Cytokeratin 5 + Cytokeratin 14 (EP1601Y + LL002)

Cytokeratin 5 is an intermediate filament protein of 58 kD molecular wt. amongst the cytokeratin family. It is a type II (basic) cytokeratin. Antibodies to this protein identify basal cells of squamous and glandular epithelia, myoepithelia, and mesothelium.1 Cytokeratin 14 is a 50 kD polypeptide found in basal cells of squamous epithelia, some glandular epithelia, myoepithelium, and mesothelial cells.1

Anti-Cytokeratin 5 has been useful in the differential diagnosis of metastatic carcinoma in the pleura versus epithelial mesothelioma.2 Almost all squamous cell carcinomas, half of transitional carcinomas, and many undifferentiated large cell carcinomas immunostain with CK5. Anti-CK14 has been demonstrated to be useful in differentiating squamous cell carcinomas6 from other epithelial tumors.3, 4 Anti-CK5, along with anti-CK14, has found application in identifying the basaloid phenotype of breast carcinoma, a tumor with poor prognosis.5,7,8