism showed that the simultaneous presence of protective genotypes, Pro/Pro at the p53 codon 72 locus and G/A at the -26 BRCA2 locus, rendered fivefold protection against breast cancer and was approximately twice of what each genotype rendered alone.