Figure 2.

Microscopy pictures illustrating the patterns of HER-2 immunostaining in breast carcinoma. (a) Weak positive (1+) pattern exemplified by weak focal membrane staining seen in more than 10% of the tumor cells. (b) Intermediate (2+) pattern, showing weak to moderate complete membrane staining in more than 10% of the tumor cells. (c) Strongly positive (3+) pattern shows intense membrane staining with weak cytoplasmic reactivity in more than 30% of the tumor cells.