In conclusion, on the basis of epidemiological evidence, genotypes of AIB1 polyglutamine polymorphism –analyzed in categories according to cut-points 1 allele ≤26, both alleles ≥28 and ≥29- do not appear to be associated to a modified risk of BC development in BRCA1 and BRCA2 mutation carriers. This evidence concerns the gene BRCA2 and breast cancer.