ERBB2 and breast cancer: It has been demonstrated that chemotherapy, radiotherapy, and endocrine therapy may upregulate the expression of HER2 in HER2-negative or HER2-low breast cancer tumors through epigenetic mechanisms or the activation of adaptive mechanisms within the NF-κB pathway, which emphasizes the necessity for more rigorous assessment of HER2-negative and HER2-low tumors for subsequent lines of therapeutic options [6,7,8].