Immunohistochemical staining for HER-2/neu (Haematoxylin & eosin, magnification × 200). Breast cancer cells were used as a positive control (not shown). a.) Faint membrane staining is shown in > 10% of tumour cells (1+). b.) Weak to moderate staining of the entire membrane (2+). c.) Strong staining of the entire membrane in > 10%.