Moreover, the overexpression of this protein has also been positively associated with well-established markers and biological parameters associated to poor prognosis in breast cancer, such as epidermal growth factor receptor (EGFR), cytokeratin 5 (CK5), vimentin, p53 and HER2, high proliferation rates (MIB-1), mitotic index, and decreased cell differentiation (31, 33, 34, 37). Here, ERBB2 is linked to breast cancer.