HER-2 (also known as HER-2/neu) is a member of the epidermal growth factor (EGF) receptor family. The amplification of oncogene HER-2 is presented in 20 to 30% of breast cancers and results in an increase of the protein expression. HER-2 over expression has also been shown to correlate with poor prognosis. It is associated with poorly differentiated high grade tumors with lymph node involvement, greater risk of recurrence and relative resistance to some types of chemotherapy. The receptor is however a target for treatment with anti HER-2 antibody trastuzumab (Herceptin). Immunohistochemistry analysis for HER 2 scoring is subjective, requires trained personnel and expertise.