In this respect, it is interesting to notice that mutations in p53 represent the most common genetic alteration in breast cancer, found in average 30% of breast tumors, with higher frequencies in most aggressive cancers (50% of HER2 amplified BC and 88% of basal-like carcinomas) whereas its frequency is lower in luminal tumors (17% of luminal A, 41% of luminal B) [22]. The gene discussed is ERBB2; the disease is cancer.