Intratumoral expression level of epidermal growth factor receptor and cytokeratin 5/6 is significantly associated with nodal and distant metastases in patients with basal-like triple-negative breast carcinoma

Triple-negative (TN) breast carcinoma, characterized by estrogen receptor, progesterone receptor, and HER2 negativity, is a group of aggressive tumors that can be further classified into 2 subtypes: basal-like, defined as CK5/6 and/or epidermal growth factor receptor (EGFR) positive by immunohistochemistry; and non-basal-like. Clinical characteristics and tumor profiles were analyzed in 105 cases of TN tumors. Among these cases, 35 had distant metastasis, 34 had axillary nodal metastasis only, and 36 were nodal negative. Our results indicate basal-like TN breast tumors with nodal and distant metastases are significantly associated with a higher intratumoral expression of EGFR and CK5/6 compared to those in the nodal negative group. High level of intratumoral EGFR and CK5/6 expression may play a role in development of nodal or distant metastases in patients with basal-like TN tumors and may be predictive of metastatic disease. Furthermore, EGFR targeted therapy may be potentially useful in the treatment of basal-like TN breast cancer.