As the majority of BRCA1 mutation-associated breast tumours are ER-negative (Lakhani et al, 2005), the absence of an association in our study of breast cancer with the TP53 and MDM2 SNPs in BRCA1 mutation carriers is consistent with the lack of an association with ER-negative cancers in the general population. This evidence concerns the gene TP53 and breast carcinoma.