ERBB2 and breast cancer: Given the increased risk of late toxicity from cytotoxic treatments (chemotherapy and radiotherapy) in germline TP53 gene carriers, treatment with targeted agents including anti‐HER2 therapies such as trastuzumab (Herceptin) or antibodies targeting the TGFβ signalling pathway may be safer treatment options for breast cancer patients found to carry a germline TP53 pathogenic variant.