Normal breast ducts and lobules are lined by a 2-cell layer composed of luminal and myoepithelial cells. There are also interspersed “basal” cells, which probably represent the epithelial progenitor cells.
|
IHC Marker
|
Luminal Cells
|
Myoepithelial Cells
|
|
LMWCKs
(CK7/8/18)
|
Positive
|
Negative
|
|
Variable Expression
|
Negative
|
|
|
HMWCKs
(CK5/14/17)
|
Negative
|
Positive
|
|
SMA
|
Negative
|
Positive
|
|
Negative
|
Positive
|
|
|
Negative
|
Positive
|
SMA=Smooth Muscle Actin, SMM-HC=Smooth Muscle Myosin Heavy Chain
An understanding of the normal IHC expression pattern in breast ductal tissue is important when considering IHC use in the differential diagnosis of breast pathology.
References
Hicks DG. Immunohistochemistry in the diagnostic evaluation of breast lesions. Appl Immunohistochem Mol Morphol. 2011;19(6):501–505. doi:10.1097/PAI.0b013e31822c8a48.
Liu H. Application of immunohistochemistry in breast pathology: a review and update. Arch Pathol Lab Med. 2014;138(12):1629–1642. doi:10.5858/arpa.2014-0094-RA.