Heterogeneity in the expression of receptors in the human breast cancer metastasized to the brain.

Assessment of the human epidermal growth factor receptor-2 (Her2/ErbB2) and estrogen receptor (ER) and progesterone receptor (PR) expression in breast cancer has been an accepted standard to predict clinical outcome. Expression of these receptors in primary breast cancer has also been an important predictor of visceral organ metastasis. Many studies of breast cancer have reported risk factors for brain metastasis that include Her2/ErbB2 positivity, ER negativity, and negativity for all the above three receptors.