For example, it is known that the loss of function of the ATM-CHEK2-p53 cascade (Ataxia-telangiectasia Mutated/Checkpoint kinase 2—tumor protein p53) is associated with resistance to anthracycline/mitomycin-containing chemotherapy in BC patients [7], or that the ATM carrier patients are more likely to develop subcutaneous necrosis and contralateral breast cancer after radiotherapy [10]. Here, CHEK2 is linked to breast cancer.