Immunohistochemical profiles of brain metastases from breast cancer

The aim of present study is to explore the immunohistochemical profiles of brain metastases from breast cancer. We retrospectively performed immunohistochemical staining for estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor type 2 (HER2/neu), and cytokeratin (CK) 5/6 in 29 patients with resected tumor specimens of brain metastases. Immunohistochemical staining for ER, PgR and HER2/neu was performed in 24 patients with primary tumors. The positive frequency of immunohistochemical profiles of ER, PgR, HER2/neu, and CK5/6, in the brain metastases were 13.8%, 6.9%, 37.9%, and 24.1%, respectively. The immunohistochemical profiles including ER, PgR, and HER2/neu of the primary tumor and the brain metastasis differed in seven patients (29.2%, N = 7/24). Interestingly, the biological characteristics of brain metastasis sometimes changed which were represented by immunohistochemical staining. Therefore, the changes in the biological features of breast cancer should be taken into account when developing treatment strategies, including new molecular-targeted drugs, for brain metastases.