For further details, refer to Specimen Instructions.

C-erb-2 oncoprotein is the product of the HER-2 (neu) oncogene which 
is overexpressed in a variety of adenocarcinomas arising at various 
sites. Overexpression of c-erb-2 is present in 15-30% of cases of 
breast carcinoma and has been demonstrated to be a negative prognostic 
indicator.

C-erb-2 overexpression can be detected by immunohistochemical staining 
of formalin-fixed paraffin-embedded sections of tumor tissue. Membrane 
staining of the cells is the only reaction considered positive. A 
positive therapeutic response to Herceptin (TM) therapy with 
anti-C-erb-2 monoclonal antibody has been reported in association with 
3+ staining intensity.