ERBB2 and cancer: TP53 has also been associated with worse outcomes in hormone receptor-positive or HER2-negative and TNBC metastatic breast cancer, such as shorter survival and resistance to endocrine treatment.[17] Tamoxifen is the most widely used endocrine therapy for hormone-positive breast cancer, and TP53 mutations have been suggested to be associated with resistance to tamoxifen.[18]TP53 mutations are highly expressed in many types of cancer, including breast cancer, and are highly correlated with cancer development.