2000; Bartkova et al. 2008). Family 1 included a heterozygous MRE11A nonsense mutation (p.G148X) that was present in probands and two relatives with breast cancer (Fig.2A). Family 2 included two aunts and one grandmother who developed breast cancer. A heterozygous ATM frameshift mutation (p.Ile2629fs) was identified in a proband who developed breast cancer at the age of 43 years (Fig.2B). This evidence concerns the gene ATM and breast cancer.