Patients with sporadic breast cancer also had lower DNA damage capacity compared to cancer-free population, suggesting other low penetrance genes involved in DNA repair pathways, and cell cycle and apoptosis cascades, such as p53bp, ATM, BARD1, and PALb2 are involved in increased radiation susceptibility and could be a risk factor for both inherited and some sporadic breast cancer development. This evidence concerns the gene ATM and breast carcinoma.