CK5, CK14, p63, CK7 and CK18 have
routinely been used as a panel of IHC markers to complement morphological
evaluation in the assessment of difficult to diagnose breast lesions; due to the
differential expression of the luminal vs. basal and myoepithelial markers(1,2).
CK5 and CK14 are high molecular weight keratins expressed in the cytoplasm of
basal cells and myoepithelium of breast tissue (1-2).
p63 is a transcription factor present
in the nuclei of myoepithelial cells (1,2). In contrast, CK7 and CK18 are low
molecular weight cytokeratins primarily expressed in luminal cells of the breast
(1-2).
ADH-5™ Breast Marker Antibody is
comprised of mouse monoclonal anti-CK5, anti-CK14 and anti-p63 antibodies and
rabbit monoclonal anti-CK7 and anti-CK18 antibodies.
Cases of Usual Ductal Hyperplasia (UDH)
have been associated with expression of high molecular weight cytokeratins (CK5,
CK14) and the nuclear marker p63 in the basal and myoepithelial cells, admixed
with luminal cells expressing low molecular weight cytokeratins (CK7, CK18)
(3-6).
Most
cases of ADH and ductal carcinoma in
situ (DCIS) were found to be negative for luminal
CK5/14 staining and positive for luminal CK7/18 staining. Breast myoepithelial
cells are usually stained with CK5/14 and/or p63(3-6).
IHC using CK5, CK14, p63, CK7 and CK18
antibodies, evaluated in combination with Hematoxylin and Eosin (H&E), has
been shown to significantly increase inter-observer agreement amongst
pathologists, compared to H&E alone (7).
Staining of breast lesions should be
carefully interpreted in conjunction with the morphological features of each
individual case by a qualified pathologist.