Significance of immunohistochemistry in breast cancer

Table 1 Diagnostic markers

Marker	Staining pattern	Useful for
Smooth muscle actin	Cytoplasmic staining	Myoepithelial differentiation
Calponin	Cytoplasmic staining	Myoepithelial differentiation
p63	Nuclear	Myoepithelial differentiation
Smooth muscle myosin heavy chain	Cytoplasmic	Myoepithelial differentiation
CD10	Membranous staining	Myoepithelial differentiation
S100	Cytoplasmic	Myoepithelial differentiation
High-molecular-weight cytokeratins (14 and 5/6)	Cytoplasmic	To distinguish invasive carcinoma from benign proliferations; expressed by lobular carcinomas
Cytokeratin 8	Peripheral cytoplasmic	Ductal carcinoma cells
Cytokeratin 8	Perinuclear staining	Lobular carcinoma cells
CK 7 and 20		Mammary origin of a metastatic carcinoma
E-cadherin	Membranous staining	Usual ductal carcinomas
Hormone receptors estrogen receptor, progesterone receptor	Nuclear	Identified subtypes, mammary origin
HER2 neu	Membranous staining	Identified subtypes
Gross cystic disease fluid protein 15	Cytoplasmic	Mammary origin of a metastatic carcinoma
Mammaglobin A	Cytoplasmic	Mammary origin of a metastatic carcinoma
Carcinoembryonic antigen, CEAD-14 clone	Cytoplasmic	Evaluation of metastatic mammary carcinoma