ABSTRACT
Human epidermal growth factor receptor 2 (HER2) has been found to be an important prognostic and predictive marker of treatment response in women with breast cancer in the adjuvant setting and advanced disease. The HER2 gene is amplified and the HER2 protein is overexpressed in 20% to 25% of breast cancers with resulting poor prognosis and shortened overall survival (OS) (1). The HER2 gene, also known as HER2/neu or c-erbB2, is located on chromosome 17q and belongs to the human epithelial receptor (HER) family of genes. It encodes a 185 kDa transmembrane tyrosine kinase growth factor receptor, which mediates signaling for cell proliferation and survival (2).
