ERBB2 and cancer: Very often (in 20% to 25% cases), this cancer is followed by the over-expression of the glycoprotein HER2 (human epidermal growth factor receptor 2, also called HER2/neu, or c-erb-B2) (Akiyama et al. 1986) which is located on the surface of breast cells and is responsible for the cell growth, differentiation and division.