Evaluation of p40 as a Myoepithelial Marker in Different Breast Lesions.
OBJECTIVE
The identification of myoepithelial cells (MEC) is a valuable clue in the differential diagnosis of breast lesions. A series of breast lesions with occasional absence of or decrease in the staining for some MEC markers was analyzed for the expression of a novel marker, p40, and results were compared to the p63 staining profile.


METHODS
Samples (n = 34) from patients with benign sclerosing lesions (n = 11), ductal carcinoma in situ (n = 13) and adenomyoepithelial lesions (n = 10) and associated normal breast tissues (n = 31) were selected to evaluate the differential expression of p40 and p63 using immunohistochemistry. Triple-negative, cytokeratin 5 (CK5)-expressing invasive breast carcinomas (n = 19) were also assessed for p40 expression.


RESULTS
Normal structures showed similar diffuse and strong MEC positivity using p40 and p63 in all 31 cases. The two antibodies performed similarly in all 34 breast lesions acknowledged to present altered expression of MEC markers; focal losses of expression occurred in a parallel fashion. CK5-positive carcinomas expressed p40 more frequently than p63 (18/19 vs. 8/19) and the staining was more marked.


CONCLUSIONS
It seems that both antibodies can be used interchangeably for MEC identification, but show differences in the labeling at least in a subset of tumor cells in triple-negative carcinomas.
Department of Pathology, University of Szeged, Szeged, Hungary.
Bence
B
Kővári
A Marcell
AM
Szász
Janina
J
Kulka
Zlatko
Z
Marušić
Bozena
B
Šarčević
László
L
Tiszlavicz
Gábor
G
Cserni
D055331:Adenomyoepithelioma / Q000378:metabolism*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D001940:Breast / Q000378:metabolism; D001941:Breast Diseases / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism; D003937:Diagnosis, Differential; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D014157:Transcription Factors / Q000378:metabolism*; D064726:Triple Negative Breast Neoplasms / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
D014408:Biomarkers, Tumor; C115051:TP63 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins