The brain is increasingly being recognized as a sanctuary site for metastatic tumor cells in women with HER2-overexpressing breast cancer who receive trastuzumab therapy. There are no approved or widely accepted treatments for brain metastases other than steroids, cranial radiotherapy, and surgical resection. However, some of these therapies may have serious consequences on quality of life of the patient, particularly with respect to cognitive function. Identification of the molecular alterations in these lesions, may help develop new therapies that may improve survival. We will study the primary tumors and metastasis in different sites and evaluate different markers such as Her2, EGFR, ER, PR, and p53 by immunohistochemistry and Chromogenic In Situ Hybridization and correlate with other clinico-pathologic parameters. Later on, we will evaluate the differentiated miRNAs expression profile in primary the primary cancers and the metastases.