Breast panel

Tumor of unknown origin -> Breast
Cytokeratin-Pan	+
CK7	+
CK20	_
GCDFP15, Mammaglobin	+
PAX8, TTF-1	-

Standard Breast panel:

Diagnosis
CIS vs carcinoma	SMMS-1	p40	CK5/6	p40/ SMMS-1
Ductal vs lobular	Ecadherin	p120
Basal like, TNBC	CK5/6
Paget	CK7	HER2+
Paget vs Bowen	CK7+ vs CK7-	CK5/6- vs CK5/6+	p63- vs p63+
Sentinel Node	CK7/19				CK8/18, pan-CK
Predictive	ER	PR	HER2	Ki67
additional markers	Calponin	EMA	MUC1

Myoepithelial Cell Markers (MEC) used in breast pathology:

S100	Less sensitive and less specific for MEC's	8S Dwarakanath, AK Lee, RA Delellis, ML Silverman, L Frasca, HJ Wolfe:  S-100 protein positivity in breast carcinomas: a potential pitfall in diagnostic immunohistochemistry. Hum Pathol. 18:1144-1148 1987
SMA	Good staining of MEC's, but substantial staining of myofibroblasts
CK5/14	Good staining of MEC's. Be aware that acinar cells (close proximity to MEC's) are stained as well
Calponin	Specific to smooth muscle, but stains high percentage of myofibroblasts (76%)	22RW Werling, H Hwang, H Yaziji, AM Gown: Immunohistochemical distinction of invasive from noninvasive breast lesions: a comparative study of p63 versus calponin and smooth muscle myosin heavy chain. Am J Surg Pathol. 27:82-90 2003
SMMS-1	Specific to smooth muscle, stains 8% of myofibroblasts
p63	Stains myoepithelium, but sometimes discontinuous epithelial layer, ánd reacts with a subset of breast tumor cells
SMMS-1/ p40	cocktail of these antibodies to easily identify difficult cases